Presto User manual

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Precast & Prestressed Concrete Beam Analysis and Design LEAP Software, Inc. P.O. Box 16827 Tampa, Florida 33687 www.leapsoft.com (800) 451-5327 toll-free (813) 985-9170 phone (813) 980-3642 fax

PRESTO ® LEAP Software, Inc. Copyright © 1980-2005 LEAP Software, Inc. All Rights Reserved.

This software program has been developed for use by professional engineers. It is the user’s responsibility to ensure that the input for the software program is complete and correct, and that the results provided by the software program are interpreted correctly and conform to any design codes and government regulations that may apply.

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Although this program has been written and tested by LEAP Software, Inc., no warranty, expressed or implied, is made as to the accuracy or functioning of the program or related program material. In no event will LEAP Software be liable for any damages for lost data or profits arising out of the use of or inability to use the licensed program.

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The PRESTO® software is Copyright LEAP Software, Inc., 1993-2005. All rights reserved.

PRESTO® is licensed to the original licensee for use only on the terms set forth in the License and Confidentiality Agreement.

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PRESTO®

The user manual is Copyright LEAP Software, Inc., 1993-2005 All rights reserved. Unauthorized reproduction, display, modification, or distribution of this manual, or any portion of it, may result in severe civil and criminal penalties, and will be prosecuted to the full extent permitted by law.

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Trademarks

PRESTO® and the PRESTO® logo are registered in the U.S. Patent and Trademark Office and are registered trademarks of LEAP Software, Inc., 1993-2005. All rights reserved. LEAP and LEAP Software are registered trademarks of LEAP Software, Inc.

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Microsoft, MS-DOS, Windows, and the Microsoft logo are either registered trademarks or trademarks of Microsoft Corporation in the United States and/or other countries.

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Tekla Structures is either registered trademarks or trademarks of Tekla Corporation.

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Version:

PRESTO® v8.6

Published by:

LEAP Software, Inc. Tampa, Florida Updated August 2005

Editor:

Pauline O’Brien

Contributing Authors:

Sri Kanneganti (Product Manager) Abdul Rauf, P.E. Tan Warraich

T A B L E OF C O N T E N T S

CHAPTER 1 INTRODUCTION..........................................................................................................IN-1 USING THE MANUAL ........................................................................................................................................................IN-1 TYPOGRAPHICAL CONVENTIONS...............................................................................................................................IN-2 PROGRAM CAPABILITIES ..................................................................................................................................................IN-3 DESIGN CODES .......................................................................................................................................................IN-3 MEMBER GEOMETRY ...............................................................................................................................................IN-3 LOAD TYPES ...........................................................................................................................................................IN-3 NON-PRESTRESSED REINFORCEMENT .....................................................................................................................IN-3 STRAND PATTERN OPTIONS ....................................................................................................................................IN-3 SECTION TYPES ......................................................................................................................................................IN-4 ANALYSIS AND DESIGN FEATURES ...........................................................................................................................IN-4 MISCELLANEOUS .....................................................................................................................................................IN-4 UNITS .............................................................................................................................................................................IN-5 PROGRAM INTERFACE .....................................................................................................................................................IN-5 USING ONLINE HELP .......................................................................................................................................................IN-6 USER MANUAL ................................................................................................................................................................IN-6

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CHAPTER 2 GETTING STARTED ................................................................................................. GS-1 SYSTEM REQUIREMENTS ............................................................................................................................................... GS-1 LEAP SOFTWARE SECURITY ......................................................................................................................................... GS-1 TYPES OF LICENSES...................................................................................................................................................... GS-1 NETWORK SETUP .......................................................................................................................................................... GS-2 AUTHORIZATION WARNINGS........................................................................................................................................... GS-2 INSTALLING THE PROGRAM ............................................................................................................................................ GS-3 NOVELL INSTALLATION........................................................................................................................................... GS-6 INSTALLING AND CONFIGURING MICROSOFT .NET FRAMEWORK ..................................................................................... GS-7 MANAGING PRODUCT SITE KEYS ................................................................................................................................... GS-8 Authorizing a Program .................................................................................................................................... GS-8 Demo Authorization....................................................................................................................................... GS-10 Transferring Authorization............................................................................................................................. GS-11

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MULTIPLE FILE COPIES ............................................................................................................................................... GS-14 PROGRAM CRASH/TEMPORARY LOSS OF LICENSE........................................................................................................ GS-14 INSTALLATION OF COMPONENTS TO WORK FROM WITHIN TEKLA STRUCTURES.............................................................. GS-14 CONTACTING TECHNICAL SUPPORT ............................................................................................................................. GS-15

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CHAPTER 3 GENERAL OPERATION ...........................................................................................GO-1 STARTING PRESTO .....................................................................................................................................................GO-1 PRESTO TAB SCREENS ...............................................................................................................................................GO-1 PROJECT TAB ...............................................................................................................................................................GO-2 SWITCH DESIGN CODE DIALOG BOX ..............................................................................................................................GO-2 MEMBER INFO TAB ........................................................................................................................................................GO-3 Member Info Screen Terms ............................................................................................................................GO-3

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OPENING DATA DIALOG BOX .........................................................................................................................................GO-6 Opening Data Screen Terms ..........................................................................................................................GO-6 TORSION PARAMETERS DIALOG BOX .............................................................................................................................GO-7 Torsion Parameter Screen Terms...................................................................................................................GO-7

MATERIALS TAB ............................................................................................................................................................GO-8 Materials Screen Terms ..................................................................................................................................GO-8 LOADS TAB .................................................................................................................................................................GO-11 Loads Screen Terms.....................................................................................................................................GO-11

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©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

ANALYSIS TAB.............................................................................................................................................................GO-12 LOAD FACTORS DIALOG BOX .......................................................................................................................................GO-13 CHECK POINTS DIALOG BOX .......................................................................................................................................GO-15 DESIGN TAB................................................................................................................................................................GO-16 DESIGN PARAMETERS DIALOG BOX .............................................................................................................................GO-17 DESIGN OPTIONS TAB .........................................................................................................................................GO-17 Design Options Screen Terms ......................................................................................................................GO-18 PRESTRESS AND LOSSES TAB .............................................................................................................................GO-20 Prestress and Losses Screen Terms ............................................................................................................GO-21 DEFLECTION MULTIPLIER TAB ..............................................................................................................................GO-22 PHI FACTORS TAB ...............................................................................................................................................GO-23 MISCELLANEOUS DATA TAB .................................................................................................................................GO-23 Miscellaneous Data Screen Terms ...............................................................................................................GO-24 ALLOWABLE STRESS TAB ....................................................................................................................................GO-25 BEARING STEEL INFO DIALOG BOX ..............................................................................................................................GO-26 ......................................................................................................................................................................GO-26 Bearing Steel Info Screen Terms ..................................................................................................................GO-27

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USER-DEFINED EFFECTIVE WIDTH OF TOPPING DIALOG BOX .......................................................................................GO-27 STRESS FACTORS DIALOG BOX ...................................................................................................................................GO-28 STRAND AND REBAR PATTERN DIALOG BOX ................................................................................................................GO-29 STRAND TAB .......................................................................................................................................................GO-30 Strand Tab Screen Terms.............................................................................................................................GO-34 LONGITUDINAL BARS TAB ....................................................................................................................................GO-39 Longitudinal Bars Screen Terms...................................................................................................................GO-40 OPTIONS TO SAVE, LOAD AND SAVE AS ...............................................................................................................GO-42 STEM STIRRUPS TAB ...........................................................................................................................................GO-43 Stem Stirrups Tab Screen Terms..................................................................................................................GO-44 STEM MESH TAB .................................................................................................................................................GO-45 Stem Mesh Tab Screen Terms .....................................................................................................................GO-45

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DESIGN RESULTS SCREEN ..........................................................................................................................................GO-46 DRAWING PRINT DIALOG BOX......................................................................................................................................GO-47 USING PRESTO FROM WITHIN TEKLA STRUCTURES....................................................................................................GO-48 PROGRAM MENU COMMANDS ......................................................................................................................................GO-54 FILE MENU..................................................................................................................................................................GO-54 FILE | NEW..........................................................................................................................................................GO-54 FILE | OPEN ........................................................................................................................................................GO-54 FILE | SAVE.........................................................................................................................................................GO-55 FILE | SAVE AS ...................................................................................................................................................GO-55 FILE MENU..................................................................................................................................................................GO-55 FILE | SAVE SETTING ...........................................................................................................................................GO-55 FILE | PRINT ........................................................................................................................................................GO-56 FILE | PRINT SETUP.............................................................................................................................................GO-57 FILE | SECURITY ..................................................................................................................................................GO-58 FILE | EXIT ..........................................................................................................................................................GO-58 SHOW MENU...............................................................................................................................................................GO-59 SHOW | IMAGE ...................................................................................................................................................GO-59 Image Button Summaries..............................................................................................................................GO-59 SHOW | MODEL ..................................................................................................................................................GO-60 SHOW | RESULTS ...............................................................................................................................................GO-60 SHOW | DIAGRAMS .............................................................................................................................................GO-61 SHOW | PREFERENCES ........................................................................................................................................GO-62

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ii / Table of Contents ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO®v8.6

T A B L E OF C O N T E N T S

LIBRARIES MENU.........................................................................................................................................................GO-62 LIBRARIES | SETUP ..............................................................................................................................................GO-63 LIBRARIES | BEAM SECTIONS ...............................................................................................................................GO-63 Drawing the Beam Section............................................................................................................................GO-65 LIBRARIES | PRESTRESSING ................................................................................................................................GO-69 LIBRARIES | REBAR .............................................................................................................................................GO-70 LIBRARIES | CONVERT FROM V. 7.........................................................................................................................GO-71 HELP MENU ................................................................................................................................................................GO-72 HELP | CONTENTS ..............................................................................................................................................GO-72 HELP | USER MANUAL ........................................................................................................................................GO-72 HELP | SEARCH FOR HELP ON ............................................................................................................................GO-72 HELP | HOW TO USE HELP .................................................................................................................................GO-72 HELP | VISIT LEAP WEB SITE ............................................................................................................................GO-72 HELP | ABOUT PRESTO ....................................................................................................................................GO-72 HELP | TECH SUPPORT ......................................................................................................................................GO-72 HELP | CHECK FOR UPDATES .............................................................................................................................GO-72

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CHAPTER 4 TUTORIAL SESSION ................................................................................................... T-1

TUTORIAL SESSION DESIGN OF A 8DT24 DOUBLE TEE ............................................................ T-3 PROBLEM DATA ............................................................................................................................................................... T-4 CONCRETE .............................................................................................................................................................. T-4 TOPPING .................................................................................................................................................................. T-4 THICKNESS .............................................................................................................................................................. T-5 STRAND ................................................................................................................................................................... T-5 OPENING DATA ........................................................................................................................................................ T-5 LOADS ..................................................................................................................................................................... T-5 STEP 1: START OF TUTORIAL ........................................................................................................................................... T-5 STEP 2: COMPLETE THE PROJECT INFORMATION ............................................................................................................... T-6 STEP 3: DEFINE THE MEMBER INFORMATION ..................................................................................................................... T-6 BEAM SECTIONS LIBRARY......................................................................................................................................... T-7 SECTION DETAIL DIALOG BOX .................................................................................................................................. T-7 TEMPLATE DIALOG BOX............................................................................................................................................ T-8 BEAM SECTIONS LIBRARY......................................................................................................................................... T-8 MEMBER INFO TAB ................................................................................................................................................... T-8 OPENING DATA DIALOG BOX .................................................................................................................................... T-9 IMAGE SCREEN ...................................................................................................................................................... T-10 STEP 4: DEFINE THE MATERIAL PROPERTIES .................................................................................................................. T-11 STEP 5: DEFINE THE LOADS ........................................................................................................................................... T-11 STEP 6: RUN THE ANALYSIS ........................................................................................................................................... T-12 LOAD FACTORS DIALOG BOX .................................................................................................................................. T-12 CHECK POINTS DIALOG BOX .................................................................................................................................. T-12 ANALYSIS TAB........................................................................................................................................................ T-13 STEP 7: DESIGN THE BEAM ............................................................................................................................................ T-14 DESIGN PARAMETERS DIALOG BOX ........................................................................................................................ T-14 STRAND AND REBAR PATTERN DIALOG BOX ........................................................................................................... T-15 STRAND TAB SCREEN ............................................................................................................................................ T-16 DESIGN RESULTS SCREEN ..................................................................................................................................... T-16 DIAGRAM SCREEN .................................................................................................................................................. T-17 STEP 9: GENERATE THE PROGRAM OUTPUT ................................................................................................................... T-18 OUTPUT ................................................................................................................................................................. T-19 OUTPUT T-19

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CHAPTER 5 THEORY ................................................................................................................... TH-1

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©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

GENERAL OVERVIEW ..................................................................................................................................................... TH-1 LAYOUT ........................................................................................................................................................................ TH-2 TOPPING ....................................................................................................................................................................... TH-2 SECTION PROPERTIES ................................................................................................................................................... TH-4 PRESTRESS LOSSES ..................................................................................................................................................... TH-5 ANALYSIS...................................................................................................................................................................... TH-6 LOADS .......................................................................................................................................................................... TH-7 STRESSES – ACI 318-99 .............................................................................................................................................. TH-8 STRESSES – ACI 318-05 .............................................................................................................................................. TH-8 STRESSES – CSA 23.3-94.......................................................................................................................................... TH-10 CRACK CONTROL – ACI 318-99/05............................................................................................................................. TH-10 CRACK CONTROL – CSA 23.3-94 AND ACI 318-95 ..................................................................................................... TH-11 ULTIMATE STRENGTH – ACI 318-99/05 ...................................................................................................................... TH-11 ULTIMATE STRENGTH – CSA 23.3-94 ......................................................................................................................... TH-12 PRESTRESSING STRAND – STRESS-STRAIN CURVES .................................................................................................... TH-14 DESIGN METHODOLOGY – ACI 318-99 ........................................................................................................................ TH-16 DESIGN METHODOLOGY – ACI 318-05 ........................................................................................................................ TH-18 SHEAR – ACI 318-99/05............................................................................................................................................. TH-19 TORSION – ACI 318-99/05 ......................................................................................................................................... TH-20 SHEAR AND TORSION - PCI DESIGN HANDBOOK, 6TH EDITION ..................................................................................... TH-21 SHEAR AND TORSION – CSA 23.3-94 ......................................................................................................................... TH-21 CAMBER AND DEFLECTIONS......................................................................................................................................... TH-22 DEVELOPMENT LENGTH ............................................................................................................................................... TH-25 LIGHTWEIGHT CONCRETE ............................................................................................................................................ TH-26 REDUCTION FACTORS ................................................................................................................................................. TH-26 BEARING ANALYSIS ..................................................................................................................................................... TH-27

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CHAPTER 1 NOMENCLATURE AND PRINTOUT EXPLANATION .............................................. A1-1 LABELS USED THROUGHOUT THE PRINTOUT ...................................................................................................................A1-1 PROJECT DATA ..............................................................................................................................................................A1-2 TOPPING DATA...............................................................................................................................................................A1-3 PRESTRESSED STRAND DATA .........................................................................................................................................A1-3 PRESTRESSED STRAND PATTERN DATA ..........................................................................................................................A1-3 STRAND GROUPS, SHIELDING AND PULL DATA ................................................................................................................A1-3 REBAR DATA .................................................................................................................................................................A1-3 REBAR PATTERN DATA...................................................................................................................................................A1-3 STIRRUPS ......................................................................................................................................................................A1-3 BEARING STEEL DATA ....................................................................................................................................................A1-4 CALCULATED INTERNAL CONSTANTS ...............................................................................................................................A1-4 STEM MESH DATA..........................................................................................................................................................A1-4 UNREINFORCED SECTION PROPERTY ZONE DATA ...........................................................................................................A1-4 THIS SECTION PRINTS ONLY IN ACI 318-05 MODE .........................................................................................................A1-4 STRUCTURAL ANALYSIS ..................................................................................................................................................A1-5 PRESTRESS LOSS COMPUTATIONS .................................................................................................................................A1-5 BEARING STEEL .............................................................................................................................................................A1-6 RELEASE AND FINAL STRESSES ......................................................................................................................................A1-6 ULTIMATE STRENGTH .....................................................................................................................................................A1-6

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iv / Table of Contents ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO®v8.6

T A B L E OF C O N T E N T S

CRACK CONTROL ........................................................................................................................................................... A1-7 CRACKING LOAD ............................................................................................................................................................ A1-7 VERTICAL SHEAR AND TORSION ..................................................................................................................................... A1-7 HORIZONTAL SHEAR....................................................................................................................................................... A1-8 CAMBER AND DEFLECTIONS ........................................................................................................................................... A1-9

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CHAPTER 2 HAND CALCULATIONS FOR SELECTED ITEMS....................................................A2-1 MEMBER SECTION - PRECAST ................................................................................................................................ A2-1 Section Properties............................................................................................................................................ A2-1 HAND CALCULATIONS FOR SELECTED ITEMS ................................................................................................................... A2-1 Zone 2 .............................................................................................................................................................. A2-2 Zone 4 .............................................................................................................................................................. A2-2 MEMBER SECTION - COMPOSITE ............................................................................................................................. A2-3 Zones 1, 3 and 5 .............................................................................................................................................. A2-3 Zones 2 and 4 .................................................................................................................................................. A2-3 PRECAST DATA ...................................................................................................................................................... A2-3 Allowable Concrete Stresses ........................................................................................................................... A2-4 Release ............................................................................................................................................................ A2-4 Final Conditions ............................................................................................................................................... A2-4 CONCRETE DATA ................................................................................................................................................... A2-5 PRESTRESSED STRAND .......................................................................................................................................... A2-5 UNREINFORCED SECTION PROPERTIES ................................................................................................................... A2-6 REINFORCED SECTION PROPERTY DATA ................................................................................................................. A2-6 Analysis............................................................................................................................................................ A2-6 Self-weight ....................................................................................................................................................... A2-7 Topping ............................................................................................................................................................ A2-7 Superimposed Dead Load on Composite (SD)................................................................................................ A2-8 Live Loads (LL) ................................................................................................................................................ A2-8 Total Moment and Shears At Final Conditions................................................................................................. A2-8 PRESTRESS LOSSES .............................................................................................................................................. A2-9 PRECAST AND COMPOSITE SECTION PROPERTIES ................................................................................................. A2-11 Miscellaneous Section Properties Computations........................................................................................... A2-11 CALCULATION OF MEMBER STRESSES .................................................................................................................. A2-12 Release Stresses: Precast Section Only ....................................................................................................... A2-12 Final Stresses: Precast Section Only............................................................................................................. A2-13 STRAND DEVELOPMENT........................................................................................................................................ A2-15 ULTIMATE STRENGTH ........................................................................................................................................... A2-15 CRACKING LOAD .................................................................................................................................................. A2-17 VERTICAL SHEAR ................................................................................................................................................. A2-17 HORIZONTAL SHEAR ............................................................................................................................................. A2-20

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CHAPTER 3 HAND CALCULATIONS FOR TORSION ..................................................................A3-1 HAND CALCULATIONS FOR TORSION ............................................................................................................................... A3-1 MATERIALS ............................................................................................................................................................ A3-2 LOADS ................................................................................................................................................................... A3-2 CRITICAL SECTION ................................................................................................................................................. A3-2 ANALYSIS RESULTS ................................................................................................................................................ A3-2 PRESTRESSING ...................................................................................................................................................... A3-3 COMPOSITE SECTION PROPERTIES ......................................................................................................................... A3-3 STRESSES ............................................................................................................................................................. A3-4 CRACKING MOMENT ............................................................................................................................................... A3-4 SHEAR DESIGN ...................................................................................................................................................... A3-4

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©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

TORSION DESIGN ...................................................................................................................................................A3-5 Cracking Torsional Moment .............................................................................................................................A3-6 Check for Minimum Transverse Steel ..............................................................................................................A3-7 CHECK FOR SPACING .............................................................................................................................................A3-7 Spacing for Shear ............................................................................................................................................A3-7 Spacing for Torsion ..........................................................................................................................................A3-7 LONGITUDINAL STEEL .............................................................................................................................................A3-7 Compression in Concrete.................................................................................................................................A3-8

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CHAPTER 4 STRAND AND REBAR PROPERTIES ...................................................................... A4-1 STRAND AND REBAR PROPERTIES ..................................................................................................................................A4-1 CHAPTER 5 SECTION TYPE AND DIMENSIONS......................................................................... A5-1 SECTION TYPE AND DIMENSIONS ....................................................................................................................................A5-1 CHAPTER 6 REFERENCES ........................................................................................................... A6-1 REFERENCES .................................................................................................................................................................A6-1

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CHAPTER 7 GLOSSARY................................................................................................................ A7-1 GLOSSARY .....................................................................................................................................................................A7-1

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INDEX ........................................................................................................................................INDEX-1

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vi / Table of Contents ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO®v8.6

L I S T OF F I G U R E S

FIGURE IN-1. FIGURE GS-1. FIGURE GS-2. FIGURE GS-3. FIGURE GS-4. FIGURE GS-5. FIGURE GS-6. FIGURE GS-7. FIGURE GS-8. FIGURE GS-9. FIGURE GS-10. FIGURE GS-11. FIGURE GS-12. FIGURE GS-13.

PRESTO Online Help Screen ...................................................................................................................IN-6 Welcome Screen..................................................................................................................................... GS-3 Choose Destination Location .................................................................................................................. GS-4 Security Directory.................................................................................................................................... GS-4 Using PRESTO From Within Tekla Structures Option............................................................................. GS-5 Ready to Install the Program................................................................................................................... GS-5 Authorize Now? Dialog............................................................................................................................ GS-6 Installation Complete.............................................................................................................................. GS-6 .Net Framework v1.1 Wizard................................................................................................................... GS-7 Security Adjustment Wizard .................................................................................................................... GS-8 LEAP Software Security Screen ............................................................................................................. GS-9 Client Licenses Screen ........................................................................................................................... GS-9 Created Site Key Screen....................................................................................................................... GS-10 Security Window Authorization Tab....................................................................................................... GS-10

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LEAP Software Security Screen – Direct Transfer Tab....................................GS-11 FIGURE GS-15. LEAP Software Security Screen – Register Transfer Tab ........................................................ GS-12 FIGURE GS-14.

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FIGURE GO-1. PRESTO Splash Screen .........................................................................................................................GO-1 FIGURE GO-2. Project Tab ..............................................................................................................................................GO-2 FIGURE GO-3. Switch Design Code Dialog Box .............................................................................................................GO-3 FIGURE GO-4. Member Info Tab .....................................................................................................................................GO-3 FIGURE GO-5. Gap Topping Adjustment.........................................................................................................................GO-5 FIGURE GO-6. Opening Data Dialog Box........................................................................................................................GO-6 FIGURE GO-7. Torsion Parameters Dialog Box...............................................................................................................GO-7 FIGURE GO-8. Materials Tab...........................................................................................................................................GO-8 FIGURE GO-9. Loads Tab.............................................................................................................................................. GO-11 FIGURE GO-10. Analysis Tab ..........................................................................................................................................GO-13 FIGURE GO-11. Load Factors Dialog Box.......................................................................................................................GO-14 FIGURE GO-12. Check Points Dialog Box.......................................................................................................................GO-15 FIGURE GO-13. Auto Generate Check Points Dialog Box ..............................................................................................GO-16 FIGURE GO-14. Design Tab ............................................................................................................................................GO-17 FIGURE GO-15. Design Options Tab in ACI 318-05 Mode..............................................................................................GO-18 FIGURE GO-16. Design Options Tab in CSA 23.3-94 Mode .........................................................................................GO-18 FIGURE GO-17. Bearing Analysis ...................................................................................................................................GO-19 FIGURE GO-18. Prestress and Losses Tab.....................................................................................................................GO-21 FIGURE GO-19. Deflection Multiplier Tab ........................................................................................................................GO-22 FIGURE GO-20. Phi Factors Tab .....................................................................................................................................GO-23 FIGURE GO-21. Miscellaneous Data Tab ........................................................................................................................GO-24 FIGURE GO-22. Allowable Stress Tab (ACI 318-99 and CSA 23.3-94) ........................................................................GO-25 FIGURE GO-23. Allowable Stress Tab (ACI 318-05) .......................................................................................................GO-26 FIGURE GO-24. Bearing Steel Info Dialog Box ...............................................................................................................GO-26 FIGURE GO-25. User Defined Effective Width of Topping Dialog Box ............................................................................GO-28 FIGURE GO-26. Stress Factors Dialog Box (ACI 318-99) ...............................................................................................GO-28 FIGURE GO-27. Stress Factors Dialog Box (ACI 318-05) ...............................................................................................GO-29

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List of Figures / 1

FIGURE GO-28. Stress Factors Dialog Box (CSA 23.3-94)...........................................................................................GO-29 FIGURE GO-29. Strand Tab Showing Live Graphics .......................................................................................................GO-30 FIGURE GO-30. Strand Tab Showing Template Definitions.............................................................................................GO-31 FIGURE GO-31. Strand Tab for Double Tee Showing Live Graphics...............................................................................GO-32 FIGURE GO-32. Strand Tab for Double Tee Showing Template Definitions ....................................................................GO-32 FIGURE GO-33. Strand and Rebar Screen Grid Menu....................................................................................................GO-34 FIGURE GO-34. One Point ..............................................................................................................................................GO-35 FIGURE GO-35. One Point Fixed.....................................................................................................................................GO-35 FIGURE GO-36. Two Point Variable.................................................................................................................................GO-36 FIGURE GO-37. Zero Point (Straight) ..............................................................................................................................GO-36 FIGURE GO-38. Left and Right Debond ..........................................................................................................................GO-37 FIGURE GO-39. Mid Debond ...........................................................................................................................................GO-38 FIGURE GO-40. Longitudinal Bars (For Sections Other Than Double Tee).....................................................................GO-39 FIGURE GO-41. Longitudinal Bars (For Double Tee Sections)........................................................................................GO-40 FIGURE GO-42. Two Point Variable Display....................................................................................................................GO-41 FIGURE GO-43. Save Components dialog ......................................................................................................................GO-42 FIGURE GO-44. Stem Stirrups (Shear Reinforcement) ...................................................................................................GO-43 FIGURE GO-45. Design Stirrups Form ............................................................................................................................GO-44 FIGURE GO-46. Stem Mesh Tab .....................................................................................................................................GO-45 FIGURE GO-47. Design Results Screen..........................................................................................................................GO-46 FIGURE GO-48. Enhanced Report View..........................................................................................................................GO-47 FIGURE GO-49. Drawing Print Dialog Box ......................................................................................................................GO-47 FIGURE GO-50. Sample Output Showing C/S.................................................................................................................GO-48 FIGURE GO-51. Tekla Structures with Beam Plug-in Icons .............................................................................................GO-49 FIGURE GO-52. Tekla Structures with PRESTO Plug-in Icon .........................................................................................GO-50 FIGURE GO-53. Member Info Tab when PRESTO is Called from Tekla Structures ........................................................GO-50 FIGURE GO-54. Double Tee Beam Information Passed from Tekla Structures...............................................................GO-51 FIGURE GO-55. Section Details for the Section Passed from Tekla Structures ..............................................................GO-52 FIGURE GO-56. Strand and Rebar Tab for Double Tee Section......................................................................................GO-53 FIGURE GO-57. Update Strand/Rebar Pattern for Beam in Tekla Structures..................................................................GO-53 FIGURE GO-58. File | New ..............................................................................................................................................GO-54 FIGURE GO-59. File | Open.............................................................................................................................................GO-54 FIGURE GO-60. File | Save As ........................................................................................................................................GO-55 FIGURE GO-61. File | Print ..............................................................................................................................................GO-56 FIGURE GO-62. File | Print Setup....................................................................................................................................GO-57 FIGURE GO-63. File | Security.........................................................................................................................................GO-58 FIGURE GO-64. Show | Image ........................................................................................................................................GO-59 FIGURE GO-65. Show | Model.........................................................................................................................................GO-60 FIGURE GO-66. Show | Results ......................................................................................................................................GO-61 FIGURE GO-67. Show | Diagram.....................................................................................................................................GO-61 FIGURE GO-68. Show | Preferences ...............................................................................................................................GO-62 FIGURE GO-69. Libraries | Setup ....................................................................................................................................GO-63 FIGURE GO-70. Libraries | Beam Sections .....................................................................................................................GO-63

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2 / List of Figures ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

FIGURE GO-71. Section Detail Dialog Box (Double Tee) ................................................................................................GO-64 FIGURE GO-72. Section Drawing Screen........................................................................................................................GO-65 FIGURE GO-73. Drawing Properties Dialog Box .............................................................................................................GO-67 FIGURE GO-74. Circular Section Dialog Box ..................................................................................................................GO-68 FIGURE GO-75. Template Dialog Box .............................................................................................................................GO-68 FIGURE GO-76. Template Auto Generation Dialog Box ..................................................................................................GO-69 FIGURE GO-77. Libraries | Prestressing..........................................................................................................................GO-70 FIGURE GO-78. Libraries | Rebar....................................................................................................................................GO-71 FIGURE GO-79. Libraries | Convert from v.7 ...................................................................................................................GO-71 FIGURE T-1. Strand Pattern ............................................................................................................................................ T-4 FIGURE T-2. PRESTO Splash Screen ............................................................................................................................ T-5 FIGURE T-3. Project Tab ................................................................................................................................................. T-6 FIGURE T-4. Member Info Tab ........................................................................................................................................ T-6 FIGURE T-5. Beam Sections Library ............................................................................................................................... T-7 FIGURE T-6. Section Detail Dialog Box (Double Tee) ..................................................................................................... T-7 FIGURE T-7. Template Dialog Box .................................................................................................................................. T-8 FIGURE T-8. Beam Sections Library (Showing New Section 8DT24)............................................................................. T-8 FIGURE T-9. Member Info Tab ........................................................................................................................................ T-9 FIGURE T-10. Opening Data Dialog Box........................................................................................................................... T-9 FIGURE T-11. Show | Image ........................................................................................................................................... T-10 FIGURE T-12. Materials Tab.............................................................................................................................................T-11 FIGURE T-13. Loads Tab..................................................................................................................................................T-11 FIGURE T-14. Load Factors Dialog Box.......................................................................................................................... T-12 FIGURE T-15. Check Points Dialog Box.......................................................................................................................... T-13 FIGURE T-16. Analysis Tab ............................................................................................................................................. T-13 FIGURE T-17. Design Tab ............................................................................................................................................... T-14 FIGURE T-18. Design Parameters Dialog Box ................................................................................................................ T-15 FIGURE T-19. Strand and Rebar Pattern (with Template Definitions) Dialog Box.......................................................... T-15 FIGURE T-20. Strand Tab................................................................................................................................................ T-16 FIGURE T-21. Design Results Screen............................................................................................................................. T-17 FIGURE T-22. Diagram Screen ....................................................................................................................................... T-17 FIGURE TH-1. User Specified Left/Right Boundary Distances ........................................................................................TH-3 FIGURE TH-2. Stress-Strain Curves per PCI Design Handbook 5th Edition .................................................................TH-14 FIGURE TH-3. Stress-Strain Cures for Prestressing Strand ..........................................................................................TH-14 FIGURE TH-4. PRESTO 8.2 and Older Methodology ....................................................................................................TH-15 FIGURE TH-5. Stress-Strain Cures for Prestressing Strand Elasticity...........................................................................TH-15 FIGURE TH-6. Variation of f with c/dt .............................................................................................................................TH-19 FIGURE TH-7. Development Curve of Prestressed Strands..........................................................................................TH-26 FIGURE A2-1. Precast Section ........................................................................................................................................ A2-1 FIGURE A2-2. Composite Section ................................................................................................................................... A2-3 FIGURE A2-3. Strand Profile ........................................................................................................................................... A2-5 FIGURE A2-4. Beam Loading .......................................................................................................................................... A2-6 FIGURE A2-5. Strain Diagram for Ultimate Strength ..................................................................................................... A2-15

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PRESTOR®v8.6

List of Figures / 3

©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

FIGURE A3-1. FIGURE A3-2. FIGURE A3-3.

Shear and Torsion Design of an L Beam on 30 Ft. Span .........................................................................A3-1 Shear and Torsion Design of an L Beam..................................................................................................A3-2 Shear and Torsion Design of an L Beam (Closed Stirrup) .......................................................................A3-6

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4 / List of Figures ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

CHAPTER ONE

Introduction

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PRESTO is a comprehensive computer program for the design and analysis of

precast, prestressed concrete beams in accordance with ACI specifications. Version 8.6 provides features to design a beam based on either ACI 318-99 or ACI 318-05, or CSA 23.3-94 with updates of 2001. It is designed to be as userfriendly as possible so that professional engineers with minimal computer experience may operate it with ease.

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Using the Manual

The intent of the PRESTO user manual is to help you become familiar with the program and its capabilities. We recommend first reading the General Operation chapter to get an overview of the program’s intended functionality and operational procedures. Review the Theory chapter for an in-depth description of the program’s technical material. The nomenclature in the Appendix describes the definitions of terms used in PRESTO.

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Table of Contents The Table of Contents lists the overall layout and topics of the

PRESTO user manual. It is advised when trying to find a particular topic in the manual, to scan through the Table of Contents. Introduction This chapter contains information that is helpful to know before attempting to use PRESTO, such as program capabilities, intended use, and key features. It also includes helpful information about using the manual. Reviewing this material prior to running the program helps to ensure smooth operation. Getting Started This chapter contains information relating to program installation, authorization, and network setup. It also includes how to transfer authorization and how to contact technical support. You should read this chapter completely before installing and running the program. General Operation The General Operation chapter includes information about each of the different input fields, main tabs, and screens in PRESTO. You can also find related information in the online help system. You can activate the context-sensitive online help at any time while running the program by pressing the F1 key on your keyboard.

PRESTO®v8.6 ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

IN-1

Using the Manual

The best way to become acquainted with the program is by actually using it to solve a few problems. In the Tutorials chapter, we walk you through a typical problem from start to finish and illustrate how PRESTO operates. We encourage you to run the tutorial on your own computer and compare monitor displays with the illustrations in this manual. By closely following these tutorials, you can quickly become familiar with a typical design situation and most of the computer data input/output process.

Tutorials

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Theory

Appendices

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Index

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Typographical Conventions

We have tried to make PRESTO as user-friendly as possible; however, there are some features that cannot be made apparent by a headlong approach to using the software. The extra time it takes to go through the tutorial will be compensated for by the knowledge gained. It is advisable for you to check several previous designs using PRESTO. This will serve to confirm your knowledge of the operation and assumptions of this program. This chapter contains details on the assumptions and methods used in PRESTO. Most in-depth technical questions can be answered by referring to this chapter. These chapters contain the nomenclature, and printout explanation, hand calculations, strand and rebar properties, section types and dimensions, a list of cited references used in the manual, and glossary. The Index contains a cross-reference of entries from the manual. Many times, information about a particular item is given from different points of view in other sections of the manual. Therefore, if you have a question regarding a particular item, it can be very helpful to refer to each entry listed under that item in the Index.

For your convenience, many of the commonly used terms and references throughout the manual appear in special styles. The following are examples of these typographical conventions that allow you to easily recognize key information.

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Button References

Add

Keyboard References

SHIFT+TAB

Option and Icon References

Option

Pull-down menus, Drop-down lists, Lists, Check Boxes, Columns, Field References

Beam ID drop-down list

Screens, Dialog Boxes, Tabs, Libraries

System Information screen

Article/Equation References

ACI Art. 9.20.2.4

Note: Unless stated otherwise, references to “Art.” refer to an article number of the ACI 318 code(s).

IN-2 / Introduction ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Program Capabilities

Program Capabilities PRESTO is a state-of-the-art design tool that has evolved from years of field use. It

provides practical features and functions that allow you to minimize your design time while maximizing your accuracy. PRESTO provides complete precast beam design with more features and options than any comparable product. The following list highlights some of PRESTO’s main features:

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Design Codes •

ACI 318-05

•

ACI 318-99

•

CSA 23.3-94 (with updates of 2001)

•

Ability to design simple-spans with unequal cantilevers.

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Ability to place rectangular or circular flange openings anywhere along the member.

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Differentiate topping width over members and between members separately.

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Vary topping thickness along members.

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Ability to place dead loads on composite or non-composite sections.

Member Geometry

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Load Types

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Apply live loads, i.e., point loads, partial uniform loads, partially distributed trapezoidal loads.

Non-Prestressed Reinforcement •

Ability to place rebar in topping or in precast.

•

Designate straight, hooked, or mechanically anchored ends on rebar.

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Specify stirrup reinforcement

•

Specify stem mesh reinforcement

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Easy-to-use graphical strand pattern input screen.

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Ability to select regular, stress-relieved, or low-relaxation strands.

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Create different strand patterns at left end, right end, and at depression point.

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Ability to shield (debond) straight patterns.

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Automatic strand pattern generation.

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Automatic shielding of strands.

•

Specify fractional strands

Strand Pattern Options

PRESTO®v8.6

Introduction / IN-3

©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

Program Capabilities

Section Types •

Design all major section types, i.e., Double Tees, Single Tees, Hollow core slabs, Solid flat slabs, Inverted T-beams, L-beams, Rectangular beams, and Keystone joists.

•

Graphical input for sections using the Drawing Editor.

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Analysis and Design Features •

Compute section properties (composite and non-composite) automatically at openings and at changes in topping thickness.

•

Ability to select computer-generated or user-specified prestress losses.

•

View complete stress histories at release and at final conditions with different support locations at release and final conditions.

•

Perform comprehensive ultimate strength computations.

•

Perform combined vertical shear, torsion, and horizontal shear computations.

•

Analyze conventional or bilinear deflection.

•

Ability to work from within Tekla Structures to design/check members.

•

Ability to export beam drawing to AutoCAD/Microstation.

•

Ability to export analysis results to spreadsheets.

•

Work with U.S. units or Metric units.

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Miscellaneous

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IN-4 / Introduction ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Units

Units PRESTO works with either U.S. or Metric (SI) units. Following is a list of units and

the conversion between both systems. English

Metric

Conversion Factor*

ft

m

0.3048

in

mm

25.4

2

in /ft

mm /m

2116.6667

in2

mm2

645.16

in4

mm4*106

0.41623

2

k

kN

4.44822

k-ft

kN-m

1.35582

klf

kN/m

14.5939

ksi

MPa

6.89476

psi

kPa

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pcf

kg/m

plf psf

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* For example, 1 ft = 0.3048 m

3

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6.89476

16.0185

N/m

14.4939

Pa

47.8803

NOTE: Although you can switch between U.S. and metric units at any time during program execution, some round-off errors may be introduced due to the fact that for converting between both systems of units, the program uses only the number of decimals that are shown on the screen.

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Program Interface

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PRESTO uses the Microsoft Windows interface elements such as tabbed dialog boxes,

pull-down menus, buttons, scroll bars, etc. This interface is very intuitive; it eliminates the need to memorize keystrokes or commands.

v E PRESTO®v8.6

Introduction / IN-5

©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

Using Online Help

Using Online Help This program uses the Microsoft Windows online help interface. To access PRESTO Online Help, select the Contents option from the Help menu or click the Help icon on the Toolbar.

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FIGURE IN-1. PRESTO Online Help Screen

While running the program, you may access context-sensitive help information by pressing the F1 key on your keyboard. To exit the Help window, click the X located in the top right corner of the screen. For example, if you are having difficulty using a particular screen or dialog box, pressing the F1 key opens the help topic associated with that screen.

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User Manual

The entire user manual is available as a PDF document from within the program. To access this manual, select the User Manual option from the Help menu, or click the User Manual icon on the toolbar.

IN-6 / Introduction ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

CHAPTER TWO

Getting Started

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This chapter contains information about installing and authorizing the program, network setup and technical support. Before installing this application, it is recommended that you read this chapter.

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System Requirements

The minimum system requirements are as follows:

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• Microsoft® Windows® NT, 2000, or XP • 128 MB RAM

• Mouse or other pointing device

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• 100 MB available uncompressed hard disk space • CD-ROM drive

• Internet access (recommended)

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• 1024 × 768 dpi with 256 colors minimum • Microsoft® .NET Framework v1.1 (Refer to “Installing and Configuring Microsoft .NET Framework” on page GS-7 for more information.)

LEAP Software Security

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LEAP Software protects all programs with software security keys which prevent the use of unauthorized copies. In order to run the program for the first time, you will need to obtain an authorization code from LEAP Software. This procedure is detailed in “Managing Product Site Keys” on page GS-8.

Types of Licenses LEAP Software offers multiuser network capabilities. All PRESTO licenses are network licenses, allowing either a single user or multiple users the flexibility to access the program simultaneously. A predetermined number of

PRESTO®v8.6 ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

GS-1

Network Setup

copies of the program may run concurrently on client machines from a single network server hosting the source copy. Users may also run the program from their local hard drive after obtaining the licensing information from a server. With a multiuser license, anyone who has access to the location where the program is installed can use the program on any networked computer; however, the number of people actually running the program at any given time may not exceed the maximum number of users specified by the license.

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Network Setup PRESTO supports the following configurations: Host/Server

Client Computers

Windows® NT/2000/XP Windows® NT, 2000, and XP

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If you are installing PRESTO for network use, you must select one computer to be the host for the program. The host will be the computer from which you will run PRESTO on network clients. The program must be installed on the host.

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After installation of the program, you need to have your copy of PRESTO authorized for network use. (Refer to “Managing Product Site Keys” on page GS-8.) When requesting your authorization code, make sure that you notify LEAP Software of the number of licensed users you are requesting.

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LEAP Software does not make any guarantees regarding program installation on a Novell Netware server. (Occasionally, network license users have had difficulties with compatibility in Novell Netware environments.)

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Authorization Warnings

It is possible that you may permanently lose your authorization when changing your computer configuration without taking the necessary precautionary steps. A few actions that may adversely affect your authorization are listed below. If any of these actions need to be taken, contact LEAP Software for assistance.

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• Formatting your hard drive. • Replacing your hard drive. • Defragmenting your hard drive, without excluding the program directory from the defragmentation path. • Installing a new operating system. • Upgrading your operating system. • Changing the system time on your computer by more than 75 minutes. • Compressing the directory where the program is located. • Moving the program to another directory or computer without first transferring authorization. • Installing the program on mirrored drives.

Note: The restoration of a license lost resulting from any of the above actions, without first consulting LEAP Software, may result in additional reauthorization fees.

GS-2 / Getting Started ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Installing the Program

Installing the Program Before installing the application it is recommended to determine the type of installation. Standalone and server installations require no options to be selected. However, a client installation requires that the application on the client be provided a path to the security file on the server, as discussed in step 5 page GS-5. Note: This program requires Microsoft .NET Framework v1.1. For more information, please refer to“Installing and Configuring Microsoft .NET Framework” on page GS-7.

