2012 IBC
®
SEAOC STRUCTURAL/SEISMIC DESIGN MANUAL
Volume 2
EXAMPLES FOR LIGHT-FRAME, TILT-UP, AND MASONRY BUILDINGS
Copyright Copyright © 2013 Structural Engineers Association of California. All rights reserved. This publication or any part thereof must not be reproduced in any form without the written permission of the Structural Engineers Association of California.
Publisher Structural Engineers Association of California (SEAOC) 1400 K Street, Ste. 212 Sacramento, California 95814 Telephone: (916) 447-1198; Fax: (916) 444-1501 E-mail:
[email protected]; Web address: www.seaoc.org The Structural Engineers Association of California (SEAOC) is a professional association of four regional member organizations (Southern California, Northern California, San Diego, and Central California). SEAOC represents the structural engineering community in California. This document is published in keeping with SEAOC’s stated mission: To advance the structural engineering profession; to provide the public with structures of dependable performance through the application of state-of-the-art structural engineering principles; to assist the public in obtaining professional structural engineering services; to promote natural hazard mitigation; to provide continuing education and encourage research; to provide structural engineers with the most current information and tools to improve their practice; and to maintain the honor and dignity of the profession. SEAOC Board oversight of this publication was provided by 2012 SEAOC Board President James Amundson, S.E., and Immediate Past President Doug Hohbach, S.E.
Editor International Code Council
Disclaimer While the information presented in this document is believed to be correct, neither SEAOC nor its member organizations, committees, writers, editors, or individuals who have contributed to this publication make any warranty, expressed or implied, or assume any legal liability or responsibility for the use, application of, and/or reference to opinions, findings, conclusions, or recommendations included in this publication. The material presented in this publication should not be used for any specific application without competent examination and verification of its accuracy, suitability, and applicability. Users of information from this publication assume all liability arising from such use. First Printing: September 2013
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Suggestions for Improvement Comments and suggestions for improvements are welcome and should be sent to the following: Structural Engineers Association of California (SEAOC) Don Schinske, Executive Director 1400 K Street, Suite 212 Sacramento, California 95814 Telephone: (916) 447-1198; Fax: (916) 444-1501 E-mail:
[email protected]
Errata Notification SEAOC has made a substantial effort to ensure that the information in this document is accurate. In the event that corrections or clarifications are needed, these will be posted on the SEAOC web site at www.seaoc.org and on the ICC web site at www.iccsafe.org. SEAOC, at its sole discretion, may issue written errata.
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Table of Contents Preface to the 2012 IBC SEAOC Structural/Seismic Design Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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Preface to Volume 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xiii How to Use This Document. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxi Design Example 1 Four-story Wood Light-frame Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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Design Example 2 Flexible Diaphragm Design. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109 Design Example 3 Three Story Light-frame Multi-family Building Design Using Cold-formed Steel Wall Framing and Wood Floor and Roof Framing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133 Design Example 4 Masonry Shear Wall Building . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 245 Design Example 5 Tilt-up Building . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 273
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Preface to the 2012 IBC SEAOC Seismic/Structural Design Manual The IBC SEAOC Seismic/Structural Design Manual, throughout its many editions, has served the purpose of illustrating good seismic design and the correct application of building-code provisions. The manual has bridged the gap between the discursive treatment of topics in the SEAOC Blue Book (Recommended Lateral Force Requirements and Commentary) and real-world decisions that designers face in their practice. The examples illustrate code-compliant designs engineered to achieve good performance under severe seismic loading. In some cases simply complying with building-code requirements does not ensure good seismic response. This manual takes the approach of exceeding the minimum code requirements in such cases, with discussion of the reasons for doing so. Recent editions of the IBC SEAOC Seismic/Structural Design Manual have consisted of updates of previous editions, modified to address changes in the building code and referenced standards. Many of the adopted standards did not change between the 2006 edition of the International Building Code and the 2009 edition. The 2012 edition, which is the one used in this set of manuals, represents an extensive change of adopted standards, with many substantial changes in methodology. Additionally, this edition has been substantially revised. New examples have been included to address new code provisions and new systems, as well as to address areas in which the codes and standards provide insufficient guidance. Important examples such as the design of base-plate anchorages for steel systems and the design of diaphragms have been added. This expanded edition comprises five volumes: • • • • •
