AGA MANUAL.pdf

SUBMARINE PIPELINE ON-BOTTOM STABILITY VOLUME 2 LEVELS 1, 2, AND 3 SOFTWARE AND MANUALS PRCI PROJECT PR-178-01132

Prepared for the Design, Construction & Operations Technical Committee of the Pipeline Research Council International, Inc.

Prepared by Kellogg Brown & Root, Inc. Houston, Texas December 2002

LEGAL NOTICE “This report is furnished to Pipeline Research Council International, Inc. (PRCI) under the terms of PRCI PR-178-01132, between PRCI and Kellogg Brown and Root, Inc. The contents of this report are published as received from Southwest Research Institute. The opinions, findings, and conclusions expressed in the report are those of the authors and not necessarily those of PRCI, its member companies, or their representatives. Publication and dissemination of this report by PRCI should not be considered an endorsement by PRCI or Kellogg Brown and Root, Inc., of the accuracy or validity of any opinions, findings, or conclusions expressed herein.

In publishing this report, PRCI makes no warranty or representation, expressed or implied, with respect to the accuracy, completeness, usefulness, or fitness for purpose of the information contained herein, or that the use of any information, method, process, or apparatus disclosed in this report may not infringe on privately owned rights. PRCI assumes no liability with respect to the use of , or for damages resulting from the use of, any information, method, process, or apparatus disclosed in this report. The text of this publication, or any part thereof, may not be reproduced or transmitted in any form by any means, electronic or mechanical, including photocopying, recording, storage in an information retrieval system, or otherwise, without the prior, written approval of PRCI.”

Pipeline Research Council International Catalog No. L51790 B Copyright, 2002 All Rights Reserved by Pipeline Research Council International, Inc.

PRCI Reports are published by Technical Toolboxes, Inc. 3801 Kirby Drive, Suite 340 Houston, Texas 77098 Tel: 713-630-0505 Fax: 713-630-0560 Email: [email protected]

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EXECUTIVE SUMMARY The state-of-the-art in pipeline stability design changed very rapidly in the 1980s. The physics governing on-bottom stability became much better understood largely because of research, including large scale model tests, sponsored by the PRCI. Analysis tools utilizing this knowledge were developed, and Windows-based software programs incorporating these analysis tools are presented in this report. These programs provide the design engineer with a rational approach for weight coating design, which can be used with confidence because the tools have been developed based on full scale and near full scale model tests. These tools represent the state-of-the-art in stability design and model the complex behavior of pipes subjected to both wave and current loads. These include •

hydrodynamic forces which account for the effect of the wake (generated by flow over the pipe) washing back and forth over the pipe in oscillatory flow; and,

•

the embedment (digging) which occurs as a pipe resting on the seabed is exposed to oscillatory loadings and small oscillatory deflections.

This report has been developed as a reference handbook for use in on-bottom pipeline stability analysis and design. It consists of two volumes. Volume 1 is devoted to descriptions of the various aspects of the problem: •

the pipeline design process;

•

ocean physics, wave mechanics, hydrodynamic forces, and meteorological data determination;

•

geotechnical data collection and soil mechanics; and,

•

stability design procedures.

Volume 2 describes, and illustrates the analysis software. A CD-ROM containing the software and examples of the software is included in Volume 2.

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Forward to Report for PR-187-01132 Submarine Pipeline On-Bottom Stability In the 1970's and 1980's PRCI undertook a major multi-year effort to develop the technical basis for the determination of the stability of pipelines on the seabed relative to the actions of waves and currents. This work culminated with the preparation of a report with the title given above in November 1988 under PRCI Project PR-187-517. Since then, the report has been reissued 3 times: September 1993 under PRCI Project PR-187-9333, December 1998 under PRCI Project PR-187-9731, and now, May 2002 under PRCI Project PR-187-01132. The objective of this Forward it to provide an overview of the evolution of this report and its associated software since 1988. Volume 1 of this report remains essentially unchanged since the original version except that • references to organizations and programs have been updated to reflect their current names (e,g. references to the American Gas Association or A.G.A. have been revised to PRCI as appropriate), and • this Forward has been added. Volume 2 has experienced more extensive changes reflecting the evolution of the associated software as discussed in more detail below. The calculation procedures contained in the software are largely unchanged. One change to the basis for the calculations was made in 1993 as will be subsequently discussed. New interfaces to the software have been developed as it has been adapted to run on more modern operating systems. The Level 3 software has changed the most since 1988. Although the interfaces are more modern, the programs provide the same results as they have since 1993. Developments after November 1998 A several papers were presented at the 1989 OTC conference reviewing the PRCI pipeline on-bottom stability projects up to that time (Refs. 1-5). The first PRCI project after 1988, PR-178-918, concerned verification of the preceding work and additional pipe-soil tests. Two reports were prepared. The first report, We Deliver