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Note: To install the program, login as an Administrator on the machine you want to do the installation. Remote installation is not allowed. 1. Download the program from the LEAP Software web site (www.leapsoft.com) and run the executable file in a temporary location for the installation files to be unzipped to (e.g., C:\Temp). After the installation is complete, you can delete all of the unzipped files from the temporary location. 2. When the Welcome screen displays, click Next and follow the on-screen instructions to complete the installation.

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FIGURE GS-1. Welcome Screen

3. The Choose Destination Location screen displays. Browse to the location where the application will be installed and click Next.

Getting Started / GS-3

©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

Installing the Program

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FIGURE GS-2. Choose Destination Location

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4. The Security Directory screen displays. This screen is used to select the location of security files for a client-server configuration.

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• If the installation is in a stand-alone configuration or on a Server, do not select the check box and click Next. • If the installation is on a client, select the check box and use the Browse button to select the license directory location on the Server. Click Next.

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FIGURE GS-3. Security Directory

GS-4 / Getting Started ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Installing the Program

5. If you want to use the program from within Tekla Structures, check the box to install PRESTO components from within Tekla Structures and select the folder in which the components are to be installed. Specify only the Tekla Structures version folder (e.g., C:\Tekla Structures\10.1) Do not point to any sub-folders within the version folder.

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FIGURE GS-4. Using PRESTO From Within Tekla Structures Option

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6. The Ready to Install the Program window displays. Click Install to start the installation.

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FIGURE GS-5. Ready to Install the Program

Getting Started / GS-5

©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

Installing the Program

7. Upon successful installation the Authorize now? dialog displays, as shown in Figure GS-6 “Authorize Now? Dialog” on page GS-6. • If you select Yes, refer to “Authorizing a Program.” • If you select No, the program will prompt for authorization when started.

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Note: The program must be authorized before it can be used.

FIGURE GS-6. Authorize Now? Dialog

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8. When the last screen displays, click Finish to exit the install wizard.

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FIGURE GS-7. Installation Complete

Note: Give all users of this program full access to the directory where the program installs and authorizes.

NOVELL INSTALLATION LEAP Software does not make any guarantees about installations in Novell Netware environments. (Occasionally, network license users have experienced difficulties with compatibility of workstations using a Windows operating system in Novell Netware environments.) The installation process is the same as described above for a Novell installation. However, one file needs to be loaded as described in the note below.

GS-6 / Getting Started ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Installing and Configuring Microsoft .NET Framework

Note: A driver called CKSERVER.NLM is copied to the program directory. On the Novell Server, load the driver and reference it in the AUTOEXEC.NCF file for automatic startup.

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Installing and Configuring Microsoft .NET Framework

To determine if this framework is installed, select: Start > Settings > Control Panel > Add/Remove Programs. Scroll through the list of programs to see if the Microsoft .NET Framework v1.1 is listed. If it is, proceed with installation and authorization of the program. If it is not listed, please go to www.leapsoft.com/dotnet.html and follow the link to download and install the latest .NET Framework files. Once the Microsoft .NET installation is complete, the next step is configuration. Refer to the following table for instructions on how to access the .NET Framework v1.1 Wizards. Operating System Access Configuration Wizard

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Windows NT

Start > Programs > Administrative tools

Windows 2000

Start > Settings > Control Panel > Administrative tools

Windows XP

Start > Settings > Control Panel > Administrative tools

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Once the .NET Framework v1.1 Wizard is open, perform the following steps to configure the framework.

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FIGURE GS-8. .Net Framework v1.1 Wizard

v E PRESTO®v8.6

Getting Started / GS-7

©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

Managing Product Site Keys

1.

Select the Adjust .NET Security icon to open the Security Adjustment Wizard.

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FIGURE GS-9. Security Adjustment Wizard

2. 3.

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Select the Make changes to this computer option and click Next. Select the Local Intranet icon, change the level to Full Trust, and click Next.

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Click the Finish button to accept the changes you made and close the .NET Framework Wizard.

Managing Product Site Keys

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The LEAP Software Online Authorization System is the recommended method for obtaining an authorization code. Note: Only the Primary Key Holder may login on the Online Authorization System.

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Authorizing a Program 1.

From the Start menu select the program from the LEAP Software folder.

2.

When the Authorization warning dialog opens, click Yes.

GS-8 / Getting Started ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Managing Product Site Keys

3.

When the LEAP Software Security screen displays, enter your company information in the Company Information tab.

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FIGURE GS-10. LEAP Software Security Screen

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4.

Go to the LEAP Software web site (www.leapsoft.com) and login.

5.

Select Online Authorization.

6.

When prompted, login with your contact email and password.

7.

At the Client Product Licenses window, click Manage Site Keys for the product for which the Site Key is required.

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FIGURE GS-11. Client Licenses Screen

PRESTO®v8.6

Getting Started / GS-9

©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

Managing Product Site Keys

8.

At the Created Site Key window, click Authorize. The Create License window opens.

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FIGURE GS-12. Created Site Key Screen

9.

Cut and paste the site code from the Authorization tab of the Security window. Enter the number of user accounts required and click GetSiteKey.

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FIGURE GS-13. Security Window Authorization Tab

10. Cut and paste the Site Key into the Site Key field of the Authorization tab. Click Authorize Program.

Demo Authorization

Upon request, LEAP Software issues special demonstration licenses. A demonstration license allows you to preview a fully functional version of the program before you purchase it. The demonstration version of the program is the same as the purchased version of the program; however, a demonstration version only lasts for a limited time. To learn more about obtaining a demonstration license, please contact LEAP Software Sales Representatives at (800) 451-5327. To authorize a demonstration version of the program, follow the instructions above for Program Authorization.

GS-10 / Getting Started ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Managing Product Site Keys

Transferring Authorization Authorizations may be transferred to different directories and computers. Essentially, there are three ways you can transfer authorizations: • Direct Transfer on a Single Computer: Transfer the authorization from one directory to another directory on the same computer.

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• Floppy Disk Transfer: Transfer the authorization from one computer to another computer when a network license is not present. • Direct Transfer to a Network Computer: Transfer the authorization from one computer to another computer on a network when a network license is present. Direct Transfer on a Single Computer

To move the program to a new directory on your computer, authorization must be transferred before the program in the new location can be run.

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For example, if PRESTO is installed in C:\Programs Files\LEAP Software\Presto (source directory) and it needs to be moved to D:\Programs (target directory), first install the program on the new target directory (that is, D:\Programs). After the installation completes, transfer authorization to the target directory as follows:

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1.

Start the original authorized copy of the program located in the source directory. Make sure the copy of the program on the target directory is not running.

2.

Select Security from the File menu to open the LEAP Software Security screen. Select the Direct Transfer tab.

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FIGURE GS-14. LEAP Software Security Screen – Direct Transfer Tab

3.

Enter the location of the target directory in the text box or click Browse to locate it and click Transfer. The authorization instantly transfers from the original installation (source directory) to the new installation (target directory). Now the original program is the unauthorized program and the new program is the authorized program.

Getting Started / GS-11

©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

Managing Product Site Keys

4.

Uninstall the copy of the program no longer using (in this case, C:\Program Files\LEAP Software\Presto).

Floppy Disk Transfer If you do not have a network license present and you would like to move the program to another computer, you first need to transfer the authorization. This can be easily accomplished via floppy disk transfer by performing the following steps:

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1.

You must first install the program on the target computer.

2.

Take a blank, formatted floppy disk to the target computer that contains the unauthorized copy of the program. This blank floppy disk will be called the transfer disk.

3.

Insert the transfer disk into the floppy drive and start the unauthorized copy of the program.

4.

When a message appears notifying you that you have an unauthorized copy of the program and asks if you would like to authorize it at this time, select Yes.

5.

When the LEAP Software Security screen displays, select the Register Transfer tab to open the appropriate screen.

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FIGURE GS-15. LEAP Software Security Screen – Register Transfer Tab

6.

Enter the path to the transfer disk (A:\ on most computers), and click the Register button.

7.

Once the disk automatically initializes, a message appears notifying you that you need to transfer authorization from an authorized version of the program. When this message appears, remove the transfer disk from the computer, exit the program, and take the transfer disk to the source computer.

GS-12 / Getting Started ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Managing Product Site Keys

8.

Insert the transfer disk into the floppy drive and start the authorized copy of the program.

9.

Select Security from the File menu to activate the LEAP Software Security screen. Select the Transfer Out tab.

10. Enter the path location of the transfer disk (A:\), and click the Transfer button. At this point, the original authorized copy of the program is unauthorized and the authorization is on the transfer disk.

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11. Take this transfer disk back to the target computer and insert it into the floppy drive.

12. Start the program. When notified that you have an unauthorized copy of the program, and asked if you would like to authorize it at this time, click Yes.

13. When the LEAP Software Security screen appears, select the Transfer In tab.

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14. Enter the location path of the transfer disk (A:\), and click the Transfer button.

15. The authorization instantly transfers from the original installation (source directory) to the new installation (target directory). At this point, the original program is the unauthorized program and the new program is the authorized program.

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Direct Transfer to a Network Computer

If you have a network license and would like to transfer the authorization to another server/host computer on the network, follow the steps below. 1.

Make sure that the program is installed on the source computer using the shared option. To check this, open the program and activate the LEAP Software Security screen. Select the Authorization tab and confirm that “Floating License” is in the Current Status field. If it says, “Fixed License,” then you do not have a network license for the program.

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v E PRESTO®v8.6

2.

Install the program on the target computer using the same setup type as on the source computer (e.g., shared). If necessary, restart the target computer to enable the network protocols.

3.

Depending on your operating system, follow the steps outlined in “Network Setup” on page GS-2, to share (with full access) the directory on the target computer where the program was installed.

4.

From the source program, open the LEAP Software Security screen and select the Direct Transfer tab. Type the location of the newly mapped network drive or click the Browse button to find it.

5.

Make sure the program on the target computer is not active. Click the Transfer button on the LEAP Software Security screen to transfer the license

from the source computer to the new target server/host computer. 6.

At this point, the program authorized on the server/host computer becomes unauthorized and the new server/host computer becomes authorized.

7.

Follow the setup procedures outlined in Network Setup to complete the setup process.

Getting Started / GS-13

©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

Multiple File Copies

Multiple File Copies Please note that LEAP Software allows multiple users to simultaneously use a single file. For example, XYZ engineers, Alex and Bob, are simultaneously using the same PRESTO project file. If Alex saves his work, his changes will be saved; however, if Bob saves his work after Alex, using that same file name, all of Alex’s work will be completely overwritten and lost. This also applies to other types of PRESTO files such as libraries and other savable files.

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To prevent users from accidentally overwriting another user’s work, it is recommended to establish different directories for each individual user.

Program Crash/Temporary Loss of License

In case of an unexpected event such as a program crash, you may be able to fix the problem by deleting the appropriate file with extension .tb2 from the program directory. In most cases, this restores authorization. If deleting this file does not correct the problem, contact the Technical Support Department at LEAP Software.

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Installation of Components to Work from Within Tekla Structures If you would like to use the program from within Tekla Structures, please make sure that during the installation you choose the option to install components necessary to run the program from within Tekla Structures. Refer to Installing the Program (step 5) on page GS-3 for more information.

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Note that you must install the program as well as Tekla Structures together on the user’s system. The program PRESTO, installed on a server accessed through a shortcut, will not allow the program to work from within Tekla Structures.

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GS-14 / Getting Started ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Contacting Technical Support

Contacting Technical Support Technical support is available Monday through Friday (except holidays) from 8:00 AM to 5:00 PM EST at the following numbers: Tampa

(813) 985-9170

U.S./Canada Toll-Free

(800) 451-5327

International

(813) 985-9170

FAX

(813) 980-3642

E-mail

[email protected]

Web Site

www.leapsoft.com

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Your calls are always welcome, but before you call, please consider the following:

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• Have you checked the user manual and online help system? Did you refer to the index for all references to the problem item? • If you encounter a problem, retrace your steps and check for incorrectly entered information.

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Also, please have the following items with you: • Have your input data ready.

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• Have the user manual at hand.

• If you think that you have found an error in the program, have the steps that we should follow to reproduce the error.

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Getting Started / GS-15

©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

Contacting Technical Support

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GS-16 / Getting Started ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

CHAPTER THREE

General Operation

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This chapter covers the concepts and procedures of program operation for PRESTO, screen by screen. Whenever appropriate, refer to the PCI Design Handbook, 6th Edition (2004), the Building Code Requirements for Reinforced Concrete (ACI 318-99), the Building Code Requirements for Reinforced Concrete (ACI 318-05), CPCI Design Manual, 3rd Edition (1996) and Design of Concrete Structures CSA 23.3-94.

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Starting PRESTO

To start PRESTO, use the standard procedure for beginning a program in Microsoft Windows. When the PRESTO splash screen appears, click anywhere in the screen area and the program’s Project tab displays.

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FIGURE GO-1. PRESTO Splash Screen

PRESTO Tab Screens PRESTO uses a tab screen interface. This means that each major screen has a

corresponding tab. You can instantly access a tab screen by selecting its tab with your mouse.

PRESTO®v8.6 ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

GO-1

Project Tab

For your convenience, PRESTO is divided into six main tabs: Project, Member Info, Materials, Loads, Analysis, and Design. Each tab allows you to enter relevant data, open various program dialog boxes, or analyze portions of the structure. Select the appropriate tab to make changes or complete an analysis. Note that when you are working on a project, the program adds a green check mark to the tab once you have entered information.

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Project Tab

This is the first screen that you encounter in PRESTO. It contains specific information related to the project, unit selection, design options, and design codes. Note, if you return to the Project tab at any time to change the units, each screen instantaneously converts its values, thereby updating the units. You must also select one of the three available design codes, ACI 318-99, ACI 318-05, or CSA 23.3-94 to proceed with your project.

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FIGURE GO-2. Project Tab

When data files are read from a version of PRESTO, prior to 8.3, those will be assigned to use ACI 318-99, ACI 318-05, or CSA 23.3-94. Please note the status bar, which shows the selected options for units, design options, and design codes. You can click directly on the status bar to change these options without returning to the Project tab.

If you change the design code, the Switch Design Code dialog box displays. This dialog box allows you to select the items to convert to the new code.

Switch Design Code Dialog Box PRESTO now allows ACI 318-99, ACI 318-05, and Canadian Code CSA 23.3-94. Each of these code has its own load factors, Phi factors, and allowable stress limits. Note that CSA code even has different concrete strain limit than ACI. If at any time you switch from one code to another, program needs to understand if you intend to maintain these factors as per your original code or change those to default values of newly selected code. To change factors to the newly. selected code, confirm that switch Design Code is

GO-2 / General Operation ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Member Info Tab

selected. Also confirm that any factor you want to adjust as per new code are checked. Select OK to switch the code. To cancel and return to your original design code, click Cancel.

FIGURE GO-3. Switch Design Code Dialog Box

Member Info Tab

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The second screen in the tab series allows you to enter the following information: Beam length, type, section ID, Interior/Exterior Location of Span, Start/End Release Supports, Start/End Final Supports, Left/Right Boundaries, and Topping.

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FIGURE GO-4. Member Info Tab

Member Info Screen Terms •

Beam Length: Overall out-to-out dimension of the beam.

•

Beam Type: This field is for beam type selection. You may choose from a list of beams contained in the menu by clicking the arrow to the immediate right of the field. Before you can select a beam type, it must first be defined in the Beam Sections Library. Refer to page GO-63 for information on using this library.

General Operation / GO-3

©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

Member Info Tab

•

Section ID: The name of the section within the beam type chosen. You may choose from the drop-down list. Before you can select a section ID, it must first be defined in the Beam Sections Library.

•

Span Location: Identifies the location of the span, either interior or end (for topping overhang). PRESTO uses the span location to determine the maximum overhang width, as specified in ACI 318-99/05, for sections with top flanges and sections with cast-in-place topping. Interior spans are defined as having effective overhanging flanges (if any) on both sides, whereas end spans are defined as having overhanging flanges on one side only.

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•

Release Supports Start/End: Start and end locations of stripping loop. The start is the loop nearest the left beam end and is measured from the left end. The right end is the loop nearest the right beam end and is measured from the right end.

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Final Supports Start/End: Start and end location of supports at erection. The start is the support point nearest the left end of the span and is measured from the left end of the span. The right end is the support point nearest the right of the span and is measured from the right end of the span.

•

Boundaries Left/Right: Usually half the center-to-center distance between members to the left or right of the centerline, respectively. Area loads (loads with units of ksf or kN/m2) act on the boundary distance.

•

Use Boundary Distance in Section Properties: This check box is enabled when the summation of the boundary distance on the left and right is smaller or equal to the topping width. If this box is checked, the parts of the precast flange protruding beyond the specified left and right boundary distances are removed and section properties computed again for the precast section, which are then used in calculations.

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•

Eccentricity: Eccentricity of the topping, if any. Values to the left of the centerline of the beam are negative, and values to the right are positive. This information is used to calculate torsional moments.

•

Gap: The region of the topping located outside the slab, defined by thickness and width. This value is usually equal to the boundary minus the width of the slab.

GO-4 / General Operation ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Member Info Tab

•

Gap Topping Adjustment: Difference in thickness between the gap and slab regions of the topping, if any. Note that this value will be added or subtracted from the thickness. This is not the overall thickness of the gap. Examples of gap topping adjustment values are illustrated below.

6"

5"

6"

+1"

-1"

(a)

(b)

Thickness = 6" G ap Topping Adjustm ent = -1"

Thickness = 6" G ap Topping Adjustm ent = 0"

FIGURE GO-5. Gap Topping Adjustment

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Thickness = 6" G ap Topping Adjustm ent = 1"

Thickness, in: Thickness of topping slab over a particular section. Topping thickness is recorded in the form, [topping thickness, in] for [length, ft] for each of the sections. Topping can have different thicknesses specified along the length of the beam.

•

Length, ft: Length of the topping over a particular section.

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Topping Gap Width: Width of the topping gap. PRESTO divides the poured-in-place portion of the composite section (topping) into two regions, slab and gap. If the top widths of the beams are adjacent then the width of the gap is zero.

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PRESTO®v8.6

(c)

7"

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6"

Topping Slab Width: Width of the topping slab. The slab is modeled as a rectangle and defined as the region directly over the beam, which has a thickness and a width. Note that the width of a slab may be less than the top width of the precast. If there is no topping set, the value is equal to zero.

Flange Opening: Click this button to open the Opening Data dialog box. This button allows you to add an opening in the flange of the beam. Refer to page GO-6 for information on using this screen. For computational purposes, circular openings are replaced internally with equivalent rectangular openings. The transverse dimension is equal to the diameter of the circle and the longitudinal dimension is set equal to one-half the diameter of the circle. Openings in hollow core slabs often occur at the strand location. In such cases, the effects of cutting the strands can be modeled by introducing midspan/interior shielding across the openings. Torsion Parameters: Click this button to open the Torsion Parameters dialog box. Refer to page GO-7 for information on using this screen. This button allows you to modify or review the torsion design parameters.

General Operation / GO-5

©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

Opening Data Dialog Box

Opening Data Dialog Box PRESTO allows you to add openings in the flange. Click the Flange Opening button

located on the Member Info tab to open this dialog box.

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FIGURE GO-6. Opening Data Dialog Box

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Select the type of opening, either rectangular or circular, from the Opening Type dropdown list and then enter the dimensions for the opening in the text boxes. Click the Add button and it appears in the list on the screen. Continue adding as many openings as necessary, using the same procedure above. When completed, click the OK button to return to the Member Info tab. You can modify an opening by highlighting it in the list, making the changes in the text boxes, and clicking the Modify button. To delete an opening, highlight it in the list, and click the Delete button.

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Opening Data Screen Terms

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•

Opening Type: This field is for the opening type selection. It can be either rectangular or circular. You may choose from a list contained in the menu, by clicking the arrow to the immediate right of the drop-down list.

•

bo: Dimension of opening transverse or perpendicular to the span. If the opening is circular, enter diameter in this field.

•

lo: Dimension of opening parallel to span. This field is disabled for circular openings since it is not applicable.

•

f1: Location of centerline of the opening, measured from the left end of the member.

GO-6 / General Operation ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Torsion Parameters Dialog Box

•

f2: Offset of opening, measured from the centerline of the member. Openings to the left of the centerline, looking toward the right end of the member, should have a negative distance; openings to the right are positive.

Torsion Parameters Dialog Box

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Click the Torsion Parameters button located on the Member Info tab to open this dialog box. This dialog box allows you to modify or edit the clearance factors for horizontal and vertical clearance as well as the areas and perimeters for torsional calculations.

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FIGURE GO-7. Torsion Parameters Dialog Box

Torsion Parameter Screen Terms

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Horizontal Clearance: Distance between centerline of closed torsional stirrup and the edge of the beam.

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Vertical Clearance: Distance between centerline of closed torsional stirrup and the top/bottom of the beam.

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•

Acp: Area enclosed by outside perimeter of concrete cross-section.

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Pcp: Outside perimeter of the concrete cross-section.

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Aoh: Area enclosed by centerline of the outermost closed transverse torsional reinforcement.

•

ph: Perimeter of centerline of outermost closed transverse torsional reinforcement.

General Operation / GO-7

©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

Materials Tab

Materials Tab This screen allows you to specify the prestressing, concrete, and rebar properties.

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FIGURE GO-8. Materials Tab

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The first area to be filled in relates to the prestressing tendon. Select the strand from the Prestressing Tendon ID drop-down list.

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Before moving on to the next section, if applicable to your project, you should enter the value for Debonding Increment and specify the maximum number of strands that can be debonded as the maximum percentage of each row, or of the total number of strands. These values are used only if the automatic shielding option is used.

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Enter the information for concrete and rebar properties by typing the values in the appropriate box, or select from the drop-down lists. The program automatically calculates the elasticity, but you can manually edit the number.

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Materials Screen Terms

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Prestressing Tendon ID: This field is for strand type selection. You may choose from a list contained in the menu, by clicking the arrow to the immediate right of the drop-down list.

•

Initial Jacking Co-efficient: By default, this value is read in from the strand library based on the tendon ID picked. This value is then used to populate the Pull field in the Strand definition grid.

•

Debonding Increment: The length at each end (left and right) measured from the precast end respectively.

•

Maximum Auto-Debonding Percentage: •

Per Row: Allows you to enter the maximum percentage of straight strands in each row that can be debonded.

•

Total: Allows you to enter the total maximum percentage of the total number of straight strands that can be debonded.

GO-8 / General Operation ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Materials Tab

•

Unit Weight (Release/Final): The unit weight of the precast concrete is a measure of the density of the material. Should be in the range of 90-160 pcf (1400-2600 kg/m3), and is usually equal to 150 pcf (2500 kg/m3). Concrete with a unit weight between 110 and 150 pcf (1800-2500 kg/m3) is assumed by the program to be “sand-lightweight” concrete. Concrete with a unit weight of less than 110 pcf (1800 kg/m3) is assumed to be “all lightweight” concrete. In CSA mode, program uses range 1500-2500 kg/m3 for lambda calculations.

•

Unit Weight (Topping): The unit weight of the topping concrete is a measure of the density of the material. Should be in the range of 90-160 pcf (1400-2600 kg/m3), and is usually equal to 150 pcf (2500 kg/m3). Concrete with a unit weight between 110 and 150 pcf (1800-2500 kg/m3) is assumed by the program to be “sand-lightweight” concrete. Concrete with a unit weight of less than 110 pcf (1800 kg/m3) is assumed to be “all lightweight” concrete. In CSA mode, program uses range 1500-2500 kg/m3 for lambda calculations.

•

Lambda: This is the lightweight factor. As per ACI, this factor is computed as per 11.2.1.2. In CSA mode, this is computed as per 8.6.5. Program updates this value when unit weight is changed.

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Strength: Strength of concrete.

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Strength (Release): Compressive strength of the precast concrete at time of release or stripping. Should be ≥ 2000 psi (≥ 13 MPa). Should not exceed strength at final.

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Strength (Final): Specified final compressive strength of the precast concrete. Also known as the 28-day strength. Should be in the range of 3000-20000 psi (20-140 MPa).

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Strength (Topping): Specified compressive strength of the topping, if any. Should be in the range of 1000-20000 psi (7-140 MPa).

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Elasticity: Modulus of elasticity. The program, using ACI 318-99/05, Art. 8.5.1, automatically calculates the elasticity; however, the user may modify it.

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Elasticity (Release): The flexural modulus of elasticity of the precast concrete at release or stripping (initial) can either be calculated by the program or entered by the user. The modulus of elasticity for precast concrete at release should be ≥ 1000 ksi (≥ 6800 MPa). PRESTO uses the following equation:

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(

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w ci1.5 33 f ci′ psi

(

)

w ci1.5 0.043 f ci′ MPa

General Operation / GO-9

©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

Materials Tab

For CSA mode, the following equation is used: 1.5

w ci ⎛ 3300 f ′ + 6900⎞ ⎛ -----------⎞ ci ⎝ ⎠ ⎝ 2300⎠ •

MPa

Elasticity (Final): The flexural modulus of elasticity of the precast concrete at final can either be calculated by the program or entered by the user. The modulus of elasticity is also defined as the ratio of the normal stress to the corresponding strain. This value should be ≥ 1000 ksi (≥ 6800 MPa). PRESTO uses the following equation:

w c1.5

(33 f c′ ) psi

(

)

w c1.5 0.043 f c′ MPa For CSA mode, the following equation is used: 1.5

wc ⎛ 3300 f ′ + 6900⎞ ⎛ -----------⎞ c ⎝ ⎠ ⎝ 2300⎠ •

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MPa

Elasticity (Topping): The flexural modulus of elasticity of the topping can either be calculated by the program or entered by the user. The modulus of elasticity for topping should be ≥ 1000 ksi (≥ 6800 MPa). PRESTO uses the following equation:

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w ct1.5 33 f ct′ psi

(

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w ct1.5 0.043 f ct′ MPa

For CSA mode, the following equation is used:

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1.5

w ct ⎛ 3300 f ′ + 6900⎞ ⎛ -----------⎞ ct ⎝ ⎠ ⎝ 2300⎠

MPa

•

εcu: Ultimate compressive strain of the concrete, usually equal to 0.003 in/in (mm/mm) in ACI and 0.0035 in/in (m/m) in CSA. This value is used in both the strain compatibility analysis and the calculation of the balanced and limiting values of the steel ratios. Should not exceed 0.003 as specified in ACI 318-99/05, Art. 10.2.3.and should be limited to 0.0035 as per CSA.

•

fct: Average splitting tensile strength of lightweight aggregate concrete. The

value fct/6.7 is used in lieu of ACI 318-99/05,

•

f c'

in some calculations. As specified in

the value fct/6.7 (1.8 fct) shall not exceed

f c'

.

fy: Specified yield strength of the mild reinforcement used to resist flexure. Should be in the range of 30-100 ksi (200-700 MPa).

GO-10 / General Operation ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Loads Tab

•

fs: The permissible tensile stress in the mild flexural steel. Can be calculated by the program or manually entered by the user. The program uses 0.6fy ksi (MPa). The tension stress should be ≤ fy and ≥ fy/4. The program uses fs to calculate the tension steel of release, if required.

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fy, shear: Specified yield strength of the mild reinforcement used to resist shear. Should be in the range of 30-100 ksi (200 - 700 MPa).

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Loads Tab

This screen is where the load information is entered. PRESTO automatically computes dead loads due to self-weight of girders and topping, based on the geometry and material information provided. You may enter additional loads as concentrated loads, uniform loads, or linearly varying loads.

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FIGURE GO-9. Loads Tab

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To define a load, select the type of load from the Type drop-down list and class from the Class drop-down list. Enter the values in the Mag, Loc, Mag, and Loc fields and, in the Description field, type a description of the load. You must click the Add button to add the load to the permanent load list. To delete a permanent load, highlight it in the list and click the Delete button. To modify a previously entered load, select it in the list, change the items or values accordingly, and click the Modify button.

Loads Screen Terms •

PRESTO®v8.6

Type: This field is for selecting the different types of loads you want. There are three types of loads available in PRESTO: Concentrated, Uniform, and Linear Loads. Note that uniform loads are not applied to openings.

General Operation / GO-11

©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

Analysis Tab

•

Class: This field is for class selection. You can select from five choices, Dead Load (non-composite), Superimposed Dead Load (composite), Composite Snow Load in ACI 318-99 or Roof Live/Snow/Rain Load on Composite in ACI 318-02, Live Load, and Sustained Live Load.

•

Mag and Loc fields: The loads are located on the member by entering data as follows:

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Mag1 at Loc 1 to Mag2 at Loc2 where:

Mag1 is the beginning magnitude of linear loads or the total of uniform and concentrated loads. Loc1 is the location of the start of linear and uniform loads or the location of a concentrated load, measured from the left beam end.

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Mag2 is the ending magnitude of linear loads.

Loc2 is the end location of the linear and uniform loads, measured from the left beam end.

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PRESTO knows which magnitudes and locations are necessary for each

load type. If a particular magnitude or location is not required for a load type, e.g., Loc2 for a concentrated load, then that field will be protected by the program and will be unavailable.

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Ecc: This field refers to the eccentricity of the load, measured from the centerline. Values to the left of the centerline are negative, and values to the right are positive.

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Description: This field should be used to enter an optional description of each load, e.g., “Office LL” or “Roofing Mat.”

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Analysis Tab

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This is the fifth screen in the tab series. Here, you can specify check points, specify load factors, run the structural analysis, and view analysis results after the analysis is complete by clicking the Run Analysis button. You must run the analysis before you can move on to the Design tab. Once the analysis is finished, the results appear onscreen, as shown below. (Use the scroll bar on the right side of the screen to view the results at the bottom.) Use the drop-down lists to select the type of results you would like to view.

GO-12 / General Operation ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Load Factors Dialog Box

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FIGURE GO-10. Analysis Tab

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Printing the individual results is as simple as clicking the Print button. This opens the Print screen. You can print the results to a printer or export to spreadsheets. If you choose to export to spreadsheets, you must first designate a file name in the text box. PRESTO also offers you the option of manually changing the load factors and check points using the Load Factors and Check Points dialog boxes. Alternatively, you can select the option to run analysis automatically by setting it up in the Show| Preferences dialog as shown in Figure GO-68.

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Load Factors Dialog Box

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Click the Load Factors button on the Analysis tab to display the Load Factors dialog box. Here, you can modify the values for ultimate and service load factors, self-weight load multipliers at release and final, and bearing. Click the OK button to accept any changes and return to the Analysis tab. Click the Cancel button to return to the Analysis tab and ignore any changes made.

General Operation / GO-13

©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

Load Factors Dialog Box

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FIGURE GO-11. Load Factors Dialog Box

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The dead and live load factors (DL and LL factors) are ultimate factors, as specified in Section 9.2 of ACI 318-99. A factor for the snow dead loads has been included on this screen. This factor is 1.2, as specified in ACI 362.1R-97, Section 2.2.5.2. For CSA, the load factors are as per CSA 23.3-94, Section 8.3.

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For ACI 318-02, the load types for snow is coupled as external loads, which may also include roof live loads and/or rain loads. The load factors are initialized either internally based on Art. 9.2.1, Eq. 9-2 or from the Settings file. Refer to page GO-55 for information on the Save Settings feature of the program.

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If, at any time, a user switches code from ACI 318-99 to ACI 318-02, or to CSA 23.3, or vice versa, the program provides the option to either retain the load factors specified or update the factors based on code-specified values.

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Multipliers of the self-weight at release and final conditions allow you to vary the effective self-weight of the member. For example, a wall panel might have a selfweight multiplier of 1.0 at release when the panel is horizontal and a multiplier of 0.0 at final when it is vertical (i.e., self-weight is not causing flexure). The Snow Loads (in ACI-99) and the external loads Lr/S/R (in ACI-05 and CSA codes) can optionally be treated acting as Live Loads by selecting the option to “model as LL” instead of “model as SDL” (default). Although these loads will be treated as live loads, they will still be able to use a different Load Factor than the live loads. The effects of this selection will be seen primarily in the losses and stress computations. Bearing refers to the bearing overload factor and is multiplied by the calculated support reactions during the bearing steel analysis. This value is usually equal to 1.15.

GO-14 / General Operation ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Check Points Dialog Box

Check Points Dialog Box Click the Check Points button on the Analysis tab to open the Check Points dialog box. Here, you can modify or add points to be checked during analysis in addition to or instead of points selected by the program. The points are measured from the left end of the member. To add a location, enter a value in the Location text box and click the Add button. It will appear in the list on the screen. To modify a previously defined location, highlight it in the list, edit the value in the text box, and click the Modify button. You can also delete a location by highlighting it in the list and clicking the Delete button.

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FIGURE GO-12. Check Points Dialog Box

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For prestressed members, the default check points are H/2 and transfer length, 0.4L, 0.5L, and 0.6L, where L is the overall length of the member and H is the overall height. For mild reinforced beams, the default check points are 0.8H, 0.25L, 0.4L, 0.5L, and 0.6L. Note that this does not mean to imply that the default check points are the critical areas of the design. You must determine the critical sections of your design. Click the Reset button to overwrite any changes made and reset the check points to the default settings. The Clear All button deletes all the check points defined. The Defaults button ads the check points at the default check points specified above. The Auto Generate button brings up the screen shown in Figure GO-13 and allows the user to specify multiple check points in an easy and rapid way. Using the auto generate feature will wipe out the existing user-defined locations.

General Operation / GO-15

©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

Design Tab

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FIGURE GO-13. Auto Generate Check Points Dialog Box

Selecting the Include User Specified Option check box makes the other controls in the group available. These start and end locations, along with the interval and include points options, allow for easy generation of check points between these locations either at specific locations (such as tenth points) or at an increment of a fixed distance increment (5, 10, 15 etc.). The options for Include Check Points at all point load locations and transfer length will automatically add check points at any location where the concentrated loads are added, and at transfer length distance from either end of the beam respectively. If the option Limit check points only for first half beam is selected, check points will be added only up to a distance of 0.5L. This option avoids adding multiple check points when working with symmetrical beams.

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Design Tab

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The final screen in the tab series allows you to select and set the parameters that control the beam design, enter either the strand pattern and/or the rebar pattern, and check the design status. Each of the associated dialog boxes, accessed by selecting the buttons at the bottom of the screen, is described on the following pages. The Design tab also shows schematic sketches of the beam cross-section along with the strands or rebar and the side view of the beam. You can click the Drawing button to print the schematic drawing, either to a printer or export to an AUTOCAD DXF format.

GO-16 / General Operation ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Design Parameters Dialog Box

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FIGURE GO-14. Design Tab

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Design Parameters Dialog Box

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Click the Design Parameters button located on the Design tab to open this dialog box. By selecting the appropriate tab, you can modify the design options, phi factors, losses, stresses, and deflection multipliers. Click the OK button at any time to accept changes in all six tabs or click the Cancel button to discard all the changes.

Design Options Tab

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Click the Design Options tab to display the appropriate screen. Here, you can select various design options to appear in the analysis, such as transform strand, bearing analysis, end rotations, composite shear depth, horizontal shear, and bilinear analysis. You can also review or modify the steel fy, bearing length, and distance of CL of bearing, etc., by clicking the Bearing Steel Info button. Refer to page GO-26 for information on using the Bearing Steel Info dialog box.

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General Operation / GO-17

©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

Design Parameters Dialog Box

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FIGURE GO-15. Design Options Tab in ACI 318-05 Mode

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FIGURE GO-16. Design Options Tab in CSA 23.3-94 Mode

Design Options Screen Terms •

Transform Strand: Usually PRESTO only takes into account the mild rebar when calculating the transformed section properties. If this option is selected, the program also considers the strand when calculating the transformed section properties.

•

Bearing Analysis: Selecting this option will have the program perform a check for required bearing steel. Note that if your member has no bottom

GO-18 / General Operation ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Design Parameters Dialog Box

flange, the bearing analysis will be performed based on the bearing load and dimensions for a single stem. At a cantilever, PRESTO only checks for unreinforced bearing capacity, it does not check crack angles. A bearing is defined as a cantilever if it is located further than a distance h from the end of the member.

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Area A1 is defined as the actual bearing area (length × width). Area A2 is that area concentric with A1 and is equally larger on all sides, if possible. A2 is limited by the first free edge that it encounters. This means that if area A1 is adjacent to a free edge, A2 will equal A1.

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FIGURE GO-17. Bearing Analysis

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PRESTO uses a modified PCI Eq. 4.6.1 that has an upper limit on φVn based

on ACI 318-99/02, Art. 10.17.1. Ash is calculated using an assumed value of 3.4 for the μ factor; therefore, you should think of it as a minimum recommended value.

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•

End Rotations: Select this option to have the program calculate end rotations and elastic shortening. Note that the elastic shortening does not include effects from creep and shrinkage.

•

Composite Shear Depth: Select this option to use the composite depth during the shear calculations. If not selected, the program uses only the noncomposite depth. If you opt to use the total composite depth to resist vertical shear, PRESTO uses the lower concrete strength (usually the topping) when calculating the capacity of the concrete to carry vertical shear, as specified in ACI 318-99/05, Art. 17.2.3.

•

Horizontal Shear: Select this option to calculate the required horizontal steel in the analysis. Note that the program does not calculate horizontal shear unless this option is selected.

•

Bi-Linear Analysis: If the net bottom tension at service conditions at midspan exceeds the cracking tension and you selected this option, PRESTO calculates the deflections based on the bilinear deflection procedure as specified in [Ref (1)] in accordance with ACI 318-99, Art.

General Operation / GO-19

©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

Design Parameters Dialog Box

18.4.2(d).

If not selected, the program performs a conventional linear elastic deflection analysis. This option is not used in ACI 318-05 because in that case, the program automatically computes bilinear deflections if the section is classified as T (Transition) or C (Cracked).

•

Live Load Recapture: Selecting this option will take into account the temporary increase in strand stress when the live load is applied (Live Load Recapture of prestress loss). If not selected, the program ignores this temporary condition. Load Live Recapture is defined as the temporary increase of tensile stress in the prestressed tendons only during the application of the superimposed live load. Note that live load recapture is only available for PCI and time-dependent losses.

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•

User Location for Cracking Moment: When this option is not selected, the program uses the location with the smallest φMn to Mu ratio and prints the calculated cracking moment. If you select this option, you must assign a section at which you want to have the program print the cracking moment in the appropriate text box. Note that if you selected this option and left the field equal to zero, the cracking moment will not be printed.

•

User Location for Detailed Losses: When this option is not selected, the program will print detailed calculations of the prestress losses at midspan of the member. If you select this option, you must enter a value in the appropriate text box for the section where you want the detailed loss calculations to be printed.

•

PCI Design Handbook (6th edition) Shear and Torsion Method: When this option is selected, PRESTO will use the methodology described in section 4.4 of the PCI Design Handbook (reference 9) to compute shear and torsion. This method is available for all sections other than for Hollow Core sections. This option is only available in the ACI design modes and not available if the Canadian code is selected on the project tab.

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•

Create Pattern Assuming: When in ACI 318-05, the program can create an automatic strand pattern for either Uncracked or Transition classes. These are two of the three listed classes in ACI 318-05, Art. 18.3.3. PRESTO does not create patterns for class C (Cracked). This option has no effect when a user enters strands manually. Further, this is applicable only to prestressed beams and has no effect on reinforced beams.

•

Shear and Torsion Calculation: In CSA mode, program provides option to do shear and torsion design using simplified method as per CSA 23.3-94 Section 11-3 or using general method as per Section 11-4.

Prestress and Losses Tab To modify any prestress loss information, click the Prestress and Losses tab to open the screen as shown in the figure below. Here, you can specify the release time and relative humidity percentage if you would prefer the program to calculate the losses using the

GO-20 / General Operation ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Design Parameters Dialog Box

PCI or time-dependent method. You may, on the other hand, enter the release and final losses manually; thereby overriding the values calculated by the program.

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FIGURE GO-18. Prestress and Losses Tab

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The PCI analysis uses the equations found in the PCI Design Handbook (5th Edition), Art. 4.7. Time-dependent losses follows the procedure defined in the article “Recommendations for Estimating Prestress Losses” from the PCI Journal, JulyAugust, 1975. Time-dependent losses assume accelerated curing, and creep and shrinkage are assumed to both start at release. User-defined losses allow you to enter the release and final losses, expressed as a percentage.

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Prestress and Losses Screen Terms •

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Hours to Release: Number of hours between tensioning and detensioning of the strands. Used in the prestressed loss computations. Note that for mathematical correctness, the tensioning of the strand is defined to take place at 1 hour (not 0 hours).

•

Relative Humidity: Average ambient humidity expressed as a percentage. The relative humidity is used to calculate prestressed losses. Refer to the PCI Design Handbook (5th Edition), Figure 3.12.2 for the average relative humidity in your area.

•

Days to Topping/Comp DL: If you specified that the program will calculate prestressed losses using the time-dependent losses, enter both the days between release and the application of the topping and the days between release and the application of the composite dead load. Note that PRESTO requires that the application of the composite dead load take place after the application of the topping. Both values must be greater than zero even if you do not have either topping or composite dead load.

•

Release/Final: If you selected to have the program calculate the prestressed losses using the user-defined losses, you must enter both the prestress loss at release and final. Both values are calculated as percentages (e.g., 10%).

General Operation / GO-21

©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

Design Parameters Dialog Box

•

Strand Stress/Strain Model: PRESTO allows users to select from three stress-strain models. One model is based on the PCI Design Handbook (5th Edition), Design Aid 11.2.5. Second model is based on CPCI Design Manual (3rd Edition). Figure 8.2.4. The third model is that which was present in older versions of this program.

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Deflection Multiplier Tab

To review or modify the deflection multipliers, click the Deflection Multiplier tab to display the screen as shown in the following figure. The default values, as specified in the PCI Design Handbook (5th Edition), Table 4.8.2, are used to estimate the long-term cambers and deflections for typical members when the Prestressed design option is selected. If the Reinforced design option is selected, these values are ignored and ACI 318-99/05, Art. 9.5.2.5 is automatically applied.

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FIGURE GO-19. Deflection Multiplier Tab

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GO-22 / General Operation ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Design Parameters Dialog Box

Phi Factors Tab To review or modify the strength reduction factors, click the Phi Factors tab to display the appropriate screen, as shown below.