Volume 1: Code Application Examples Volume 2: Examples for Light-Frame, Tilt-Up, and Masonry Buildings Volume 3: Examples for Reinforced Concrete Buildings Volume 4: Examples for Steel-Framed Buildings Volume 5: Examples for Seismically Isolated Buildings and Buildings with Supplemental Damping
Previous editions have been three volumes. This expanded edition contains more types of systems for concrete buildings and steel buildings. These are no longer contained in the same volume. Volumes 3 and 4 of the 2012 edition replace Volume 3 of the 2009 edition. Additionally, we have fulfilled the long-standing goal of including examples addressing seismic isolation and supplemental damping. These examples are presented in the new Volume 5. In general, the provisions for developing the design base shear, distributing the base-shear-forces vertically and horizontally, checking for irregularities, etc., are illustrated in Volume 1. The other volumes contain more extensive design examples that address the requirements of the material standards (for example, ACI 318 and AISC 341) that are adopted by the IBC. Building design examples do not illustrate many of the items addressed in Volume 1 in order to permit the inclusion of less-redundant content. Each volume has been produced by a small group of authors under the direction of a manager. The managers have assembled reviewers to ensure coordination with other SEAOC work and publications, most notably the Blue Book, as well as numerical accuracy. This manual can serve as valuable tool for engineers seeking to design buildings for good seismic response. Rafael Sabelli Project Manager
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Preface to Volume 2 Volume 2 of the 2012 IBC SEAOC Structural/Seismic Design Manual addresses the design of light-frame, concrete tilt-up, and masonry shear wall building systems for seismic loading. These include the illustration of the design requirements for the shear walls and diaphragms, as were illustrated in previous editions, and also important interfaces with the rest of the structure. The design examples in this volume represent a range of structural systems and seismic systems. The design of each of these systems is governed by standards developed by the American Concrete Institute (ACI) and the American Wood Council (AWC). The methods illustrated herein represent approaches consistent with the ductility expectations for each system and with the desired seismic response. In most cases there are several details or mechanisms that can be utilized to achieve the ductility and resistance required, and the author of each example has selected an appropriate option. In many cases alternatives are discussed. This manual is not intended to serve as a building code, or to be an exhaustive catalogue of all valid approaches and details. This manual is presented as a set of examples in which the engineer has considered the building-code requirements in conjunction with the optimal seismic response of the system. The examples follow the guidelines of the SEAOC Blue Book and other SEAOC recommendations. The examples are intended to aid conscientious designers in crafting designs that are likely to achieve good seismic performance consistent with expectations inherent in the requirements for the systems. Four examples have been included in past editions of this manual and are updated in this edition: four-story wood light-frame structure, light-gage framed building on podium structure, masonry shear wall building, and tilt-up building with windows. One example—wood diaphragm—is new and is included in this edition of the manual. Douglas Thompson Volume 2 Manager
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Acknowledgements Volume 2 of the 2012 IBC SEAOC Seismic/Structural Design Manual was written by a group of highly qualified structural engineers, chosen for their knowledge and experience with structural engineering practice and seismic design. The authors are: Douglas S. Thompson, S.E., S.E.C.B. – Volume Manager and Example 1 Doug Thompson has over 35 years of experience in designing of wood structures. He is author several publications in timber design including the WoodWorks publications: Four-story Wood-frame Structure over Podium Slab and Five-story Wood-frame Structure over Podium Slab. Doug has instructed license review classes in timber design for the PE and SE exams for 20 years. He is the 2013-2014 president of the Structural Engineers Association of Southern California and holds licenses in six states. www.stbse.com John Lawson, S.E. – Examples 2 and 5 Assistant Professor John Lawson has provided structural engineering consulting services for over 30 years, including overseeing more than 100 million square feet of low-sloped roof and tilt-up