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FIGURE GO-20. Phi Factors Tab

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Edit the factors by typing over them. Phi factors, are either strength reduction factors, or material resistance factor. Phi factors in ACI code as equal to the ratio of the design strength to the nominal strength. PRESTO provides strength reduction phi factors for flexure, shear, and bearing. In ACI 318-05, phi for tension controlled sections as well as compression controlled sections are to be specified. The phi factor for compressioncontrolled sections is 0.65, flexure (tension-controlled sections) is 0.90, and shear is 0.85. In the U.S., concrete and steel phi factors are generally not used, so in ACI mode these should be set equal to 1.0. The phi factor for bearing is applied to the calculation of the required bearing steel, if any, and is usually equal to 0.85 contrary to ACI 318-99/ 05. Canadian code CSA 23.3-94 Section 8.4 requires that material resistance factors to be used with force components within each material rather than overall strength reduction factors. Even though program uses material and strength factors in design, it is suggested the only one of the two sets be used. The c/dt ratio is enabled and used only in ACI 318-05. PRESTO uses these limits to determine if the section is tensioncontrolled, compression-controlled, or is in transition. Thus, it determines appropriate phi values for its behavior as per ACI 318-02, Art. 9.3.2.2.

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Miscellaneous Data Tab

PRESTO®v8.6

To modify or review data for shoring, length multipliers, and effective width of topping, click the Miscellaneous Data tab. The appropriate screen will display, as shown in the figure below.

General Operation / GO-23

©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

Design Parameters Dialog Box

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FIGURE GO-21. Miscellaneous Data Tab

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There are three types of shoring allowed in PRESTO: None, Elevated, and Touch. None indicates that the member is erected and is supported at its final support locations only. Elevated specifies that the entire weight of the system, self-weight included, is temporarily supported by shoring until the topping has cured. Therefore, the composite section supports all gravity loads. And the last type of shoring, Touch, is where the member is erected and then supports its own self-weight (SW) and dead loads (DL) specified to be supported by the precast (non-composite dead loads, excluding topping weight). However, all additional weight added to the system is supported by a theoretical uniform shoring system placed under the member until the topping has cured, after which the shoring is removed. The following table shows the section type (N = non-composite (precast), C = composite) supporting each loading type under various shoring condition after the shoring is removed.

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SW

DL

Topping

SD

LL

None

N

N

N

C

C

Elevated

C

C

C

C

C

Touch

N

N

C

C

C

Length Multipliers are used to calculate the development and transfer lengths for bonded and debonded strands based on the basic development and transfer lengths. Bonded strands are those that have no debonding.

Miscellaneous Data Screen Terms •

Transfer - Bonded: This number is multiplied by the basic transfer length to obtain the transfer length for bonded strands.

GO-24 / General Operation ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Design Parameters Dialog Box

•

Transfer - Debonded: The basic transfer length is multiplied by this number to obtain the transfer length for debonded strands.

•

Development - Bonded: The basic development length is multiplied by this number to obtain the development length for bonded strands.

•

Development - Debonded: The basic development length is multiplied by this number to obtain the development length for debonded strands.

•

Topping Effective Width: If the Computed option is selected, the program automatically computes the effective width of the topping and uses this value in all of the calculations. (For details on effective width computation, refer to Section Properties in the Theory chapter.) However, if the Manual option is selected, then the Modify button becomes available. Clicking this button will open the User Defined Effective Width of Topping dialog box. Refer to page GO-27 for information on using this screen.

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Allowable Stress Tab

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Click the Allowable Stress tab to review or modify the release stresses and final stresses, as shown in the following figures. You are free to alter the allowable stress values by typing over the default values. In order to have the program use the default stress factors to calculate the stresses; you must select the Use Factors check box. Note that if this box is checked, the fields on this screen are disabled and the program will use the values specified in the Stress Factors dialog box. Refer to page GO-28 for information on using this screen.

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The default factors calculated by the program are as specified in ACI 318-99/05, Chapter For each design code, the corresponding values are initialized. There are various values that are specific to ACI 318-05 and are enabled only when that code is selected.

18.

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FIGURE GO-22. Allowable Stress Tab (ACI 318-99 and CSA 23.3-94)

PRESTO®v8.6

General Operation / GO-25

©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

Bearing Steel Info Dialog Box

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FIGURE GO-23. Allowable Stress Tab (ACI 318-05)

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Click the Edit Factors button to modify the stress factors using the Stress Factors dialog box. Refer to page GO-28 for information on using this screen.

Bearing Steel Info Dialog Box

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Click the Bearing Steel Info button located on the Design Options tab of the Design Parameters dialog box to open this screen. Here, you can modify or review the bearing shear data for steel, bearing length, and distance to CL of bearing. Click the OK button to accept any changes and return to the Design Options tab. Click the Cancel button to discard any changes.

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FIGURE GO-24. Bearing Steel Info Dialog Box

GO-26 / General Operation ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

User-Defined Effective Width of Topping Dialog Box

Bearing Steel Info Screen Terms •

Steel Fy: Specified yield strength of mild reinforcement used to resist bearing forces, if required by analysis. Should be in the range of 30-100 ksi (200-700 MPa).

•

Bearing Length: Length of the bearing surface, measured parallel to the span of the member from the end of the member to the back of the bearing plate.

•

Bearing Width: Width of the bearing plate or surface, measured perpendicular to the span of the member. Note that if your member does not have a bottom flange, PRESTO assumes that the bearing analysis will be performed for a single stem.

•

Distance to CL of Bearing: Distance from the end of the member to the centerline of the bearing reaction, measured parallel to the span of the member.

•

Nu/Vu: Ratio of the horizontal force to the vertical force at the support. Usually equal to 0.20.

•

Theta Min/Max/Inc: The minimum and maximum angles to be checked for possible cracking, along with the increment between the minimum and maximum. The number of sections checked by the program during the bearing analysis is equal to the maximum crack angle minus the minimum crack angle divided by the increment. The maximum and minimum angles should be in the range of 0 to 90 degrees.

•

Use Manual Input Cr value: When reinforcement is provided in direction of Nu or when Nu is zero, the Cr value can be manually input as 1.0 in this field.

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User-Defined Effective Width of Topping Dialog Box To open this dialog box, select the Manual option on the Miscellaneous Data tab of the Design Parameters dialog box, then click the Modify button. Here, you can modify the effective width of topping (Beff) for the different topping sections along the beam. The Reset button overrides any changes you make and internally recomputes the Beff based on the ACI code.

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General Operation / GO-27

©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

Stress Factors Dialog Box

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FIGURE GO-25. User Defined Effective Width of Topping Dialog Box

Note that the program internally adjusts the Beff value specified here by the user to handle opening information.

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Stress Factors Dialog Box

To define the stress factors, select the Use Factors check box and click the Edit Factors button on the Allowable Stress tab of the Design Parameters dialog box. Edit the values as required by the project parameters and click the OK button to accept the values and return to the Allowable Stress tab.

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FIGURE GO-26. Stress Factors Dialog Box (ACI 318-99)

GO-28 / General Operation ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Strand and Rebar Pattern Dialog Box

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FIGURE GO-27. Stress Factors Dialog Box (ACI 318-05)

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FIGURE GO-28. Stress Factors Dialog Box (CSA 23.3-94)

Note that the stress specified at the ends are considered for a distance of transfer length from the ends of the beams. For ACI 318-05, additional factors are specified to classify the section as uncracked, transition, or cracked. For CSA 23.3-94, the allowable tension factors are multiplied with

λ (the lightweight factor).

Strand and Rebar Pattern Dialog Box To modify or review strand and rebar data, click the Strand and Rebar button on the Design tab. The Strand and Rebar dialog displays. On this tab dialog, the Strand tab allows you to define strands. The Longitudinal Bars tab allows you to define rebars.

PRESTO®v8.6

General Operation / GO-29

©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

Strand and Rebar Pattern Dialog Box

The Stem Stirrups tab allows you to define shear reinforcement (vertical stirrups). The layout of these tabs are further dependent on section type of the beam being designed. For double tee sections, the program expects input of strands/rebars per web. For all other sections, the program expects total input. Therefore, you will see a somewhat different dialog while editing a double tee section and a different dialog for all other sections, as explained below.

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Strand Tab

The Strand tab allows you to define strand grid template, strand profile, and groups of strand with details of each group including strand heights, strand ID, debonding and pull.

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FIGURE GO-29. Strand Tab Showing Live Graphics

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GO-30 / General Operation ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Strand and Rebar Pattern Dialog Box

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FIGURE GO-30. Strand Tab Showing Template Definitions

The Strand tab displays two graphic areas (Figures GO-28, GO-29, GO-30,.and GO31). The left graphic area shows beam cross section and the right area shows beam elevation. These two graphics depend on the check box View Template with definitions. If you elect to check that box, template graphics are shown in which you can refer various inputs on this screen. However, when this box is unchecked, both views show live graphics. As you add or delete strand, they are shown graphically, in section and elevation. You can even use the scroll bar to see any section along beam length.

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General Operation / GO-31

©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

Strand and Rebar Pattern Dialog Box

FIGURE GO-31. Strand Tab for Double Tee Showing Live Graphics

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FIGURE GO-32. Strand Tab for Double Tee Showing Template Definitions

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Additionally you can either manually specify the strands or click Auto Design button and PRESTO will automatically design the strand pattern. For all sections other than Double Tee, you can define a grid for strand template and specify strands at the grid crossings. Update that before performing the generation of strands by performing the following steps:

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For sections other than Double Tee strands, perform the following steps: 1.

Specify the X-Axis Grid Definitions for strand template at ends for sections other than double tee.

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Example: if you want to specify location of first strand from left face of beam section at 3 inches and then five more possible locations as 2 inches, specify 1*3, 5*2.

2.

Specify the Y-Axis Grid Definitions.

This is the placement of strand layers (rows) with respect to the bottom of beam. If you want to place the first row at 2.5 inches from bottom and then four more rows at 2 inches, then specify 1*2.5, 4*2.

3.

Specify maximum number of strands that you want to provide in each layer. Use this value for sections such as Inverted Tee, I and L which allows many more strands in the bottom rows but fewer strand in the web. If you want to allow a maximum of six strands in layer 1, four strands in layer 2, and two strands in layers 3 through 6, specify 1*6, 1*4, and 4*2 in the Max Strands for Rows. At this point you can either do Auto Design or manually input strands.

GO-32 / General Operation ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Strand and Rebar Pattern Dialog Box

For a Double Tee section, perform the following steps: 1.

Select Strand Vertical Planes. By default program uses Single. When single is selected, program provides only one strand per web at any height. Select Double, or Triple if you have two or three strands at same height per web. (Check the box View Template to see the grid graphically)

2.

Specify spacing between Strand vertical planes. If the strand vertical planes field is set to single, this spacing is not used. However, when more than one vertical planes are used, specify their spacing.

3.

Y-Axis Grid definition. Specify the heights of possible strand layers from bottom.

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After specifying the data items explained above, you can either do Auto Design or manually input strands in any section I type. To generate the strand pattern, click the Auto Design button. To manually input the pattern, perform the following steps for any section. To manually specify strands, perform the following steps: 1.

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Select the strand profile.

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Choose one of the following options for strand profiles: •

One Point

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One Point Fixed

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Two Point Variable

•

Zero Point (straight)

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2.

Select if the strands profile at left and right ends are the same, or not.

3.

Specify strand profile distances A, B, C or D (whichever is applicable) for the selected profile.

4.

To add group of strands, click in the Strand Definition Grid in Column Left Row.

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Specify the row number in which to place the strand at left end of beam.

5.

Specify the debond distance from left end of beam for this group of strands.

6.

Specify the column numbers in which the strands are to be placed. Example: to specify strands in columns 2, 4, 5, and 7 of defined grid, type in 2, 4-5, 7 or 2, 4, 5, 7.

7.

Select the strand ID from the available list.

8.

Specify the pull ratio in the Pull column (default value is invoked from the library).

9.

Define mid debonding beginning location and ending location when unsymmetrical strands are provided. Specify only beginning locations when strand profile is symmetric.

PRESTO®v8.6

General Operation / GO-33

©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

Strand and Rebar Pattern Dialog Box

10. For strand profile when left profile is not the same as right profile, specify the Right Row where strands end. 11. For unsymmetrical profiles, also specify if there is any debonding at right. To add additional groups, repeat steps 4 through 11.

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Note that while using the Strand and Rebar screen, all of the grids feature a right mouse click menu. The menu includes the Insert, Delete, Cut, Copy and Paste for quick input of data in the grids. This menu is shown in Figure GO-34.

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FIGURE GO-33. Strand and Rebar Screen Grid Menu

Strand Tab Screen Terms •

X-Axis Grid Definition: X-Axis Grid Definition allows you to define column locations of the strand template grid from the left edge of the section. For example: 7*2 means there are seven columns with 2 inch spacing. First column is at 2 inches from the left edge of the section. The Second column is at 4 inches, and the seventh column is at 14 inches from the left edge of the section.

•

Y-Axis Grid Definition: Y-Axis Grid Definition allows you to define the row location of template grid of the section along Y-Axis. For example, 8*2 means eight rows along the y-axis. Therefore, the first row is at 2 inches from bottom, and the second row is at 4 inches, and eighth row is at 16 inches from the bottom. The measurements, 2*2,1*3,1*5 means there are four rows with previous first row at 2 inches from the bottom, second row is at 2 inches from the previous row, and the third row is at 3 inch spacing from previous row. Overall, this makes it 7 inches from the bottom and fourth row is 5 inches from previous row – making it 12 inches from the bottom.

•

Max Strands for Rows: Max Strands in Rows are used to determine the maximum number of strands allowed in rows. This is especially needed for Auto Design. Functionally it restricts the number of strands to a number which can actually be specified within a solid beam portion. This is useful for I, L and IT sections. For example, 3*6, 2*2, 2*1 means that for the first three rows six strands could be specified. For the next two rows only two strands could be specified, and for the last two rows only one strand may be placed.

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GO-34 / General Operation ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Strand and Rebar Pattern Dialog Box

•

Strand Profile: The four strand profiles available with Presto are as follows:

1. One Point: Enables you to define a strand profile with one depress point which is defined by A, C, and D definitions. The depress position A can either be a fixed distance or as a percentage of member length. The C and D definitions are optional distances. If pattern is symmetric, D is set equal to C by the program. This pattern is shown in Figure GO34.

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FIGURE GO-34. One Point

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2. One Point Fixed: Enables you to specify straight portion on sides of the depress position A. Definition B could be either a fixed distance or as percentage of member length. C and D are optional distances. If Left = Right option is set, program automatically sets D equal to C. See Figure GO-35 for this pattern.

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FIGURE GO-35. One Point Fixed

v E PRESTO®v8.6

General Operation / GO-35

©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

Strand and Rebar Pattern Dialog Box

3. Two Point Variable: Enables you to specify the depress position A and B as either as fix distances or as percentage of member length. You can also specify the vertical positions for each strand at A and B depress positions. Definition C and D are optional end distances. For symmetric patterns, B is set equal to A, and D is set equal to C as shown in Figure GO-36.

FIGURE GO-36. Two Point Variable

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4. Zero Point (Straight): Strands run straight between left and right end locations as shown in Figure GO-37.

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FIGURE GO-37. Zero Point (Straight)

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Right Pattern = Left Pattern: If yes is selected, then you only need to define the strands profile. The strands profile for half are assumed symmetric to the left half. If “no” is selected, then strand profiles need to be defined for left as well as right half.

•

Group: Group is a number (serial) which is automatically defined by the program – assigned to various group of strands. This is not an editable field. As you keep adding groups, the number keeps increasing.

•

Left Row: Row number in which the group of strands starts at the left end of the beam. Program then internally determines height. For example, if Y-Axis Grid Definition is 2*2, 1*3, 3*1.5 and you specify Left Row = 5, then program interprets that strands start in 5th grid row which is at 2x2 + 1x3 + 2x1.5 = 10 inches from the bottom of the section.

•

Right Row: Row number in which the group of strands ends at the right end of the beam. This field will only be available when Left strand pattern is not symmetric with right strand pattern.

GO-36 / General Operation ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Strand and Rebar Pattern Dialog Box

•

Left Debond: The debonded length of the strands at left end for a specific group. This distance is measured from the left end of the beam See Figure GO-38. Left Debond

Right Debond

FIGURE GO-38. Left and Right Debond

Right Debond: The debonded length of the strands at right end for a specific group. This distance is measured from the right end of the beam. If strands are symmetric on left and right, then this column does not appear and right debond is considered to be equal to left debond. See Figure GO-38.

•

Column List: Defines the column list in which the strands are present for current group. For example, if Column List = 1,3-5,6 means strands are defined to be present in columns 1,3,4,5, and 6 of the grid for current row.

•

Strand Id: Select any strand Id from the pull down list. Note, at this time, PRESTO allows only one strand ID to be used for all groups.

•

Pull: The initial jacking force of the strand expressed as a fraction of fpu (e.g., 0.70). Low relaxation strands are usually pulled to 0.75 and stressed relieved strands to 0.70. Note that you can override the value loaded in from the Prestressing Library. To permanently modify this value, select the Prestressing Library command from the Libraries menu and modify the appropriate strand. Refer to page GO-69 for information on using this library.

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PRESTO®v8.6

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Depress Height A: Defines the height of strand from the bottom of the section at distance A. For straight strands this column will not be available. For definition of A, refer to Strand Profile.

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Depress Height B: Defines the height of strand from the bottom of the section at distance B. For straight strands this column will not be available. For definition of B, refer to Strand Profile.

General Operation / GO-37

©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

Strand and Rebar Pattern Dialog Box

•

Mid Debond Begin: Distance from the left end of the beam to the start of midspan shielding. See Figure GO-39, “Mid Debond,” on page GO-38..

Mid Debond End

Mid Debond Begin

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Mid Span Debonding

FIGURE GO-39. Mid Debond

Mid Debond End: Distance from the right end of the beam to the start of midspan shielding. See Figure GO-39, “Mid Debond,” on page GO-38.

•

Auto Design: Clicking this button allows the program to automatically create the strand pattern. When the ACI 318-02 design code is selected, this design is based on the class selected in the Design Options tab located in the Design Parameters dialog box.

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Auto Debond: Clicking this button makes the program automatically generate an optimized debonding pattern. Only straight strands will be debonded.

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Design Status: Clicking this button opens the Design Results screen. PRESTO calculates the results and lists them in tabular format on the screen. Refer to Figure GO-47, “Design Results Screen,” on page GO-46 for information on using this screen

•

Strand Vertical Planes: The number of vertical planes for double T-Beam may be selected from the pull down menu. Available vertical planes are single, double, double staggered, Triple, and triple staggered.

•

Spacing Between Strand Vertical Planes: This dialog box allows you to define spacing between vertical planes.

•

Reset Button: Clears the entire grid/table on this screen, by deleting all rows of previously entered information.

GO-38 / General Operation ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Strand and Rebar Pattern Dialog Box

Longitudinal Bars Tab This screen allows you to specify different layers of mild reinforcement. To modify or review the rebar pattern information, click on Longitudinal Bars tab to display this screen as shown in Figure GO-40.

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FIGURE GO-40. Longitudinal Bars (For Sections Other Than Double Tee)

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To add rebar for sections other than double tee, specify rebar, Id, distance X and Y, Length Definition with distances, end hook conditions and position. You may add a new row by clicking in the last row.

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You may edit any information that you entered in the above screen at any time. To delete a row, highlight the row and press the delete key. See Figure GO-40.

v E PRESTO®v8.6

General Operation / GO-39

©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

Strand and Rebar Pattern Dialog Box

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FIGURE GO-41. Longitudinal Bars (For Double Tee Sections)

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You may edit any information that you entered in the above screen at any time. To delete a row, highlight the row and press the delete key. See Figure GO-41.

Longitudinal Bars Screen Terms

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Minimum Left End Clear Cover: Allows entering of Minimum clear cover at the left end of the beam. This applies only to full length bars.

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Minimum Right End Clear Cover: Allows entering of Minimum clear cover at the right end of the beam. This applies only to full length bars.

•

Quantity: (Applies to Double Tee section only). The number of bars in the current layer per web for double tee section.

For a Double Tee section: a. if rebars are in top flange, specify total rebars in flange. b. if rebars are in web, specify the rebars per web. •

Rebar ID: Selecting the arrow to the right of the list displays the list of the rebars currently in the Rebar Library. If a rebar is not in the list, you must add that rebar to the library by selecting the Rebar command from the Libraries menu.

•

Ht: (Applies to Double Tee section only) The height is measured from bottom of the member. Rebar may be placed anywhere within the composite

GO-40 / General Operation ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Strand and Rebar Pattern Dialog Box

section. No distinction as to whether a rebar level is in the precast or in the topping is required. Presto automatically detects the location of the rebar based on the assigned height and place that layer in the correct portion of the composite section (precast or topping). •

Reset Button: Clears the entire grid/table on this screen, by deleting all rows of previously entered information.

•

Length Definition: Rebar could be placed with any of the five length definitions available in the program as listed below.

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FIGURE GO-42. Two Point Variable Display

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1. Full Length: Bars with full length definition do not require any of the L, C, or D fields to be defined. However note that, when bars are defined this way, minimum left end clear cover and minimum right end clear cover are used to determine the actual starting and ending location of bar.

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2. Centered Length: Using this option, the user can place a rebar of specified length L which will be centered in the length of the member. For this case, C and D fields are not needed.

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•

3. Known L & C: User can specify a fixed length of rebar L which starts at location C from the left end of the beam by using this option. The field D is ignored in this case.

4. Known L & D: User can specify a fixed length of rebar L which ends at a location D from the right end of the beam by using this option. The filed C is ignored in this case.

5. Known C & D: By using this option, a user can specify a rebar which starts at a distance C from the left end, and ends at a distance D from right end. Position: This defines the outer corners of a cross section where the longitudinal bars will be placed. Every cross sections defined by PRESTO has a bottom left corner, bottom right corner, top left corner and top right corner. If you choose to place the bar at bottom left corner, x and y are measured from bottom left corner, and x is positive towards right, and y is positive up. If you choose to place the bar at top right, then x is measured positive towards left, and y is measured positive downwards. For that reason, X and Y may also be called as cover to bar center. Further, if you choose to specify the position as bottom left and right, program will place two bars.

General Operation / GO-41

©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

Strand and Rebar Pattern Dialog Box

First with reference to bottom left, and another with reference to bottom right. Finally, if you choose to use Bottom Top, Left Right, program will place four bars at bottom left, bottom right, top left, and top right corners. •

L (ft): This field is not editable for length definitions Full Length and known C & D. For the remaining Length definitions, option allows entering of length of bars.

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C (ft): This field is available for various definitions which allows you to specify distance from left end of the beam. Refer to Figure GO-40.

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D (ft): This field is available for various definitions and when available it allows you to specify distance from the right end of the beam. Refer to Figure GO-40.

•

Hook Start/End: These fields are for end anchorage selection. The end anchorage determines the required development length calculated as specified by ACI or CSA code. PRESTO automatically determines if rebar is in compression or tension and adjust the required development length accordingly. There are three choices available, Straight, hooked and mechanical.

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Options to Save, Load and Save As

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The top portion of the Strand and Rebar screen has buttons titled Save, Load and Save As. PRESTO now allows you to save or load either the strand pattern (along with the grid definitions), and/or the longitudinal rebar and/or the stirrups, rather than re-input this frequently used information across different files. The concept supports the notion that a user may define a strand pattern in the Strand Pattern tab and may wish to save this information for re-use in a different file. Currently the program will allow you to save this information as when working with any particular section type (for example, in a hollow core slab) and allows you to reload this information for a different section type (for example, in a flat slab).

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Each time the Save button or the Load button is clicked, PRESTO displays the dialog shown below, and allows you to set the specific parameters to be saved or loaded. You can choose to save only the strand patterns and the stirrups, and choose to ignore the longitudinal rebars. All of the information is saved in a file called pattern.spf. To delete certain predefined elements, you can edit the information in this file by directly editing it in Note Pad.

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FIGURE GO-43. Save Components dialog

GO-42 / General Operation ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Strand and Rebar Pattern Dialog Box

Stem Stirrups Tab This screen allows you to define shear reinforcement in the webs/stems of members. To input, modify or review the stem stirrup reinforcement information, click on the Stem Stirrups tab to display this screen as show in Fig. GO-43 and edit the information accordingly.

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FIGURE GO-44. Stem Stirrups (Shear Reinforcement)

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The top portion of this tab shows the definition views for both the elevation and section view of the stirrups. The details such as the stirrup parametrics (dimensions C1, C2, C3, C4, etc.) are necessary only when importing from BIM software such as Tekla Structures, and will be available within PRESTO only when working with such software. Alternatively, you can use the Auto Design button and let PRESTO generate a stirrup schedule automatically, based on the parameters selected in the dialog as shown below. After either inputting a stirrup pattern manually or generating a stirrup pattern using the auto generate feature, you can check the design status to make sure that area of shear steel provided is sufficient.

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v E PRESTO®v8.6

General Operation / GO-43

©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

Strand and Rebar Pattern Dialog Box

FIGURE GO-45. Design Stirrups Form

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Note: For Double-Tee beams, the information specified on this screen is per web and is automatically duplicated by the program to the other web.

Stem Stirrups Tab Screen Terms

Left Offset: Distance from the reference edge to the first stirrup.

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Right Offset: Distance from the right face of beam to the first stirrup.

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Stirrups: Number of stirrups. For Double-Tee this number represents the number of bars in one web.

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ID: Rebar ID. Selecting the arrow to the right of the list displays the list of the rebars currently in the Rebar Library. If a rebar is not in the list, you must add that rebar to the library by selecting the Rebar command from the Libraries menu.

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Spacing: Centre-to-centre spacing of the stirrups for the selected group.

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End Beam: Specify the reference edge of the beam for the selected group. Can be either left or right or both. When the option for both is selected, program will place the stirrups in two separate groups symmetrically from both ends.

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Paired: This is to accommodate the industry practice of using the same size bar, but effectively doubling the area of shear reinforcement by the use of double stirrups (or paired stirrups).

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Type: Select from the drop-down list showing different configurations (90 degree closed, 135 degree closed, open U, etc.). This selection will not make a difference in the analysis, but is used primarily for the data exchange with BIM software such as Tekla Structures.

GO-44 / General Operation ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Strand and Rebar Pattern Dialog Box

Stem Mesh Tab This screen allows you to define commonly used welded wire mesh reinforcement in the webs of members rather than specifying vertical shear reinforcement. PRESTO currently only considers the contribution of the vertical bars of the mesh towards the vertical shear reinforcement provided. To input, modify or review the stem mesh reinforcement information, click on the Stem Mesh tab to display the screen as show in Figure GO-46 and edit the information accordingly.

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FIGURE GO-46. Stem Mesh Tab

Note: For double-Tee beams, the information entered on this tab is per web and is automatically duplicated by the program to the other web.

v E PRESTO®v8.6

Note: Currently PRESTO version 8.6 does not support the transfer of stem mesh data in or out to BIM software such as Tekla Structures. Future version will support this information exchange.

Stem Mesh Tab Screen Terms •

Top Clearance: Distance of the top most longitudinal bar of the stem mesh measured from the top of the beam. Not used for engineering calculations; only for representation in drawings.

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Bottom Clearance: Distance of the lowest longitudinal bar of the stem mesh measured from the bottom of the beam. Not used for engineering calcuations; only for representation in drawings.

General Operation / GO-45

©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

Design Results Screen

•

Vertical Bar ID: Rebar ID for specifying the vertical bars of the mesh. Selecting the arrow to the right of the list displays the list of rebars currently in the Rebar library. If a rebar is not in the list, you must add that rebar to the library by selecting the Rebar Command from the libraries menu.

•

Vertical Bar Spacing: Center to center spacing of the vertical bars on the welded wire reinforcement mesh.

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Start: The dstance from the left end of beam to the first vertical bar of the mesh.

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End: The distance from the left end of beam to the last vertical bar of the mesh.

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Design Results Screen

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Clicking the Design Status button on the Design tab, or on the Strand and Rebar dialog will instantaneously have the program calculate and list the results in tabular format. The table shows a summary of stresses, ultimate moment calculations, shear design, and camber and deflection results for the beam using the currently entered number of strands and rebar. Quantities that have exceeded the limiting stress values or do not provide sufficient strength are marked with asterisks for quick identification. Use the Stage drop-down list to see the results for service checks or ultimate strength.

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FIGURE GO-47. Design Results Screen

You can print the results by clicking the Print button. Click the Cancel button to close this screen and return to the Design tab or click the X in the top right corner of the screen.

GO-46 / General Operation ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Drawing Print Dialog Box

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FIGURE GO-48. Enhanced Report View

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The standard report view is a simple text file. However, the enhanced report view is a HTML file with enhanced functionality. It shows any violations not only with an asterisk but also in red color for the text, and highlighted with yellow color to bring your attention to the problem area. The enhanced report can be saved by clicking on Save As. Other options include Page Setup, Print Preview and Print. Figure GO-48 shows a sample enhanced report dialog.

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Drawing Print Dialog Box

PRESTO allows you to print the drawing displayed in the Design tab. Click the Drawing button on the Design tab to open the Drawing Print dialog box. Select from

the options to Print c/s (cross section) or Print Elevation or Export to AutoCad DXF file option. Click the OK button to accept the choice. When the Print options are selected, the program will first show the image in an enhanced report viewer format; from there you can choose to print, print/preview or even save as an HTML file with embedded images.

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FIGURE GO-49. Drawing Print Dialog Box

PRESTO®v8.6

General Operation / GO-47

©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

Using PRESTO from Within Tekla Structures

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FIGURE GO-50. Sample Output Showing C/S

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Using PRESTO from Within Tekla Structures PRESTO can design and/or check prestressed precast beams defined and detailed in Tekla Structures. PRESTO in this operation provides design or check of rectangular,

inverted tee, ledge and double tee sections.

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PRESTO works in two modes when activated from within Tekla Structures:

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Design Mode: If there is no reinforcement present in the beam, you can design the beams in PRESTO and then transfer reinforcement back into Tekla Structures.

2.

Check Mode: If you have already detailed a beam and want to check its adequacy, you can transfer the member and reinforcement data from Tekla Structures to PRESTO and then check if it satisfies all the design checks per selected code. In this process, if you revise the reinforcement, that will be updated back in the Tekla Structures beam.

If a design check of any beams by PRESTO is desired from within Tekla Structures, you should first detail the section using macro plug-in number 51, 52, 53, or 54. Refer

GO-48 / General Operation ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Using PRESTO from Within Tekla Structures

to Figure GO-51 to view tool bar for plug-in icons located on the right side of the Tekla Structures with Beam Plug-ins Icons screen.

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FIGURE GO-51. Tekla Structures with Beam Plug-in Icons

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In order for you to use PRESTO from within Tekla Structures, you need concrete detailing versions of Tekla Structures. Note, you also need to install PRESTO components to work with Tekla Structures during installation process. Refer to Figure GS-6 for more information on installation of PRESTO for Tekla Structures. To design a beam in PRESTO from within Tekla Structures, perform the following steps:

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Detail a beam with beam plug-ins number 51, 52, 53, or 54.

2.

Scroll plug-ins page by using directional arrows until PRESTO icon displays as shown in Figure GO-52.

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v E PRESTO®v8.6

General Operation / GO-49

©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

Using PRESTO from Within Tekla Structures

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FIGURE GO-52. Tekla Structures with PRESTO Plug-in Icon

3.

Click the PRESTO icon.

4.

Select the beam you want to design (select only one beam).

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PRESTO will start and display beam length, cross-section type,

topping data, flange opening information and cross-section dimensions as passed from Tekla Structures for the selected member..

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FIGURE GO-53. Member Info Tab when PRESTO is Called from Tekla Structures

GO-50 / General Operation ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Using PRESTO from Within Tekla Structures

Note: Certain items in PRESTO are not enabled for editing purposes when called from within Tekla Structures.This ensures that data integrity remains intact. For this reason when PRESTO is activated from within Tekla Structures, the File menu, Open and New selections are disabled. In addition, on the Member Info tab, beam length, beam cross-section type and beam ID are also unavailable.

5.

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To verify section/beam data has transferred from Tekla Structures, click the Show Image button as sown below in Figure GO-54.

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FIGURE GO-54. Double Tee Beam Information Passed from Tekla Structures

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General Operation / GO-51

©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

Using PRESTO from Within Tekla Structures

6.

If you wish to view section details, click the Libraries: Beam Sections, and select beam type passed from Tekla Structures. Section ID displays for beam name. Refer to Figure GO-55.

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FIGURE GO-55. Section Details for the Section Passed from Tekla Structures

7.

Upon verification of section/beam data, you can modify any other data items on the Member Info tab. Refer to GO-3 for more information.

8.

Once geometry is verified, switch to the Materials tab to edit information for beam material data. Refer to page GO-8 for more information on using the Materials tab.

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Access the Load tab to define loads.

10. Access the Analysis tab and execute required analysis for section/beam data. Refer to page GO-13 for more information on the Analysis tab.

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11. Access the Design tab and review design parameters.Then access the Strand and Rebar dialog. Check design status and make revisions to the strand, longitudinal bar and stirrup information. Refer to page GO-16 regarding the Design tab. Note that you will see the strand ID defined in the Tekla catalog. For strand, select the strand ID. For rebar, select the rebar ID correctly based on steel type and strength. Refer to page GO-30 for information on using the Strand and Rebar dialog.

GO-52 / General Operation ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Using PRESTO from Within Tekla Structures

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FIGURE GO-56. Strand and Rebar Tab for Double Tee Section

12. After you finalize the strand and rebar pattern, close the program by selecting File exit. At this point, PRESTO will ask you if you want to update the pattern in Tekla Structures. Select Yes to update, or no to discard the pattern.

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FIGURE GO-57. Update Strand/Rebar Pattern for Beam in Tekla Structures

General Operation / GO-53

©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

Program Menu Commands

Program Menu Commands PRESTO comes with a large collection of timesaving commands and functions. Please

make yourself familiar with these features in order to maximize your ability to take advantage of PRESTO’s many features.

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File Menu File | New

This command clears the workspace and prepares PRESTO for a new project. If there is a file with new data in the workspace when you select the New command, a warning message appears and asks if any current changes in the file are to be saved. Selecting Yes will save the existing data. You must supply a file name of your choice, if the file was not previously saved.

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FIGURE GO-58. File | New

File | Open

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FIGURE GO-59. File | Open

GO-54 / General Operation ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

File Menu

If there is existing data in the workspace when you select the Open command, a message appears and asks if you would like to save your latest changes to the existing file in the workspace. Click Yes to save the data. Supply a file name of your choice if requested. Click No to open the data without saving current data. If you are an existing user, you can import your old data files (*.prt) from a previous version of the program and old DOS data files (*.prs) from version 7.x. To select a file type, click the arrow to the right of the Files of Type drop-down list. You will see a list of the available file types. Click the type you want.

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File | Save

This command saves the existing project using the current name. No warnings will be issued from this command. This command is useful for quickly saving intermediate steps during a work session.

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If the data is not saved using the Save As command first, the file will not have a specified name and the Save command will (by default) name the file UNTITLED.prt. In this case, the user will be asked for a file name to save the data under a different name.

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File | Save As

The Save As command allows you to rename a project file and save it under a new name. The previous data file will be retained under the original name.

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File Menu

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FIGURE GO-60. File | Save As

You can save the file by selecting the appropriate drive and directory and then entering a file name. Select Save to save the file under the new name. Select Cancel to cancel the file saving and return to the program.

File | Save Setting The Save Setting command allows you to save current data as default data, and is especially useful when performing repetitious designs with only a small amount of input variation. This command will save the current member and material information and the next time the program is started or File | New is selected, these previously saved

PRESTO®v8.6

General Operation / GO-55

©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

File Menu

settings will exist as defaults. These values are stored in a default file specified under the Show | Preferences option. For multiple projects, you can have multiple setting files created and then select the desired setting using the Show | Preferences option.

File | Print The Print command allows the printing of project data and the result summary, as shown in the following figure. The user can choose to view the results on-screen, send it to the printer, or print to a file. Also, the user can select specific parts of the results or input data to print.

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FIGURE GO-61. File | Print

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Checking the option for Enhanced Report will produce the output in the HTML format as shown in Figure GO-48.

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GO-56 / General Operation ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

File Menu

File | Print Setup Selecting the Print Setup command opens the Print Setup screen. The options presented in this screen can be changed to recognize the printers installed in the operating system.

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FIGURE GO-62. File | Print Setup

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Different printers or plotters can be selected from this screen. Once the output device is selected, the Properties option can be used to configure the selected output device. A typical setup for a HP LaserJet printer is illustrated.

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For detailed information about configuring printers or plotters, refer to the appropriate documentation for your printer.

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v E PRESTO®v8.6

General Operation / GO-57

©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

File | Security The Security command opens the LEAP Software Security screen. This screen gives the user access to PRESTO’s built-in electronic security. Here, you can transfer authorization to different directories or computers, and also kill an existing license. One valuable feature on this screen is the Security Dir. tab. This option allows the user to install the program on a local computer but use the security from another directory, usually from a network. Selecting this option allows you to have multiple users, without diminishing server or network speed. For detailed information about LEAP Software Security, please refer to the Getting Started chapter.

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FIGURE GO-63. File | Security

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File | Exit

The Exit command exits PRESTO. If there is any data not saved, the program displays a message asking if you want to save before exiting.

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v E GO-58 /

©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Show Menu

Show Menu Show | Image Selecting the Image command from the Show menu or selecting its respective icon opens the Image screen as shown below.

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FIGURE GO-64. Show | Image

A three-dimensional image of the member, along with any topping, flange openings, or support conditions is displayed in this screen. This image can be seen after the input data for the Member Info tab is completed. The control buttons on the left side of the Image screen are explained below.

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Image Button Summaries

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Rotate. This button allows you to rotate the view. After selecting this icon, you must simply bring the mouse pointer anywhere within the image area. Hold down the left mouse button while dragging the pointer. The image regenerates as you move the pointer.

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Zoom-In. This button allows you to zoom in on a part of the image. After clicking this icon, you must select the area to enlarge by holding down the left mouse button, and then dragging the pointer over the part to be enlarged. While dragging the mouse pointer, a selection will be defined. Release of the button completes the task, and the selected part of the image appears magnified. Zoom-Out. This button allows you to zoom out. As with the zoom-in feature, select an area to zoom out of by holding down the left mouse button, and then dragging the pointer over the part to be reduced. Release of the button completes the task, and the selected part of the image appears reduced. Pan. This button allows you to pan the image. After selecting this button, you can then place the pointer anywhere in the image, hold down the left mouse button, and then drag the pointer in order to pan the view.

PRESTO®v8.6 ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ GO-59

Show Menu

Reset. This button allows you to reset the image. If you have “zoomed-in” on a part of the image, for example, clicking this button restores the image to its original size and location. Print. This button allows you to print the image. Selecting this button sends the view to the default printer. Note, however, that PRESTO prints in a “WYSIWYG” format. That is, if the image appears “zoomed-in” on your monitor, then it prints as shown on the monitor, enlarged.

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Front View. This button allows you to view the image from the front. By default, this screen opens to a side view of the section. Clicking this button rotates the image 90 degrees.

Show | Model

Selecting the Model command from the Show menu or selecting its respective icon opens the Model screen.

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FIGURE GO-65. Show | Model

The FEM model generated internally for the analysis appears in this screen. To view the node and/or member numbers, select the appropriate check boxes on the top part of this screen. The control buttons located on the left of this screen perform the same actions as described in the Image Button Summaries located on page GO-59.

Show | Results

This menu command displays the results in tabular format, and is accessible by selecting the Results command from the Show menu or by its respective icon. After selecting this menu item, you may view specific beam design results.

GO-60 / ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Show Menu

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FIGURE GO-66. Show | Results

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The results available can be selected, from either Service or Ultimate stage, from the Type drop-down list. Any of the results displayed on this screen can be printed individually by selecting the Print button. If this button is selected, the printout will be sent to the default printer without any other prompt. To close the Results screen, click the X located at the top right hand corner of the results display.

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Show | Diagrams

This menu command displays the results in graphical format and is accessible from the Show menu or selecting its respective icon. After selecting this menu item, the display requires you to select specific information from the Stage, Case, Type, and Factor dropdown lists to view the graphics. After the analysis is complete, Moment and Shear diagrams are available. Stress results in graphical format are only available after either rebar or strands have been specified by selecting the Design option.

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FIGURE GO-67. Show | Diagram

PRESTO®v8.6 ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ GO-61

Libraries Menu

Any of the diagrams displayed on this screen can be printed individually by selecting the Print button. If this button is selected, the printout will be sent to the default printer without any other prompt. NOTE: PRESTO prints in a “WYSIWYG” format. That is, the image prints exactly as shown on the monitor.

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Show | Preferences

Selecting the Preferences command from the Show menu opens the Preferences dialog box. Here, the user can specify a default file name and default directory. Any previously saved settings will be stored in this specified default file, such as member and material information. For more information on saving settings, see File | Save Setting on page GO-55. The default directory is the location where your data files and libraries are saved automatically.

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FIGURE GO-68. Show | Preferences

The Enhanced Design Status option allows you to choose the format of the reports showing the Design Status screen.

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The option Auto Run analysis if needed by Design Tab page allows you to directly skip over to the Design tab once the geometry information is complete, instead of explictly clicking the Run Analysis button the Analysis tab.

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Libraries Menu

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Commonly used data is grouped in PRESTO in the form of Libraries. Libraries are used to store data that does not change often and is to be used repeatedly across projects. The three library types used in PRESTO are Beam Sections, Prestressing Tendons, and Rebar, all of which store information as suggested by their titles. Each library type can contain a number of different files (for example, section files can be named default.pr1, LEAP.pr1 etc.) and each file can have a number of items (for example STANDARD-I, STANDARD-II etc.).

PRESTO includes a set of default libraries namely default.pr1, default.pr2 and

default.pr3. Most users may find it convenient to work with a single file for each library type, modifying, adding and deleting items in these files rather than creating and setting up different library files for the same library type.

GO-62 / ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Libraries Menu

Libraries | Setup The Setup command opens the Library Setup dialog box. Here, the user can select the specific library files to be used as program defaults, for each of the three library types (Beam Sections, Prestressing, and Rebar). Once the libraries have been set up in this screen, PRESTO keeps the library setup selections in the computer registry, and the next time the program is started, it automatically loads the appropriate files.

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FIGURE GO-69. Libraries | Setup

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Different library files can be created for the different library types from the Libraries | Beam Sections, Libraries | Prestressing, and Libraries | Rebar menus, as explained in the following sections.

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Libraries | Beam Sections

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This command is used to access Beam entries in the library file currently loaded. To view the contents of this library, select Beam Sections from the Libraries menu or from its respective icon. The sections listed upon opening this screen correspond to the currently loaded section library file (*.pr1) selected under Libraries | Setup. To load a different library file, you must use the Libraries | Setup menu.

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FIGURE GO-70. Libraries | Beam Sections

PRESTO®v8.6 ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ GO-63

Libraries Menu

Note that a list of predefined section types appear on the left of the Beam Sections Library. These sections are standard sections, and although you cannot add a new type, you can add to or modify an item in the list. The beam types are used by the program to automatically identify various specific design and code criteria. To add or modify an item, highlight the section type from the list on the Beam Sections Library and click the Add button. When the appropriate Section Detail dialog box appears, fill in the data for ID, Description, and dimensions. Note that each item ID must be unique (i.e., you cannot have two double-T beams with an ID of 12DT24).

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FIGURE GO-71. Section Detail Dialog Box (Double Tee)

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Notice the three options under Section Properties: User Input, Dimensions, and Drawing. You can enter your own values for center of gravity, area, moment of inertia and vol/ area by selecting the User Input option. For hollow cores, this option also allows users to specify the top and bottom flange thickness and web thickness to be used in design calculations. If you select the Dimensions option, the program calculates the section properties based on the section dimensions entered above. (Note that the fields under Section Properties will be unavailable.) The third option, Drawing, allows you to draw your own beam section, as explained in the following section. In this case, the program computes the section properties based on the drawing. Note that, in any case, the user must enter some dimensions, regardless of the option selected for computing section properties. These dimensions are used for various engineering calculations by the program. To better understand this feature, we recommend experimenting using all three options offered. You will quickly observe the differences between each option. The Volume/Surface Area ratio is used in the computation of losses and is computed as the ratio of the cross sectional area of the member divided by the perimeter of the beam.

GO-64 / ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Libraries Menu

Drawing the Beam Section Click the Edit button on the Section Detail dialog box to open the Section Drawing screen, as shown below. Use the control buttons on the left of the screen to define your own beam section. If you move the mouse over these control buttons, a description of the button displays in the status bar at the bottom of the screen.

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FIGURE GO-72. Section Drawing Screen

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The control buttons on the left side of the Section Drawing screen are explained below. Return and Update. This button accepts the section drawing and returns to the Section Detail dialog box.

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Drawing Properties Settings. This button allows you to edit the drawing limits, grid and snap settings. This button opens the Drawing Properties dialog box. Enter the desired information and click the OK button. Add New Polygon. This button starts the mode to draw polygons composed of straight lines. Click the left mouse button to add sides; a node will appear. Right-click on the last node to close the drawing. Add New Circle. This button allows you to add a circle to your drawing. First, click the location where you want the center of the circle. Move the mouse until the desired circular radius is reached and click again. The Circular Section dialog box displays; modify the values if desired and click the OK button. The circle will be added to the drawing. If a circle is drawn completely inside another polygon, then it is treated as a cut-out (or hollow). Add Nodes. This button allows you to add nodes to the polygon. When you click this button, all the nodes that comprise the polygon and circles become visible. To add

PRESTO®v8.6 ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ GO-65

Libraries Menu

additional nodes, click anywhere on any polygon edge (between two nodes). Note that to add a new point between two existing points, both existing points must be visible on the screen. You can zoom in, zoom out, or expand the size of the drawing editor window. To add a node between existing nodes, make sure you can see both nodes on the screen.

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Delete Nodes. This button allows you to delete a node on the polygon or entire circle. Selecting this button displays all the composing nodes. Click any node on the polygon to delete that node. Click any node on the circle to delete the entire circle.

Modify Nodes. Click this button to modify the shape of the polygon. Clicking this button displays all the composing nodes for the polygon. To move a node, drag any node to another location. Click on a node and move the mouse without releasing the mouse button. Move to desired location and release the left mouse button. Show Vertex. Click this button to display a list of vertices in a tabular format. You can modify the X and Y coordinate values for any node if desired.

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Fillet. Selecting this button displays all the nodes that compose the polygon and circles. If you click any node in the corner of the polygon, a dialog box displays that allows you to select if the fillet is Chamfer or Fillet. You can also edit the fillet dimensions in this dialog box. Click the OK button to accept any changes and return to the drawing.

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Zoom-In. This button allows you to zoom in on a part of the drawing. After clicking this button, you must select the area to enlarge by holding down the left mouse button, and then dragging the pointer over the part to be enlarged. While dragging the mouse pointer, a selection will be defined. Release of the button completes the task, and the selected part of the image appears magnified.

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Zoom-Out. This button allows you to zoom out. As with the zoom-in feature, select an area to zoom out of by holding down the left mouse button, and then dragging the pointer over the part to be reduced. Release of the button completes the task, and the selected part of the image appears reduced.

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Pan. This button allows you to pan the image. After selecting this button, you can then place the pointer anywhere in the image, hold down the left mouse button, and then drag the pointer in order to pan the view.

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First, click the Drawing Properties button to specify the type of grid, spacing, and color, drawing limits, and snap dimensions. This opens the Drawing Properties dialog box.

GO-66 / ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Libraries Menu

FIGURE GO-73. Drawing Properties Dialog Box

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For example, if the grid has 25 units in the X direction and 25 units in the Y direction, enter “25” in the X and Y fields under Grids. Select the Active check box. You can also specify the type of gridline and color you want. Next, if the overall size of the section is 500in × 600in, the drawing limits in the X direction are (-250, 250) and in the Y direction, (0,600). Therefore, enter “–250” in the Min X field and “250” in the Max X field and enter “0” in the Min Y field and “600” in the Max Y field. Under Snap, select a useful snap spacing. Generally this number is a small common denominator of the drawing dimensions. For this example, the snap spacing is 10in. Enter “10” in the X and Y field and select the Active check box. Click the OK button and return to the Drawing Properties dialog box. Notice that the grid with your grid selections will be displayed in the drawing area.

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Now you can start to draw the section beam. Select the Add New Polygon button. Move the cursor inside the drawing area and click the left mouse button to click the starting point. This will be the first node. Although any starting point can be selected, do not select a starting point that will force the drawing outside the drawing limits. Move the mouse across to the next location and click again. This creates the first edge of the section (and also the second point). Next, move to the third point and click to create the second edge. Repeat this until all points and edges have been entered and the drawing is complete. Right-click on the last node to close the drawing; it will fill in the drawing with color. To show the nodes on the drawing, click the Add Nodes button. Note that to be able to add a new point between two existing points, both existing points must be visible on the screen. You can zoom in or zoom out or expand the size of the drawing editor window.

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You can insert a circle in your drawing by clicking the Add New Circle button. Move the cursor to where you want the center of the circle and click the left mouse button. Move the mouse until the desired circular radius is reached and click the left mouse button again. The Circular Section dialog box displays. Modify the values if desired and click the OK button to return to the Section Drawing screen. The drawing will be changed to show the circle you just created.

PRESTO®v8.6 ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ GO-67

Libraries Menu

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FIGURE GO-74. Circular Section Dialog Box

When you have completed your drawing, click the Return and Update button to return to the Section Detail dialog box.

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Click the Template button to open the Template dialog box, as shown below. This screen shows all possible locations where strands may be placed. Enter the values for height and the maximum number of strands allowed at that height. The height of the strands is measured from the bottom at the end of the beam. Remember that you are not entering the strand pattern here, but only the possible locations where strands may be located, used by the program in the auto-strand generation module in the Strand Pattern dialog box. It might help to visualize this template as the end beam template used in the casting yard by the fabricator to place the prestressing tendons.

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FIGURE GO-75. Template Dialog Box

The program can also generate the Strand template automatically, by clicking Auto Generate button in the Template dialog box to open the Template Auto Generation dialog box, as shown in the following figure.

GO-68 / ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Libraries Menu

FIGURE GO-76. Template Auto Generation Dialog Box

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NOTE: If the template data already displays on the Template dialog box, then clicking the Auto Generate button will lead to the appearance of a warning message, “Existing template will be erased. Do you wish to continue?” Selecting Yes will result in the deletion of any existing template data and enable the user to enter a few key parameters in the Template Auto Generation dialog box. To prevent this message from appearing, click the Clear All button prior to the Auto Generate button.

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In the Template Auto Generation dialog box, four parameters to be entered are: Distance from bottom to the first Row, Distance between Rows, Min. distance from the last Row to top, and Number of strands per Row. After entering the data for these four parameters, click the Generate button to perform the template generation. After the template automatically generates, the data can still be edited on the Template dialog box by using the Add, Delete, and Modify buttons.

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Click the OK button to close the Template dialog box and return to the Section Detail dialog box.

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When you are satisfied with the section data, click the OK button and return to the Beam Sections Library. Notice that the ID and Description for the section you created appears in the Items list. Click the Save button to save the newly created section in the currently loaded library (or you can also save it under a different name by selecting Save As). At this stage you will get a message informing you that the beam section has been saved to the library. To modify an existing item in the list, highlight it and click the Modify button to edit the values. To delete existing items, highlight the item in the list and click the Delete button. Now that the section file has been saved, click the Close button to close the screen and end this procedure.

Libraries | Prestressing This menu command is used to access the strand values in the library file. To view the contents of this library, select Prestressing from the Libraries menu or its corresponding icon, and the Prestressing Tendon Library displays. The strands listed upon opening

PRESTO®v8.6 ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ GO-69

Libraries Menu

this menu correspond to the currently loaded strand library file (*.pr2) selected under the Libraries | Setup option. To load a different library file, you must use the Libraries | Setup option.

FIGURE GO-77. Libraries | Prestressing

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PRESTO is released with a set of predefined tendon IDs. To add a tendon to a library,

select a tendon ID from the ID drop-down list, or type in a new ID, a type from the Type drop-down list (Stress Relieved or Low Relaxation), and enter the values for specified tensile strength (fpu) of prestressing steel, the Jacking multiplier, the modulus of elasticity (ES), and the diameter (d). PRESTO automatically calculates the strand area; however, you can edit this value. Click the Add button to add the tendon to the list. To save the newly created section in the currently loaded library, click the Save button. Click the Save As button if you want to save it under a different library file. A message will display verifying that the tendon has been saved to the library. Once the prestressing tendon file has been saved, click the Close button to close the screen and end this procedure.

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Libraries | Rebar

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The Rebar command is used to access the reinforcement values in the library file. To view the contents of this library, select the Rebar command from the Libraries menu or its corresponding icon. The reinforcement listed upon opening this screen corresponds to the currently loaded reinforcement bar library file (*.pr3) selected under Libraries | Setup.

GO-70 / ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Libraries Menu

FIGURE GO-78. Libraries | Rebar

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Libraries | Convert from v. 7

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This menu item allows you to convert the section libraries from earlier versions of PRESTO (v7.1 or higher) into a version 8.x format. Select the Convert option from the Libraries menu to open the Convert Libraries from v.7 dialog box, as shown below. Click the Browse button to locate the path and file names, or type in the desired path and file name in the text boxes and then click the Convert button. After the library is converted, you can select to use it by following the procedures outlined in Libraries | Setup section.

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FIGURE GO-79. Libraries | Convert from v.7

PRESTO®v8.6 ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ GO-71

Help Menu

Help Menu Help | Contents This menu item opens the Help file, which lists the items contained in PRESTO Online Help. You may select an item to display the information associated with that item.

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Help | User Manual

This menu item opens PRESTO’s User Manual in pdf format. You must have Adobe Reader installed on your system.

Help | Search for Help on

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This menu item opens PRESTO’s Help search engine. You simply type in the topic(s) to search for information on, and the Help program will compile a listing of the matches it finds. Selecting an item displays the associated information.

Help | How to Use Help

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Help | Visit LEAP Web Site

If you have Internet access, selecting this menu item open the dial-up feature, loads your browser, and directs you to LEAP’s Web site. Check this site frequently for important program updates, news, technical support questions, and more.

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Help | About PRESTO

This menu item lists the general information, a disclaimer on the PRESTO program, as well as the computer’s physical memory.

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Help | Tech Support

This menu items shows you helpful information regarding LEAP technical support.

Help | Check for Updates

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This menu item allows you to check (via the Internet) if a new version of the software is available.

GO-72 / ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

CHAPTER FOUR

Tutorial Session

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This chapter consists of a tutorial introduction for PRESTO. This tutorial is designed to familiarize users with PRESTO’s capabilities through a “handson” approach. This tutorial takes you through the entire design session, screen by screen, demonstrating the basic operation of the program. To assist you in completing this tutorial, we have included the output generated by the program.

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©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

T-1

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THIS PAGE INTENTIONALLY LEFT BLANK.

T-2 / Tutorial Session ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

TUTORIAL SESSION

Design of a 8DT24 Double Tee

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This tutorial takes you through a typical start-to-finish prestressed beam design, step-by-step. In this tutorial, We recommend that you run this tutorial problem before starting a design of your own. We will be using a standard PCI 8DT24 double tee.

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The information for this tutorial is contained in an input file called “Tutor1.prt.” As an alternative to entering all the information from scratch, as directed in this tutorial, you can load this file and only work on the sections you wish. To load this file, select the Open command from the File menu. Browse to the PRESTO/Examples subdirectory, if it is not already showing, and select the file “Tutor1.prt.”

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©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

T-3

Problem Data

SD , LL

0 .5 "

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.5 "

50'

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3.75" 2 @ 16" 2 @ 14"

2 @ 4" 2 @ 2"

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E n d P a tte rn

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Problem Data Concrete

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2 2 2 2

@ @ @ @

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24" 26"

2"

2"

96" 5.75"

3 .5 " 3" 2 .5 " 2"

M id P a t t e r n

FIGURE T-1. Strand Pattern

Unit Weight

=

150 pcf

f'c

=

5500 psi

f'ci

=

4500 psi

Unit Weight

=

150 pcf

f'c

=

3000 psi

Topping

T-4 / ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Step 1: Start of Tutorial

Thickness From 0 to 14

=

2 in

From 20.5 to 50

=

2 in

Type

=

Low relaxation

fpu

=

270 ksi

Pull

=

75%

Profile

=

1 pt depressed

Strand

Opening Data Rectangular: 1' × 2', @ 15' from left end + 1' offset Circular: 2' diameter, @ 20' from left end - 1' offset

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Loads Dead Load

=

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10 psf

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Live Load

Step 1: Start of Tutorial

=

50 psf

Start PRESTO as you would any other application using Microsoft Windows. By default, the program installs in Programs > LEAP Software > PRESTO. To open, click the Start button, select Programs, then LEAP Software, and then select PRESTO.

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When PRESTO splash screen appears, click the START button to clear the screen and view the Project tab.

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FIGURE T-2. PRESTO Splash Screen

PRESTO®v8.6 ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ T-5

Step 2: Complete the Project Information

Step 2: Complete the Project Information The Project tab allows you to enter general information about the project. You can return to this tab at any time and make changes.

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FIGURE T-3. Project Tab

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Enter in the general information in the text boxes, as shown in the figure above. Select US (English) under Units and Prestressed (w or w/o rebar) under Design Options and select the Design Code as ACI 318-99.

Step 3: Define the Member Information

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Click the Member Info tab to access the appropriate screen. Enter “50” in the Length field and select Double Tee from the Beam Type drop-down list, as shown in the figure below.

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FIGURE T-4. Member Info Tab

T-6 / ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Step 3: Define the Member Information

For this tutorial, you want to use the section 8DT24; however, this is not available in the Section ID drop-down list. You will need to add this section to the library, as follows.

Beam Sections Library Select the Beam Sections option from Libraries menu. The Beam Sections Library displays, as shown in the figure below. Highlight Double Tee under Type and click the Add button.

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FIGURE T-5. Beam Sections Library

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Section Detail Dialog Box

When the Section Detail dialog box displays, enter the values as shown below. Under Calculation based on, select the Dimensions option. This allows the program to automatically calculate the section properties based on the dimensions of the cross-section specified above. Notice that the text boxes under Section Properties become unavailable.

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FIGURE T-6. Section Detail Dialog Box (Double Tee)

PRESTO®v8.6 ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ T-7

Step 3: Define the Member Information

Template Dialog Box Click the Template button to activate the Template dialog box, as shown in the following figure. Enter “2” in the Height field and “2” in the # of Strands field (for maximum number of strands at that height). Click the Add button. It will appear in the list on the screen. Repeat this for the remaining strands. Click the OK button when finished.

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FIGURE T-7. Template Dialog Box

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Beam Sections Library

Click the OK button again to return to the Beam Sections Library. Notice that the section 8DT24 appears in the list under Items, as shown below. Click the Save button to save the section to the library. A message will display confirming that the section has been saved to the library; click the OK button to close this window. Click the Close button to exit the Beam Sections Library and return to the Member Info tab.

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FIGURE T-8. Beam Sections Library (Showing New Section 8DT24)

Member Info Tab Now you can select 8DT24 from the Section ID drop-down list. Continue entering the rest of the data, as shown in the following figure. To define the

T-8 / ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Step 3: Define the Member Information

topping, enter “2” in the Thickness field and “14” in the Length field. Click the Add button and it will appear in the list under Topping. Repeat this for the remaining two topping sections. Also change the Final Support locations to be “0.5” ft from each end. Enter “96” in the Topping Slab Width field (the same as the top flange width of the Double Tee).

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FIGURE T-9. Member Info Tab

Opening Data Dialog Box

Now, click the Flange Opening button to activate the Opening Data dialog box, as shown in the following figure.

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FIGURE T-10. Opening Data Dialog Box

Here, you will define one rectangular opening and one circular opening, as follows. Select Rectangular from the Opening Type drop-down list. Then, enter “1” in the bo field, “2” in the lo field, “15” in the f1 field, and “1” in the f2 field. Click the Add button. Notice that it will appear in the list. Repeat the above

PRESTO®v8.6 ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ T-9

Step 3: Define the Member Information

steps to define the circular opening as shown in the figure. Click the OK button and return to the Member Info tab.

Image Screen Select Image from the Show menu to activate the Image screen. You will see a 3-D image of the structure, as shown below. Use the buttons on the left side of the screen to manipulate your view of the image. Experiment with the buttons to become familiar with their functions. Once you have become familiar with this screen, close or minimize the screen to return to the Member Info tab. Note that on any screen in the program, you can press F1 to get context-sensitive help.

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NOTE: You will need to use the Rotate button in order to see the view shown here.

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FIGURE T-11. Show | Image

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©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Step 4: Define the Material Properties

Step 4: Define the Material Properties Click the Materials tab to activate the appropriate screen. Select 1/2-270K-LL from the Prestressing Tendon ID drop-down list and enter “0.75” in the Initial jacking coefficient field.

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FIGURE T-12. Materials Tab

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Continue entering the rest of the data as shown above. Note that PRESTO will automatically calculate the elasticity.

Step 5: Define the Loads

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Click the Loads tab to access the appropriate screen. Since PRESTO automatically calculated the self-weight and topping, you only need to define the external loads. For this tutorial, you will enter a Superimposed Dead Load on Composite (SDL) with a magnitude of 0.01 ksf from 0 ft to 50.0 ft.

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FIGURE T-13. Loads Tab

PRESTO®v8.6 ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ T-11

Step 6: Run the Analysis

Select UNI from the Type drop-down list and SD from the Class drop-down list. Enter “0.01” in the Mag field, “0” in the Loc field, “0.01” in the Mag field, and “50” in the Loc field. Click the Add button. The load will appear in the list. Repeat this to add the second load, as shown above.

Step 6: Run the Analysis

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Load Factors Dialog Box

Click the Analysis tab to activate the appropriate screen. PRESTO allows you to modify or review the default load factors by clicking the Load Factors button to activate Load Factors dialog box, as shown below. Click the OK button to accept any changes. Clicking the Cancel button will return to the Analysis tab ignoring any changes made.

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FIGURE T-14. Load Factors Dialog Box

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Check Points Dialog Box

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Click the Check Points button to open the Check Points dialog box. This screen allows you to review or add points to be checked during analysis in addition to or instead of points selected by the program. Add a new check point by typing “12.50” in the Location field and then clicking the Add button. Delete the check point at 2.08 ft by selecting it and then clicking the Delete button. Continue adding and/or deleting check points until you have the check points shown in the following figure.

T-12 / ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Step 6: Run the Analysis

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FIGURE T-15. Check Points Dialog Box

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When you are done, click the OK button to return to the Analysis tab.

Analysis Tab

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Click the Run Analysis button. This will automatically launch the solver engine and you will see a progress bar showing you the progress while this module is running. PRESTO will calculate the different moments, shears, and deflections for various load cases and then display the results on the screen.

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FIGURE T-16. Analysis Tab

After the analysis is complete, the results will display on the screen, as shown above. By selecting the Type, Case, and Stage drop-down lists, you can see

PRESTO®v8.6 ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ T-13

Step 7: Design the Beam

individual load case results and the envelope of results. You can print the results directly to the printer or to a Microsoft Excel file by clicking the Print button. NOTE: “Analysis” does not mean that the program checks the entire beam design for stresses and computes moment and shear capacities; it simply means that it calculates the results for the static loads on beam analysis.

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Step 7: Design the Beam

Now, click the Design tab. This is where the actual beam design is carried out. By selecting the buttons at the bottom of the screen, you can modify data pertaining to the design parameters, rebar, and strands, as explained on the following pages. Note that since the Prestressed (w or w/o rebar) option was selected on the Project tab, both the rebar pattern and strand pattern buttons are available here.

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FIGURE T-17. Design Tab

Design Parameters Dialog Box

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Click the Design Parameters button to activate the Design Parameters dialog box. It should default to the Design Options tab. Notice there are six tabs available on this screen. You can step through each of these tabs to see the different factors available and their default values. However, for this tutorial, you will only be modifying the design options. Select the Design Options tab and check the boxes for Horizontal Shear and Bi-Linear Analysis, as shown in the following figure. Click the OK button and the program returns to the Design tab.

T-14 / ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Step 7: Design the Beam

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FIGURE T-18. Design Parameters Dialog Box

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Strand and Rebar Pattern Dialog Box

Click the Strand and Rebar button to activate the Strand and Rebar Pattern dialog box. Note that this screen is very different from the previous version of PRESTO. You can specify draped as well as straight strands here. You can also specify debonding information on the screen.

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FIGURE T-19. Strand and Rebar Pattern (with Template Definitions) Dialog Box

PRESTO®v8.6 ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ T-15

Step 7: Design the Beam

Strand Tab Screen For this tutorial we will be using only strand which will be placed in a single column per web. Select Strand Vertical Planes as single. For single strand per web, change spacing between strand vertical planes as zero. Then change strand profile to one point. Next select Yes for Right pattern = Left pattern.

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The Y-axis grid definition is based on the template defined in the Strand Library. In this tutorial we will keep this definition unchanged.

Next define the depress point locations to see what exactly these locations reference. Check the box View Template with definitions. In the elevation view you will see A and C. Uncheck the box View Template with definitions. Specify A as 25 feet and C as zero.

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To define the first row, click in the left row and type 1. Specify left debond as zero and specify 1 in the column list. Select the Strand ID to 1/2 – 270K LL. Then confirm the pull to be 0.75. In depress Height A column, specify the height at point A. This strand is straight, therefore, specify 2 inches.

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Follow this same procedure to specify all the strand layers as shown in Figure T-20. .

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FIGURE T-20. Strand Tab

Design Results Screen Click the Design Status button to display the Design Results screen, as shown below. Quantities that have exceeded the limiting stress values or do not provide sufficient strength are marked with asterisks on the printout. Click the X in the top right corner to close the Design Results screen (or the Cancel

T-16 / ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Step 7: Design the Beam

button) and return to the Strand Pattern dialog box. Click the OK button to close the Strand Pattern dialog box and return to the Design tab.

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FIGURE T-21. Design Results Screen

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Diagram Screen

PRESTO provides you with many graphical outputs for your project results.

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Select Diagrams from the Show menu to activate the Diagram screen, as shown below. Experiment with the drop-down lists and buttons until you become familiar with the many options in this feature, including the different graph types and analysis or design level graphs.

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FIGURE T-22. Diagram Screen

PRESTO®v8.6 ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ T-17

Step 9: Generate the Program Output

At this point, it would be a good idea to save your project. Select the Save As option from the File menu. Enter the file name you want to save your data to (e.g., MyTutor1) in the File name field and click the Save button. The default extension is “*.prt”.

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Step 9: Generate the Program Output

Select Print from the File menu to display the Print screen. Select the appropriate options and click the OK button. Note that certain results are only available after certain design options have been selected on the Print screen. NOTE: Following is the output obtained from this tutorial.

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This completes this PRESTO tutorial session. To exit the program, select Exit from the File menu.

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©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Output

Output

OUTPUT

Company Name PHONE: 813 555 5555 | SHEET 1 OF 14 Address Here City, ST 12345 | JOB NO. 001 PROGRAM: Presto v. 8.6.0 LEAP Software Inc., Tampa, Fl | BY Lea DATE Oct, 2004 PHONE : TOLL-FREE 1-800-451-5327 TAMPA AREA: 813-985-9170 | CKD. DATE --------------------------------------------------------------------------------------PROJECT: Tutor 1 for Presto

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INPUT DATA -------------------------------------------------------------------------------------PROJECT DATA Project Name User Job Number State Description Design Code

: : : : : :

Tutor 1 for Presto 001 FL State Job Number : DOT-001 Double Tee example with openings and different thickness topping in r egions ACI 318-99

PRECAST DATA Section Id Type Area,in2 Yb,in M.I.,in4 Bfl-top,in Tfl-top,in H,in Bfl-bot,in Tfl-bot,in Web extnt,in Shear wid,in V/S,in Aoh,in2 ph,in Stems, No top wid,in bot wid,in

: 8DT24a : DOUBLE TEE : 401.0 : 17.1 : 20985 : 96.00 : 2.00 : 24.00 : 0.00 : 0.00 : 53.75 : 9.50 : 1.43 : 121.00 : 99.00 : 2 : 5.75 : 3.75

CONCRETE DATA

Overall Len : 50.00 ft Support Loc Left,ft Right,ft Release : 0.00 0.00 Final : 0.50 0.50 Boundaries : 4.00 4.00 Use Boundary: NO Location : INTERIOR

Precast f’c,psi : f’ci,psi : Wc,lb/ft3 : Ec,ksi : Eci,ksi : fct,psi : eccu : Topping f’ct,psi : Wct,lb/ft3: Ect,ksi :

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ALLOWABLE CONCRETE STRESSES Release Comp,psi Prec-top 2700.0 Bottom 2700.0 Final Total Topg-top 1350.0 Prec-top 2475.0 Bottom 2475.0 Final Sustained Topg-top 1350.0 Prec-top 2475.0 Bottom 2475.0

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SPAN DATA

Tens,psi -402.5 -201.2 -328.6 -445.0 -445.0

5500 4500 150.0 4496.1 4066.8 0 0.0030 3000 150.0 3320.6

PHI FACTORS Flexure : Shear : Concrete,P: Concrete,T: Steel : Prestress : Bearing :

0.90 0.85 1.00 1.00 1.00 1.00 0.85

LOAD MULTIPLIER Service Ultimate

CAMBER AND DEFLECTION MULT. W/o Topg W/ Topg DL Factor : 1.000 1.400 At erection MISCELLANEOUS DATA SD Factor : 1.000 1.400 Self Wt : 1.85 1.85 SDS Fac. : 1.000 1.200 Prestress : 1.80 1.80 Shoring : NONE LL/SL Fac : 1.000 1.700 Final Transform : NO Self Wt Self Wt : 2.70 2.40 Bearing : NO Release : 1.000 Prestress : 2.45 2.20 Comp Shear: NO Final : 1.000 S.D.L : 3.00 3.00 Hor Shear : YES Bearing : 1.150 Topg Wt : 0.00 2.30 Bi-Linear : YES -------------------------------------------------------------------------------------TOPPING DATA Dimensions : Topg.,in Gap,in Topg. Adjust.,in : 0.00 Ecc.,in : 0.000 Width : 96.00 / 0.00 Thickness : 2.00 / 0.00 for 14.00 ft Thickness : 0.00 / 0.00 for 6.50 ft Thickness : 2.00 / 0.00 for 29.50 ft --------------------------------------------------------------------------------------

v E PRESTO®v8.6

©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ T-19

Output

Company Name PHONE: 813 555 5555 | SHEET 2 OF 14 Address Here City, ST 12345 | JOB NO. 001 PROGRAM: Presto v. 8.6.0 LEAP Software Inc., Tampa, Fl | BY Lea DATE Oct, 2004 PHONE : TOLL-FREE 1-800-451-5327 TAMPA AREA: 813-985-9170 | CKD. DATE --------------------------------------------------------------------------------------PROJECT: Tutor 1 for Presto

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OPENING DATA Type Width Length from Start from Center Line Rectangular : 1.00 ft by 2.00 ft at 15.00 ft offset 1.00 ft Circular : 2.00 ft diameter at 20.00 ft offset -1.00 ft -------------------------------------------------------------------------------------LOADING DATA Ecc,in Description SW 0.418 k/ft at 0.00 ft to 0.418 k/ft at 14.00 ft 0.000 Self Wt SW 0.393 k/ft at 14.00 ft to 0.393 k/ft at 16.00 ft 0.000 Self Wt SW 0.418 k/ft at 16.00 ft to 0.418 k/ft at 19.50 ft 0.000 Self Wt SW 0.368 k/ft at 19.50 ft to 0.368 k/ft at 20.50 ft 0.000 Self Wt SW 0.418 k/ft at 20.50 ft to 0.418 k/ft at 50.00 ft 0.000 Self Wt Topp 0.200 k/ft at 0.00 ft to 0.200 k/ft at 14.00 ft 0.000 Topping Wt Topp 0.200 k/ft at 20.50 ft to 0.200 k/ft at 50.00 ft 0.000 Topping Wt SD 0.010 k/ft2 at 0.00 ft to 0.010 k/ft2 at 50.00 ft 0.000 SD-Comp LL 0.050 k/ft2 at 0.00 ft to 0.050 k/ft2 at 50.00 ft 0.000 LL -------------------------------------------------------------------------------------PRESTRESSED STRAND DATA Strand ID: 1/2-270K-LL LOW RELAXATION Fpu,ksi : 270.00 Area,in2 : 0.153 Dia,in : 0.50 Eps,ksi : 29000.0 Length Multipliers: Transfer Development Bonded: 1.00 1.00 Debonded: 1.00 2.00 Losses : PCI Hours to release: 24.00 Rel. humidity: 75 -------------------------------------------------------------------------------------PRESTRESSED STRAND PATTERN DATA Strands: 8.00 Draped Strands: 6.00 Profile: SYMMETRICAL - ONE POINT Pull : 0.75 * fpu * Area = 30.98 kip per strand

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Basic Transfer Length : 25.00 in Strand patterns L1,ft = 0.00 L2,ft = 25.00 Ycg, in = 9.00 (left) Left Straight ( 2) 2.00 at 2.00 Draped ( 2) 2.00 at 4.00 Draped ( 2) 2.00 at 14.00 Draped ( 2) 2.00 at 16.00

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R1,ft =

in in in in

STRAND GROUPS, SHIELDING AND PULL DATA Group No of Strand Height, in No Strands Left----Depr----Right 1 2.00 2.00 2.00 2.00 2 2.00 16.00 3.50 16.00 3 2.00 14.00 3.00 14.00 4 2.00 4.00 2.50 4.00

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Basic Development Length : 79.38 in

0.00 R2,ft = 25.00 2.75 (mid) Mid -------2.00 at 2.50 in 2.00 at 3.00 in 2.00 at 3.50 in

Pull Frac 0.75 0.75 0.75 0.75

9.00 (right) Right ( 2) 2.00 at ( 2) 2.00 at ( 2) 2.00 at ( 2) 2.00 at

Debonding,ft Left---Left Middle 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

2.00 4.00 14.00 16.00

in in in in

Right---Right 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

Auto Debonding Limits: Maximum % of debonded strands: per Row = 25.0% Total = 40.0% -------------------------------------------------------------------------------------REBAR DATA Tension Steel Shear Steel

T-20 / ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Output

Company Name PHONE: 813 555 5555 | SHEET 3 OF 14 Address Here City, ST 12345 | JOB NO. 001 PROGRAM: Presto v. 8.6.0 LEAP Software Inc., Tampa, Fl | BY Lea DATE Oct, 2004 PHONE : TOLL-FREE 1-800-451-5327 TAMPA AREA: 813-985-9170 | CKD. DATE --------------------------------------------------------------------------------------PROJECT: Tutor 1 for Presto Es,ksi : 29000.0 Fy,ksi : 60.0 Fs,ksi : 30.0 Rebar Development Length Multiplier : 1.00

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Fy,ksi : 60.0

-------------------------------------------------------------------------------------REBAR PATTERN DATA None STIRRUPS DATA: None -------------------------------------------------------------------------------------STEM MESH DATA: None -------------------------------------------------------------------------------------BEARING STEEL DATA Fy,ksi : 60.0 Nu/Vu : 0.200 Length,in : 0.00 Width,in : 0.00 Dist to Brg,in : 0.00 Theta,min : 0.00 Theta,max : 0.00 Theta,increment : 0.00 --------------------------------------------------------------------------------------

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Company Name PHONE: 813 555 5555 | SHEET 4 OF 14 Address Here City, ST 12345 | JOB NO. 001 PROGRAM: Presto v. 8.6.0 LEAP Software Inc., Tampa, Fl | BY Lea DATE Oct, 2004 PHONE : TOLL-FREE 1-800-451-5327 TAMPA AREA: 813-985-9170 | CKD. DATE --------------------------------------------------------------------------------------PROJECT: Tutor 1 for Presto

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STRUCTURAL ANALYSIS -------------------------------------------------------------------------------------CALCULATED INTERNAL CONSTANTS Beta-1,p/c : 0.775 Beta-1,tpg : 0.850 fct/6.7,psi : 0.0 Lambda,p/c : 1.000 Lambda,tpg : 1.000 Trans Length,in : 25.00 Sqrt(f’c),psi : 74.2 Sqrt(f’ct),psi : 54.8 -------------------------------------------------------------------------------------UNREINFORCED SECTION PROPERTY DATA /------------Precast-----------/ /------------Composite-----------/ From,ft A,in2 I,in4 H,in Yb,in Beff,in Ac,in2 Ic,in4 Hc,in Ybc,in To,ft Sb,in3 Bf,in Bv,in (gross) Sbc,in3 Tt, in Bt,in Bg,in 0.00 401.00 20984.9 24.00 17.15 96.00 542.80 27490.9 26.00 19.20 14.00 1223.8 96.00 9.50 1431.9 2.00 96.00 0.00 14.00 377.00 20102.7 24.00 16.78 84.00 377.00 20102.7 24.00 16.78 16.00 1198.3 84.00 9.50 1198.3 0.00 0.00 0.00 16.00 401.00 20984.9 24.00 17.15 96.00 401.00 20984.9 24.00 17.15 19.50 1223.8 96.00 9.50 1223.8 0.00 0.00 0.00 19.50 353.00 19101.6 24.00 16.35 72.00 353.00 19101.6 24.00 16.35 20.50 1168.1 72.00 9.50 1168.1 0.00 0.00 0.00 20.50 401.00 20984.9 24.00 17.15 96.00 542.80 27490.9 26.00 19.20 50.00 1223.8 96.00 9.50 1431.9 2.00 96.00 0.00 -------------------------------------------------------------------------------------REINFORCED SECTION PROPERTY DATA Loc,ft A,in2 I,in4 Yb,in Sb,in3 Ac,in2 Ic,in4 Ybc,in Sbc,in3 1.50 401.00 20984.9 17.15 1223.8 542.80 27490.9 19.20 1431.9 12.50 401.00 20984.9 17.15 1223.8 542.80 27490.9 19.20 1431.9 20.00 353.00 19101.6 16.35 1168.1 353.00 19101.6 16.35 1168.1 25.00 401.00 20984.9 17.15 1223.8 542.80 27490.9 19.20 1431.9 30.00 401.00 20984.9 17.15 1223.8 542.80 27490.9 19.20 1431.9 37.50 401.00 20984.9 17.15 1223.8 542.80 27490.9 19.20 1431.9 48.50 401.00 20984.9 17.15 1223.8 542.80 27490.9 19.20 1431.9 --------------------------------------------------------------------------------------

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©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ T-21

Output

STRUCTURAL ANALYSIS ( Units: ft , k , kft ) Loc SWrel SWfin DL Topg SD SL LL Ms Vs Mu Vu Tu 1.5 15.1 9.9 0.0 3.9 1.9 0.0 9.4 25.1 24.7 38.0 37.4 0.0 12.5 97.1 91.9 0.0 34.1 17.4 0.0 87.2 230.6 12.6 349.0 19.2 0.0 20.0 124.3 119.1 0.0 44.4 22.6 0.0 113.0 299.0 5.9 452.6 8.8 0.1 25.0 129.7 124.5 0.0 49.1 23.7 0.0 118.3 315.5 0.6 477.2 0.8 0.0 30.0 124.6 119.4 0.0 48.8 22.7 0.0 113.6 304.6 4.9 460.6 7.5 0.0 37.5 97.5 92.3 0.0 39.0 17.6 0.0 87.9 236.8 13.2 357.9 19.9 0.0 48.5 15.1 9.9 0.0 4.3 1.9 0.0 9.5 25.6 25.2 38.7 38.1 0.0 Reactions: Sup-L 10.4 10.4 0.0 4.1 2.0 0.0 9.9 26.4 39.9 0.0 Sup-R-10.4 10.4 0.0 4.6 2.0 0.0 9.9 26.9 40.6 -0.0 -------------------------------------------------------------------------------------PRESTRESS LOSS COMPUTATIONS ( Length = 50.00 ft Loss computed at 25.00 ft) A. Final Loss (Re: PCI Design Handbook, 5th Ed, p.4-64) : Kcir = 0.9 Eci,ksi = 4066.8 Mbm,kft = 129.7 A,in2 = 401.0 Kes = 1.0 Eps,ksi = 29000 Mll,kft = 118.3 I,in4 = 20985 Pi,k = 247.9 ecc,in = 14.4 fcir,psi = 1692.4 (Eq 4.7.3) ES,psi = Kes * Eps * fcir / Eci = 12068.6 (Eq 4.7.2) Kcr = 2.0 Ec,ksi = 4496 Shoring = NONE fcds,psi = 574.2 (Mod. Eq 4.7.5) CR,psi = Kcr * (Es / Ec) * (fcir - fcds) = 14424.8 (Eq 4.7.4) Ksh = 1.0 V/S ratio = 1.43 RH = 75%

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©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Output

Company Name PHONE: 813 555 5555 | SHEET 5 OF 14 Address Here City, ST 12345 | JOB NO. 001 PROGRAM: Presto v. 8.6.0 LEAP Software Inc., Tampa, Fl | BY Lea DATE Oct, 2004 PHONE : TOLL-FREE 1-800-451-5327 TAMPA AREA: 813-985-9170 | CKD. DATE --------------------------------------------------------------------------------------PROJECT: Tutor 1 for Presto SH,psi Tendon C = RE,psi

= (8.2E-6) * Ksh * Es * (1 -0.06* V/S) * (100 - RH) = 5434.3 type: LOW RELAXATION fpu,ksi = 270.0 Kre = 5000 J = 0.040 1.00 fpi/fpu = 0.75 fpi,ksi = 202.5 Aps,in2 = 1.224 = [ Kre - J * (SH + CR + ES) ] * C = 3722.9

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(Eq 4.7.6) (Table 4.7.1) (Eq 4.7.7)

B. Release Loss (Re: PCI JR 162, Sec 2.7, p.9) : fst,psi = 202500.0 fpy,psi = 243000.0 (also ACI Comm Sec 18.5) fst/fpy - 0.55 = 0.283 24t = 1 hrs 24t1 = 24 hrs RE,psi = 1759.8 (Eqs 16,17) Long term: 24t1 = 100000 hrs RE,psi = 6375.0 (Eqs 16,17) RE adjusted,psi = 1759.77 * 3722.89 / 6375.00 = 1027.68

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-------------------------------------------------------------------------------------PRESTRESS LOSS SUMMARY (Computed) Item Release,psi Final,psi Elastic Shortening ES 12068.6 ( 5.96%) ES 12068.6 ( 5.96%) Relaxation RE 1027.7 ( 0.51%) RE 3722.9 ( 1.84%) Creep -------CR 14424.8 ( 7.12%) Shrinkage -------SH 5434.3 ( 2.68%) ------------------------Total loss 13096.3 ( 6.47%) 35650.6 (17.61%) --------------------------------------------------------------------------------------

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v E PRESTO®v8.6

©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ T-23

Output

Company Name PHONE: 813 555 5555 | SHEET 6 OF 14 Address Here City, ST 12345 | JOB NO. 001 PROGRAM: Presto v. 8.6.0 LEAP Software Inc., Tampa, Fl | BY Lea DATE Oct, 2004 PHONE : TOLL-FREE 1-800-451-5327 TAMPA AREA: 813-985-9170 | CKD. DATE --------------------------------------------------------------------------------------PROJECT: Tutor 1 for Presto

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RELEASE AND FINAL STRESSES -------------------------------------------------------------------------------------RELEASE STRESSES (psi) ( Note: f’ci-min = 3390.5 psi ) Loc, ft -> 1.50 12.50 20.00 25.00 30.00 37.50 48.50 Prestress Top -50 -279 -494 -512 -421 -279 -50 Bottom 1626 2755 3136 3306 3095 2755 1626 Losses % 3.67 5.05 5.63 6.47 5.66 5.04 3.67 Self Weight Top 59 380 597 508 488 382 59 Bottom -148 -952 -1277 -1271 -1222 -956 -148 Total (Prestress + Self Weight) Top 9 101 103 -4 68 102 10 Bottom 1478 1803 1859 2034 1873 1799 1478 -------------------------------------------------------------------------------------TENSION STEEL (in2) Top: Reqd 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Prvd 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Bot: Reqd 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Prvd 0.00 0.00 0.00 0.00 0.00 0.00 0.00 --------------------------------------------------------------------------------------

Loc, ft -> 1.50 12.50 Prestress Topping 0 0 Top -45 -249 Bottom 1464 2459 Losses % 13.26 15.25 Self Wt Topping 0 0 Top 39 360 Bottom -97 -901 DL-Precast Topping 0 0 Top 0 0 Bottom 0 0 Topping Wt Topping 0 0 Top 15 134 Bottom -38 -334 SD-Composite Topping 4 38 Top 4 37 Bottom -16 -146 Total (Prestress + All DL) Topping 4 38 Top 13 281 Bottom 1313 1077 Sustained Live Load Topping 0 0 Top 0 0

20.00

25.00

30.00

37.50

48.50

0 -442 2804 15.63

0 -451 2912 17.61

0 -376 2766 15.71

0 -250 2465 15.03

0 -45 1464 13.25

0 572 -1223

0 488 -1220

0 468 -1171

0 362 -905

0 39 -97

0 0 0

0 0 0

0 0 0

0 0 0

0 0 0

0 213 -456

0 192 -482

0 191 -479

0 153 -383

0 17 -42

0 109 -232

52 50 -198

50 48 -190

39 37 -147

4 4 -16

0 452 892

52 279 1012

50 331 925

39 301 1030

4 15 1309

0 0

0 0

0 0

0 0

0 0

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FINAL STRESSES (psi)