concrete engineering. He now teaches in the Architectural Engineering department at California Polytechnic State University in San Luis Obispo. John is the recipient of the 2006 Tilt-up Concrete Association’s David L. Kelly Distinguished Engineer Award. www.arce.calpoly.edu Michael Cochran, S.E., S.E.C.B – Example 3 Michael Cochran is an Associate Principal with Weidlinger Associates, Inc. in Marina del Rey, California, with over 25 years of design experience. He has an extensive background in the design of multi-story light-framed commercial and multifamily residential wood and cold-formed steel-stud buildings. He is a registered structural engineer in California, an active member of the AISC Connection Prequalification Review Panel, a past president of the Structural Engineers Association of Southern California (SEAOSC), and incoming 2013-2014 president for the Structural Engineers Association of California. Jeff Ellis, S.E. – Example 3 Manager of Codes, Standards, and Special Projects for Simpson Strong-Tie Company Inc., he has more than 22 years of experience in the construction industry. Mr. Ellis manages the company code and standards involvement as well as code reports. Additionally, he is involved in product development and offers technical guidance to customers for connectors, fastening systems, and lateral systems. He was a practicing design engineer for commercial, residential, and forensic projects for more than nine years prior to joining Simpson Strong-Tie at the end of 2000. He has served on the Board of Directors for SEAOSC, as chair of the 2011 and 2012 SEAOSC Buildings At Risk Summit, as chair of the AISI COFS Lateral Design Subcommittee, as president of the CFSEI and authored the Cold-Formed Steel Engineers Institute’s (CFSEI) Design Guide: Cold-Formed Steel Framed Wood Panel or Steel Sheet Sheathed Shear Wall Assemblies.
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Chukwuma G. Ekwueme, PhD, SE, LEED AP – Example 4 Dr. Ekwueme is an Associate Principal with Weidlinger Associates, Inc. in Marina del Rey, California. He has an extensive background in the design and analysis of a wide variety of structures, including concrete and masonry construction, steel and aluminum structures, and light-framed wood buildings. He is a registered Structural Engineer in California and Nevada and is an active member of the main committee, the seismic subcommittee, and the axial flexural loads and shear subcommittee of the Masonry Standards Joint Committee (MSJC). Additionally, a number of SEAOC members and other structural engineers helped check the examples in this volume. During its development, drafts of the examples were sent to these individuals. Their help was sought in review of code interpretations as well as detailed checking of the numerical computations. The reviewers include: James Lai, S.E. Alan Robinson, S.E. Tim Stafford, S.E. Doug Thompson, S.E. Tom VanDorpe, S.E. Close collaboration with the SEAOC Seismology Committee was maintained during the development of this document. The Seismology Committee has reviewed the document and provided many helpful comments and suggestions. Their assistance is gratefully acknowledged. Production and art was provided by the International Code Council.
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References Standards ACI 318, 2011, Building Code Regulations for Reinforced Concrete, American Concrete Institute, Farmington Hills, Michigan. American Forest and Paper Association, 2012, National Design Specification for Wood Construction Including Supplements, NDS-12. American Forest and Paper Association,Washington D.C. American Forest and Paper Association, 2008, AF&PA Special Design Provisions for Wind and Seismic, American Forest and Paper Association, Washington, D.C. AISI S100-07/S2-10, North American Specification for the Design of Cold-Formed Steel Structural Members with Supplement 2. American Iron and Steel Institute, Washington, DC. AISI S200-07, 2007. North American Standard for Cold-Formed Steel Framing – General Provisions. American Iron and Steel Institute, 1140 Connecticut Avenue, Suite 705, Washington, DC 20036. AISI S201-07, North American Standard for Cold-Formed Steel Framing-Product Data. American Iron and Steel Institute, Washington, DC. AISI S211-07, 2007. North American Standard for Cold-Formed Steel Framing – Wall Stud Design. American Iron and Steel Institute, 1140 Connecticut Avenue, Suite 705, Washington, DC 20036. AISI S213-07, 2007. North American Standard for Cold-Formed Steel Framing – Lateral Design. American Iron and Steel Institute, 1140 Connecticut Avenue, Suite 705, Washington, DC 20036. ASCE/SEI 7, 2010, Minimum Design Loads for Buildings and Other Structures, American Society of Civil Engineers, Structural Engineering Institute, Reston, Virginia. ICC, 2012, International Building Code (IBC). International Code Council, Falls Church, Virginia. Masonry Standards Joint Committee (MSJC), 2011. Building Code Requirements for Masonry Structures (TMS 402-11/ACI 530-11/ASCE 5-11), Reported by the Masonry Standards Joints Committee, The Masonry Society, Boulder, Colorado. Masonry Standards Joint Committee (MSJC), 2011. Specification for Masonry Structures (TMS 602-08/ACI 530.1-08/ASCE6-08), Reported by the Masonry Standards Joints Committee, The Masonry Society, Boulder, Colorado.