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T-24 / ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Output

Company Name PHONE: 813 555 5555 | SHEET 7 OF 14 Address Here City, ST 12345 | JOB NO. 001 PROGRAM: Presto v. 8.6.0 LEAP Software Inc., Tampa, Fl | BY Lea DATE Oct, 2004 PHONE : TOLL-FREE 1-800-451-5327 TAMPA AREA: 813-985-9170 | CKD. DATE --------------------------------------------------------------------------------------PROJECT: Tutor 1 for Presto

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Bottom 0 0 0 0 0 0 0 Total (Prestress + All DL + Sustained LL) Topping 4 38 0 52 50 39 4 Top 13 281 452 279 331 301 15 Bottom 1313 1077 892 1012 925 1030 1309 Live Load Topping 21 191 0 259 249 193 21 Top 20 183 543 248 238 184 20 Bottom -79 -731 -1160 -991 -952 -737 -79 Total (Prestress + All DL + All LL) Topping 25 229 0 311 299 231 25 Top 33 464 995 527 569 486 35 Bottom 1234 347 -268 20 -27 294 1229 --------------------------------------------------------------------------------------

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v E PRESTO®v8.6

©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ T-25

Output

Company Name PHONE: 813 555 5555 | SHEET 8 OF 14 Address Here City, ST 12345 | JOB NO. 001 PROGRAM: Presto v. 8.6.0 LEAP Software Inc., Tampa, Fl | BY Lea DATE Oct, 2004 PHONE : TOLL-FREE 1-800-451-5327 TAMPA AREA: 813-985-9170 | CKD. DATE --------------------------------------------------------------------------------------PROJECT: Tutor 1 for Presto

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ULTIMATE STRENGTH Phi-Flexure = 0.9000

Loc, ft -> 1.50 12.50 20.00 25.00 30.00 37.50 48.50 -------------------------------------------------------------------------------------Mu, k-ft 38.0 349.0 452.6 477.2 460.6 357.9 38.7 bfl, in 96.00 96.00 72.00 96.00 96.00 96.00 96.00 tfl, in 2.00 2.00 2.00 2.00 2.00 2.00 2.00 bw, in 9.50 9.50 9.50 9.50 9.50 9.50 9.50 Aps, in2 0.54 1.22 1.22 1.22 1.22 1.22 0.54 fse, ksi 175.65 171.62 170.85 166.85 170.68 172.07 175.68 As, in2 0.00 0.00 0.00 0.00 0.00 0.00 0.00 A’s, in2 0.00 0.00 0.00 0.00 0.00 0.00 0.00 d’, in 0.00 0.00 0.00 0.00 0.00 0.00 0.00 f’c, ksi 3.00 3.00 5.50 3.00 3.00 3.00 3.00 c, in 0.70 1.58 1.26 1.58 1.58 1.58 0.70 Beta-1 0.850 0.850 0.775 0.850 0.850 0.850 0.850 a, in 0.59 1.34 0.98 1.34 1.34 1.34 0.59 Controls TENS TENS TENS TENS TENS TENS TENS fps, ksi 269.38 268.84 269.12 269.04 268.98 268.85 269.38 Msc,k-ft 188.0 480.2 482.1 557.7 526.7 480.3 188.0 dsc, in 17.38 20.13 20.00 23.25 22.00 20.13 17.38 cor, in 7.36 8.52 8.47 9.85 9.32 8.52 7.36 Mor,k-ft 1661.6 2012.2 1198.3 2428.7 2259.7 2012.2 1661.6 pMn,k-ft 188.0 480.2 482.1 557.7 526.7 480.3 188.0 pMn/Mu 4.95 1.38 1.07 1.17 1.14 1.34 4.85 -------------------------------------------------------------------------------------CRACKING LOAD (ACI Sec 18.8.3) Auto detection Bottom - max at 20.00 ft Mcr = 327.09 k-ft pMn = 482.11 k-ft pMn/Mcr = 1.47 fr = 556.43 psi (ACI Sec 9.5.2.3) -------------------------------------------------------------------------------------NOTE: Use Formulae compatible with Presto 8.2 and older to generate Strand Stress/Strain model. --------------------------------------------------------------------------------------

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©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Output

Company Name PHONE: 813 555 5555 | SHEET 9 OF 14 Address Here City, ST 12345 | JOB NO. 001 PROGRAM: Presto v. 8.6.0 LEAP Software Inc., Tampa, Fl | BY Lea DATE Oct, 2004 PHONE : TOLL-FREE 1-800-451-5327 TAMPA AREA: 813-985-9170 | CKD. DATE --------------------------------------------------------------------------------------PROJECT: Tutor 1 for Presto

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VERTICAL SHEAR AND TORSION Aoh,in2 Acp,in2 Phi-Shear

= 121.00 = 401.00 = 0.8500

ph,in pcp,in

= 99.00 = 280.09

Ao,in2 theta

= 102.85 = 37.50

Loc, ft -> 1.50 12.50 20.00 25.00 30.00 37.50 48.50 -------------------------------------------------------------------------------------Vu, k 37.4 19.2 8.8 0.8 7.5 19.9 38.1 Mu, k-ft 38.0 349.0 452.6 477.2 460.6 357.9 38.7 Tu, k-ft 0.0 0.0 0.1 0.0 0.0 0.0 0.0 bw, in 9.50 9.50 9.50 9.50 9.50 9.50 9.50 Aps, in2 1.22 1.22 1.22 1.22 1.22 1.22 1.22 d, in 19.20 19.20 20.00 21.25 20.00 19.20 19.20 Vd, k 15.4 7.8 3.8 0.5 3.0 8.2 15.9 Md, k-ft 15.7 143.4 186.1 197.2 191.0 148.9 16.2 Vi, k 21.9 11.4 5.0 0.3 4.5 11.7 22.2 Mmax,k-ft 22.3 205.6 266.5 280.0 269.6 209.0 22.6 Mcr, k-ft 209.7 181.6 130.2 173.8 163.5 176.1 209.2 Vci, k 229.9 26.0 24.2 25.8 24.2 26.2 230.0 P-eff, k 154.8 210.1 209.1 204.2 208.9 210.6 154.8 Ybc, in 19.20 19.20 16.35 19.20 19.20 19.20 19.20 fpc, psi 273 440 592 425 450 447 274 Vp, k 3.2 4.4 4.4 0.0 4.3 4.4 3.2 Vcw, k 65.5 75.8 87.4 78.2 79.3 76.2 65.6 Vc, k 65.5 26.0 24.2 25.8 24.2 26.2 65.6 Vs req, k 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Vs,max, k 108.2 108.2 112.7 119.8 112.7 108.2 108.2 AvC,in2/ft 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Tlim,k-ft 4.1 4.7 5.2 4.7 4.7 4.7 4.1 AtC,in2/ft 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Av+2At,min 0.06 0.06 0.00 0.00 0.00 0.06 0.06 Av+2At 0.06 0.06 0.00 0.00 0.00 0.06 0.06 Av-prvd 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Phi*Vn/Vu 1.49 1.15 2.34 27.09 2.76 1.12 1.46 Al, in2 0.00 0.00 0.00 0.00 0.00 0.00 0.00 S-max, in 18.0 18.0 18.0 18.0 18.0 18.0 18.0 S-prvd, in 0.0 0.0 0.0 0.0 0.0 0.0 0.0 f-act,psi 205 105 47 4 39 109 209 f-alw,psi 810 625 613 613 613 626 810 --------------------------------------------------------------------------------------------------------------------------------------------------------------------------Units: Av+2At,min -> in2/ft; Av+2At -> in2/ft; Av-prvd -> in2/ft -------------------------------------------------------------------------------------HORIZONTAL SHEAR

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Loc, ft -> 1.50 12.50 20.00 25.00 30.00 37.50 48.50 -------------------------------------------------------------------------------------Vnh, k 21.6 11.3 0.0 0.2 4.5 11.5 21.7 bv, in 96.00 96.00 0.00 96.00 96.00 96.00 96.00 Vnh,max 17280.0 17280.0 0.0 17280.0 17280.0 17280.0 17280.0 Avh,min 0.09 0.09 0.00 0.09 0.09 0.09 0.09

PRESTO®v8.6 ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ T-27

Output

Company Name PHONE: 813 555 5555 | SHEET 10 OF 14 Address Here City, ST 12345 | JOB NO. 001 PROGRAM: Presto v. 8.6.0 LEAP Software Inc., Tampa, Fl | BY Lea DATE Oct, 2004 PHONE : TOLL-FREE 1-800-451-5327 TAMPA AREA: 813-985-9170 | CKD. DATE --------------------------------------------------------------------------------------PROJECT: Tutor 1 for Presto

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Ahs,in2/ft 0.09 0.09 0.00 0.09 0.09 0.09 0.09 Ahr,in2/ft 0.00 0.00 0.00 0.00 0.00 0.00 0.00 -------------------------------------------------------------------------------------Units: Vnh,max -> k; Avh,min -> in2/ft --------------------------------------------------------------------------------------

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©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Output

Company Name PHONE: 813 555 5555 | SHEET 11 OF 14 Address Here City, ST 12345 | JOB NO. 001 PROGRAM: Presto v. 8.6.0 LEAP Software Inc., Tampa, Fl | BY Lea DATE Oct, 2004 PHONE : TOLL-FREE 1-800-451-5327 TAMPA AREA: 813-985-9170 | CKD. DATE --------------------------------------------------------------------------------------PROJECT: Tutor 1 for Presto

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CAMBER AND DEFLECTIONS -------------------------------------------------------------------------------------CAMBER AND DEFLECTION MULTIPLIERS Erection: SW = 1.85 Prest = 1.80 Final : SW = 2.40 Prest = 2.20 DL = 3.00 Topg = 2.30 -------------------------------------------------------------------------------------BI-LINEAR COMPUTATIONS (Ref: Branson and Trost, PCI Journal Sep/Oct 1982) Ig, in4 = 27491 Icr, in4 = 5139 Mc0,kft = 261.9 Mcr(-Mc0),kft = 122.4 Load Level : Prest. +SW (1) +DL (2) +Topg (3) +SD+SDS (4) +SL+LL (5) Ma(-Mc0),kft : -137.4 -137.4 -88.3 -64.7 53.6 Ie, in4 : 27491 27491 27491 27491 27491 Ig / Ie : 1.0 1.0 1.0 1.0 1.0 -------------------------------------------------------------------------------------CAMBER AND DEFLECTIONS (in) Loc, ft -> RELEASE Prestress Self Wt TOTAL

1.50

12.50

20.00

25.00

30.00

0.16 -0.07 0.09

1.12 -0.49 0.63

1.46 -0.66 0.81

1.53 -0.69 0.84

1.46 -0.65 0.80

ERECTION Prestress Self Wt TOTAL

0.16 -0.08 0.08

1.88 -0.82 1.06

2.51 -1.12 1.39

2.63 -1.17 1.45

FINAL Prestress Self Wt DL-Prec Topping SD-Comp TOTAL

0.20 -0.10 0.00 -0.03 -0.02 0.05

2.30 -1.07 0.00 -0.36 -0.19 0.68

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3.21 -1.52 0.00 -0.52 -0.27 0.90

2.50 -1.11 1.38

3.05 -1.44 0.00 -0.50 -0.25 0.86

37.50

48.50

1.11 -0.49 0.62

0.16 -0.07 0.09

1.87 -0.82 1.05

0.16 -0.08 0.08

2.29 -1.07 0.00 -0.37 -0.18 0.67

0.20 -0.10 0.00 -0.03 -0.02 0.04

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SL-Sust L 0.00 0.00 0.00 0.00 0.00 0.00 0.00 LL-Live -0.03 -0.32 -0.43 -0.44 -0.42 -0.30 -0.03 TOTAL 0.02 0.37 0.44 0.46 0.44 0.36 0.02 -------------------------------------------------------------------------------------*NOTE: Positive deflection is up, negative deflection is down.

v E PRESTO®v8.6

©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ T-29

Output

Company Name PHONE: 813 555 5555 | SHEET 12 OF 14 Address Here City, ST 12345 | JOB NO. 001 PROGRAM: Presto v. 8.6.0 LEAP Software Inc., Tampa, Fl | BY Lea DATE Oct, 2004 PHONE : TOLL-FREE 1-800-451-5327 TAMPA AREA: 813-985-9170 | CKD. DATE --------------------------------------------------------------------------------------PROJECT: Tutor 1 for Presto

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DESIGN SUMMARY -------------------------------------------------------------------------------------MEMBER INFO ----------Section Id : 8DT24a Support Loc Left,ft Right,ft Type : DOUBLE TEE Release : 0.00 0.00 Overall Len,ft : 50.00 Final : 0.50 0.50 Location : INTERIOR Boundaries : 4.00 4.00 f’c,psi: 5500 f’ci,psi: 4500 f’ct,psi: 3000 Strand ID: 1/2-270K-LL LOW RELAXATION Eps,ksi: 29000.0 Strands: 8.00 Draped Strands: 6.00 Profile: SYMMETRICAL - ONE POINT L1,ft = 0.00 L2,ft = 25.00 R1,ft = 0.00 R2,ft = 25.00 Ycg,in = 9.00 (left) 2.75 (mid) 9.00 (right) Release Losses,%: 6.47 at 25.00ft Final Losses,%: 17.61 at 25.00ft STRESSES (psi) --------------

-------- Allowable ------Topping Top Bottom

RELEASE STRESSES Compression Tension at the Ends FINAL STRESSES Compression Tension ULTIMATE STRENGTH ------------------Loc,ft : 20.00 Mu,k-ft : 452.6 pMn,k-ft : 482.1 pMn/Mu : 1.07 Aps,in2 : 1.22 fse,ksi : 170.85 As,in2 : 0.00 A’s,in2 : 0.00 dsc,in : 20.00 c,in : 1.26 a,in : 0.98 fps,ksi : 269.12

----------

2700.0 -402.5 -402.5

1350.0 -328.6

2475.0 -445.0

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PROPERTIES AND ANALYSIS RESULTS ------------------------------Loc,ft : 1.50 20.00 Ac,in2 : 542.80 353.00 Ic,in4 : 27490.9 19101.6 Mu,kft : 38.0 452.6 Vu,k : 37.4 8.8

30.00 542.80 27490.9 460.6 7.5

CAMBER AND DEFLECTIONS (in) --------------------------Release Erection Loc,ft : 25.00 25.00 Prestress : 1.53 2.63

Final 25.00 3.21

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----------

311/25.00

VERTICAL SHEAR AND TORSION -------------------------Loc,ft : 48.50 Vu,k : 38.1 Tu,k-ft : 0.0 Mu,k-ft : 38.7 Vc,k : 65.6 Tlim,k-ft : 4.1 Av+2At : 0.06 Al,in2 : 0.00 S-max,in : 18.00 Loc,ft : 48.50 f-act,psi : 209 f-alw,psi : 810

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2700.0 -201.2 -201.2 2475.0 -445.0

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-------------- Computed -------------Topping/Loc Top/Loc Bottom/Loc

37.50 542.80 27490.9 357.9 19.9

103/20.00 -4/25.00

2034/25.00

995/20.00

1234/ 1.50 -268/20.00

HORIZONTAL SHEAR -------------------Loc,ft : 48.50 Vnh,k : 21.7 Ahs,in2/ft : 0.09 Ahr,in2/ft : 0.00

48.50 542.80 27490.9 38.7 38.1

Erection Mult. Prestress

:

Final Mult.

1.80

T-30 / ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

2.20

PRESTO® v8.6

Output

Company Name PHONE: 813 555 5555 | SHEET 13 OF 14 Address Here City, ST 12345 | JOB NO. 001 PROGRAM: Presto v. 8.6.0 LEAP Software Inc., Tampa, Fl | BY Lea DATE Oct, 2004 PHONE : TOLL-FREE 1-800-451-5327 TAMPA AREA: 813-985-9170 | CKD. DATE --------------------------------------------------------------------------------------PROJECT: Tutor 1 for Presto Self Wt : DL-Prec : Topping : SD-Comp : SL-Sust L : LL-Live : TOTAL :

-0.69

-1.17

0.84

1.45

-1.52 0.00 -0.52 -0.27 0.00 -0.44 0.46

Self Wt DL Topping

: : :

1.85

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2.40 3.00 2.30

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©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ T-31

Output

Company Name PHONE: 813 555 5555 | SHEET 14 OF 14 Address Here City, ST 12345 | JOB NO. 001 PROGRAM: Presto v. 8.6.0 LEAP Software Inc., Tampa, Fl | BY Lea DATE Oct, 2004 PHONE : TOLL-FREE 1-800-451-5327 TAMPA AREA: 813-985-9170 | CKD. DATE --------------------------------------------------------------------------------------PROJECT: Tutor 1 for Presto

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PRODUCTION SUMMARY -------------------------------------------------------------------------------------PROJECT DATA Project Name : Tutor 1 for Presto User Job Number : 001 Description : Double Tee example with openings and different thickness topping in r : egions -------------------------------------------------------------------------------------SECTION DATA: DOUBLE TEE 8DT24a Overall Member Length: 50.00 ft Height: 24.00 in Top Flange: Width: 96.00 in Thickness: 2.00 in Bottom Flange: Width: 7.50 in Thickness: 22.00 in Initial Camber: 0.84 in -------------------------------------------------------------------------------------CONCRETE: Normal Weight Release Strength: 4500 psi Density : 150.00 lb/ft3 Final Strength : 5500 psi Beam weight: 20885.42 lb -------------------------------------------------------------------------------------PRESTRESSING: Use 8.00 1/2-270K-LL Fu: 270.00 ksi LOW RELAXATION Strand patterns Left Mid Right Straight ( 2) 2.00 at 2.00 in -------( 2) 2.00 at 2.00 in Draped ( 2) 2.00 at 4.00 in 2.00 at 2.50 in ( 2) 2.00 at 4.00 in Draped ( 2) 2.00 at 14.00 in 2.00 at 3.00 in ( 2) 2.00 at 14.00 in Draped ( 2) 2.00 at 16.00 in 2.00 at 3.50 in ( 2) 2.00 at 16.00 in Holddown: 5.16 k at 25.00 ft from left end 5.16 k at 25.00 ft from right end Stress

: :

191.09 psi at 170.85 psi at

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25.00 ft release 25.00 ft final

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Initial Prestress Force: 0.75*fpu*Area = 30.98 k / Str Elongation per member : 4.19 in -------------------------------------------------------------------------------------MATERIAL REQUIRED ( per member ) Concrete : 5.16 Cubic Yards Strand : 400.00 Linear Feet --------------------------------------------------------------------------------------

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©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

CHAPTER FIVE

Theory

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This chapter explains some of the assumptions and procedures of PRESTO in greater detail than found elsewhere in this manual. Unless otherwise stated, references in this manual refer to the Building Code Requirements for Reinforced Concrete (ACI 318-99) and the Building Code Requirements for Reinforced Concrete (ACI 318-05). Separate sections are provided for methodologies where the two codes are significantly different. We have provided common sections where the methodologies are similar. Design code references that are the same and apply to both codes are listed as ACI 318-99/05. Code references for CSA A23.3-94 with 2001 revisions are provided separately. When a requirement applies to only one code, the appropriate reference is listed.

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PRESTO is a program for the design and analysis of precast, prestressed, and

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mild reinforced beams. The following lists some of the basic features of

PRESTO:

•

The program operates in modes.

ACI 318-99, ACI 318-05,

and

•

Draped or straight strand profile

•

Stress-relieved or low relaxation strands

•

Point, uniform, or trapezoidal loads

•

Rectangular and circular openings

•

Members with mild steel only

•

Complete flexibility regarding specification of materials used in design

•

Complete libraries of strand and rebar that can be edited by the user

•

Stem Mesh and/or Stirrup Specification

PRESTO®v8.6 Theory ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

CSA 23.3-94

/ TH-1

Layout

Some advanced features of the program include: •

Cantilevers

•

Variable topping thickness

•

Strain compatibility

•

Bilinear deflection analysis

•

Combined shear and torsion analysis

•

Cracked section properties and stresses

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Beam self-weight and topping weight are automatically computed and applied to the member. These weights are calculated based on the user-specified unit weights for these materials. The user may specify dead and live loads that are point, uniform, or partially distributed on the composite or non-composite section.

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PRESTO automatically selects several typical points for analysis. You may specify

additional points for the analysis.

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Straight, one-point, or two-point depressed strand patterns may be modeled. Multiple layers of rebar in the precast or the topping can be specified with straight, hooked, or mechanical anchorage. PRESTO automatically determines whether a given layer of reinforcement is in tension or compression and handles it accordingly. Strand patterns can vary from the depression point (if present) and at each end.

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At release conditions, the amount of non-prestressed reinforcement is computed, if required to control excess tension in the precast. Also indicated are hold-down forces at one or both depression points and the minimum release strength of the concrete.

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Total stresses at the top and bottom of the beam and the top of the topping at each check point are included in the final design. Calculations for ultimate strength and cracking ratio are also performed.

Layout

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The beam is modeled as a simply supported beam with up to 2 unequal cantilevers. The overall length of the member is the out-to-out dimension of the beam. The end support lengths are treated as cantilevers during release and service conditions.

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Flange openings can be rectangular or circular. The size of a rectangular opening is defined by its transverse and longitudinal dimensions. For computational purposes, circular openings are replaced internally with equivalent rectangular openings. The transverse dimension is equal to the diameter of the circle and the longitudinal dimension is equal to one-half of the diameter of the circle.

Topping Members may be non-composite (untopped) or composite (topped). The topping has both a thickness and a width, and is divided into two portions, the slab and the gap. The slab is modeled as a rectangle and is defined by PRESTO as the portion of the topping that is directly over the precast section. The gap is defined as the portion of the topping

TH-2 / Theory ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Topping

outside the slab, which also has a thickness. The gap width is usually calculated as the boundary width minus the slab width. Boundary distance is separated into left and right boundary distances on either side of the centerline of the web extent (see effective width and web extent definitions in Appendix 1). The left and right boundary distances can be equal or unequal in size depending on the location of the precast member (i.e. interior or exterior).

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When the user-specified boundary distance is less than the actual precast section width, the parts of the precast flange protruding beyond the specified left and right boundary distances will be removed upon user choice. An example of this may be seen in the figure below where, if the left and right boundary distances are equal to 3 feet (0.91 m) and the user selects to adjust the section properties based on boundary distances, the portions of the flange (cross-hatched) that protrude past the boundary distances are ignored (chopped off), thereby resulting in a smaller effective width. These changes to the internal dimensions of the member will produce different section properties in subsequent calculations and also alter the self-weight of the actual section. 4'-0" 2"

4'-0"

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2'-0"

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4'-0"

2'-0"

4'-0"

2'-0"

2'-0" 5.75 "

4'-0"

4'-0"

3'-0"

Left Boundary Width

2'-0" 3'-0"

Right Boundary Width

2'-0" 3.75 "

5.75 "

FIGURE TH-1. User Specified Left/Right Boundary Distances

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Boundary distance also affects the design loads since any assigned uniform loads are converted internally into linear loads of constant magnitude. This happens when the uniform load is multiplied by the total (left + right) boundary distance specified. For example, if both the left and right boundaries are equal to 4 feet (1.22 m), and the uniform load is equal to 2 ksf (95.76 kN/m²), then the magnitude of the linear load is equal to (4 + 4) × 2 = 16 klf ((1.22 + 1.22) × 95.76 = 233.5 kN/m). The calculated linear load will then be applied to the applicable areas of the member. If the left boundary distance is not equal to the right boundary distance, additional torsion effect is calculated. However, for members with openings, a different situation results. For example, if there is an opening of 2 feet × 2 feet (0.61 m × 0.61 m) within the section of the right

PRESTO®v8.6 Theory ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ TH-3

Section Properties

boundary distance located 5 feet (1.52 m) from the left end, the program will divide the member into three zones, 1, 2, and 3 (Zone 2 being the 2 foot (0.61 m) section with the opening). The magnitude of the linear load will then be ePqual to (8 - 2) × 2 = 12 klf ((2.44 - 0.61) × 95.76 = 175.1 kN/m) applied the length of Zone 2. For hollow core sections, this boundary width is used somewhat differently for section properties. The program first determines the properties for the entire precast section and then determines a ratio of boundary width to total precast section width. It then reduces the section properties by that ratio.

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Section Properties

In the calculation of section properties, PRESTO first subdivides the member into zones of uniform, unreinforced sections. Both unreinforced non-composite and composite section properties are then computed. Next, reinforced (transformed) section properties are calculated at selected check points. By default, the reinforced section properties only include effects from the mild reinforcement. However, the user may override this default behavior by specifying that the program also use the strand in the calculation of the transformed section properties. PRESTO computes unreinforced section properties in the following manner:

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1.

After the topping is placed and the gap width computed, PRESTO calculates the effective width of the combined topping slab and gap. This is called the gross effective width (Beff).

2.

PRESTO then uses the opening data to reduce the precast flange as well as

i t

the gross effective width. 3.

Finally, precast section properties are recomputed from the reduced precast section combined with the net effective topping slab and gap, modified by the ratio of elasticities for the topping and precast concrete.

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All of the precast flange (after consideration of boundary distance) is considered effective for both section properties and ultimate strength calculations. While the provisions of Arts. 8.10.2 and 8.10.3 of ACI 318-99/05 are not applicable to precast concrete (as per Art. 18.1.3), they are utilized for computing the effective width of the topping. The program also assumes that the effective width of topping cannot be smaller than the width of the precast top flange. Since the provisions in ACI 318-99/05 for effective width do not take into account the possibility of uneven lateral spacing of the prestressed members, the effective width of each side of an interior beam is computed separately. The first criterion of ACI 318-99/05, Art. 8.10.2 is reinterpreted as 1/8th span length on each side of the centerline of the member. In CSA mode, effective width is computed based on 10.3.3 (a), (c), and (d).

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For exterior beams, ACI 318-99/05, Art. 8.10.3 and CSA 23.3-94, Art. 10.3.4 are applied to both sides of the section making it applicable to cases with a small overhang on one side. For beams with multiple webs, the overhang is measured from the outer faces of the end webs. The value of the “web-extent” (calculated as the out-to-out distance of the two end webs) is utilized for this purpose. A similar approach is adopted in CSA 23.3-94 when Arts. 10.3.3 and 10.3.4 are applied.

TH-4 / Theory ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Prestress Losses

For beams with both a topping slab and a topping gap, subparagraphs (a) and (b) of ACI 318-99/05, Art. 8.10.3 are independently applied to: (1) combined topping slab and precast flange measured from the faces of the end webs; and (2) gap concrete measured from the edge of the precast flange. NOTE: When computing the negative moment capacity of sections with tapered stems (such as double tees, key joists, etc.), the total bottom width of the stems is considered as the compression width.

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Other important section properties include the moment of inertia, distance to the centroid of section, and volume to surface ratio of the cross-section. These values are calculated during the addition or modification of sections in the Beam Sections Library. The program approximates the volume to surface ratio by calculating the area to perimeter ratio.

When in ACI 318-05 mode, the program also computes section properties for final behavior under total loads. These properties are for the gross section if the section at final behaves as an Uncracked or In Transition section. However, if the section’s behavior at final is as a Cracked section, PRESTO determines the side of the crack as Bottom, TopTopg, or TopPrec. TopTopg suggests that the top of the topping starts to crack first. TopPrec means the section is cracked at the top of the precast.

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PRESTO in ACI 318-05 reports the computed crack depth. If the crack starts at the

bottom, this is measured from the bottom of the precast up. If the crack starts at the top, and there is no topping slab, crack depth is measured from the top of the precast. If a slab is present, it is measured from the top of topping slab downwards. In both cases, crack depth is reported as a real number. The program then uses the uncracked concrete and steel transformed to arrive at the cracked section properties.

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Prestress Losses

PRESTO allows four different types of analysis for the prestressed losses:

•

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•

PCI Design Handbook (5th Edition).

PCI losses are computed using the procedures described in Refs. [8] and [9]. The PCI Design Handbook (Ref. [9]) is used to compute final losses, including elastic shortening and long-term steel relaxation, while Journal Art. (Ref. [8]) is used to compute steel relaxation at release. The equations from Ref. [8] for computing steel relaxation at release are modified so that longterm steel relaxation loss, when computed on the basis of 100,000 hours, coincides with the value given by Ref. [9].

CPCI Design Handbook (3rd Edition) Simplified Method.

Losses are computed using the simplified approach presented in the CPCI Design Handbook. This has been adopted from Ref. [4]. •

Time-Dependent.

Time-dependent prestress losses are computed using the procedures outlined in Ref. [8]. Note that the program assumes there is accelerated curing of the concrete and that the creep and shrinkage of the concrete both start at release.

PRESTO®v8.6 Theory ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ TH-5

Analysis

•

Manual (User-Defined).

User-defined prestressed losses allow the user to specify both release and final losses. Note that in this last case, the program only checks to see if the release losses are less than the final losses, it does not check the validity of the assigned values.

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Live load recapture is an option presented to the user to take into account the temporary increase in strand stress, calculated as a decrease in prestress losses, which occurs only during the application of the live load.

Analysis

PRESTO establishes several check points for prestressed members at the following

locations:

C

•

H/2: As per ACI 318-99/05, Art. 11.1.3.2 and CSA 23.3-94, Art. 11.3.2 (b), sections between H/2 and the face of the support may be designed for the same shear that exists at H/2.

•

Transfer: In a prestressed member, the prestress force is transferred to the concrete by bond. The length required to accomplish this transfer is referred to as the transfer length. PRESTO uses 50 strand diameters as allowed in ACI 318-99/05, Art. 11.4.3 and CSA 23.3-94, Art. 11.2.12 to calculate the transfer length.

•

0.4L from Each End: For members with 1-pt depress, this point is usually close to the critical point for service loads, and is also usually the depress point for 2-pt depressed strand profiles.

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a u •

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Midspan: This is usually the point of maximum moment.

The critical point is defined as the point of minimum margin of safety under working loads. For members with a straight strand profile, the critical section is also the point of maximum moment (usually the midspan). For members with a 1-pt depress, the critical point is close to 0.4L. For simply supported members with a 1-pt depress and uniform loads, the location of the critical point can be calculated using the following equation:

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P ⎤ ⎡ x = ⎢0.5 − (e mid − e end ) L (48M s ) ⎥⎦ ⎣

where: x

=

location of the critical point, measured from the end of the member

emid =

eccentricity of the strands at midspan

eend =

eccentricity of the strands at the end

P

effective prestressing force after all losses

=

Ms =

service load moment at midspan

L

overall length of the member

=

TH-6 / Theory ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Loads

For members with a 2-pt depress strand profile, nonlinear loads, or cantilevers, the critical point can occur practically anywhere. Note that PRESTO does not directly calculate the location of the critical point. The user should use the preceding discussion and their own judgment to determine if they need to enter additional analysis points to find the critical point.

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For members with only mild reinforcement, the program generates check points at the following locations: •

D: As per ACI 318-99/05, Art. 11.1.3.1 and CSA 23.3-94, Art. 11.3.2(a), sections between D and the face of the support may be designed for the same shear as that computed at a distance D.

•

L/4: It is a widely followed practice to use the shear steel required at L/4 through the middle half of the span.

•

Midspan: As with prestressed members, the maximum moment usually occurs at the midspan of the member.

C

The critical point for mild reinforced members usually occurs at the midspan, especially for simply supported members with uniform loads.

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Loads

PRESTO recognizes the following load classifications:

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•

Self-weight (SW): The program automatically calculates self-weight using the defined cross-section and any openings entered by the user.

•

Non-Composite Dead Load (DL): Non-composite dead loads are those permanent loads that are resisted by the precast section alone. One special non-composite dead load is the topping.

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•

Topping: The program automatically calculates the dead load of the topping based on the width and thickness assigned by the user.

•

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Superimposed Dead Load (SD): Superimposed dead loads (or the composite dead load) are those permanent loads applied to the composite section.

•

Composite Loads: These are presented to the user in slight variation in ACI 318-99 and CSA 23.3-94 with ACI 318-05 modes.

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•

•

Composite Snow Loads (SDS): In ACI 318-99 and CSA 23.3-94, the composite snow load is the load due to snow applied to the composite section.

•

External Loads on Composite (Lr/S/R): The external loads on composite that come from roof live loads/snow loads/rain loads according to ACI 318-05.

Live Loads (LL): Live loads are applied either to the non-composite or the composite section, whichever is applicable. Note that the live loads are not considered permanent.

PRESTO®v8.6 Theory ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ TH-7

Stresses – ACI 318-99

•

Sustained Live Loads (SL): Sustained live loads are the same as live loads but they apply on the beam for a considerably longer period of time (but not permanent).

Load factors are available to the user for both dead loads and live loads. Note that the topping is considered a dead load for the application of load factors. Multipliers are provided for self-weight at both release and service, thereby enabling the user to simulate inclined members (ignoring axial effects) and to analyze such members as horizontally cast wall panels.

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Stresses – ACI 318-99

Stresses are calculated at both release and final conditions. The calculated stresses are checked against the user-specified allowable stresses, and any calculated stresses found to be in excess of the allowable are flagged. Note that the program automatically calculates the allowable stresses based on ACI 318-99, Art. 18.4. Any of the calculated stresses may be overridden. One case where the user may want to override the calculated stress is when the member meets the requirements of ACI 318-99, Art. 18.4.2(d). In applying Art. 18.4.1(c), the end distance is considered as the transfer length distance from end.

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At release, the minimum required compressive strength of the precast is also calculated and printed for the user. If tension stresses are in excess of the allowable stresses at release, PRESTO automatically calculates the tension steel necessary to satisfy ACI 318-99, Art. 18.4.1.

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Stresses – ACI 318-05

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In ACI 318-05, stress computations and allowable limits are very similar to those in ACI 318-99 at release. PRESTO computes these stresses in accordance with ACI 318-05, Art. 18.4.1. At final, ACI 318-02, Art. 18.3.3 requires sections to be classified as U/T/C (Uncracked/Transition/Cracked) based on the total stress. Following is the classification criteria:

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Class

Tension Stress Range

U (Uncracked)

f t ≤ 7.5 f c′

T (Transition)

7.5 f c′ < f t ≤ 12 f c′

C (Cracked)

f t > 12 f c′

At final, PRESTO first computes individual stresses due to prestress, dead load, topping, etc. separately based on gross section properties. These computations are very similar to those for ACI 318-99. After computing the individual stress, the program computes total stress at each location. It then tries to classify the section as U/T/C.

TH-8 / Theory ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Stresses – ACI 318-05

There are several possible scenarios. In the first scenario, the entire section is in compression. In this case, the section is classified as U (Uncracked). In the second scenario, there is tension at the bottom of the section. PRESTO compares the stress at the precast bottom to the uncracked stress limit specified by the user. If stress is less than the maximum allowed for uncracked, the section is classified as U (Uncracked). If the actual total stress is more than the maximum allowed for uncracked but is less than the maximum allowed for in transition, the section is classified as T (Transition). If the total stress is more than the maximum allowed for transition, the section is classified as C (Cracked).

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In the third scenario for classification, tension exists at the top of the section. This tension could be at the top of the precast section or at the top of topping (in the case of a composite section), or at the top of both the precast section and the topping. If the section is non-composite (no topping present) and tension is less than the maximum allowed for an uncracked section, it is classified as U (Uncracked). If the tension is greater than the maximum allowed for uncracked but less than the maximum allowed for transition, it is classified as T (Transition). For a composite section classified as U (Uncracked), the stress at the precast top is less than the maximum allowed for the uncracked precast section and the stress at the topping top is less than the maximum allowed for the uncracked slab.

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C

A section will be classified as CS (Cracked Slab) if the stress in the slab is more than the maximum allowed in transition but stress in the precast top is less than the maximum allowed in transition. A section will be classified as CB (Cracked Beam) only if the stresses at the top of the precast beam exceed the maximum allowed for in transition. The remaining cases are classified as T (Transition) sections.

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When a section is classified as CS or CB, PRESTO recomputes the cracked section properties and total stresses in the cracked section. In this scenario, the program assumes the concrete in a cracked section does not take any tension. Its tension contribution is ignored. This is in line with the methodology presented in the paper, “Analysis of Cracked Prestress Concrete Sections: A Practical Approach,” by Dr. Robert F. Mast (Ref. [5]). This has been suggested in ACI 318-05, Art. R18.3.2.2 for such stress calculations.

a u

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When crack is at the bottom, the program-computed crack depth is from the bottom of the section to the neutral axis. Stresses are then computed that are zero at the location of the section and at the top of the crack depth (neutral axis). In this case, all tension is resisted by transformed steel. Refer to the detailed methodology in the paper by Dr. Mast (Ref. [5]). For a composite section with cracking at the top, PRESTO uses the following approach. It first computes stresses at the top of the precast and the top of the slab using uncracked section properties. If stresses at the top of topping are such that it is cracked, the program checks the top of the precast section for cracked stresses and classifies the section as C (Cracked). The program then computes crack depth, cracked section properties, and compressive stress at the bottom of the precast. If, on the other hand, stresses computed with uncracked section properties show that only the slab is cracked, the stresses are computed again. This time, the program ignores any concrete slab and uses the uncracked section properties of the precast section along with any rebar in the slab to determine stresses at the precast top. If stresses are such that the section is cracked, it is classified as C (Cracked) and the

PRESTO®v8.6 Theory ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ TH-9

Stresses – CSA 23.3-94

approach previously discussed is used to compute crack depth, section properties, and stresses. In a case where the topping is cracked but the precast section is not, the section is classified as CS. The crack depth will be equal to the thickness of the slab at that location. However, the stresses will be based on the uncracked precast section ignoring any slab concrete but considering any slab rebar.

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In the last possible scenario, topping does not crack but the precast section cracks. This is classified as CB. In this scenario, the program conservatively ignores the slab and crack is considered to extend from the top of the slab to the neutral axis of the section and considers only the cracked precast section and any rebar in the topping. Stresses are based on these section properties. In order to compute sections based on gross (uncracked section properties), change the allowables for U and T limits to a large value that does not let this section crack. The results based on gross section can then be waived; however, this should be exercised very carefully.

C

The limits specified in Art. 18.4.2 are applicable only for U and T sections.

Stresses – CSA 23.3-94

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Stresses are calculated at both release and final conditions. The calculated stresses are checked against the user-specified allowable stresses, and any calculated stresses found to be in excess of the allowable are flagged. Note that the program automatically calculates the allowable stresses based on CSA 23.3-94, Art. 18.4.2. Any of the calculated stresses may be overridden. One case where the user may want to override the calculated stress is when the member meets the requirements of CSA 23.3-94, Art. 18.4.2(d).

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At release, the minimum required compressive strength of the precast is also calculated and printed for the user. If tension stresses are in excess of the allowable stresses at release as per CSA 23.3-94, Art. 18.4.1, PRESTO automatically calculates the tension steel necessary to satisfy CSA 23.3-94, Art. 18.4.1.2.

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Crack Control – ACI 318-99/05 requires a check on the distribution of reinforcement in nonprestressed beams to control cracking. PRESTO determines the required spacing of rebar based on Eq. 10-4 as required in Art. 10.6.4. To determine this required spacing, the program uses the fs value, which is 2/3 of fy. This check is done at the bottom of a reinforced section if it is under positive moment or at the top if it is under negative moment. In a negative moment scenario, the program computes the provided spacing at the top of section at the location of steel closest to the extreme tension face.

ACI 318-99/05, Art. 10.6

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requires a check for the spacing of rebar and bonded prestressing for sections that are classified as C (Cracked). This ensures that cracks are controlled. For cases where crack occurs at the bottom, the program checks crack control at bottom. For cases when crack occurs at top, the program checks this in the slab if the section is cracked and has a slab. When there is no slab and crack is at top, the program checks the top of the precast section.

ACI 318-05, Art. 18.4.4

For a precast section, if the provided steel closest to the extreme tension face is nonprestressed steel, the program computes the required spacing as per Art. 10.6.4.

TH-10 / Theory ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Crack Control – CSA 23.3-94 and ACI 318-95

However, if the steel is a strand, the program computes required spacing based on Arts. 18.4.4.2 and 18.4.4.3. If mixed rebar and strands are present, the program computes required spacing for strand and rebar and uses whichever is critical. For required spacing (S-req) calculations, clear cover plays an important role. A large value may result in a negative value for S-req and the program limits S-req to 7.00 inches. Please note that the user must revise the steel pattern to reduce clear cover that results in adequate crack control.

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To compute provided spacing, the program determines the number of rebar plus any strands that are distributed in the tension width (TensWid). When there is only one bar/ strand present at the tension face, S-prov is equal to TensWid. When two or more bars/ strands are provided in a section, considering the largest spacing between any two bars as the provided spacing. PRESTO indicates if the bars/strands are provided with more average spacing than

C

required. For C (Cracked) sections, delta fps is determined based on the stress/strain diagram for the cracked section. If delta fps is less than 20 ksi, there is no need to check this spacing as suggested in Art. 18.4.4.3 and the program reports it as not required. For U (Uncracked) and T (Transition) prestressed concrete sections, this requirement does not apply and the program does not compute required spacing.

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Crack Control – CSA 23.3-94 and ACI 318-95

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and ACI 318-95, Art. 10.6.4 require quantity z to be computed. These codes also provide limiting values for interior and exposure. For the calculation of z, the program uses fs = 0.6fy as permitted by CSA 23.3-94 as well as ACI 318-95. If the clear concrete cover is greater than 2 inches (50 mm), the program uses a limiting value of de = 2 in (50 mm). For epoxy-coated rebar, CSA 23.3-94, Art. 10.6.1 allows for the modification of the value of z by a factor of 1.2. In this case, the user may specify the computed value in the program. CSA 23.3-94, Art. 10.6.1

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Ultimate Strength – ACI 318-99/05

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The nominal internal resisting moment Msc is computed using strain-compatibility assumptions, which conform to ACI 318-99/05. The following assumptions are used:

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1.

A rectangular “Whitney stress block” replaces the parabolic concrete stress block as allowed per ACI 318-99/05, Art. 10.2.7.1. The depth of the stress block, a, is calculated as: a = β1c where: ß1 =

factor defined in ACI 318-99/02, Art. 10.2.7.3, using the compressive strength of the concrete at the compression face

c

depth to the neutral axis

=

NOTE: When computing the depth of the neutral axis, the program uses f’c (slab) for computing the positive moment region and f’c (precast) for the negative moment regions.

PRESTO®v8.6 Theory ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ TH-11

Ultimate Strength – CSA 23.3-94

2.

An elastic-ideal plastic stress-strain relationship is used for mild steel as allowed in ACI 318-99/05, Art. 10.2.4. The modulus of elasticity for mild steel can be specified by the user.

3.

Two options for idealized stress-strain curve are available for the prestressing strand.

4.

Plane sections remain plane.

5.