Other References ACI 551.2R-10, 2010. Design Guide for Tilt-up Concrete Panels. American Concrete Institute, 38800 Country Club Drive, Farmington Hills, Michigan 48331.
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ACI 551.1R-05, 2005. Tilt-up Concrete Construction Guide. American Concrete Institute, 38800 Country Club Drive, Farmington Hills, Michigan 48331. AISI D110-07, Cold-Formed Steel Framing Design Guide, Second Edition. American Iron and Steel Institute, Washington, DC. AISI D100-08, AISI Manual, Cold-Formed Steel Design. American Iron and Steel Institute, Washington, DC. American Forest and Paper Association, 1996, Wood Construction Manual. American Forest and Paper Association, Washington D.C. American Plywood Association, 1997, Design/ Construction Guide—Diaphragms and Shear Walls. From L350, Engineered Wood Association, Tacoma, Washington. American Plywood Association, 2007, Diaphragms and Shear Walls. Engineered Wood Association, Tacoma, Washington. American Plywood Association, 1993, revised, Wood Structural Panel Shear Walls. Report 154, Engineered Wood Association, Tacoma, Washington. American Plywood Association, 1994, Northridge, California Earthquake. Report T-94-5. Engineered Wood Association, Tacoma, Washington. American Plywood Association, Performance Standards and Policies for Structural-Use Panels [Sheathing Standard, Sec. 2.3.3]. Standard PRP-108. Engineered Wood Association, Tacoma, Washington. American Plywood Association, 1997, Plywood Design Specifications, From Y510, Engineered Wood Association, Tacoma, Washington. American Plywood Association, 1988, Plywood Diaphragms, Research Report 138. American Plywood Association, Tacoma, Washington. American Plywood Association, 2002. Effect of Green Lumber Framing on Wood Structural Panel Shear Wall Performance. APA Report T2002-53. American Plywood Association, Tacoma, Washington. American Plywood Association, 2005, Using Narrow Pieces of Wood Structural Panel Sheathing in Wood Shear Walls, APA T 2005-08, The Engineered Wood Association, Tacoma, Washington. Applied Technology Council, 1995, Cyclic Testing of Narrow Plywood Shear Walls ATC R-1. Applied Technology Council, Redwood City, California. Applied Technology Council, 1981, Guidelines for Design of Horizontal Wood Diaphragms, ATC-7. Applied Technology Council, Redwood City, California. Applied Technology Council, 1980, Proceedings of a Workshop on Design of Horizontal Wood Diaphragms, ATC-7-1. Applied Technology Council, Redwood City, California. APA, 2011, Evaluation of Force Transfer around Openings—Experimental and Analytical Studies, APA, Tacoma, Washington. xiv
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Arevalo, Ricardo, 2012, Tie-Down Systems for Multi-Story Wood Structures, Wood Design Focus, Fall 2012, Forest Products Society, Madison, Wisconsin. Bendsten, B.A. and W.L. Galligan, 1979, Mean and Tolerance Limit Stresses and Stress Modeling for Compression Perpendicular to Grain in Hardwood and Softwood Species, Research Paper FPL 337. US Department of Agriculture, Forest Service, Forest Products Laboratory, Madison, Wisconsin. Bendsten, B.A. and W.L. Galligan, Vol. 29, No. 2: Pg. 42-48, 1979, Modeling and StressCompression Relationships in Wood in Compression Perpendicular to Grain. U.S. Department of Agriculture, Forest Products Research Society (Forest Products Society) Forest Products Journal, Madison, WI. Building Seismic Safety Council, 2003, National Earthquake Hazard Reduction Program, Recommended Provisions for Seismic Regulations for New Buildings, parts 1 and 2. Building Seismic Safety Council, Washington D.C. Brandow, Gregg E., Chukwuma G. Ekwueme and Gary C. Hart, 2009. Design of Reinforced Masonry Structures, Concrete Masonry Association of California and Nevada, Sacramento, California. Breyer, Donald E., Kenneth J. Fridley, David G. Pollock, Jr. and Kelly E. Cobeen, 2007. Design of Wood Structures ASD. McGraw-Hill Book Co., New York, New York Bugni, David A., 1999, “A Linear Elastic Dynamic Analysis of a Timber Framed Structure.” Building Standards, International Conference of Building Officials, Whittier, California Cobeen, K. E., 1996, “Performance Based