Any change of strain in the reinforcement after release is accompanied by an equal change of strain in the adjacent concrete (i.e. no slippage).

6.

Final concrete strain at the extreme compression fiber is limited to 0.003 as per ACI 318-99/05, Art. 10.2.3.

7.

If the topping is in the compression zone then the concrete strength of the topping is used when calculating the internal resisting moment.

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C

The equilibrium of forces (ΣC = ΣT) is determined from the geometry of the strain diagram and the stress-strain curves for both strand and mild steel. An iterative approach is used to calculate the depth of the neutral axis, and after each iteration, ΣC and ΣT are recalculated and compared. The iteration loop proceeds until the difference between the two values is negligible. Note that in the calculation of ΣC an equivalent force is subtracted for each steel level within the compressive stress block to account for the displaced concrete. When ΣC and ΣT have converged, the moments are summed about the compression face and the provided moment is:

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where:

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l a

n o Msc = φMn

Msc =

provided moment strength based on strain compatibility

f

strength reduction factor for flexure

=

Mn =

nominal moment strength

Ultimate Strength – CSA 23.3-94

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The nominal internal resisting moment Msc is computed using strain-compatibility assumptions, which conform to CSA 23.3-94. The following assumptions are used: 1.

Equivalent rectangular concrete stress distribution replaces the parabolic concrete stress as allowed in CSA 23.3-94, Art. 10.17. The depth of the stress block, a, and the stress in the rectangular block, are calculated as: Concrete strength = α1φcf’c a = β1c where: α1 =

factor defined in CSA 23.3-94, Art. 10.1.7(c) to compute equivalent rectangular compressive stress in concrete

TH-12 / Theory ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Ultimate Strength – CSA 23.3-94

φc =

resistance factor for concrete. As per CSA 23.3-94, Art. 8.4.2.

f’c =

specified compressive strength of concrete

ß1 =

factor defined in CSA 23.3-94, Art. 10.1.7(c) using the compressive strength of the concrete at the compression face

c

depth to the neutral axis

=

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NOTE: When computing the depth of the neutral axis, the program uses f’c (slab) for computing the positive moment region and f’c (precast) for the negative moment regions.

2.

An elastic-ideal plastic stress-strain relationship is used for mild steel as allowed in CSA 23.3-94, Art. 8.5.3.2. The modulus of elasticity for mild steel can be specified by the user.

3.

Three options for idealized stress-strain curve are available for the prestressing strand including the one specified in Fig. 8.2.4 of the CPC1 Design Manual, 3rd Edition (Ref. [4]).

4.

Plane sections remain plane.

5.

Any change of strain in the reinforcement after release is accompanied by an equal change of strain in the adjacent concrete (i.e. no slippage).

6.

Final concrete strain at the extreme compression fiber is limited to 0.0035 as per CSA 23.3-94, Art. 10.1.3.

7.

If the topping is in the compression zone then the concrete strength of the topping is used when calculating the internal resisting moment.

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C

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The equilibrium of forces (ΣC = ΣT) is determined from the geometry of the strain diagram and the stress-strain curves for both strand and mild steel with φc, φs, and φp applied to forces computed in concrete, reinforcing bar, and prestressing tendons respectively as specified in CSA 23.3-94, Arts. 8.4.2 and 8.4.3. An iterative approach is used to calculate the depth of the neutral axis, and after each iteration, ΣC and ΣT are recalculated and compared. The iteration loop proceeds until the difference between the two values is negligible. Note that in the calculation of ΣC an equivalent force is subtracted for each steel level within the compressive stress block to account for the displaced concrete. When ΣC and ΣT have converged, the moments are summed about the compression face and the provided moment is φ = Msc.

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PRESTO®v8.6 Theory ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ TH-13

Prestressing Strand – Stress-Strain Curves

Prestressing Strand – Stress-Strain Curves PRESTO has three sets of stress-strain curves for prestressing strands. The first set is

as per the PCI Design Handbook (5th Edition). As per Design Aid 11.2.5, the following equations are used to determine the stress for a specific strain value. fps

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Eps = 28,500 ksi fpu = 270 ksi fpu = 250 ksi

0.0086

0.0076

C

ps

FIGURE TH-2. Stress-Strain Curves per PCI Design Handbook 5th Edition

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PCI Design Handbook (5th Edition) 250ksi

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f ps = 28,500εps (ksi) when εps ≤ 0.0076

f ps = 250 −

0.04

εps − 0.0064

(ksi ) when εps > 0.0076

a u

270 ksi

f ps = 28,500εps (ksi ) when εps ≤ 0.0086

f ps = 270 −

0.04

εps − 0.007

(ksi ) when εps > 0.0086

There is slight discontinuity in the two equations for 270 ksi steel. To overcome this in this program, we limited the computed stress to be less than 245 ksi when we use the equation for the elastic region. The stress-strain curve for prestressing strand has a linear and a nonlinear segment. Previous versions of PRESTO used different stress-strain curves than specified by code because of discontinuity in the linear and nonlinear segments of the curve. This is available as an option and uses the following equations.

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fps fpu = 270 ksi fpu = 250 ksi

Es

0.0078

Eps

FIGURE TH-3. Stress-Strain Cures for Prestressing Strand

TH-14 / Theory ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Prestressing Strand – Stress-Strain Curves

PRESTO 8.2 and Older Methodology 250ksi

270 ksi

f ps = E sεps when εps ≤ 0.0078

f ps = E sεps when εps ≤ 0.0078

⎡ f ps = 250 − ⎢ ⎢⎣

⎡ 0.03816 ⎤ f ps = 270 − ⎢ ⎥ when ε ps > 0.0078 ⎢⎣ (ε ps − 0.007)⎥⎦

0.2361 εps + 0.0017

(

)

⎤ ⎥ when εps > 0.0078 ⎥⎦

FIGURE TH-4. PRESTO 8.2 and Older Methodology

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where: Es =

Elasticity of strand = 28,500 ksi

εps =

strain in strand

fps =

stress in strand corresponding to εps

fpu =

ultimate tensile strength of the strand

a u

l a

n o

i t

Ep = 190,000 MPa

fps

C

fpu = 1860 MPa

fpu = 1720 MPa

0.0065 0.008

Ep

FIGURE TH-5. Stress-Strain Cures for Prestressing Strand Elasticity

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CPCI Design Handbook (Metric units) 1860 MPa

f ps = E s ε ps when ε ps ≤ 00.008 .0078

f ps = 1848 −

where: Es

0.517

εps − 0.0065

=

< 0.98 f pu ( MPa )

1720 MPa

f ps = E s ε ps when ε ps ≤ 00.008 .0078

f ps = 1710 −

0.400

εps − 0.006

< 0.98 f pu (MPa )

Elasticity of strand = 190,000 MPa

PRESTO®v8.6 Theory ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ TH-15

Design Methodology – ACI 318-99

εps

=

strain in strand

fps

=

stress in strand corresponding to εps

fpu

=

ultimate tensile strength of the strand

Design Methodology – ACI 318-99

y p o

Before a prestressed section is checked to see if it is over-reinforced, the average depth, dsc, to the tension force centroid based on strain-compatibility is computed using the following equation: d sc =

(∑ Psi d si + ∑ Pmjd mj ) (∑ Psi + ∑ Pmj )

where:

C

Psi =

prestressed force in the ith strand level as determined by straincompatibility (including strands in the compression block, if any)

dsi =

depth to Psi

Pmj =

mild steel force for the jth steel level in the tension zone only, as determined from strain-compatibility

dmj =

depth to Pmj

n o

i t

If the depth to the neutral axis calculated from strain-compatibility, c, is greater than the over-reinforced limit implied by ACI 318-99 of cor = 0.4235 dsc, then the section is considered over-reinforced. Reduced design strength is calculated as required by ACI 318-99, Art. 18.8.2. A new strain diagram is drawn where the depth to the neutral axis is taken as equal to cor. Only the forces in the compression zone are considered and moments are taken about dsc. The following equation is used to calculate Mor:

a u

l a

Mor = φ[dsc – dc)Cc + Σ(dsc – dmj)Cmj]

where:

v E

f

=

0.9

Cc =

concrete compression force

dc =

depth to the centroid of Cc

Cmj =

compressive force in the mild steel at the jth level in the compression zone

dmj =

depth to Cmj

The factor 0.4235 can be derived from the relationship between ωp and the depth to the neutral axis. The critical ratio, ωp, for the rectangular section is defined in ACI 318-99 as:

TH-16 / Theory ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Design Methodology – ACI 318-99

⎛ A ps ω p = ⎜⎜ ⎝ bd sc

⎞⎛ f ps ⎟⎟⎜⎜ ⎠⎝ f c′

⎞ A ps f ps ⎟⎟ = = 0.36β1 ⎠ (bd or f c′ )

Given that (Apsfps) = T (total tensile force at ultimate), and T = C (total compressive force), we can say that:

y p o

(A ps f ps ) = C = 0.85f c′ bβ1c or

Substituting the above equation into the equation for ωp, we obtain the following:

(0.85f c′ bβ1c or )

(bd sc f c ' )

= 0.36β1

which reduces to: cor 0.36 = = 0.4235 dsc 0.85

n o

C

Over-reinforcement for a member reinforced with only mild steel is calculated differently than that for a prestressed member. Mild reinforced members use reinforcement ratios to check for both minimum reinforcement and overreinforcement. The intent remains the same as for prestressed members, however, to ensure ductile behavior at ultimate conditions. The maximum amount of tension reinforcement is calculated as per ACI 318-99, Art. 10.3.3. Required minimum reinforcement is checked against the provisions of ACI 318-99, Art. 10.5.

i t

a u

The cracking load provision for prestressed members from ACI 318-99, Art. 18.8.3 is interpreted as the lower limit of the ratio of the ultimate moment capacity and the cracking moment at that section which will fail first if the applied loads are increased linearly to failure. This is the section with the least value of moment capacity/ultimate moment ratio Mn/Mu (i.e., the least factor of safety).

l a

v E

The cracking moment (Mcr) computed in this context is the sum of the total dead load moment plus the additional live load moment required to develop a tensile stress equal to the modulus of rupture. The point of reference for computing Mcr for sections with net positive moment is the bottom of the precast section. However, it should be noted that for sections of net negative moment, the point of reference is: (1) the top of the precast for untopped sections; or (2) the top of the topping for topped members. Satisfaction of the cracking moment criteria can sometimes be difficult to achieve. Two conditions seem to recur which we will identify here in order to give insight into this problem. •

First, short members with very stiff sections and few strands tend to have very large cracking moments (high denominators) with low ultimate capacities (low numerators). The result then is low cracking ratios. The strategy of effective treatment for this problem is to increase the amount of non-prestressed reinforcement. This can be accomplished by increasing the

PRESTO®v8.6 Theory ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ TH-17

Design Methodology – ACI 318-05

number of strands while reducing the overall pull, or adding supplemental rebar, or both. •

Second, short members, though not necessarily unusually stiff, can suffer cracking ratio problems near the end regions due to insufficient development of the strands at ultimate conditions. This is especially common when a development length multiplier greater than one is used. Adding nonprestressed reinforcement can often remedy this situation.

•

Finally, note that Art. 18.8.3 of ACI 318-99 allows you to ignore the cracking moment if the member has twice the shear and flexural capacity required by Art. 9.2.

y p o

In ACI 318-99, the specifications to control cracking in reinforced concrete sections were revised completely. Now, the maximum bar spacing is specified instead of cracking index, z. PRESTO uses ACI 318-99 Eq. 10-5 to calculate the required spacing of bars. In Art. 10.6.4, it is permitted to use fs as 60 percent of specified yield strength. By default, PRESTO uses this value but you may specify a different value. Clear cover is the distance between the extreme tension rebar face to the tension face of the beam.

n o

Design Methodology – ACI 318-05

C

In the ACI 318-05, Art. 10.3 requires the sections to be classified as Tension Controlled, In Transition, or Compression Controlled. PRESTO uses the criteria outlined in Arts. 10.3.3 and 10.3.4 to determine this and then applies φ factors as per Art. 9.3.2. PRESTO first determines the layer of strand or rebar closest to tension face. Distance from extreme compression fiber to this layer of steel closest to the extreme tension face is defined as dt. The program then computes the distance to neutral axis, c, for the applied moment from extreme compressive force and then determines c/dt value. It then compares these c/dt values with those in Art. R9.3.2.2. PRESTO uses the following ranges as per that section:

i t

a u

l a

v E

Controls

TENS (Tension Controlled)

TRANS (In Transition)

COMP (Compression Controlled)

c/dt range

Phi Factor

c ≤ 0.375 dt

0.90

0.600 ≤

c ≤ 0.375 dt

c > 0.600 dt

0.90 ≤ φ ≤ 0.65

0.65

If the section is classified as an In Transition section, PRESTO calculates an interpolated value based on a linear variation of φ with c/dt. Note that the values used in this section are as per code and are default values set in this program. However, users can override these values by either manually modifying these values or using the Save Settings feature.

TH-18 / Theory ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Shear – ACI 318-99/05

y p o

FIGURE TH-6. Variation of φ with c/dt

Shear – ACI 318-99/05

C

Vertical shear is usually considered resisted by the precast section web only. However, if the user directs the program to use the composite depth for shear, then both the precast web and the topping directly above the web will be used to resist shear. In this case, the user must make sure that the web reinforcement extends into the topping as required by ACI 318-99/05, Art. 17.4. When you select composite depth, f'c for girder is used for composite section shear calculations.

n o

i t

For prestressed members, there is generally some confusion associated with the terms Mmax (maximum factored moment at section due to externally applied loads), Mcr (moment causing flexural cracking at section due to externally applied loads), and Vi (factored shear force at section due to externally applied loads occurring simultaneously with Mmax) as defined in ACI 318-99/05, Eq. (11-10). The Commentary for Art. 11.4.2 states, “In deriving Eq. (11-10) it was assumed that Vci is the sum of the shear required to cause a flexural crack at the point in question…plus an additional increment of shear required to change the flexural crack to a flexure-shear crack.”

a u

l a

VM Vci = 0.6 f c′ b w d + Vd + i cr M max

v E

When coupled with the equations for Vi and Mmax, (ACI 11.4.2), it implies that:

Eq. (11-10) 318-99/05, Commentary, Art

•

Vd is the shear force due to dead load (Md being the corresponding moment);

•

(Vi Mcr)/Mmax is the shear force due to live load causing flexural cracking; and

•

0.6( fc' )bwd is the extra shear required to turn it into the flexure-shear crack.

PRESTO®v8.6 Theory ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ TH-19

Torsion – ACI 318-99/05

From the mechanics of failure described above, it is clear that Vd is the shear force resulting from total dead load at the section (assuming it does not cause cracking). The equations in ACI 318-99/05 Commentary indicate that Mmax is the difference between Mu (factored moment at the section) and Md (moment due to unfactored dead load), and that Vi is the difference between Vu (factored shear force at the section) and Vd (shear force due to unfactored dead load). Since the term (Vi Mcr)/Mmax represents the extra shear developed at the section (in addition to Vd) when the section develops

y p o

6 f c′ , it follows that the term Mcr (for the purpose of shear

cracking tension of

computations) is the live load moment required to develop this cracking tension. ACI appears to assume a linear increase in shear as the applied moment is increased from Md to Mu. This definition of Mcr also agrees with ACI 318-99/05, Eq. (11-11) when applied to a purely precast section. Nevertheless, Mcr is computed from the first principles since Eq. (11-11), in its given form, is unsuitable for composite sections and for various shoring conditions. 318-99

C

According to the Commentary for ACI 318-99/05, Art. 11.5.5.4, tests of prestressed beams with minimum web reinforcement based on Eq. (11-13) and Eq. (11-14) (if applicable) indicated that the smaller Av obtained from these two equations was sufficient to develop ductile behavior. Therefore, PRESTO computes minimum shear steel from both equations unless midspan effective pressure is less than 40 percent, and adopts the smaller value. The gross prestressed steel area, Aps, used in Eq. (11-14) disregards the effects of shielding and development length. Peff used in calculations is reduced according to the transfer length near the end of the member. For beams where midspan prestress is less than 40 percent, PRESTO computes minimum steel only based upon Eq. 11-13.

n o

i t

a u

Vertical shear for mildly reinforced members is calculated using the applicable equations from ACI 318-99/05, Arts. 11.3 and 11.5. It is assumed that the axial tension is not significant.

l a

v E

As required by ACI 318-99/05, Art. 17.5.2, PRESTO uses the total vertical shear for the horizontal shear computation at the section under consideration. This is equivalent to setting “Q/IB” of the classical relation “VQ/IB” equal to 1. Only loads applied on the composite section are considered.

Torsion – ACI 318-99/05 Torsion design specifications in ACI 318-99/05 are based on the thin-walled, space truss analogy. PRESTO follows Art. 11.6 of this code for design of sections subjected to torsion.

According to ACI 318-99/05, it ignores the concrete torsional capacity of the section. This means that value of concrete shear capacity (Vc) is not affected by the presence of torsion at a section. Further all the torsion has to be resisted by providing closed stirrups. recommends that you ignore the torsion if it is less than 25 percent of the cracking torsional moment. However, if the present torsion is more than

ACI 318-99/05, Art. 11.6.1

TH-20 / Theory ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Shear and Torsion - PCI Design Handbook, 6th Edition

that, the section must contain closed shear stirrups to resist the total torsion present. Section capacity with additional torsional reinforcement is computed using ACI 318-99/ 02, Eq. 11-21. For a prestressed section with effective prestress of larger than 40 percent of its tensile strength, the value of θ is taken as 37.5 degrees. For sections with lesser prestress or reinforced sections it is taken as 45 degrees. Acp and Pcp computed by PRESTO are based on the actual concrete section. However, Aoh and ph computation is based on the entire section for rectangular, hollow core, key joist and slab. For other shapes, only the web stem widths are used to compute these parameters and will be equal to results for one stem multiplied by number of stems. For variable width stems, the average width is used in computations.

y p o

When torsional reinforcement is required, PRESTO also checks for additional longitudinal reinforcement as per ACI 318-99/05, Eq. 11-22. This reinforcement should be distributed uniformly around the sides of the perimeter. PRESTO does not reduce the longitudinal reinforcement as specified in ACI 318-99/02, Art. 11.6.3.9.

C

If torsional steel is required, minimum transverse reinforcement must be checked according to ACI 318-99/02, Art. 11.6.5.2 and minimum longitudinal reinforcement is checked as per Art. 11.6.5.3. The maximum spacing of the torsion design required is determined based upon ACI 318-99/02, Art. 11.6.6.1. However, since PRESTO only computes the additional reinforcement, the distribution along the perimeter is left to the user to define, and who should follow the guidelines of ACI 318-99/05, Arts. 11.6.6.2 and 11.6.6.3 for the detailing of such reinforcement.

n o

i t

PRESTO also checks for compression allowed and compression present in the section

as per ACI 318-99/05, Eq. 11-18 for nonvoided section and Eq.11-19 for voided (hollow) sections. The correction of Art. 11.6.3.3 is applied for thin sections for the computation of compression present in the section.

a u

Shear and Torsion - PCI Design Handbook, 6th Edition When this option is selected on the Design Parameters screen, the program calculates the shear and torsion as per the PCI Design Handbook (6th edition) methodology section 4.4 Torsion. (Reference 9 in Appendix 6). This option is provided as an alternate to the conservative design suggestions from ACI 318-02. This option is available for all sections other than hollow core slabs in the current version due to complications in the computation of x2y for hollow core sections.

l a

v E

Shear and Torsion – CSA 23.3-94 provides two methods for shear and torsion design. As per CSA 23.3-94, Art. sections not subject to significant axial tension may be designed using the simplified approach as per Art. 11.3. For other cases, it requires that shear and torsion be designed using the general method as per Art. 11.4 of the code or using the STA option of Art. 11.5. PRESTO provides user options to design for shear and torsion using either the simplified method (Art. 11.3) or the general method (Art. 11.4). CSA 23.3-94 11.1.1,

When applying the simplified method, concrete section shear capacity, Vc, for reinforced sections is based on Art. 11.3.5 and, for prestressed concrete sections, is computed using CSA 23.3-94, Arts. 11.3.6 and 11.3.7. CSA 23.3-94, Eq. 11-8 is very similar

PRESTO®v8.6 Theory ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ TH-21

Camber and Deflections

to ACI 318-99/05, Eq. 11-10, which is discussed in detail beginning on page TH-19. The same approach is adopted for CSA implementation. If applied torsion on the section is less than the limiting value of 0.25Tcr, as specified in CSA 23.3-94, Art. 11.2.9.1, no torsion reinforcement is needed. However, if applied torsion is more than the limiting value, the program computes the required torsional steel based on Art. 11.3.9.4 and longitudinal steel using Art. 11.3.9.5. Minimum total transverse steel requirements are based on Arts. Maximum spacing of transverse stirrups is based on Art. 11.2.11.

y p o

11.2.8.1

Program uses fps as computed by strain compatibility.

and

11.2.8.4.

When a user applies the general method for shear and torsion calculations, the program computes Vc based on Art. 11.4.3.1. For calculations using this method, the programs uses dv in computations. Where dv is the distance between the resultant compressive and tension forces due to flexure but not less than 0.9d.

C

In Vc calculations, the program uses the computed value of θ and β as per Art. 11.4.4, Table 11.1 for sections with at least the minimum transverse steel. The program computes ∈ x using Eq. 11-22 and factored shear stress using Eq. 11.21. It then interpolates in Table 11.1 to arrive at the θ and β values. Once β is determined, required stirrup area is determined using Eq. 11-19 in CSA 23.3-94, Art. 11.4.3.2.

n o

When torsion is also present and the general method is used, the program uses

i t

Art.

11.4.10.3 for computation of Σx and Vf. Torsion reinforcement is computed using Eq. 11-

of CSA 23.3-94. Art. 11.4.10.3.

25

When selecting the composite depth for using shear calculations, program still uses the girder fc and φc values to arrive at concrete capacity.

a u

Camber and Deflections

Camber and deflections are computed using the procedure outlined in the PCI Design Handbook (5th Edition). Release, erection, and final conditions are checked. This procedure requires applying the coefficients to the release deflections for prestress and self-weight; cantilevered sections were handled as follows:

l a

v E

1.

A set of initial deflections was computed for prestress and self-weight using release properties but final support conditions.

2.

Appropriate multipliers were applied to these values in order to arrive at the erection and final deflection.

3.

The actual computational procedure used was a variation of the standard conjugate beam method.

Using the symbol M-I(J) as the moment of the M/EI diagram between two points, I and J, about the point J, and denoting the left and right supports as points A and B, it can be shown that the deflection at any point X, from the chord AB, is the reaction at B when a downward force equal to M-A(B) is applied at point X and an upward force equal to M-A(X) is applied at point B. This procedure is valid for the simple span region and the right cantilever. A slightly modified procedure is applicable to the left cantilever.

TH-22 / Theory ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Camber and Deflections

Long-term camber and deflections are computed using multipliers suggested by Table of the PCI Design Handbook (5th Edition) and Fig. 3.5.4 of the CPCI Design Manual (3rd Edition); however, the user may modify these.

4.8.2

If non-prestressed reinforcement is added to a member, final camber and deflection multipliers are recomputed by Eq. 4.8.6 of the PCI Design Handbook (5th Edition) or Art. 3.5.4 of the CPCI Design Manual (3rd Edition):

C1 + C2 = 1+

y p o

As A ps

As A ps

PCI, Eq. 4.8.6

where:

C

C1 =

multiplier from the PCI Design Handbook, the CPCI Design Handbook, Fig. 3.5.4

C2 =

revised multiplier

As =

area of non-prestressed steel

Aps =

area of prestressed steel

n o

Figure 4.8.2 (Ref. [9])

or

i t

ACI 318-99, Art. 18.4.2(d), requires that the deflection be computed using the bilinear load-deflection relationship for the case of fiber stress in tension in a precompressed tensile zone of members exceeding the modulus of rupture (fr). In ACI 318-99 mode, the program leaves it to the user to activate the option to compute bilinear deflections.

a u

ACI 318-05, Art. 18.3.5 provides guidance on calculation of deflections. For uncracked sections, the code suggests to use Art. 9.5.4.1. For transition and cracked sections, the code suggests to use Art. 9.5.4.2, which provides guidance of calculations using bilinear deflections methodology. Depending upon the behavior if a section is cracked, PRESTO automatically computes deflections based on bilinear methodology.

l a

v E

The code stipulation “to compute the deflection, using the cracked cross-section and the transformed areas of bonded reinforcement to compute the member stiffness” was limited to the midspan point (halfway between the supports) since Art. 9.5.2.4 of the Commentary states that: “The use of the midspan section properties for continuous prismatic members is considered satisfactory in approximate calculations primarily because the midspan rigidity (including the effect of cracking) has the dominant effect of deflections....” The effective moment of inertia used to calculate deflections is calculated by:

⎡ ⎛M ⎛M ⎞ I e = ⎜⎜ cr ⎟⎟ I g + ⎢1 − ⎜⎜ cr ⎢ ⎝ Ma ⎝ Ma ⎠ ⎣ 3

⎞ ⎟ ⎟ ⎠

3⎤

⎥ I cr ⎥ ⎦

ACI 318-99, Eq. (9-7)

ACI 318-05, Eq. (9-8)

PRESTO®v8.6 Theory ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ TH-23

Camber and Deflections

where:

M cr = f r

ACI 318-99, Eq. (9-8)

Ig yt

ACI 318-05, Eq. (9-9)

fr

=

modulus of rupture

Ig

=

moment of inertia of the gross section

y p o

Icr =

moment of inertia of the cracked section transformed to concrete

Ma =

maximum moment at stage deflection is computed

PRESTO considers the following five load stages:

A

=

Prestress + Self weight

B

=

A + Dead load on precast

C

=

B + Topping weight

D

=

C + Dead load on composite

E

=

D + Live load

n o

C

i t

An interesting problem arises from ACI 318-99, Art. 9.0, which defines the gross moment of inertia, Ig, as “the moment of inertia of gross concrete section about centroidal axis, neglecting reinforcement.” It is unclear why the transformed moment of inertia has been omitted since the above definition creates an anomalous condition where in cases of heavily reinforced, flanged members, Ie may be larger than Ig of the concrete section alone.

a u

The reason for this anomaly is simple. Eq. (9-7) of ACI 318-99 (Eq. (9-8) of ACI 318-05) is a curve representing the transition of the effective moment of inertia. As stated in the Commentary to Art. 9.5.2.5, “The effective Ie was developed to provide a transition between the upper and lower bounds of Ig and Icr as a function of the ratio Mcr/Ma. For most practical cases Ie will be less than Ig.”

l a

v E

This transition ranges from an uncracked section for low levels of applied moment (Ma) to a cracked section when Ma literally approaches infinity. However, while the uncracked moment of inertia (Ig) does not consider the transformed steel, the cracked moment of inertia (Icr) does. It would appear logical to consider the transformed steel in both the calculations of Ig and Icr in order to eliminate the possibility of an actual increase in moment of inertia when a section cracks. PRESTO adopts the following procedure when the ACI 318-99/05 code definition of Ig

is used to compute uncracked deflections: 1.

Ig and Icr are computed at midspan.

2.

Ma and Ie are computed for the five load stages.

TH-24 / Theory ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Development Length

3.

A deflection multiplier (Ig/Ie) is computed for each load stage, with a lower limit of 1 (to avoid the anomalous condition where Ie > Ig).

4.

The uncracked deflection for each load component is computed with an applicable long-term modifier (PCI Design Handbook (5th Edition), Eq. 4.8.6 and Table 4.8.2 or the CPCI Design Manual (3rd Edition), Art. 3.5.4 and Fig. 3.5.4).

5.

Uncracked deflections for each load stage are obtained by adding the component values.

6.

The cracked deflection for each load stage is obtained by multiplying the uncracked value with corresponding Ig/Ie.

7.

Finally, the cracked deflection due to each load component is obtained by subtracting the deflection for each load stage from the successive stage.

y p o

C

Note that the effective moment of inertia, Ie, is not applied to all loads, but only to those cases where loadings cause the curvature of the beam to exceed zero.

It is clear that a considerable gap can occur between computed deflections and actual deflections when one considers the approximate nature of prestress losses, long-term coefficients, elasticity, modulus of rupture, applied loading, extent of cracking, ambient conditions and myriad other factors. Therefore, extreme accuracy for a basically imprecise computation as prestressed member deflection seems unwarranted. Please note that this computation is not an accurate prediction but rather the translation of certain code formulas and provisions based on LEAP’s knowledge and understanding.

Development Length

n o

a u

i t

Computation of development length (ld) of prestressed strand from ACI 318-99/05, Art. 12.9.1 and CSA 23.3-94, Art. 12.9.1 results in a circular calculation. To calculate the development length we must first calculate fps (stress in prestressed reinforcement at nominal strength). This requires, however, that we first calculate the effective area of strand present at a section.

l a

v E

In addition, fps itself varies from point-to-point. To calculate the effective area of strand at a specific section, we must first know the development length. It is readily apparent that an “exact” application of the ACI Code provisions will result in a computational complexity of unwarranted magnitude that yields no perceptible benefit.

In the past, it has been customary to use simplifying assumptions to break the impasse, with fps computed at midspan being the most commonly used assumption. While this approach is satisfactory for basic cases such as simple span symmetrical beams with symmetrical strand patterns, it presents problems for the cases with end-pattern extents and unsymmetrically located multiple depress points that PRESTO simulates. Thus, it was considered prudent to compute ld with fps set equal to fpu (specified tensile strength of prestressing tendons), which results in conservative values. PRESTO computes an effective area of strand in regions of partial development at

ultimate conditions by handling each strand separately. The development curve of prestressed strands is idealized as the bilinear curve in the following figure. The

PRESTO®v8.6 Theory ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ TH-25

Lightweight Concrete

effective area of strand is the full area of a strand times the percentage of fps that the strand realizes as determined from the curve below.

f ps

y p o

f se S tra nd S tres s ( k s i)

d b 50 D is t a n c e F r o m B e a m E n d

n o

C ld

FIGURE TH-7. Development Curve of Prestressed Strands

Development length calculations for mild rebar follows the procedures outlined in Chapter 12 of ACI 318-99/05 and Chapter 12 of CSA 23.3-94. PRESTO automatically determines whether the bar is in compression or tension and uses the correct development length for that case. Program uses the formulas for other case rebars of ACI 318-99/05 Arts 12.2.2 and CSA 23.3-94 Table 12-1. Note that rebar which is mechanically anchored is always assumed to be fully developed.

a u

i t

Lightweight Concrete

The provisions of Arts. 9.5.2.3(b) and 11.2.1.2 of ACI 318-99/02 and Art. 8.6.5 of CSA 23.394 refer to grades of lightweight concrete as “all-lightweight” and “sand-lightweight.” To simplify computations, the lightweight concrete multiplier (Lambda) was assumed to vary linearly from 0.75 to 1.0 over a concrete unit weight range from 110 pcf to 150 pcf (1750 kg/m3 to 2400 kg/m3).

l a

v E

Reduction Factors The user can assign capacity reduction factors (φ) for flexure and shear, as well as the reduction factors for concrete, rebar, and prestressing. These factors, in conjunction with the load factors available to the user, are helpful for conformance with codes other than ACI and CSA. Please note that ACI requires only φ for flexure and shear to be used and does not use material related to φ factors. Whereas CSA uses φ factors for material only and does not use f flexure or shear. The program internally uses both sets to arrive at the final results. It sets the non-required factors to 1.0. However, the user may specify both sets, in which case, caution is warranted.

TH-26 / Theory ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Bearing Analysis

Bearing Analysis If requested by the user, PRESTO can check to see if the bearing satisfies the requirement for an unreinforced bearing and the required steel for a reinforced bearing following the procedure outlined in Arts. 6.7-6.9 of the PCI Design Handbook (5th Edition). An upper limit of the bearing load is calculated using ACI 318-99/02, Art. 10.17, instead of the equation (Vu,max = 1.2 f'c A1) found in the PCI Design Handbook (5th Edition). Also, a suggested minimum value of Ash is calculated using a value of 3.4 for µe. Cantilevered bearing points (if any) are automatically checked, along with the simple span bearing with the largest value of Vu. Note that the program does not calculate the required steel for cantilevered bearings, it only checks to see if the conditions satisfy the requirements for an unreinforced bearing.

y p o

The area of the crack plane, Acr, in PCI Eq. 6.7.2 takes into account the bottom flange but not the top flange of the precast section. The area A2 in Eq. 6.8.1, is determined by first calculating the distance from the edge of the bearing area A1 to the nearest free edge. If the bearing area A1 is adjacent to a free edge, then A2 will be equal to A1.

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PRESTO®v8.6 Theory ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ TH-27

Bearing Analysis

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TH-28 / Theory ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Appendix One

Nomenclature and Printout Explanation

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C

This section is an explanation of the items that appear in the output. They are presented in the order in which they appear.

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Labels Used Throughout the Printout A, Ac

:

Area of non-composite or composite section

As, A's

:

Total area of mild tension or compression steel

Aps

:

Total area of prestressing strand

Class

:

In ACI 318-05 mode, the classification of a section based on Art. 18.3.3

Comp

:

Compression or Composite

DL Ec Ecc

l a

Eci

Eps Ect

i t

a u

dia

:

Diameter

:

Dead Load

:

Modulus of elasticity of the precast concrete at final

:

Eccentricity

:

Modulus of elasticity of the precast concrete at release

:

Modulus of elasticity of the prestressing strand

:

Modulus of elasticity of the topping concrete

:

Compressive strength of the precast concrete at final

:

Compressive strength of the precast concrete at release

:

Compressive strength of the topping concrete

:

Splitting tensile strength of lightweight aggregate concrete

fpy

:

Yield strength of the prestressing strand

fpu

:

Ultimate tensile strength of the prestressing strand

Fy

:

Yield strength of the mild steel

H, Hc

:

Height of non-composite or composite section

I, Ic

:

Moment of inertia of the non-composite or composite section

LL

:

Live Load

Loc

:

Location

f'c

v E f'ci

f'ct fct

PRESTO®v8.6 Nomenclature and Printout Explanation ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ A1-1

Appendix One

Mcr

:

Total moment required to cause cracking

M.I.

:

Moment of Inertia of the precast section

Mu

:

Factored moment

Prec

:

Precast

RH, Rel Hum

:

Relative Humidity

Sb, Sbc

:

Section modulus w.r.t. bottom of non-composite and composite section

SD

:

Superimposed Dead Load

SDS

:

Superimposed Dead Load of Snow

SL

:

Sustained Live Load

Tens

:

Tension

Topg

:

Topping

Theta

:

Crack angle to be checked during bearing analysis

Tu

:

Factored torsion

Vu

:

Factored shear

Wc, Wct

:

Unit weight of the precast/topping concrete

Wct

:

Unit weight of the topping concrete

Yb, Ybc

:

Distance between c.g. and bottom of non-composite and composite section

Zone

:

Prismatic zone in which section properties do not change

:

Area enclosed by centerline of the outermost closed transverse torsional reinforcement

a u :

Width of the bottom and top precast flanges (if any)

:

Bottom width of a typical stem

:

Ultimate concrete compressive strain

:

Interior or exterior (ACI 318-95, Art.10.6.4)

:

Height of the precast section

:

Length

:

End or Interior span (ACI 318-95, Art.8.10)

ph

:

Perimeter of centerline of outermost closed transverse torsional reinforcement

SDL

:

Superimposed Dead Load

Shear wid

:

Width of member used to resist vertical shear

Stems

:

Web(s) of the precast section

Tfl-bot, top

:

Thickness of the bottom and top precast flanges (if any)

top wid

:

Top width of a typical stem

Trib. Wid

:

Tributary width

V/S

:

Volume to Surface ratio

Web extnt

:

Web extent, out to out dimension of the tops of exterior webs

wt

:

Weight

Bfl-bot, top Bot wid ecu

l a Exposure H

Len

Location

v E

C

i t

Project Data Aoh

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y p o

A1-2 / Nomenclature and Printout Explanation ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Appendix One

Topping Data Gap

:

Portion of topping not directly on top of the precast section

Topg

:

Portion of topping directly on top of the precast section

Days to top

:

Number of days between release and placement of Topping

Days to Comp DL

:

Number of days between release and application of composite DL

Hours to release

:

Hours between tensioning and release

Length Multipliers

:

Strand development and transfer length multiplier.

Prestressed Strand Data

Prestressed Strand Pattern Data Depress point

C

Dep. pt

:

Spacing

:

Distance between c.g.’s of adjacent strand levels at depress

Str

:

Strand

Y-cg

:

Distance between strand c.g. and bottom of precast section

n o

Strand Groups, Shielding and Pull Data

i t

Depr

:

Depress

L1

:

Left straight extent for draped strands

L2

:

Left depress point location from left end for draped strands

Pull Frac

:

Pull Fraction

:

Right straight extent for draped strands

:

Right depress point location from right end for draped strands

:

Modulus of elasticity

:

Allowable stress in the mild steel

Dev. len

:

Development length

L-c, R-c

:

Development length of left/right ends of rebar in compression

L-t, R-t

:

Development length of left/right ends of rebar in tension

a u

R1 R2

Rebar Data

l a

Es Fs

y p o

Rebar Pattern Data

v E Stirrups

Distance from left edge of beam to the first stirrup in the group closest to end.

Left Offset Right Offset

:

Distance from right edge of beam to the first stirrup in the group closest to end.

No. of Stirrups

:

Physical number of stirrups in group.

Id

:

Rebar Id from library designating size.

PRESTO®v8.6 Nomenclature and Printout Explanation ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ A1-3

Appendix One

Spacing

:

c/c spacing of stirrups for selected group.

End Beam

:

Reference face of beam for selected group. Can be left or right. When both option is selected, program places two groups - one starting from each face of the beam.

Paired

:

Paired bars denote double the reinforcement of selected stirrup Id.

Type

:

Will not affect engineering calculations. Only for use with detailing/drafting packages.

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Bearing Steel Data Dist to Brg

:

Distance between centerline of bearing and end of the member

Length

:

Length of bearing surface measured parallel to span

Nu/Vu

:

Ratio of the horizontal to the vertical force at supports

Width

:

Width of bearing surface measured perpendicular to span

Calculated Internal Constants

n o

C

Beta-1, p/c

:

Factor defined in ACI 319-99, Art. 10.2.7.3 for the precast

Beta-1, tpg

:

Factor defined in ACI 319-99, Art. 10.2.7.3 for the topping

Lambda, p/c

:

Lightweight modifier for the precast (ACI 318-99, Art. 11.2.1.2)

Lambda, tpg

:

Lightweight modifier for the topping (ACI 318-99, Art. 11.2.1.2)

Trans Length

:

Transfer Length

i t

Stem Mesh Data

a u :

Distance from the bottom of beam to lowest horizontal bar in mesh

Bottom Clearance

:

Distance from the bottom of beam to lowest horizontal bar in mesh

ID

:

Rebar ID from library designating size of vertical bars of mesh reinforcement

Top Clearance

Spacing

l a Start End

:

Distance between the vertical bars of the mesh reinforcement

:

Distance from left end of beam of the start of the mesh reinforcement

:

Distance from left end of beam of the end of mesh reinforcement

Unreinforced Section Property Zone Data

v E

Beff

:

Effective width of the top flange (topping or precast)

Bf

:

Top precast flange width

Bg

:

Width of the gap, or the total boundary distance less Bt

Bt

:

Width of the topping over the precast section

Bv

:

Shear width of the member

Bw

:

Web width used in shear calculations

Tt

:

Thickness of the topping over the precast section

This Section Prints Only In ACI 318-05 Mode Ace

:

Area of composite effective (after crack) sections

A1-4 / Nomenclature and Printout Explanation ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Appendix One

Crack Depth

:

Depth of crack. For crack at bottom, measured from bottom of uncracked section. For crack at top, measured from top of topping if precast or from top of precast if there is no topping.

Ice

:

Inertia of composite effective (after crack) sections

Sbce

:

Section modulus of composite effective section (after crack, if any)

TensSide

:

Side of the beam that is in tension. None means the entire section is in compression

Ybce

:

Distance between C.G. and bottom of composite effective (after crack) section

Ms

:

Unfactored moment

Supp-L/R

:

Left and right support

SWfin, SWrel

:

Self-weight at final and at release

Vs

:

Unfactored shear

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Structural Analysis

Prestress Loss Computations

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C

A

:

Area of the non-composite transformed section

Accel

:

Accelerated

C

:

Factor obtained from PCI Handbook, 5th Ed, Table 4.7.2

CR

:

Creep of the concrete

ES

:

Elastic shortening

fcds

:

Stress in concrete due to all superimposed dead loads

:

Net compressive stress in concrete at release

a u

fcir fcr fpi fst

l a

I

i t

:

Net compressive stress in concrete at time t

:

Total stress in the prestressing strand at tensioning

:

Stress in the strand at time t

:

Moment of inertia of the non-composite transformed section

:

Factor obtained from PCI Handbook, 5th Ed, Table 4.7.1

:

Factor used to calculate fcir

Kcr

:

Factor used to calculate creep

Kes

:

Factor used to calculate elastic shortening

Kre

:

Factor obtained from PCI Handbook, 5th Ed, Table 4.7.1

Ksh

:

Factor used to calculate shrinkage

Mbm

:

Moment caused by the member dead load at release

Mcdl

:

Moment caused by composite dead loads

MCF

:

Factor to account for the effect of age at release on creep

Mdl

:

Moment caused by non-composite dead loads (excluding topping)

Mll

:

Moment caused by live loads

Mtopg

:

Moment cause by topping

PCR

:

Amount of creep over time interval t1 to t

J

Kcir

v E

PRESTO®v8.6 Nomenclature and Printout Explanation ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ A1-5

Appendix One

Pi

:

Total force in the prestressing strand at tensioning

PSH

:

Amount of shrinkage over time interval t1 to t

RE

:

Relaxation of the prestressing tendons

SCF

:

Factor to account for the effect of size and shape on creep

SH

:

Shrinkage

SSF

:

Accounts for the effect of size and shape on shrinkage

t1, t

:

Beginning and end of time interval

UCR

:

Ultimate loss of prestress due to creep of concrete

USH

:

Ultimate loss of prestress due to shrinkage of concrete

V/S ratio

:

Volume to Surface ratio

A1, A2

:

Loaded area at the bearing surface and in the precast member

Acr

:

Area of the assumed crack plane

An

:

Area of reinforcement required to resist axial tension

Ash, min

:

Vertical area of reinforcement across horizontal cracks

Avf

:

Area of steel perpendicular to the assumed crack plane

Cr

:

Reduction coefficient

mu-eff

:

Effective shear friction coefficient

phiVn

:

Design bearing strength

s

:

Distance from end of member to centerline of bearing

Bearing Steel

Vu-max w

C

i t

a u

Vu

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y p o

:

Factored stem reaction at the support

:

Maximum allowable support reaction (ACI 318-99/02, Art. 10.17)

:

Width of bearing area measured parallel to member span

:

Minimum required concrete compressive strength at release

Release and Final Stresses

l a f'ci-min

:

Provided

:

Required

a

:

Depth of compression block obtained from strain compatibility

Beta1

:

Factor defined in ACI 318-99/02, Art. 10.2.7.3

bfl

:

Width of the compression flange

bweb

:

Web width adjacent to the compression flange

c

:

Depth to neutral axis obtained from strain compatibility

c/dt

:

Ratio of depth of neutral axis to depth of extreme steel in tension

Controls

:

Controlling factor in strain compatibility (COMP or TENS in ACI 318-99 mode or COMP, TENS, TRANS in ACI 318-05 mode

Prvd

v E

Reqd

Ultimate Strength

A1-6 / Nomenclature and Printout Explanation ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Appendix One

cor

:

Maximum depth to neutral axis for over-reinforced condition

d, d'

:

Depth to c.g. of mild tension or compression steel

dsc

:

Average depth to tension steel based on strain compatibility

dt

:

Distance from extreme compression fiber to extreme tension steel

fps

:

Calculated fps from stress-strain curve for strand

fse

:

Effective prestressing force after all losses

Mor

:

Calculated capacity for over-reinforced section

Msc

:

Capacity of section obtained from strain compatibility

phiMn/Mu

:

Ratio of the capacity of section to the applied moment

pMn

:

Adopted value of nominal moment capacity

Rho-bal

:

Balanced reinforcement ratio

Rho-calc

:

Calculated reinforcement ratio.