Design of Wood Structures.” Proceeding: Annual SEAOC Convention. Structural Engineers Association of California, Sacramento, California. Coil, J., 1999, “Seismic Retrofit of an Existing Multi-Story Wood Frame Structure,” Proceedings: Annual SEAOC Convention. Structural Engineers Association of California, Sacramento, California. Commins, A. and Gregg, R., 1996, Effect of Hold Downs and Stud-Frame Systems on the Cyclic Behavior of Wood Shear Walls, Simpson Strong-Tie Co., Pleasanton, California. Commins, Alfred D., August 2008, Rod Tie-Down Systems, Part 5-Inspection, Structure Magazine, National Council of Structural Engineers Associations (NCSEA). Cook, R. A., 1999, “Strength Design of Anchorage to Concrete.” Portland Cement Association, Skokie, Illinois. Cook, J., 2010, “Simplified Analysis of Wood Shear Walls with Multiple Openings” Proceedings: Annual SEAOC Convention. Structural Engineers Association of California, Sacramento, California. Countryman, D., and Col Benson, 1954, 1954 Horizontal Plywood Diaphragm Tests. Laboratory Report 63, Douglas Fir Plywood Association, Tacoma, Washington. CUREe, 1999, Proceedings of the Workshop on Seismic Testing, Analysis, and Design of Wood Frame Construction. California University for Research in Earthquake Engineering. 2012 IBC SEAOC Structural/Seismic Design Manual, Vol. 2
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Dolan, J. D., 1996, Experimental Results from Cyclic Racking Tests of Wood Shear Walls with Openings. Timber Engineering Report No. TE-1996-001. Virginia Polytechnic Institute and State University, Blacksburg, Virginia. Dolan, J. D. and Heine, C. P., 1997a, Monotonic Tests of Wood Frame Shear Walls with Various Openings and Base Restraint Configurations. Timber Engineering Report No. TE-1997-001, Virginia Polytechnic Institute and State University, Blacksburg, Virginia. Dolan, J. D. and Heine, C. P., 1997b, Sequential Phased Displacement Cyclic Tests of Wood Frame Shear Walls with Various Openings and Base Restrain Configurations. Timber Engineering Report No. TE-1997-002, Virginia Polytechnic Institute and State University, Blacksburg, Virginia. Dolan, J. D., and Heine, C. P., 1997c, Sequential Phased Displacement Test of Wood Frame Shear Walls with Corners. Timber Engineering Report No. TE-1997-003, Virginia Polytechnic Institute and State University, Blacksburg, Virginia. Earthquake Engineering Research Institute, 1996, “Northridge Earthquake of January 17, 1994,” Reconnaissance Report, Earthquake Spectra. Vol. 11, Supplement C. Earthquake Engineering Research Institute, Oakland, California. Ellis, Jeff, August 2012, “Designing Cold-Formed Steel Framed Lateral Force-Resisting Systems,” Structure magazine. National Council of Structural Engineers Associations (NCSEA). Faherty, Keith F., and Williamson, Thomas G., 1995, Wood Engineering Construction Handbook. McGraw Hill, Washington D.C. Federal Emergency Management Agency, 2003, National Earthquake Hazard Reduction Program, Recommended Provisions for Seismic Regulations for New Buildings and Other Structures and Commentary. Federal Emergency Management Agency,Washington D.C. Ficcadenti, S. K., T. A. Castle, D. A. Sandercock, and R. K. Kazanjy, 1996, ‘Laboratory Testing to Investigate Pneumatically Driven Box Nails for the Edge Nailing of 3/8” Plywood Shear Walls,’ Proceedings: Annual SEAOC Convention. Structural Engineers Association of California, Sacramento, California. Foliente, Greg C., 1994, Analysis, Design and Testing of Timber Structures Under Seismic Loads. University of California Forest Products Laboratory, Richmond, California. Foliente, Greg C., 1997, Earthquake Performance and Safety of Timber Structures. Forest Products Society, Madison, Wisconsin. Forest Products Laboratory, 2010, Wood Handbook Publication FPL—GTR—113. Madison, Wisconsin. Ghosh, A., S. Pryor, and R. Arevalo, June 2006, “Multistory Light-frame Construction: Understanding Tiedown Systems,” Structure magazine. National Council of Structural Engineers Associations (NCSEA). Goers R. and Associates, 1976, A Methodology for Seismic Design and Construction of SingleFamily Dwellings. Applied Technology Council, Redwood City, California.
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Gupta, R., H. Redler, and M. Clauson, 2007. “Cyclic Tests of Engineered Shear Walls with Different Bottom-plate and Anchor-bolt sizes (Phase II).” Department of Weed Science and Engineering, Oregon State University, Corvallis, Oregon. Haygreen, J.G. and Bowyer, J.L., 1989, Forest Products and Wood Science-An Introduction. University of Iowa Press, Ames, Iowa. Hess. R., 2008, “For What Planet Is This Code Written?,” Structure magazine, November. National Council of Structural Engineers Associations (NCSEA). Hohbach, D., S. Shiotani, 2012. Improved Seismic Analysis of Wood Light-Framed Multi-Story Residential Buildings, Wood Design Focus, Fall 2012, Forest Products Society, Madison, Wisconsin. Ju, S. and Lin, M., 1999, “Comparison of Building Analysis Assuming Rigid or Flexible Floors,” Journal of Structural Engineering. American Society of Civil Engineers, Washington, D.C. Knight, Brian, June 2006, High Rise Wood Frame Construction. Structure Magazine. NCSEA. Lawson, John, 2007, “Deflection Limits for Tilt-up Wall Serviceability,” Concrete International, American Concrete Institute. September. Matteri, Dominic, 2009, 5 Over 1 High Rise Podium Structures, Wood Solutions Fair Presentation. Matteson, Thor, 2004, Wood-Framed Shear Wall Construction. International Code Council, Country Club Hills, Illinois. Mayo, John L., 2001, “Metal Roof Construction on Large Warehouses or Distribution Centers,” Steel Tips. Structural Education Council, 141 Greenbriar, Moraga, CA 94556, June. Mendes, S., 1987, “Rigid versus Flexible: Inappropriate Assumptions Can Cause Shear Wall Failures!” Proceedings: Annual SEAOC Convention. Structural Engineers Association of California, Sacramento, California. Mendes, S., 1995, “Lessons Learned From Four Earthquake Damaged Multi-Story Type V Structures,” Proceedings: Annual SEAOC Convention. Structural Engineers Association of California, Sacramento, California. Murphy, Michael, 2012, Shrinkage Challenges with Mid-Rise Construction, Wood Design Focus, Fall 2012. Forest Products Society, Madison, Wisconsin. Nelson, R. F. and S. T. Patel, 2003, “Continuous Tiedown Systems for Wood Panel Shear Walls in Multistory Structures”, Structure Magazine, March. NCSEA. Rose, J. D., 1998, Preliminary Testing of Wood Structural Panel Shear Walls Under Cyclic (Reversed) Loading. Research Report 158, APA—Engineered Wood Association, Tacoma, Washington. Rose, J. D., and E. L. Keith, P. E., 1996, Wood Structural Panel Shear Walls with Gypsum Wallboard and Window [Sheathing Standard, Sec. 2.3.3]. Research Report 158. APA—The Engineered Wood Association, Tacoma Washington.