Rho-max

:

Maximum allowable reinforcement ratio

Rho-min

:

Minimum required reinforcement ratio

tfl

:

Thickness of the compression flange

S-req

:

Required spacing of reinforcement (ACI 318-99/02, Arts. 10.6.4 and 18.4.4).

# of Steel

:

Number of rebar of strand or their summation depending upon what controls

cc

:

Clear cover to extreme tension steel

Control

:

Reports what steel is closest to the extreme tension face

Crack Control

s-prov s-req TensWid

l a

Cracking Load

C

i t

a u

fs, Dfps

n o

y p o

:

Stress in rebar or strand closest to the extreme tension face

:

Provided spacing of steel

:

Required spacing of steel

:

Width of the section in tension that will be checked for crack control

:

Modulus of rupture (ACI 318-99/02, Art. 9.5.2.3)

phi*Mn

:

Adopted value of nominal moment capacity

phi*Mn/Mcr

:

Ratio of the capacity of section to the cracking moment

Al

:

Calculated longitudinal steel

AtC

:

Calculated area of vertical reinforcement to resist torsion

Av+2At

:

Adopted area of reinforcement to resist shear and torsion

Av+2At, min

:

Minimum required combined shear and torsion reinforcement

AvC

:

Calculated area of vertical reinforcement to resist shear

Av-prvd

:

Provided area of vertical shear reinforcement to resist shear and torsion

bw

:

Web width considered effective to resist shear

fr

v E

Vertical Shear and Torsion

PRESTO®v8.6 Nomenclature and Printout Explanation ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ A1-7

Appendix One

d

:

Depth from compression face to c.g. of tension steel

fpc

:

Compressive stress in concrete at centroid of cross-section

f-act

:

Actual stress in concrete due to combined shear and torsion (ACI 318-99/02, Art. 11.6.3.1)

:

f-alw

Total allowed stress in concrete due to shear and torsion (ACI 318-99/02, Art.

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11.6.3.1)

Md

:

Moment at section due to unfactored dead load

Mmax

:

Maximum factored moment at a section (Mu-Md)

P-eff

:

Effective prestressing force after all losses

phi*Vn/Vu

:

Flagged by asterisk if ratio is smaller than 1.0. Vs computed using only provided stirrup

rho-w

:

Mild reinforcement ratio obtained from As/(bw*d)

s-max

:

Maximum allowable spacing of shear steel

s-prvd

:

Spacing of stirrups provided at specific point

T’c

:

(Only applicable to PCI method) Nominal torsional moment strength of concrete under pure torsion

Tc

:

(Only applicable to PCI method) Nominal torsional moment strength of concrete under combined shear and torsion, computed per PCI equation 4.4.4

Tlim

:

Limiting value of torsion below which torsional steel is not required (ACI 31899/02, Art. 11.6.1)

Tnmax

:

(Only applicable to PCI method) Maximum nominal torsional moment, computed per PCI equation 4.4.2

Tumin

:

(Only applicable to PCI method) Minimum torsional moment, computed per PCI equation 4.4.1

i t

a u :

(Only applicable to PCI method) Nominal shear strength of concrete under pure torsion

:

(Only applicable to PCI method) Nominal shear strength of concrete under combined shear and torsion, computed per PCI equation 4.4.5

:

Flexural shear resisted by concrete (ACI 318-99/02, Eq. 11-10)

:

Web shear resisted by concrete (ACI 318-99/02, Eq. 11-12)

:

Shear force at section due to unfactored dead load

Vi

:

Factored shear force coincident with Mmax (Vu-Vd)

Vp

:

Vertical component of effective prestress force

Vs

:

Portion of applied shear resisted by steel

Vs, max

:

Maximum allowable shear resisted by steel

x1

:

(Only applicable to PCI method) Short side of closed tie

x2y

:

(Only applicable to PCI method) Σx2y as in equation 4.4.1

y1

:

(Only applicable to PCI method) Long side of closed tie

Ycrit

:

Location of fpc in ACI 318-99/02, Eq. 11-12

:

Required horizontal shear steel based on roughened interface

V’c Vc

l a Vci

Vcw Vd

v E

n o

C

Horizontal Shear Ahr

A1-8 / Nomenclature and Printout Explanation ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Appendix One

Ahs

:

Required horizontal shear steel based on smooth interface

Ayh, min

:

Minimum required horizontal shear steel

Bv

:

Width of member used to resist horizontal shear

Vnh

:

Nominal horizontal shear

Vnh, max

:

Maximum allowable horizontal shear

Icr

:

Cracked moment of inertia

Ie

:

Effective moment of inertia used to compute deflections

Ig

:

Gross moment of inertia

Ma

:

Cumulative moment at a section

Mc0

:

Moment which produces zero curvature

Md0

:

Moment which produces zero deflection

Ig/Ie

:

Deflection multiplier used when Ie > Ig

Prest

:

Prestressing

y p o

Camber and Deflections

n o

C

i t

a u

l a

v E

PRESTO®v8.6 Nomenclature and Printout Explanation ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ A1-9

Appendix One

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A1-10 / Nomenclature and Printout Explanation ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Appendix Two

Hand Calculations for Selected Items Hand Calculations for Selected Items

y p o

Tutorial: Design of a 8DT24 Double Tee

n o

Member Section - Precast

C

i t

a u

FIGURE A2-1. Precast Section

l a

Section Properties

Section above is a standard PCI section with the following section properties. =

401 in2

I

=

20985 in4

Yb

=

17.15 in

Yt

=

6.85 in

A

v E

For analysis, the member is divided into five zones referenced from the left end. Note that the circular opening is converted into an equivalent rectangular opening.

PRESTO®v8.6 Hand Calculations for Selected Items ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ A2-1

Appendix Two

Zone

Location

Openings

1

0 to 14 ft

None

2

14 to 16 ft

12 in × 24 in

3

16 to 19.5 ft

None

4

19.5 to 20.5 ft

24 in × 24 in (equivalent rectangular)

5

20.5 to 50 ft

None

y p o

Zones 1, 3, 5 have the section properties listed above. While section properties for Zones 2 and 4 are different.

Zone 2

H

=

24 in

A

=

401 + (-12) 2 = 377.0 in2

Yb

=

401(17.15) + (-24)23 = 16.78 in 377

I

=

⎛ - 12(2) 3 ⎞ ⎟ + [401(17.15) 2 + (-24)(23) 2 ] - [(410 - 24)(16.78) 2 ] = 20103 in 4 20985 + ⎜ ⎜ 12 ⎟ ⎠ ⎝

H

=

24 in

A

=

401 + (-24) 2 = 353.0 in2

Yb

=

401(17.15) + (-48)23 = 16.35 in 377

=

⎛ - 12(2) 3 ⎞ ⎟ + [401(17.15) 2 + (-48)(23) 2 ] - [(410 - 48)(16.35) 2 ] = 19103 in 4 20985 + ⎜ ⎜ 12 ⎟ ⎠ ⎝

i t

Zone 4

a u

l a

I

v E

n o

C

A2-2 / Hand Calculations for Selected Items ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Appendix Two

Member Section - Composite

y p o

FIGURE A2-2. Composite Section

Acomp = Aprec + nAtop where n =Etop/Eprec

Yb-comp =

A prec (Yprec ) + nA top (Ytop )

n o

A prec + nA top

C

Icomp = Iprec + Itop + [Aprec(Yprec)2 + nAtop (Ytop)2] - [(Aprec + nAtop) (Yb-comp)2]

i t

1.5

Zones 1, 3 and 5

n

=

(150) (33) (3000) (150)1.5 (33) 5500

a u

Acomp =

401 + (0.738) (2) (96) = 542.8 in2

Yb-comp =

(401)(17.15) + (0.738)(192)(25) 542.8

l a

Icomp

v E

Zones 2 and 4

= 0.7385

= 19.20 in

=

⎡ (0.7385 )(96 )( 2) 3 ⎤ 2 2 2 20985 + ⎢ ⎥ + [( 401)(17 .15) + (0.7385 )(192 )( 25) ] - (542 .8)(19 .20 ) 12 ⎦⎥ ⎣⎢

= 27487 in4 Hcomp =

24 + 2 = 26 in

Since there is no topping in these sections, the composite section properties are the same as the precast section properties.

Precast Data

Shear width = combined average width of stems

PRESTO®v8.6 Hand Calculations for Selected Items ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ A2-3

Appendix Two

=

⎡ 3.75 + 5.75 ⎤ 2 = 9.5 in ⎢⎣ ⎥⎦ 2

Web extent = out to out distance at tops of exterior stems =

y p o

⎡ 48.00 + 5.75 ⎤ 2 = 53.75 in ⎥⎦ ⎢⎣ 2

Volume/surface ratio is approximated by the area of the section divided by the perimeter of the section. V/S is used in loss calculation.

Allowable Concrete Stresses

Release

401.00 [2(96.00 + 24.00) + 2(22.00)]

V/S

≅

f'c

=

5500 psi

Wc

=

150 pcf

f'ci

=

4500 psi

f'ct

=

3000 psi

i t

n o

a u

f ci'

Tension at other places of member = 3

l a

v E

C

Compression = 0.6 0 (f’ci) = 0.60 (4500) =2700.0 psi (+) Tension at ends of member = 6

Final Conditions

≅ 1.41

(ACI 18.4.1)

= 402.5 psi (-)

f ci'

= 201.2 psi (-)

Compression for topping due to prestressed plus sustained loads ' = 0.45 ( f ct ) = 0.45 (3000) = 1350.0 psi (+)

(ACI 18.4.2)

Compression for precast due to prestressed plus sustained loads ' = 0.45 ( f c ) = 0.45 (5500) = 2475.0 psi (+)

Compression for topping due to prestressed plus total load ' = 0.60 ( f ct ) = 0.60 (3000) = 1800 psi (+)

Compression for precast due to prestressed plus total load

A2-4 / Hand Calculations for Selected Items ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Appendix Two

' = 0.60 ( f c ) = 0.60 (5500) = 3300 psi (+)

' Tension for topping = 6 ( f ct ) = 0.45 ( 3000 ) = 328.6 psi (-)

y p o

' Tension for precast = 6 ( f c ) = 0.45 ( 5500 ) = 445.0 psi (-)

Concrete Data 1.5 ' Modulus of elasticity = w c ( f c )

(ACI 8.5.1)

Ec

=

(150)1.5 (33) ( 5500 ) = 4496 ksi

Eci

=

(150)1.5 (33) ( 4500 ) = 4067 ksi

Ect

=

(150)1.5 (33) ( 3000 ) = 3321 ksi

n o

C

i t

Prestressed Strand

fpy, the yield strength, is specified as 90% of tensile strength, fpu, for the low-relaxation strands. 0.9 fpu = 0.9 (270) = 243 ksi

a u

(ACI 18.5.1)

Tension in each strand = 0.75 (270) 0.153 = 30.98 kip The depressed strands have a profile as shown in Fig. A2-3.

l a

v E

FIGURE A2-3. Strand Profile

PRESTO®v8.6 Hand Calculations for Selected Items ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ A2-5

Appendix Two

The following table summarizes the depressed distance, depressed angle and the vertical component of the prestressing force. Group

Depressed Dis. x (in)

Tan (Theta) x/300

1

0.0

0/300

Theta Sin Vertical Component (Degrees) (Theta) (kips)

0.0

0.0

2

4.0 - 2.5 = 1.5

1.5/300

0.29

0.005

3

14.0 - 3.0 = 11.0

11.0/300

2.10

0.037

4

16.0 - 3.5 = 12.5

12.5/3000

2.39

0.042

0.0

y p o 0.16

1.14

1.29

Each strand has two vertical components and each group has two strands. Total depression force = 2 (2 (0 + 0.16 + 1.14 + 1.29)) = 10.3 k

Unreinforced Section Properties The following table gives the precast section properties. Zone Area, in2

Self-Weight, plf

I (in4)

n o

C Bf, in

1

401

w1 = (401/144)150 = 417.7 20985

2

377

w2 = (377/144)150 = 392.7 20103 96 - 12 = 84 16.78

3

401

4

353

5

410

Reinforced Section Property Data

w3 = 417.7

a u

i t

20985

96

Yb, in

96

17.15

17.15

w4 = (353/144)150 = 367.7 19103 96 - 24 = 72 16.35 w5 = 417.7

20985

96

17.15

No mild reinforcement is present. Therefore, section properties are identical to those in unreinforced sections.

l a

v E

Analysis

FIGURE A2-4. Beam Loading

The structural analysis is performed at the different checkpoints specified to obtain the design moment and shear values. Sample hand calculations at the 25' location are shown below.

A2-6 / Hand Calculations for Selected Items ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Appendix Two

General equation for 25 ft location is:

R1 at release =

[29.5w 5 (14.75) + w 4 (30.0) + 3.5w 3 (32.25) + 2w 2 (35.0) + 14w1 (43)] 50

y p o

R1 at final =

[29.0w5 (14.5)+ w4 (29.5)+ 3.5w3 (31.75)+ 2w2 (34.5)+14w1 (42.5)- 0.5w1(0.25)] 49

M at release = 25 R1 - 14w1 (18) - 2w2 (10) - 3.5w3 (7.25) - w4 (5) - 4.5w5 (2.25) M at final = 24.5R1 - 14w1 (18) - 2w2 (10) - 3.5w3(7.25) - w4 (5) - 4.5w5 (2.25) V at final = R1 - 14w1 - 2w2 - 3.5w3 - w4 - 4.5w5

Self-weight

C

Using the values of (w) on page A3-6, in the equation above, the moments and shears are calculated as follows:

n o

R1 at release = 10.378 k R2 at release = 10.377 k

Mswrel, self-weight at release = 129.7 kft

i t

Mswfin, self-weight at final = 124.5 kft

Vswfin, self-weight at final = 0.0355 kft

Topping

a u

The topping values in the different zones along the length of the member are listed below, where

l a

v E

Topg wt (plf) =

(96)(2)(150) = 200plf 144

Zone

Topg wt (plf)

1

200

2

0

3

0

4

0

5

200

Based on the above values, the following quantities were calculated using the equations listed above. R1

=

Mtopg = Vtopg

=

4.14 k 49.1 kft 0.44 k

PRESTO®v8.6 Hand Calculations for Selected Items ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ A2-7

Appendix Two

Superimposed Dead Load on Composite (SD)

The superimposed dead load values in the different zones are listed in the following table. Zone

SD wt (plf)

1

80

2

70

3

80

4

60

5

80

y p o

A sample equation for SD wt (plf) for Zone 1 is:

(0.01)(1000)

(96) lb = 80 ft 12

C

Based on the above table, the following quantities were calculated using the equations listed above.

Live Loads (LL)

R1

=

1.974 k

MSD

=

23.7 kft

VSD

=

0.014 k

n o

i t

The live load values in the different zones are listed in the following table. Zone

a u

l a

1

LL wt (plf)

400

2

350

3

400

4

300

5

400

A sample equation for LL wt (plf) for Zone 2 is:

v E

Total Moment and Shears At Final Conditions

(0.05)(1000)

(84) lb = 350 ft 12

Based on the above table, the following quantities were calculated using the equations listed above. R1

=

9.869 k

MLL

=

118.3 kft

VLL

=

0.070 k

Ms

=

Msw-fin + Mtopg + Mdl + Mll

Ms

=

315.5 kft

Vs

=

Vs-sw + Vs-topg + Vs-dl + Vs-ll

A2-8 / Hand Calculations for Selected Items ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Appendix Two

Vs

=

0.6 kft

Mu

=

1.4 (Msw-fin + Mtopg + Mdl) + 1.7 Mll

Mu

=

477.2 kft

Vu

=

1.4(Vs-sw + Vs-topg + Vs-dl) + 1.7 Vs-ll

Vu

=

0.8 kft

y p o

Prestress Losses

The PCI method is used to calculate the prestress losses at the 25' location. At final conditions: TL = ES + CR + SH + RE

C

ES

=

Kes

=

1.0 for pretensioned members

Eps

=

modulus of elasticity for prestressing tendons

Eci

=

modulus of elasticity of concrete at time prestress is applied

fcir

=

Kcir ((Pi / Ag) + (Pi e2) / Ig) - Mg e / Ig

Kcir

=

0.9 for pretensioned members

Pi

=

initial prestress force (after anchorage seating loss)

=

8 (0.153) (0.75) 270

=

247.86 k (assume no loss)

=

eccentricity = Yb - Ycgs = 17.15 - 2.75 = 14.40 in

=

area of gross concrete section = 401 in2

=

moment of inertia = 20985 in4

=

bending moment due to dead weight = 129.7 kft

e

Ig

Mg

fcir

=

(PCI Eq. 4.7.2)

E ci

n o

i t

a u

l a Ag

v E

K es E ps f cir

(PCI Eq. 4.7.1)

⎡ 247860 (247860)(14.4) 2 ⎤ 129700 (14.4)(12) 0.9 ⎢ + ⎥20985 20985 ⎦ ⎣ 401

(PCI Eq. 4.7.3)

= 1692.9

psi

ES

=

CR

=

1.0(29.0 × 10 6 )(1692.9) 4.067 × 10 6

= 12071.9 psi

Kcr (Es / Ec) (fcir - fcds)

PRESTO®v8.6 Hand Calculations for Selected Items ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ A2-9

Appendix Two

Kcr

=

2.0 for normal weight concrete

fcds

=

Msd (e) / Ig

=

49.1 (12000) 14.4 24 (12000) (19.20 - 2.75) + = 574.3 psi 20985 27488

y p o

4.7.5)

⎡ 29.0 × 10 6 ⎤ 2.0 ⎢ (1692.9 - 574.3) =14429.5 psi 6⎥ ⎣ 4.496 × 10 ⎦

CR

=

SH

=

shrinkage of concrete

=

(8.2 × 10 -6) Ksh Es (1 - 0.06 V/S) (100 - RH)

Ksh

=

1.0 for pretensioned members

V/S

=

volume to surface ratio

RH

=

average ambient relative humidity = 75%

SH

=

(8.2 ×10 -6) 1.0 (29 × 106) (1 - 0.06 (1.43) (100 - 75) = 5434.9 psi

RE

=

[Kre - J (SH + CR + ES)] C

Kre

=

5000, from Table 4.7.1

C

=

1.0, for fpi/fpu = 0.75, from Table 4.7.2

n o

i t

a u

v E

C

(PCI Eq. 4.7.6)

(PCI Eq. 4.7.6)

(PCI Eq. 4.7.7)

J

=

0.04, from Table 4.7.1

RE

=

[5000 - 0.04 (5434.9 + 14429.5 + 12071.9)] 1.0 = 3722.5 psi

=

ES + RE + CR + SH

=

12071.9 + 3722.5 + 14429.5 + 5434.9

=

35658.9 psi

At final:

l a

(PCI Eq.

TL

% loss =

TL 35658.9 = 0.75(270000) 0.75(270000)

= 17.61%

At release conditions: TL

=

ES + RET

RET at final, t=100,000 hours fst

=

0.75 (270000) = 202500 psi

fpy

=

0.9 (270000) = 243000 psi

A2-10 / Hand Calculations for Selected Items ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Appendix Two

RET

log24t - log24t i ⎤ f st f st ⎡⎢ ⎥⎦ ( f − 0.55) 10 ⎣ py

=

f st 202.5 − 0.55 − 0.55 = f py 243.0 t1

=

RET

=

202500 ⎡⎢ ⎣

REmax =

3722.5 psi

y p o

= 0.28

1/24 log(100000) ⎤ ⎥⎦ 0.28 = 28350 psi 10

Ratop

=

REmax /RET = 0.1313

At t

=

24 hours

RET

=

202500 ⎡⎢ ⎣

n o

log(24) ⎤ 0.28 = 7826 psi 10 ⎥⎦

C

i t

Adjusted= 7826 (0.1313) = 1027.6 psi TL

=

12071.9 + 1027.6 = 13099.5 psi TL 0.75(270000)

a u

% loss =

Precast and Composite Section Properties

l a

= 6.47%

The precast and composite section properties at locations 1.5' and 25.0' are summarized in the following table. Loc. (ft)

v E

Miscellaneous Section Properties Computations

Ac (in2)

A (in2)

I (in4)

Ic (in4)

Yb (in)

Ybc (in)

Yt (in)

Ytc (in)

1.5

401.0

542.8

20985

27487.7

17.15

19.20

6.85

4.80

25.0

401.0

542.8

20985

27487.7

17.15

19.20

6.85

4.80

At 1.5 ft and 25.0 ft locations:

Sb

=

I Yb

Sbc

=

I Ybc

= 1223.6 in3

= 1431.6 in3

PRESTO®v8.6 Hand Calculations for Selected Items ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ A2-11

Appendix Two

St

=

I Yt

Stc

=

I Ytc

= 3063.5 in3

y p o

= 5726.6 in3

At Loc = 1.5 ft:

Ycgs

=

9.0 - (1.5/25.0)(9.0 - 2.75) = 8.63 in

e

=

Yb - Ycgs = 8.53 in

ec

=

Ybc - Ycgs = 10.57 in

At Loc = 25.0 ft:

Ycgs

=

9.0 - (25.0/25.0)(9.0 - 2.75) = 0.75 in

e

=

Yb - Ycgs = 14.4 in

ec

=

Ybc - Ycgs = 16.45 in

Calculation of Member Stresses Release Stresses: Precast Section Only

n o

i t

C

Pi = fpu × no. of strands × area of strands ×(1 - initial losses) Transfer length = 50 strand diameters = 50 (0.5) = 25 in = 2.08 ft

a u

Note prestress is partially transferred at 1.5 ft Loc. ft

1.50

l a

25.0

Pi

0.75 (270.0) 8 (0.153) (1 - 0.0494) [(1.5) 12 / 25] = 169.64 k 0.75 (270.0) 8 (0.153) (1 - 0.065) = 231.75 k

Note the positive sign stands for compression, negative sign stands for tension. For Loc = 1.5 ft:

v E

ftop, due to prestress=-Pi e/St + Pi/A = -49 psi fbot, due to prestress=Pi e/Sb + Pi/A = 1605 psi Msw

=

15.1 kft

ftop, due to self-weight=(12) (1000) (Msw) / St = 59 psi fbot, due to self-weight=(12) (1000) (Msw) / Sb = -148 psi ftop, total at release=-49 + 59 = 10 psi fbot, total at release=1605 - 148 = 1457 psi Compare these total stresses with the stress limits for stresses in concrete immediately after prestress transfer, as in Art. 18.4.1 of ACI 318-99 code.

A2-12 / Hand Calculations for Selected Items ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Appendix Two

Compression Limit = 0.60(f’ci) = (0.60) (4500) = 2700 psi

OK

For Loc = 25.0 ft:

ftop, due to prestress=-Pi e/St + Pi/A = -512 psi fbot, due to prestress=Pi e/Sb + Pi/A = 3306 psi Msw

=

y p o

129.7 kft

ftop, due to self-weight=(12) (1000) (Msw) / St = 508 psi fbot, due to self-weight=(12) (1000) (Msw) / Sb = -1272 psi ftop, total at release=-512 + 508 = -4 psi fbot, total at release=3306 Compression Limit, as per Art. 18.4.1 of ACI 318-99 = 2700 psi

Final Stresses: Precast Section Only

Po = fpu × no. of strands × area of strands × (1 - final losses)

n o

C

OK

Transfer length = 50 strand diameters = 50 (0.5) = 25 in = 2.08 ft Note prestress is partially transferred at 1.5 ft Loc. ft

i t

Pi

1.50

0.75 (270.0) 8 (0.153) (1 - 0.168) [(1.5) 12 / 25] = 148.48 k

25.0

0.75 (270.0) 8 (0.153) (1 - 0.176) = 204.23 k

For Loc = 1.5ft:

a u

ftop, due to prestress=-Po e/St + Po/A = -43 psi fbot, due to prestress=Po e/Sb + Po/A = 1405 psi Based on the support conditions at final, Msw = 10.0 kft

l a

ftop, due to self-weight=(12) (1000) (Msw) / St = 39 psi fbot, due to self-weight=(12) (1000) (Msw) / Sb = -98 psi

v E

Due to topping self weight: Mtopg = 3.9 kft ftop, due to topping=(12) (1000) Mtopg / St = 15 psi

fbot, due to topping=(12) (1000) Mtopg / Sb = -38 psi

For Loc = 25.0 ft:

ftop, due to prestress=-Po e/St + Po/A = -451 psi fbot, due to prestress=Po e/Sb + Po/A = 2915 psi Based on the support conditions at final, Msw = 124.5 kft ftop, due to self-weight=(12) (1000) (Msw) / St = 488 psi fbot, due to self-weight=(12) (1000) (Msw) / Sb = -1221 psi

PRESTO®v8.6 Hand Calculations for Selected Items ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ A2-13

Appendix Two

Due to topping self weight: Mtopg = 49.1 kft ftop, due to topping self weight=(12) (1000) Mtopg / St = 192 psi fbot, due to topping self weight=(12) (1000) Mtopg / Sb = -482 psi Final Stresses: Composite Section

y p o

Mdlcomp (kft)

Loc (ft)

Ytt = Hc - Ybc (in)

Stt = Ic / Ytt (in3)

1.5

26.0 -19.20=6.80

4046.2

1.9

25.0

26.0-19.20=6.80

4046.2

23.7

For Loc = 1.5ft:

Moment due to SDL on composite, MSD = 1.9 kft

9.4

118.3

C

ftop, due to SDL on composite=(12) (1000) (MSD) / St = 4 psi

fbot, due to SDL on composite=(12) (1000) (MSD) / Sb = -16 psi

n o

Mll (kft)

fttop, due to SDL on composite=(12) (1000) (MSD) (Ect / Ec) / Stt = 4 psi Moment due to live load (LL) on composite, MLL = 9.4 kft

ftop, due to LL on composite=(12) (1000) (MLL) / St = 20 psi

i t

fbot, due to LL on composite=(12) (1000) (MLL / Sb = -79 psi fttop, due to SDL on composite=(12) (1000) (MSD) (Ect / Ec) / Stt = 21 psi For Loc = 25.0 ft:

a u

Moment due to SDL on composite, MSD = 23.7 kft ftop, due to SDL on composite=(12) (1000) (MSD) / St = 50 psi

l a

fbot, due to SDL on composite=(12) (1000) (MSD) / Sb = -201 psi

fttop, due to SDL on composite=(12) (1000) (MSD) (Ect / Ec) / Stt = 53 psi

Moment due to live load (LL) on composite, MLL = 118.3 kft

v E

ftop, due to LL on composite=(12) (1000) (MLL) / St = 248 psi fbot, due to LL on composite=(12) (1000) (MLL / Sb = -996 psi fttop, due to SDL on composite=(12) (1000) (MSD) (Ect / Ec) / Stt = 259 psi

Total ft, psi, at the final condition. ft

=

ftprestress + ftselfwt + ftdl + fttopg + ftdlcomp + ftll

Total fb, psi, at the final condition. fb

=

fbprestress + fbselfwt + fbdl + fbtopg + fbdlcomp + fbll

A2-14 / Hand Calculations for Selected Items ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Appendix Two

Total ftt, psi, at the final condition. ftt

=

fttdlcomp + fttll

The table below summarizes the calculated stresses. Loc. (ft)

ft (psi)

fb (psi)

ftt (psi)

1.5

35.0

1174

25.0

25.0

527.0

20

311

y p o

Note that all of the above stresses are within the allowable stresses based on ACI 318-99, Art. 18.4.2.

Strand Development

C

Ld

=

(fps - 2/3 (fse)) db

fps

=

stress in prestressed reinforcement at nominal strength, approximately equals fpu

fse

=

effective stress in prestressed reinforcement after losses

=

0.75 (270) (1 - 0.176)

=

166.8 ksi

=

[270 - 2/3 (166.9)] 0.5 = 79.4 in

Ld

n o

(ACI 12.9)

i t

Ultimate Strength

a u

The ultimate moment is calculated using the strain compatibility method. Strand is initially tensioned to 75% of fpu. After final losses of 17.61%, effective stress in prestressing steel is fse

l a εse

v E

=

(1 - 0.1761) (0.75) (270) = 166.84 ksi f se 166.84 = 0.00575 = E ps 29000

=

The strain diagram for this situation is illustrated in Fig. A2-5 . 0.003

96"

c 2" 24" eps

esa

ese

FIGURE A2-5. Strain Diagram for Ultimate Strength

PRESTO®v8.6 Hand Calculations for Selected Items ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ A2-15

Appendix Two

dp ε sa + 0.003 = 0.003 c

εsa

εps

=

0.003d p c

=

0.003 (26 − 2.75) − 0.003 c

=

0.06975 − 0.003 c

=

=

y p o

− 0.003

εsa + εse

n o

0.06975 + (0.00575 - 0.003) c

C

Note that PRESTO iterates by trial and error to find the correct value for (c). Try c = 1.58in.

i t

εps

=

0.06975 + 0.0027 = 0.0468 c

fps

=

0.04 ⎞ 270 − ⎛⎜ ⎟ = 269 ksi ⎝ 0.0468 - 0.007 ⎠

a

=

β1 c = (0.85) (1.58) = 1.34

C

=

(0.85) (3) (1.34) (96) = 328 kips

T

=

Aps fps = (0.153) (8) (269) = 329.56 kips ≅ C

φMn

=

a⎞ ⎛ φ A ps f ps ⎜ d p − ⎟ 2⎠ ⎝

a u

l a

v E

OK

=

1.34 ⎞ (0.9) (1.224) (269) ⎛⎜ 23.25 − ⎟ = 6691.14 kip-in 2 ⎠ ⎝

=

6691.14 12

= 557.5 kip-ft

A2-16 / Hand Calculations for Selected Items ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Appendix Two

φM n Mu

=

557.5 477.2

= 1.17 > 1.0

OK

Cracking Load

y p o

Cracking section is at 12.50 ft. phiMn = 480.25 kft Cracking stress =

f c'

7.5

= 7.5 5500 = 556 psi Stress (psi)

-909

92.7

Topping

-334

34.1

Dead Load

-149

17.1

1069

144.5

n o

=

27487 = 1431.6 in3 19.20

Sb

=

= 1223.8 in3

l a

v E Vertical Shear

i t

a u

Mcr

=

C

2461

Self weight

Sbc

=

Moment (kft)

Prestress

Total

Mcr

(ACI 9.5.2.3)

⎡ P Pe Sbc ⎢ + + ⎣ A Sb

⎛ ⎞ ⎤ fr ⎥ - Muc ⎜⎜ Sbc −1⎟⎟ ⎝ Sb ⎠ ⎦

338.40 kft

phi M n = 1.42 M cr

Vu

=

factored shear force.

Mu

=

ultimate design moment.

bw

=

shear width.

d

=

distance from extreme compression fiber to centroid of longitudinal tension reinforcement, but not less than 0.8h.

Vd

=

shear force due to unfactored dead load.

PRESTO®v8.6 Hand Calculations for Selected Items ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ A2-17

Appendix Two

Md

=

moment due to unfactored dead load.

Vi

=

factored shear force at section due to externally applied loads occurring simultaneously with Mmax.

Mmax

=

maximum factored moment due to externally applied loads.

Mc

=

moment causing flexural cracking due to externally applied loads.

Vci

=

nominal shear strength provided by concrete when diagonal cracking results from combined shear and moment.

Ycrit

=

(used for computation of fpc, resultant compressive stress) centroid of composite section, or at junction of web and flange when the centroid lies within the flange.

fpc

=

compressive stress in concrete (after allowance for all prestress losses) at centroid of cross section resisting externally applied loads or at junction of web and flange when the centroid lies within the flange. (In a composite section, or at junction of web and flange, due to both prestress and moments resisted by prestress member acting alone)

Vp

=

vertical component of effective prestress force at section.

Vcw

=

nominal shear strength provided by concrete when diagonal cracking results from excessive principle tensile stress in web.

Vc

=

nominal shear strength provided by concrete.

y p o

n o

i t

a u Vs-max =

l a

v E

C

maximum shear strength which may be provided by shear reinforcement.

Vs

=

nominal shear strength provided by shear reinforcement.

Aps

=

area of prestressing steel.

Av-min =

area of shear reinforcement, per ACI 318-99, 11.5.5.3.

Av

=

area of shear reinforcement per foot of length.

Smax

=

maximum spacing for shear reinforcement.

In the following table, the calculations were done at 1.5 ft from left end. Loc (ft)

Vu (k)

Mu (kft)

bw (in)

d (in)

Vd = Vsw+Vtopg+Vsd (k)

1.5

37.4

38

9.5

19.2

15.4

Md

=

Msw + Mtopg + Msd = 9.97 + 3.92 + 1.91 = 15.7 kft

Mmax

=

Mu - Md = 38.0 - 15.7 = 22.3 kft

Vi

=

Vu - Vd = 37.4 - 15.4 = 22.0 k

Mcr

=

(I / Yc) [6 (

f c' ) + fpe - fd]

A2-18 / Hand Calculations for Selected Items ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Appendix Two

fpe

=

compressive stress in concrete extreme fiber due to effective prestress forces only.

fd

=

stress due to unfactored dead load at extreme fiber where tensile stress is caused by externally applied loads.

I

=

moment of inertia.

Yt

=

distance from centroid axis to extreme tension fiber.

[

Mcr

=

Vci

=

27488 6 5500 + 1404 − (97 + 38 + 16) 19.20 12000

0.6 f c' b w d + Vd +

Vi M cr M max

n o

Note that Vci should not be less than 1.7

f c' bwd

= 202.6 kft

C

Vci

=

0.6 5500

9.5(19.20) 22.0(202.6) + 15.4 + = 223.4 k 1000 22.3

Vci

=

1.7 5500

9.5(19.20) 1000

fpc

=

i t

a u

l a Po

=

fpc

=

y p o

]

= 23.0 k

Po / A + [A + [-Po e (Ybc - Yb) + (Msw + M topg) 12000 (Ybc - Yb)] / I

Transfer Length= 50 ×

1 = 25 in 2

At 1.5 ft effective steel

v E

Aps-eff =

1.5 × 12 × (1.22) = 0.8784 in2 25

(1 - 0.1679) × 0.8784 × 0.75 × 270 = 148.01 k

148010 [-148010(8.53)(19.20 17.15) + (9.97 + 3.92) 12000 (19.20 17.15)] + 401 20985

Vp

=

262 psi

=

147.05 Sin (θ) = 3.06 k

PRESTO®v8.6 Hand Calculations for Selected Items ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ A2-19

Appendix Two

Vcw

=

= =

(3.5

)

f c' + 0.3f pc × b w d + Vp

(3.5

(ACI 11.4.2.2)

5500 + 0.3(262)) × 9.5(19.2) + 3.06 1000

y p o

64.74 k

Vc is the lesser of Vci and Vcw Vc

=

Vsmax =

64.74 k

Vs

=

Av fyd / s

Vs

=

0.0 as φVc > Vu, (Av = 0)

Aps

=

8 (0.153) = 1.22 in2

A vmin = s

v E

n o

i t

50b w s = fy

a u A vmin = s

l a

8 5500 × 9.5 × 19.2 1000

8 f c' b w d =

A ps f pu 80f y d

50(9.5) × 12 60000

d bw

=

= 0.095

C

= 108.2 k

in 2 ft

⎛ 1.22(270000) × 12 ⎞ ⎜ ⎟ ⎝ 80 (60000) × 19.2 ⎠

(ACI 11.5.5.3)

19.2 in 2 = 0.061 9.5 ft (ACI 11.5.5.4)

Av

=

2 0.06 in

Smax

=

(3 /4) h = 18 in

Vnh

=

factored shear force acting on composite section only.

bv

=

width of cross section at contact surface being investigated for horizontal shear

ft

Horizontal Shear

Avhmin =

minimum area of horizontal shear steel required.

Ahs

=

area of horizontal shear steel required for smooth contact surface.

Ahr

=

area of horizontal shear steel required for roughed contact surface.

Vnh

=

(1.4 Vssd + 1.7 Vssl) / φ

A2-20 / Hand Calculations for Selected Items ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Appendix Two

At Loc = 1.5 ft:

Vnh

=

[1.4 (1.854 + 1.7 (9.269)] / 0.85 = 21.59 k

bv

=

96.0 in

Avh-min =

y p o

50 × b w × s fy

A vh-min 50 × b w × s 50 × 9.5 = = = 0.09 s fy 60000 Ahs

=

Avhmin = 0.095 in2/ft

Ahr

=

0.0 in2/ft since Vnh req'd < 80 bvd (Vnh-min) in2/ft

n o

C

i t

a u

l a

v E

PRESTO®v8.6 Hand Calculations for Selected Items ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ A2-21

Appendix Two

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C

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a u

l a

v E

A2-22 / Hand Calculations for Selected Items ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Appendix Two

THIS PAGE INTENTIONALLY LEFT BLANK

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PRESTO®v8.6 Hand Calculations for Selected Items ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ A2-23

Appendix Two

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A2-24 / Hand Calculations for Selected Items ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Appendix Three

Hand Calculations for Torsion Hand Calculations for Torsion

y p o

Shear and Torsion Design of an L Beam

C

This appendix illustrates the shear and torsion design of an L beam 18LB40 on

n o

a 30ft span subjected to eccentric point loads on it. *A 2" topping is present only at the top of beam. (Figs. A3-1 and A3-2) This section provides hand calculations, which explain how the shear and torsion design is implemented in PRESTO. Please refer to data file Torsion.prt in the PRESTO/Examples directory.

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a u

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FIGURE A3-1. Shear and Torsion Design of an L Beam on 30 Ft. Span

* All ACI references for these hand calculations refer to the Building Code Requirements for Reinforced Concrete (ACI 318-99) and all references to PCI refer to the PCI Design Handbook (6th Edition).

PRESTO®v8.6 Hand Calculations for Torsion ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ A3-1

Appendix Three

y p o

FIGURE A3-2. Shear and Torsion Design of an L Beam

Materials f’c = 5000 psi

Wc = 150 pcf

n o

f’ct= 3500 psi

Wct = 150 pcf

Cover to stirrup center = 1.75"

C

Ec = 4286.8 psi

Ect = 3586.6 psi

i t

Loads

DL = 14.5k and LL = 99k at 5', 15' and 25' from left end at 7.5 inch eccentricity.

Critical Section

a u

h = 40 in

h = 20 in 2

l a

20 in from support = 20 + 3 = 23 in from end

v E

loc =

23 = 1.92 ft 12

Analysis Results

Vsw

= 7.85k

Tsw

= 0 kft

Msw

= 13.92 kft

Vtopping

= 0.33k

Ttopping

= 0 kft

Mtopping

= 0.58 kft

VDL

= 1.31 k

TDL

= 0 kft

MDL

= 2.32 kft

VSD+SDS

= 21.75 k

T SD+SDS

= 13.59 kft

M SD+SDS

= 36.32 kft

A3-2 / Hand Calculations for Torsion ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

AppendixThree

VLL

= 14.85 k

TLL

= 9.28 kft

MLL

= 24.80 kft

Vu

= 68.97 k

Tu

= 34.81 kft

Mu

= 116.566 kft

Vd = 7.85 + 0.33 + 1.31 + 21.75 = 31.24k

Md = 13.92 + 0.58 + 2.32 + 36.32 = 53.14 kft

Vi = Vu - Vd

y p o

Mmax = Mu - Md

= 68.97 - 31.24

= 115.76 - 52.57

= 37.73k

= 63.19 kft

Prestressing Aps = (6 + 6 + 6) × 0.153 = 2.75 in2 Transfer Length = 50 × 0.5 = 25 in Effective Area of Prestress: Aps-eff =

n o

1.92 × 12 × 2.75 = 2.54 in 2 25

C

i t

Losses at current location at final = 24.98 % Peff

=

⎛ 24.98 ⎞ 0.75 × ⎜1 ⎟ × 270 × 2.54 = 385.9 k ⎝ 100 ⎠

a u

Composite Section Properties

3586.6 = 0.837 4286.8

l a n=

This reduces the topping width to:

v E

12 × 0.837 = 10.04 in Ac = 18 × 16 + 24 × 12 + 10.04 × 2 = 596.08 in2

yc

Ic

2⎞ ⎛ 18 ×16 × 8 + 24 ×12 × (16 + 12) + 10.04 × 2 × ⎜16 + 24 + ⎟ 2⎠ ⎝ = 18.77 in = 596.08

=

18 × 16 3 16 ⎞ ⎛ + 18 × 16 × ⎜18.77 − ⎟ 12 2⎠ ⎝

2

PRESTO®v8.6 Hand Calculations for Torsion ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ A3-3

Appendix Three

2

+

12 × 24 3 24 ⎛ ⎞ + 12 × 24 × ⎜18.77 − − 16 ⎟ 12 2 ⎝ ⎠

+

10.04 × 2 3 2⎞ ⎛ + 10.04 × 2 × ⎜18.77 − 24 − 16 − ⎟ = 87839.2 in 4 12 2⎠ ⎝

y p o

2

Stresses Stresses at final at bottom after losses: fprestress =

1922 psi (compression)

fsw

=

39 psi (tension)

fdl

=

6 psi (tension)

ftopping =

2 psi (tension)

fsd+sds =

93 psi (tension)

n o

C

Total (Prestress + all dl) = 1922 - 39 - 6 - 2 - 93 = 1782 psi

i t

Cracking Moment

l a

Shear Design

v E

Vci

(

)

=

I 6 f c' + f pe y

=

87839.2 1 = 860.4 kft 6 5000 + 1782 × 18.77 12000

=

0.6 f c' bw dp + Vd +

=

Vci ≥ 1.7 f c' b w d p

a u Mcr

fd

(

)

Vz. (M cr ) M max

where Vci

1.7 fc b w d p = 1.7 5000 ×

12 × 36 = 51.9 k 1000

Therefore,

A3-4 / Hand Calculations for Torsion ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

AppendixThree

Vci

=

0.6 5000 12 × 36 37.73 + 31.24 + × 860.4 = 563.3 k > 51.9 k 1000 63.19

Stress due to prestress and DL on precast at composite centroid:

y p o

Top Stress = -862 + 47 + 8 + 2 +105 = -699 psi Bottom Stress = 1922 - 39 - 6 - 2 - 93 = 1782 psi At 18.77 in from bottom:0

fpc

=

1782 + 699 × (40 - 18.77 ) - 699 = 618 psi 40

Vcw

=

(3.5

=

Vc sφVc

)

f c' + 0.3f pc b w d + Vp

(3.5

n o

5000 + 0.3 × 618) × 12 × 36 +0 1000

C

i t

=

187.0 k

=

smaller of Vci and Vcw

=

187.0 k

=

158.9k > Vu = 68.5 k, provide minimum shear reinforcement.

a u

Vs max =

8 5000 × 36 ×12 = 244.4 k 1000

l a

Torsion Design

Area enclosed by outside concrete perimeter:

v E

Acp = 12 × 40 + 6 × 16 = 576 in2 Perimeter of outside concrete: Pcp = 12 75 + 40 + 18 + 16 + 6 + 24 = 116 in

PRESTO®v8.6 Hand Calculations for Torsion ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ A3-5

Appendix Three

y p o

n o

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FIGURE A3-3. Shear and Torsion Design of an L Beam (Closed Stirrup)

i t

Cover to Stirrup Center is 1.75" Aoh

l a

v E

36.5 × 8.5 + (14.5 - 8.5) × 12.5

=

385.25 in2

a u ph

Cracking Torsional Moment

=

=

36.5 + 8.5 + (36.5 - 12.5) + (14.5 - 8.5) + 12.5 + 14.5

=

102 in

Tcr

=

⎛ 576 2 ⎞ ⎟ 1 + 618 = 120.3 kft 4 5000 ⎜ ⎜ 116 ⎟ 4 5000 ⎠ ⎝

Tlim

=

0.85 × 120.3 = 25.5 kft 4

Tu

=

34.8 kft > 25.5 kft, so we require design for torsion

Aoh

=

(40 - 2 × 1.75) × (12 - 2 × 1.75) + (16 - 2 × 1.75) × 6 = 385.25 in2

Ao

=

0.85 × 385.25 = 327.46 in2

Ph

=

(40 - 2 × 1.75) + (18 - 2 × 1.75) + (16 -2 × 1.75) + 6 + 24 + (12 - 2 × 1.75)

=

102 in

=

37.5 degrees

θ

A3-6 / Hand Calculations for Torsion ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

AppendixThree

At S

34.8 ×12000 in 2 in 2 = 0.01 = 0.12 2 × 0.85 × 60000 cot(37.5) in ft

=

A v 2A t + S S

Check for Minimum Transverse Steel

= 0.0 + 0.24 = 0.24

in 2 ft

y p o

A v + 2A t in 2 in 2 12 = 0.01 = 0.12 > 50 × S 60000 in ft At midspan Peff = 435.5 kips (from PRESTO) fps

=

435.5 2.75

= 158 ksi > 108 = 0.8 fpu

Therefore, also check minimum steel as per Eq. 11-14: A ps f pu 80f y d

Smax =

36 in 2 in 2 = 0.007 = 0.09 12 in ft

i t

Check for Spacing Spacing for Shear

n o

d 2.75 × 270 = bn 80 × 60 × 36

C

3 3 h = × 40 = 30 in 4 4

a u

Smax = 24 in

' Since Vs not > 4 f c bwd

l a

Therefore, no need to reduce spacing.

Spacing for Torsion

v E

Smax =

ph 102 = = 12.75 8 8

Smax = 12 in ← Use the lower Smax due to shear and torsion requirements. Therefore, Smax = 12 in

Longitudinal Steel For minimum longitudinal steel: At S

=

0.01

in 2 25bw 25 × 12 in 2 = ≥ = 0.005 in fy 60000 in

PRESTO®v8.6 Hand Calculations for Torsion ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ A3-7

Appendix Three

Almin

=

5 5000 × 576 60000 - 0.01 × 102 × = 2.45 in 2 60000 60000

Al

=

0.01 × 102 ×

60000 × cot(37.5) 2 = 1.73 in 2 60000

y p o

Since Al < Almin, use Al = Almin Therefore, Al = 2.45 in2

Compression in Concrete

187.0 × 1000 ⎞ Compression allowed = 0.85⎛⎜ + 8 5000 ⎟ = 849 psi ⎝ 12 × 36 ⎠

2

Compression present =

C 2

⎛ 68.97 × 1000 ⎞ ⎛ 34.81× 12000 × 102 ⎞ ⎜ ⎟ +⎜ ⎟ = 232 psi ⎝ 12 × 36 ⎠ ⎝ 1.7 × 385.25 2 ⎠

n o

Compression allowed > Compression present

OK

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A3-8 / Hand Calculations for Torsion ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Appendix Four

Strand and Rebar Properties

y p o

Strand and Rebar Properties

Strand Properties fpu (ksi)

Type

6/10

270

LL

0.217

270

SR

0.217

270

LL

0.192

i t

6/10 9/16 9/16 1/2

a u 1/2 1/2

7/16

l a

v E

n o

C

Nominal Diameter (in)

Area (in2)

270

SR

0.192

270

LL

0.153

270

SR

0.153

250

SR

0.144

270

LL

0.115

7/16

270

SR

0.115

7/16

250

SR

0.108

3/8

270

LL

0.085

3/8

270

SR

0.085

3/8

250

SR

0.080

where LL = Low Relaxation and SR = Stress Relieved

PRESTO®v8.6 Strand and Rebar Properties ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ A4-1

Appendix Four

Rebar Properties Bar Size

Diameter (in)

Area (in2)

3

0.375

0.11

4

0.500

0.20

5

0.625

0.31

6

0.750

0.44

7

0.875

0.60

8

1.000

0.79

9

1.128

1.00

10

1.27

1.27

11

1.410

14

1.693

18

2.257

n o

y p o

C 1.56

2.25 4.00

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a u

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v E

A4-2 / Strand and Rebar Properties ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Appendix Fi ve

Section Type and Dimensions

y p o

Section Type and Dimensions

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PRESTO®v8.6 Section Type and Dimensions ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ A5-1

Appendix Five

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A5-2 / Section Type and Dimensions ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Appendix Six

References

y p o

References

Branson, Dan E. and Trost, Heinrich. “Application of the I-Effective Method in Calculating Deflections of Partially Prestressed Members,” PCI Journal, Prestressed Concrete Institute, Chicago, IL, September-October 1982, pp. 62-77.

2.

Building Code Requirements for Reinforced Concrete (ACI 318-99). American Concrete Institute, Farmington Hills, MI, 1999.

3.

Building Code Requirements for Reinforced Concrete (ACI 318-05). American Concrete Institute, Farmington Hills, MI, 2005.

4.

CPCI Design Manual, Precast and Prestressed Concrete. Third Edition. 1996.

v E

n o

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a u

l a

C

1.

5.

Mast, Robert F. “Analysis of Cracked Prestressed Concrete Sections: A Practical Approach.” PCI Journal, Prestressed Concrete Institute, Chicago, IL, July-August 1988, pp. 80-91.

6.

Metric Design Manual, Precast and Prestressed Concrete. Second Edition. Canadian Prestressed Concrete Institute, Ottawa, ON, 1987.

7.

Notes on ACI 318-95 Building Code Requirements for Reinforced Concrete with Design Applications. Portland Cement Association, Skokie, IL, 1996.

8.

PCI Committee on Prestress Losses, “Recommendations for Estimating Prestress Losses,” PCI Journal, Prestressed Concrete Institute, Chicago, IL, July-August 1975, pp. 43-75.

9.

PCI Design Handbook, Precast and Prestressed Concrete. Sixth Edition. Prestressed Concrete Institute, Chicago, IL, 2004.

10. Seminar Notes on ACI 318-02 Code Revisions. Portland Cement Association, Portland, OR, 2002. 11. Young, Warren C. Roark's Formulas for Stress and Strain. Sixth Edition. McGraw-Hill, Inc, 1989. 12. A23.3-94 (Reaffirmed 2000) Design of Concrete Structures, Canadian Standard Association, 1994.

PRESTO®v8.6 References ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ A6-1

Appendix Six

13. General Instruction No. 2 for A23.3-94 Design of Concrete Structures, Canadian Standard Association, 1994.

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A6-2 / References ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Appendix Seven

Glossary

y p o

Glossary

C

Allowable Stresses:

While PRESTO computes a default table of allowable stresses at release and final conditions, the user may override any or all values. A computed stress that exceeds the corresponding allowable stress is flagged with an asterisk. In ACI 318-05 mode, the user specifies limits that are used to classify a section as U/T/C (Uncracked/Transition/Cracked) as well in allowable stress.

Alphanumeric:

Consisting of both alphabetic and numeric characters.

Analysis Locations:

User-specified locations, measured from the extreme left end of the beam, where the analysis is to be performed.

Asterisk:

A warning flag issued when the stress at a location is above an allowable value, a calculated moment capacity is below a required moment, or a specific warning has been issued to the user.

l a

Beta-1 (β1):

v E

i t

a u

Bar Size:

n o

A standard numerical designation for rebar. Indicates the specific diameter and cross-sectional area. Factor defined in ACI 318-99, Art. 10.2.7.3, used in the calculation of the height of the equivalent concrete compressive stress block in ultimate strength calculations.

Bfl-bot, Bfl-top:

Widths of the bottom and top flanges of the precast section, respectively. Set equal to zero if no flange exists.

Bilinear:

An idealized deflection method for prestressed members when loaded into the cracking range.

Boundary Distance:

The boundary distances are the portions to the left and right of the centerline of the member. Like tributary width, the boundary distances are used to convert uniform loads to linear loads for the member being analyzed. PRESTO accepts non-symmetrical boundary distances. Based on user choice, this also modifies the section properties of the precast section if total boundary distance is less than the section flange width.

PRESTO®v8.6 Glossary ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ A7-1

Appendix Seven

c/dt:

PRESTO uses this to determine the behavior of a section in ACI 318-05 code. As per the default values if this value is less than or equal to 0.375, the section is tension controlled (TENS) and a phi value of 0.9 can be used. If this ratio is larger than 0.600, the section is compression controlled (COMP) and a phi value of 0.65 should be used. For intermediate values of this ratio, the section is in transition (TRANS) and the program will compute the phi value.

Camber and Deflection Multipliers:

Component prestress uplift and deflection multipliers (see PCI Handbook, 5th edition). Used to predict long-term time-dependent behavior.

Check point Properties:

Non-composite and composite section properties computed at user-specified check points. Both the slab and mild reinforcement are transformed.

Class:

ACI 318-05

Context Sensitive:

The help system for PRESTO is context sensitive; the information on the help screen relates to the specific part of the program from which it was called.

Crack Control:

Codes requires a check of the spacing of steel for a section that cracks. In ACI 318-99, this is required for all reinforced sections. In ACI 318-05, this is required for prestressed concrete sections that crack as well as reinforced sections. S-req and s-prov are computed. S-prov is flagged if it is more than s-req.

Crack Depth:

For a cracked section, this is reported as the depth from the extreme geometric tension face. For a section with crack at bottom, it is the depth from the bottom of the geometric section to a point of zero tension stress. For a section with crack at top, this is the depth from the top of the section (precast or composite top) to the zero tension stress level.

Cracked Section Properties:

In ACI 318-05, if a precast/prestressed section gets cracked, PRESTO computes the section properties for a cracked section. These are reported in a separate table as effective properties. For an uncracked section, effective section properties are the same as the gross section properties.

Current Data File:

Data File that is open for input.

Data File:

A disk file used by PRESTO to store information for a task created by a user.

y p o

requires precast/prestressed sections to be classified based on total tension stress at final. Based on this classification, a precast section may be classified as Uncracked (U), In Transition (T), or Cracked (C).

n o

C

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a u

l a

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Data file List:

PRESTO maintains a list of the last five data files that you have opened. To reopen a data file, you may select directly from this list.

Days to Topping, Comp. DL:

Number of days between the release of the strand and the placement of the topping or the addition of the composite dead load, respectively. Used for the time dependent loss analysis.

Dead Load, Composite:

Dead load defined by the user to act on the composite section.

A7-2 / Glossary ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Appendix Seven

Dead Load, Noncomposite:

Dead load defined by the user to act on the bare precast section.

Debonding:

See “shielding.”

Default Directory:

Location where the program will store data files unless that location is explicitly changed while saving newly created files.

Default File Name:

A disk file that contains user defined material properties, which are supplied when a new data file is created.

Default Value:

The preset (usually the standard) value or option.

Depress Point:

Point at which the strand profile is depressed mechanically, as with a harping fork in a double tee.

Development Length:

Length of embedded reinforcement required to develop the design strength of the reinforcement at a critical section.

Development Length Multiplier:

A user defined number that determines how many computed development lengths are required to fully develop the prestressing strand. The calculated development length for all strands will be multiplied by this value.

Dialog Box:

A mini “input screen” produced by the program to obtain further information from the user. Dialog boxes may contain several types of input fields.

Ec, Eci, Ect:

The flexural modulus of elasticity of the precast concrete at final, the precast concrete at initial, and the topping concrete, respectively.

Ecc:

Eccentricity.

ecu:

Ultimate compressive strain of the concrete. Usually equal to 0.003 µ-in/in.

Effective Width of Section:

The limiting effective width of a T-beam per Art. 8.10.

End Anchorage:

PRESTO recognizes three types of end anchorage for mild reinforcement: straight, hooked and mechanical. Mechanical anchorage is defined in ACI 318-99 as any mechanical device capable of developing the strength of the reinforcement without damage to the concrete.

C

a u

i t

l a

v E Eps:

n o

y p o

Modulus of elasticity of the prestressing tendons.

Es:

Modulus of elasticity of the mild steel.

f'c, f'ci, f'ct:

The compressive strength of the precast concrete at final, of the precast concrete at initial, and of the topping, respectively.

Field Length:

The maximum number of characters that can be input for a particular item of data.

File Extension:

A description of up to 3 characters that is separated from the file name by a period (.). Useful for categorizing files. PRESTO reserves the file extensions “.prt” for data files, and “.txt” for output files.

PRESTO®v8.6 Glossary ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ A7-3

Appendix Seven

File Name:

Alphanumeric name of a disk file as allowed by the operating system. PRESTO allows the use of long file names.

fpu:

Specified tensile strength of the prestressing tendons.

fpy:

Calculated yield strength of the prestressing tendons, taken as equal to 0.9fpu for low relaxation strand and 0.85 for stress-relieved strand.

fy:

Specified yield strength of the mild reinforcement.

Gap:

PRESTO defines the gap as the boundary distance minus the width of the topping slab. The gap may also be thought of as the region between the beams. See Slab.

Hard Disk:

Fixed disk.

Hours to Release:

Number of hours between tensioning and detensioning the strands. Used in prestress loss computations.

Input Data File:

See “data file.”

Input Field:

Specific positions on the computer screen in which the program can accept input (usually alphanumeric) from the user.

Input Screen:

A collection of related input fields which allow the user access to the current data file.

Invalid Entry:

Your input in the current field exceeds either the minimum or maximum limit for this value. The allowable range for the current field (if any) is usually listed in the message box that shows this error.

Jacking Ratio:

The initial jacking force of the strand expressed as a fraction of fpu (e.g. 0.70).

Kern Points:

The boundary points of a beam cross-section whereby strands placed within that region will cause compression in both the top and bottom of the section: k1 = yb - St/A and ku = yb - St/A.

C

i t

a u

l a

v E Lambda:

n o

y p o

Strand Added

Effect at bottom

Effect at top

Below kern pts.

Compression

Tension

Between kern pts.

Compression

Compression

Above kern pts.

Tension

Compression

As sand is replaced with lightweight fines in a concrete mix, the unit weight decreases and the mix is usually referred to as “sand-lightweight” concrete. Lambda is defined in ACI 318-99 to account for changed properties of such concrete.

Ld Multiplier:

See “development length multiplier.”

Lightweight Concrete:

Concrete that contains lightweight aggregate and has a unit weight not exceeding 110 pcf (1800 kg/m³).

Linearly Varying Load:

Trapezoidal load defined by beginning and ending locations and beginning and ending magnitudes.

A7-4 / Glossary ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Appendix Seven

Live Load Recapture:

Temporary increase of tensile stress in prestressed tendons due to superimposed live load.

Load Classes:

PRESTO recognizes five load classes:

DL

dead load (non-composite)

SD

superimposed dead load (composite)

SDS

Superimposed dead load of snow (composite) in ACI 318-99

y p o

Lr/S/R External loads (composite) in ACI 318-05 LL

live load

SL

Sustained live load

Load Factors:

Dead and live load factors in accordance with modified by the user.

Load Type:

PRESTO recognizes three types of loads:

n o

CON

concentrated (point), kips or kN

UNI

uniform, ksf or kN/m2

LIN

linearly varying, klf or kN/m

C

ACI 318-99 Art. 9.2,

which may be

i t

PRESTO supports three methods to calculate prestress losses. The first (PCI) follows

Loss Analysis:

the method presented in the PCI Design Handbook, 5th Edition. The second method (Time-dependent) follows the time-dependent method described in the article “Recommendations for Estimating Prestress Losses,” PCI Journal, Vol. 20, No. 4, July-August 1975. The last method (Manual), allows the user to input losses directly as a percentage of the initial prestressing force. Magnitude:

a u

The absolute value of a particular quantity.

l a

Midspan Spacing:

The distance between c.g.’s of adjacent strand levels at the depress point(s) (if any).

Modulus of Elasticity:

Ratio of normal stress to the corresponding strain for tensile or compressive stresses. The material property that determines the deformability under load.

v E

Moment of Inertia:

Also known as the second moment of an area, it is defined as the product of the area of an element and the square of the distance from the axis to that element.

Non-reinforced Section Properties:

Computed section properties that include the effects of openings but not reinforcement.

Normal Weight Concrete:

Concrete that has a unit weight equal to 150 pcf (2400 kg/m3) is generally referred to as normal weight concrete.

Opening:

A void introduced into a hollow core slab or the flange of a flanged member. Openings may be either rectangular or circular. PRESTO automatically recomputes the section properties in zones where openings are present.

PRESTO®v8.6 Glossary ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ A7-5

Appendix Seven

Output File:

A disk file in which PRESTO stores results from calculations. Output files are given the extension “.txt”.

Overall Length:

The out-to-out dimension of the beam.

Partial Strands:

(also referred to as fractional strands) PRESTO allows the user to specify a decimal value less than 1.0 for the number of strands in a location.

Radio Buttons:

A related group of input fields, only one of which may be “selected” at any one time. This type of field derives its name from the old style car radio push buttons, when you pushed one of the buttons down, all of the other buttons came up.

Rebar ID:

A unique identifier assigned by the user to differentiate between rebar types.

Rebar Library:

A disk file (“REBAR.pr3”) that contains user defined rebar type data.

Relative Humidity:

The average ambient relative humidity expressed as a percentage (e.g., 75%).

Results Display:

A display of the results of the calculations for a user requested analysis. This display can be viewed on the screen, sent to the printer, or saved in a disk file (for later printing).

Rho-calc:

For a flanged section, if the compression block is within the top flange, the width of the top flange is used in this formula. PRESTO does not consider the width of the web or distinguish between the web and flange.

S-req:

If just one bar is used, a warning message displays to notify the user that the program does not consider horizontal spacing.

Sand Lightweight Concrete:

Defined by PRESTO as concrete with a unit weight between 110 and 150 pcf (18002500 kg/m³).

Section ID:

A unique identifier assigned by the user to differentiate between entries in the section library.

y p o

n o

C

i t

a u

l a

Section Library:

A disk file (“beams.pr1”) in which section data may be stored by the user.

Section Type:

PRESTO recognizes ten different section types, including Double Tees, Single Tees, Keystone Joists, Rectangular Beams, Inverted Tee Beams, L-Beams, Reversed Lbeam, Hollow Core, Solid Slabs, and I-Girders.

v E

Self-Weight Multipliers:

Multipliers of the self-weight at release and final conditions that allow the user to vary the effective self-weight of the member. For example, a wall panel might have a selfweight multiplier of 1.0 at release when the panel is horizontal and a multiplier of 0.0 at final when it is vertical (i.e., self-weight is not causing flexure).

Shielding:

A method of reducing the effectiveness of a strand over a given portion of the beam. PRESTO can model both exterior (end) and interior shielding.

Slab:

This is a term used by PRESTO for that portion of the topping that is directly on top of the precast. The portion of the topping that is not over the precast is referred to as the gap. See “gap.”

A7-6 / Glossary ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Appendix Seven

Span Location:

The span location in can be either Exterior of Interior. PRESTO uses the span location to determine the maximum overhang width for sections with top flanges and topped sections in accordance with ACI 318-99, Sections 8.10.2 and 8.10.3.

Stem Mesh:

Structural welded wire reinforcement. PRESTO only considers the vertical component of this reinforcement for vertical shear calcuations.

Strand Grouping:

PRESTO groups the strand pattern into groups of 1 or 2 strands from the top level of the pattern a pair at a time until all strands have been removed from that level. If there are an odd number of strands at that level then the last group will consist of 1 strand. Strands are removed from successive levels until the pattern has been exhausted.

Strand ID:

A unique identifier assigned by the user to differentiate between strand types.

Strand Initial Pull:

See “jacking ratio.”

Strand Library:

A disk file (strand.pr2) that contains user-defined strand type data.

Strand Type:

Strand may be either low-relaxation or stress-relieved. Both types of strands must conform to ASTM A416.

Support Locations:

Support locations measured in from the ends of the beam, which may be different at release and at final conditions.

Topping:

Topping is that portion of the section, which combined with the precast section, makes up the composite section. Topping may be split into the slab (that portion directly on top of the precast) and the gap (boundary width minus the width of the slab).

Uniform Load:

A load that is measured in weight/area.

Unit Weight:

A measure of the density of a material, expressed in weight per volume.

Units of Measurement:

measures.

n o

y p o

C

i t

a u

PRESTO supports both the ft-lbs system and the metric system of weights and

l a

Volume to Surface Ratio:

Usually approximated by the ratio of the area of a section to its perimeter.

Web-extent:

The distance between the tops of the exterior stems of a member. If a member has only one stem then the web-extent is the stem width at the top. Used in computing the effective width.

v E Zone:

A prismatic zone along the member in which the section properties are the same.

PRESTO automatically creates as many zones as necessary depending on how many

openings and changes in topping are introduced.

PRESTO®v8.6 Glossary ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

/ A7-7

Appendix Seven

y p o

n o

C

i t

a u

l a

v E

A7-8 / Glossary ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

I N D E X

Index Symbols # of steel A1-7

Ash, min A1-6

A A A1-5, A1-6

Bo GO-6

Authorization GS-8

Bot wid A1-2

Accelerated A1-5 Ace A1-4 Acp GO-7 Acr A1-6 Add New circle GO-65

Authorization tab GS-13

Distance in section properties GO-4

AUTOCAD DXF format GO-16 Auto-debond Percentage GO-8

Width TH-3 Bt A1-4

Av+2At A1-7

Bw A1-4, A1-7

AvC A1-7

Bweb A1-6

Average depth TH-16

New polygon GO-65 Nodes GO-65

Ayh, min A1-9

Ahr A1-8

i t

B b1 A7-1

Ahs A1-9 Al A1-7 Allowable Reinforcement ratio, maximum A1-

Balanced reinforcement ratio A1-7 Bar size A7-1

Reinforcement ratio, minimum A17

Stress tab GO-25 Stresses A7-1

l a

Alphanumeric A7-1 An A1-6

Analysis TH-2, TH-6

v E

Aps A1-1 Area Assumed crack plane A1-6

Basic features TH-1 Beam Length GO-3

a u

7

Sections library GO-63

Type GO-3 Bearing Analysis GO-18, TH-27 Length GO-27 Steel A1-6 Steel data A1-4 Steel Info dialog box GO-26 Width GO-27 Beff GO-27, TH-4, A1-4 Beta-1 A7-1

Composite section A1-1

P/c A1-4

Compression Steel A1-1

Tpg A1-4

Mild Tension A1-1

Beta1 A1-6

Non-composite section A1-1 Non-composite transformed section A1-5

Bf A1-4

Prestressing Strand A1-1

Bfl-top A1-2, A7-1

As, A’s A1-1

C

Bv A1-4, A1-9

n o

Avf A1-6

Advanced features TH-2

y p o

Boundaries left/right GO-4 Boundary Distance TH-3, A7-1

Warnings GS-2

About PRESTO GO-72

Tab GO-12

AtC A1-7

Transfer GS-11

A1, A2 A1-6

Aoh GO-7, A1-2

Analysis GO-19

Demo GS-10

A, Ac A1-1

Locations A7-1

Bilinear A7-1

Asterisk A7-1

C C A1-5

c/dt TH-18, A1-6, A7-2 Calculated Internal constants A1-4 Longitudinal steel A1-7

Reinforcement ratio A1-7 Calculations Camber and deflections TH-22 Cracking moment TH-17 Cracking ratio TH-2 Development length TH-25 Gap TH-3 Over-reinforcement TH-17 Section properties TH-4 Ultimate strength TH-2 Camber and deflections TH-22, A1-9 Multipliers A7-2 Cc A1-7 Check points TH-6 Dialog box GO-15 Properties A7-2 Circular Openings TH-2 Section dialog box GO-67

Bfl A1-6

Class GO-12, A1-1, A7-2

Bfl-bot A1-2, A7-1

Clearance GO-7

Bg A1-4

Comp A1-1 Composite A1-1

PRESTO®v8.6 ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

Index / 1

D D A1-8

Dfps A1-7

Compression A1-1

D, d’ A1-7

Diagrams GO-61

Compression controlled TH-18 Compressive strength Precast concrete at final A1-1

Data file A7-2

Dialog box A7-3

List A7-2 Days To Comp DL GO-21, A1-3, A7-2

Diameter A1-1

Shear depth GO-19 Snow load GO-12, TH-7

Precast concrete at release A1-1 Topping concrete A1-1

To topping GO-21, A1-3, A7-2 Dead load GO-12, A1-1, A7-2, A7-3

Concentrated loads GO-11

Dead, non-composite load TH-7 Debonding Increment GO-8

Concrete stress distribution TH-12 Contents GO-72 Context-sensitive help IN-6, A7-2

DebondingSee Shielding A7-3 Default Directory A7-3

Control A1-7 Controls A1-6 Convert libraries GO-71

File name A7-3

Cor A1-7

Value A7-3

CR A1-5

Multiplier tab GO-22 Delete nodes GO-66 Depress A1-3

Point A1-3, A7-3

ACI 318-95 TH-11

l a

Sections TH-9

v E

Depressed strand patterns TH-2 Depth Of compression block A1-6

a u

ACI 318-99 TH-10

Section properties A7-2

i t

Demo authorization GS-10

Depth A1-5, A7-2 Crack Control ACI 318-02 TH-10

CSA 23.3-94 TH-11 Cracked Beam TH-9

n o

Deflection TH-23

Cr A1-6 Crack Control A1-7, A7-2

Slab TH-9 Cracking Load A1-7

Multiplier A7-3

To neutral axis A1-6 To neutral axis, maximum A1-7

Description GO-12 Design Bearing strength A1-6 Methodology, ACI 318-02 TH-18 Methodology, ACI 318-99 TH-16

Load prestressed members TH-17

Options tab GO-17

Moment GO-20, TH-17

Parameters dialog box GO-17

Crash GS-14 Create pattern Assuming GO-20 Creep A1-5 Critical Point TH-6

Ratio TH-16 Current data file A7-2

Results screen GO-46 Status screen GO-46 Tab GO-16 Detailed losses GO-20 Developed Bonded GO-25 Debonded GO-25 Development length TH-25, A1-3, A7-3

y p o

Dimensions option GO-64 Direct transfer GS-11

On a network GS-13

Direct Transfer tab GS-11, GS-13 Dist to Brg A1-4

Distance to CL of bearing GO-27 Drawing Option GO-64

C

Print dialog box GO-47

Properties dialog box GO-66 Properties settings GO-65 The beam section GO-65 Dsc A1-7 Dt A1-7 E Ec A1-1, A7-3 Ecc GO-12, A1-1, A7-3 Eccentricity GO-4, A1-1 Eci A1-1, A7-3 Ect A1-1, A7-3 Ecu A1-2, A7-3 ecu GO-10 Effective Moment of inertia TH-23

Shear friction coefficient A1-6 Width of section A7-3 Elastic shortening A1-5 Elasticity GO-9 Final GO-10 Release GO-9 Topping GO-10 End Anchorage A7-3 Rotations GO-19 Eps A1-1, A7-3 Equilibrium of forces TH-12, TH-13 Es A1-3, A7-3 Exit GO-58

2 / ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Exposure A1-2

Fpu A1-1, A7-4

I, Ic A1-1

External load on composite TH-7

Fpy A1-1, A7-4

Ice A1-5

Fr A1-7

Icr A1-9

Front View GO-60

Ie A1-9

Fs GO-11, A1-3, A1-7

Ig A1-9

Fse A1-7

Ig/Ie A1-9

Fst A1-5

Image GO-59

F F’c A1-1, A7-3 F’ci A1-1, A7-3 F’ci-min A1-6 F’ct A1-1, A7-3

Fy GO-10, A1-1, A7-4

F1, F2 GO-6 F-Act A1-8 Factored Moment A1-2

In transition TH-18

G Gap GO-4, TH-2, A1-3, A7-4

Shear A1-2

Topping adjustment GO-5 General Operation GO-1

Torsion A1-2 F-alw A1-8 Fcds A1-5

Overview TH-1

Fcir A1-5

Getting started GS-1

Fcr A1-5

Gross moment of inertia TH-24

Fct GO-10, A1-1

H H, Hc A1-1

Field length A7-3 File Extension A7-3 File menu GO-54, GO-55

a u

Hard disk A7-4

Exit GO-58 New GO-54 Open GO-54 Print GO-56

l a

Print setup GO-57 Save GO-55 Save as GO-55

Save setting GO-55

v E Security GO-58

Fillet GO-66 Final Stresses A1-6

Supports GO-4

Fixed license GS-13 Flange opening GO-5, TH-2 Floating license GS-13 Floppy disk transfer GS-12 Fpc A1-8 Fpi A1-5

i t

A2-1, A3-1, A4-1, A5-1, A6-1, A7-1

Initial Jacking Co-efficient GO-8 Input Data fileSee Data file A7-4

C

Field A7-4

Screen A7-4

Installation GS-3

Introduction IN-1

n o

Hand calculations for selected items

Name A7-4

y p o

Button summaries GO-59

Shear GO-11

Invalid entry A7-4 J J A1-5

Jacking ratio A7-4 K Kcir A1-5 Kcr A1-5

Hardware requirements GS-1 Height Precast section A1-2

Kern points A7-4

Help desk GS-15

Ksh A1-5

Kes A1-5 Kre A1-5

Help menu GO-72 Contents GO-72

L L1, L2 A1-3

How to use help GO-72

Lambda A7-4

About PRESTO GO-72

Search for help on GO-72 Visit LEAP Web site GO-72 Hollow core sections TH-4 Horizontal Clearance GO-7 Shear GO-19, A1-8 Hours to release GO-21, A1-3, A7-4 How to use help GO-72 I I A1-5

p/c A1-4 tpg A1-4 Layout TH-2 L-c, R-c A1-3 Ld multiplier See Development length multiplier A7-4 LEAP Software Sales department GS-1 Security GS-9 Technical support GS-15 Length GO-5, A1-2, A1-4

Fps A1-7

PRESTO®v8.6 ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

Index / 3

M M.I. A1-2

Non-composite transformed section A1-5

Beam sections GO-63

Ma A1-9

Precast section A1-2

Convert from v. 7 GO-71

Mag GO-12

Prestressing tendon GO-69

Magnitude A7-5

Mor A1-7

Rebar GO-70

Manual TH-6

Ms A1-5

Setup GO-63

Materials tab GO-8 Maximum Auto-debonding percentage GO-8

Msc A1-7

Mbm A1-5

Mu-eff A1-6

Mc0 A1-9

Multiple file copies GS-14

Multipliers A1-3 Libraries menu GO-62

License GS-1 Fixed GS-13 Floating GS-13 Loss of GS-14 Site GS-1 Linear loads GO-11 Linearly varying load A7-4 Live load GO-12, TH-7, A1-1

Classes A7-5 Composite external TH-7

Factors dialog box GO-13 Live TH-6, TH-7

l a

v E

Loads tab GO-11

Location A1-1, A1-2

Longitudinal Bars Screen Terms GO40

Longitudinal Bars Tab dialog box GO39

Loss Analysis A7-5 L-t, R-t A1-3

Non-reinforced section properties A7-

n o

i t

Show GO-59

a u

Factors TH-8, A7-5

Loc GO-12

Md0 A1-9

Libraries GO-62

Dead, non-composite TH-7

Type A7-5

New GO-54

Help GO-72

Composite snow TH-7

Topping TH-7

Md A1-8

Member Info tab GO-3 Menus File GO-54, GO-55

Load TH-3

Sustained live TH-8

Mcr A1-2

Measurement units IN-5, A7-7

Lo GO-6

Superimposed dead TH-7

Mu A1-2

N Network setup GS-2

MCF A1-5

Mdl A1-5

Recapture GO-20, A7-5

Stages TH-24

y p o

Mtopg A1-5

Mcdl A1-5

Lightweight concrete TH-26, A7-4

Self-weight TH-7

Section A1-1

Mid Debond GO-38 Midspan Spacing A7-5

Miscellaneous Data tab GO-23 Mll A1-5

C 5

Normal weight concrete A7-5 Nu/Vu GO-27, A1-4 O Open GO-54 Opening TH-2, TH-3, A7-5 Data dialog box GO-6 Type GO-6 Output file A7-6 Overall length A7-6 Over-reinforcement TH-17

Mmax A1-8

P Pan GO-59, GO-66

Model GO-60

Pcp GO-7

Modify nodes GO-66

PCR A1-5

Modulus of elasticity TH-12, TH-13,

P-eff A1-8

A1-3, A7-5

Ph GO-7, A1-2

Precast concrete at final A1-1

Phi Factors tab GO-23

Precast concrete at release A1-1

Phi*Mn A1-7

Prestressing strand A1-1

Phi*Mn/Mcr A1-7

Topping concrete A1-1

PhiMn/Mu A1-7

Modulus of rupture TH-23, A1-7

PhiVn A1-6

Moment of inertia TH-25, A7-5

Pi A1-6

Cracked A1-9

PMn A1-7

Effective A1-9

Precast A1-2 Precast section Modeled TH-2

Gross A1-9

4 / ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Properties TH-4 Preferences GO-62 Prestress And Losses tab GO-20 Losses TH-5 Prestressed Strand data A1-3

Load TH-7 Set up libraries GO-63

Release supports GO-4

Setup Type GS-6 Shear ACI 318-02 TH-19

CSA 23.3-94 TH-21

Reset GO-60

Shear wid A1-2

Results GO-60

Shielding A7-6

Display A7-6

Tendon library GO-69

Show menu GO-59

Return and update GO-65

Print GO-56, GO-60 Setup GO-57 Program Authorization GS-8 Crash GS-14

Diagrams GO-61

Rho-bal A1-7

Image GO-59

Rho-calc A1-7, A7-6

Model GO-60

Rho-max A1-7

Preferences GO-62

Security GS-1 Project Data A1-2

n o

Roof live/snow/rain load GO-12

Shrinkage A1-6

Rotate GO-59

Site license GS-1

i t

S S A1-6

Tab GO-2 Provided A1-6 Pull fraction A1-3

l a

Rebar TH-2

v E

Library GO-70, A7-6 Pattern data A1-3

Properties A4-2 Reduction Coefficient A1-6 Factors TH-26

Register Transfer tab GS-12 Reinforcement ratio Balanced A1-7

Source directory GS-11 Spacing A1-3 Span location GO-4, A7-7

Setting GO-55

RE A1-6

S-max A1-8

Save GO-55

As GO-55

Radio buttons A7-6

Slab TH-2, A7-6

Sand lightweight concrete A7-6

a u

PSH A1-6

Results GO-60

Show vertex GO-66

Rho-w A1-8

Menu commands GO-54

C

RH A1-2

Rho-min A1-7

Installation GS-3

y p o

ACI 318-99 TH-19

Spacing of reinforcement A1-7

Tendon ID GO-8

R R1, R2 A1-3

Multipliers A7-6

Release stresses A1-6

Required A1-6

Prestressing A1-9

Calculated A1-7

Minimum allowable A1-7

Release/final GO-21

Strand pattern data A1-3

ID A7-6

Self-weight TH-2

Relative humidity GO-21, A1-2, A7-6

Loss computations A1-5

Data A1-3

Maximum allowable A1-7

Sb, Sbc A1-2 Sbce A1-5 SCF A1-6

Search for help on GO-72 Section Detail dialog box GO-64, GO-65

Splash screen GO-1 Splitting tensile strength Lightweight aggregate concrete A1-1

S-prov TH-11, A1-7, A7-2 S-req TH-11, A1-7, A7-2, A7-6 SSF A1-6 Starting the program GO-1

Drawing screen GO-65

Steel Fy GO-27

ID GO-4, A7-6

Stems A1-2

Library GO-63, A7-6

Strand GO-30, A1-3

Properties TH-4

Grouping A7-7

Type A7-6

Groups A1-3

Types and Dimensions A5-1 Section drawing screen Control Buttons GO-65

ID A7-7

Security GS-1

Pull data A1-3

Security protection GO-58

Shielding A1-3

Initial pullSee Jacking ratio A7-7 Properties A4-1

PRESTO®v8.6 ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

Index / 5

Stress/strain model GO-22

Tension A1-2

Tutorial Session T-1

Type A7-7

Tension controlled TH-18

Type GO-11

TensSide A1-5

Types of shoring GO-24

Strand and Rebar Pattern dialog box GO-29

Strand library A7-7 Strand Tab GO-30

TensWid TH-11, A1-7

Elevated GO-24

Tfl A1-7

None GO-24

Tfl-bot A1-2

Strand Tab Screen Terms GO-34 Strength GO-9

Typographical conventions IN-2

Theory TH-1

Final GO-9

Theta A1-2

Release GO-9

Theta Min/Max/Inc GO-27

Topping GO-9

Thickness GO-5

Stress Factors dialog box GO-28 Stresses ACI 318-02 TH-8

Thickness of compression flange A1-7 Time-dependent method TH-5 Tlim A1-8

ACI 318-99 TH-8

Top wid A1-2

CSA 23.3-94 TH-10

Topping TH-2, TH-5, A1-2, A1-3,

Stress-strain curve TH-14

n o

A7-7

Structural analysis A1-5 Superimposed dead load GO-12, TH7, A1-2

Data A1-3

Effective Width GO-25

i t

Elasticity GO-10

Of snow A1-2

Gap width GO-5

Supp-L/R A1-5

Load TH-7

Support locations A7-7

Slab width GO-5

Sustained live load GO-12, TH-8,

a u

A1-2

SWfin A1-5

Strength GO-9

Unit weight GO-9 Weight TH-2

SWrel A1-5 System Information GS-3, GS-4

l a

System requirements GS-1

T T1, t A1-6 tab Direct Transfer GS-11, GS-13

v E

Torsion TH-20, A1-7

Factors GO-14

C

Strength A1-6 Tensile strength, prestressing strand A1-1 Ultimate Strength ACI 318-02 TH-11 ACI 318-99 TH-11 CSA 23.3-94 TH-12 Uncracked sections TH-9 Unfactored Moment A1-5 Shear A1-5 Uniform Load A7-7 Loads GO-11 Unit weight A1-2, A7-7 Release/final GO-9

ACI 318-99 TH-20

Topping GO-9

CSA 23.3-94 TH-21

Parameters dialog box GO-7 Transfer Bonded GO-24 Debonded GO-25

Transfer In GS-13

Length A1-4

Transfer Out GS-13

U UCR A1-6 Ultimate Concrete compressive strain A1-2

ACI 318-02 TH-20

Register Transfer GS-12

Transfer authorization GS-11

TB2 file GS-14

Transfer In tab GS-13

Technical support GS-15 Tekla Structures using within PRESTO GO-48 Template Auto generation dialog box GO-68

Transfer Out tab GS-13

Dialog box GO-68

y p o

Touch GO-24

Tfl-top A1-2

Transform strand GO-18 Transition sections TH-9 Tributary Width A1-2 Tt A1-4 Tu A1-2

Units IN-5, A7-7 Unreinforced section property zone data A1-4 Use Manual Input Cr value GO-27 User input option GO-64 User location For cracking moment GO-20 For detailed losses GO-20 User-Defined Effective Width of Topping dialog box GO-27 User-defined method TH-6 USH A1-6 Using Online help IN-6 User manual IN-1

6 / ©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6

Vu A1-2, A1-6

V Vci A1-8

Y Yb, Ybc A1-2

Vu-max A1-6

Vcw A1-8

Ybce A1-5 W W A1-6

Vd A1-8 Vertical Clearance GO-7

Y-cg A1-3 Ycrit A1-8 Yield strength Mild steel A1-1

Wc A1-2

Shear TH-19, TH-20, A1-7

Wct A1-2

Vi A1-8

Web-extent TH-4, A1-2, A7-7

Visit LEAP Web site GO-72

Weight A1-2

Vnh A1-9

Welcome GS-3

Volume to surface ratio A1-2, A1-6,

Z Zone A1-2, A7-7

Whitney stress block TH-11

A7-7

Zoom-In GO-59, GO-66

Width A1-4

Volume/surface area ratio GO-64

Zoom-Out GO-59, GO-66

Wt A1-2

Vp A1-8

www.leapsoft.com GO-72

Vs A1-5, A1-8

y p o

Prestressing strand A1-1

n o

C

i t

a u

l a

v E PRESTO®v8.6

©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

Index / 7

y p o

n o

C

i t

a u

l a

v E 8 /

©LEAP Software, Inc. No part of this user manual may be reproduced in any form or by any means without the written permission of the publisher.

PRESTO® v8.6