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SCCACI/SEAOSC, 1982, Report of the Task Committee on Slender Walls, Southern California Chapter American Concrete Institute and Structural Engineers Association of Southern California, Los Angeles, California. September. Schmid, Ben L. (1996), Three-Story Wood Apartment Building-1994 Northridge Earthquake Buildings Case Studies Project, Seismic Safety Commission, State of California. Sacramento, CA. SEAOC, 1999, Acceptable Diaphragm-Rigidity Assumptions for Distribution of Horizontal Forces in Light-Frame Construction. Structural Engineers Association of California, Sacramento, California. SEAOC Blue Book, 1999, Recommended Lateral Force Requirements and Commentary, Structural Engineers Association of California, Seventh Edition, Sacramento, California. SEAOC, 1997, Seismic Detailing Examples for Engineered Light Frame Timber Construction. Structural Engineers Association of California, Sacramento, California. SEAOC, 1999, Guidelines for Diaphragms and Shear Walls. Structural Engineers Association of California, Sacramento, California. SEAOC, 1999, Plan Review—Codes and Practice. Structural Engineers Association of California, Sacramento, California. SEAOC Seismology Committee, 2009, “Anchor Bolts in Light-frame Construction at Small Edge Distances,” June, M5, M6, M7 in The SEAOC Blue Book: Seismic Design Recommendations, Structural Engineers Association of California, Sacramento, California. http://www.seaoc.org/ bluebook/index.html SEAOC Seismology Committee, 2008, “Light-frame Wall Hold-downs,” August, in The SEAOC Blue Book: Seismic Design Recommendations, Structural Engineers Association of California, Sacramento, California. www.seaoc.org/bluebook/index.html SEAOC Seismology Committee, 2008. “Tilt-up Buildings,” The SEAOC Blue Book: Seismic Design Recommendations. Structural Engineers Association of California, Sacramento, California at: www.seaoc.org/bluebook/index.html SEAOC Seismology Committee, 2007, “Wood-framed Shear Walls with Openings,” May, in the SEAOC Blue Book: Seismic Design Recommendations, Structural Engineers Association of California, Sacramento, California. www.seaoc.org/bluebook/index.html SEAOSC, 1979. Recommended Tilt-up Wall Design, Structural Engineers Association of Southern California, Los Angeles, California. June. SEAOSC/COLA, 1994. 1994 Northridge Earthquake (Structural Engineers Association of Southern California/City of Los Angeles) Special Investigation Task Force, Tilt-up Subcommittee. Final report dated September 25, 1994. Shiotani, S., D. Hohbach, J. Roberts, 2011, Lateral System for Multi-Unit Construction, Wood Products Council Workshops.
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Shipp, John and D. Thompson, 2001 Timber Design I, II, and III, Volumes VIII, IX, and X. Professional Engineering Development Publications, Inc., Irvine, California. Simpson, William T. 1998. Equilibrium Moisture Content of Wood in Outdoor Locations in the United States and Worldwide. Res. Note FPL-RN-0268. Forest Products Laboratory, Madison, Wisconsin. Skaggs, T.D. and Z.A. Martin, 2004. “Estimating Wood Structural Panel Diaphragm and Shear Wall Deflection.” Practice Periodical on Structural Design and Construction. ASCE, May 2004. Steinbrugge, J., 1994, “Standard of Care in Structural Engineering Wood Frame Multiple Housing,” Proceedings: Annual SEAOC Convention. Structural Engineers Association of California, Sacramento, California. Technical Coordinating Committee for Masonry Research (TCCMAR), 1985. James Noland – Chairman, U.S.-Japan Coordinated Program for Masonry Building Research, U.S. Research Plan, Thompson, D. S., 2009, Four-story Wood-frame Structure over Podium Slab. Woodworks, Tacoma, Washington. Thompson, D. S., 2012, Five-story Wood-frame Structure over Podium Slab, Woodworks, Tacoma, Washington. Thompson, D. S., 2012, 2009 IBC Structural/Seismic Design Manual, Volume 2, Design Example 1, 2 & 3 Structural Engineers Association of California. Sacramento, California. USGS, 2012, U.S. Seismic Design Maps Web Application, Retrieved from http://geohazards.usgs. gov/designmaps/us/application.php. United States Geological Survey, Washington, D.C. VanDorpe, Tom and Andy Fennell. 2010, 2010 Building Code Update Re-tooling your office for changes to the 2010 California Building Regulations that affect light-fame structures. Orange, California. Washington Association of Building Officials and Structural Engineers Association of Washington (WABO/SEAW) Liaison Committee, 2013, White Paper 9-2013: Threaded Rod Holdown Systems in Wood Frame Buildings, Seattle, Washington. www.wabo.org/waboseaw-white-papers Western Wood Products Association (WWPA), November 2002, Tech Notes Report No. 10-Shrinkage Calculations for Multi-Story Wood Frame Construction, Portland, Oregon. WWPA, 1990, Dimensional Stability of Western Lumber, Portland, Oregon. Yousefi, Ben, Son, James, and Sabelli, Rafael, 2005. Structural Engineering Review Manual (2005 Edition), BYA Publications, Santa Monica, California.
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Design Example 1 Four-story Wood Light-frame Structure
OVERVIEW This design example illustrates the seismic design of selected elements for a four-story wood-frame hotel structure. The gravity-load framing system consists of wood-frame bearing walls. The lateral-loadresisting system consists of wood-framed bearing shear walls (common box-type system). A typical building elevation and floor plan of the structure are shown in Figures 1-1 and 1-2 respectively. A typical section showing the heights of the structure is shown in Figure 1-3. The wood roof is framed with premanufactured wood trusses. The floor is framed with prefabricated wood I-joists. The floors have a 1½-inch lightweight concrete topping. The roofing is composition shingles. When designing this type of “mid-rise” wood-frame structure, there are several unique design elements to consider. The following steps provide a detailed analysis of some of the important seismic requirements of the shear walls per the 2012 IBC. This design example represents a very simple wood-framed wood structure; most wood-framed structures have several unique features requiring engineering design and detailing not shown in this design example. This design example is not a complete building design. Many aspects have not been included, specifically the gravity-load framing system, and only certain steps of the seismic design related to portions of a selected shear wall have been illustrated. In addition, the lateral requirements for wind design related to the selected shear wall have not been illustrated (only seismic). The steps that have been illustrated may be more detailed than what is necessary for an actual building design but are presented in this manner to help the design engineer understand the process. For a more detailed listing of the items not addressed see Section 10.
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Design Example 1
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OUTLINE 1. Building Geometry and Loads 2. Calculation of the Design Base Shear 3. Location of Shear Walls and Diaphragms 4. Mechanics of Multi-story Segmented Shear Walls and Load Combinations 5. Mechanics of Multi-story Shear Walls with Force Transfer around Openings 6. The Envelope Process 7. Design and Detailing of Shear Wall at Line C 8. Diaphragm Deflections to Determine if the Diaphragm is Flexible 9. Special Inspection and Structural Observation 10. Items Not Addressed in This Example
1. Building Geometry and Loads
ASCE 7
1.1 GIVEN INFORMATION The roof is 15/32-inch-thick DOC PS 1- or DOC PS 2-rated sheathing, with a 32/16 span rating and Exposure I glue. The floor is 23/32-inch-thick DOC PS 1- or DOC PS 2-rated Sturd-I-Floor 24 inches o.c. rating, with a 48/24 span rating (40/20 span rating with topping is also acceptable) and Exposure I glue. DOC PS 1 and DOC PS 2 are the U.S. Department of Commerce (DOC) Prescriptive and Performancebased standards for plywood and oriented strand board (OSB), respectively. Wall framing is a “modified balloon framing” where the joists hang from the walls in joist hangers. (See Figure 1-7 detail of this and an explanation of other common framing conditions.) Framing lumber for studs and posts
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NDS T 4A
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Douglas Fir Larch-No. 1 Grade: Fb = 1,000 psi Fc = 1,500 psi Ft = 675 psi E = 1,700,000 psi Emin = 620,000 psi Cm = 1.0 Ct = 1.0 Common wire nails are used for shear walls, diaphragms, and straps. When specifying nails on a project, specification of the penny weight, type, diameter, and length (example 10d common = 0.148 inch × 3 inches) are recommended.
Figure 1–1. Building elevation
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Figure 1–2. Typical foundation plan
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Figure 1–3. Typical floor framing plan
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Figure 1–4. Typical roof framing plan
Notes for Figure 1-2 through 1-4: 1. Non-structural “pop-outs” on the exterior walls at lines 1, 4 need special detailing showing the wood structural panel sheathing running continuous at lines 1, 4 and the pop-outs framed after the sheathing is installed. 2. All walls stack from the foundation to the fourth floor. 3. 6
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Designates sheathed wall per shear-wall schedule (see Table 1-32).
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