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Submarine Pipeline On-Bottom Stability, 1989 Comparison/Verification Work, • compared the PRCI pipeline stability design methodologies with those presented in Veritec's Recommended Practice for On-Bottom Stability Design of Submarine Pipelines, RP-E305, • compared weight coating designs using the PRCI Level 2 and RP-E305's generalized procedures for approximately 200 pipeline designs, and • compared results of Level 3 numerical simulations of pipe/soil interactions with full scale model tests of irregular sea loadings. This report provided confidence in the PRCI procedures (Ref. 6). The second report for PRCI project PR-178-918, "Weight Coating Design for Submarine Pipeline Stability, 1990 - 1991 Pipe-Soil Interaction Work," October 1992, concerned the results of additional pipe-soil interaction tests conducted in clay soils with shear strengths of 30, 75, and 150 psf (1.4, 3.6, and 7.2 kPa). Previous tests with clay had been done in soft clay soils of 20 to 30 psf (1 to 1.4 kPa) or in very stiff clay, 5000 psf (240 kPa). The results of the new tests led to modifications to the formulas used to predict pipeline stability in clay soils (Ref. 7). The changes of clay soils were reflected in reissue of the reports and software in 1993 under PRCI Project PR-187-9333. Simple input preprocessor programs were written for the Level 1 and Level 2 programs, and were issued with the software accompanying Volume 2 of the report. The next project, designated PR-178-9731, involved a major effort to make the Level 3 programs easier to use. The three programs that comprised Level 3 analysis were combined into a single program with Windows interfaces for input and output. The design and software manuals were again updated and reissued in December 1998. The project associated with the present reissue of these reports, designated PR-17801132, is aimed at improving the ease of use of the software for Level 1 and Level 2 analysis. These programs were written to work on PC's prior to the development of the Microsoft's Windows operating systems. The project has provided them with a modern look and feel and assured that the programs for all three Levels work with current Windows operating systems. Rick Weiss May 2002 References We Deliver

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1. Allen, D.W., Lammert, W.F., Hale, J.R., and Jacobsen, V., "Submarine Pipeline OnBottom Stability: Recent AGA Research," Proc. 21st Offshore Technology Conference, Paper No. OTC 6055, Houston, 1989. 2. Jacobsen, V., Bryndum, M.B., and Bonde, C., "Fluid Loads on Pipelines: Sheltered or Sliding," Proc. 21st Offshore Technology Conference, Paper No. OTC 6056, Houston, 1989. 3. Brennodden, H., Lieng, J.T., Sotberg, T., and Verley, R.L.P., "An Energy-Based PipeSoil interaction Model," Proc. 21st Offshore Technology Conference, Paper No. OTC 6057, Houston, 1989. 4. Lammert, W.F., Hale, J.R., and Jacobsen, V., "Dynamic Response of Submarine Pipelines Exposed to Combined Wave and Current Action," Proc. 21st Offshore Technology Conference, Paper No. OTC 6058, Houston, 1989. 5. Hale, J.R., Lammert, W.F., and Jacobsen, V., "Improved Basis for Static Stability Analysis and Design of Marine Pipelines," Proc. 21st Offshore Technology Conference, Paper No. OTC 6059, Houston, 1989. 6. Hale, J.R., Lammert, W.F., and Allen, D.W., "Pipeline On-Bottom Stability Calculations: Comparisons of Two State-of-the-Art Methods and Pipe-Soil Model Verification," Proc. 23rd Offshore Technology Conference, Paper No. OTC 6761, Houston, 1991. 7. Hale, J.R., Morris, D.V., Yen, T.S., and Dunlap, W.A., "Modeling Pipeline Behavior on Clay Soils During Storms," Proc. 24th Offshore Technology Conference, Paper No. OTC 7019, Houston, 1992.

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PRCI PROJECT PR-178-01132 SUBMARINE PIPELINE ON-BOTTOM STABILITY VOLUME 2 LEVELS 1, 2, AND 3 SOFTWARE AND MANUALS Table of Contents Page i ii iii

LEGAL NOTICE EXECUTIVE SUMMARY FORWARD 1.0 INTRODUCTION TABLE 1.0-1 PRCI Submarine Pipeline On-Bottom Stability Analysis Software FIGURE 1.0-1 PRCI Submarine Pipeline On-Bottom Stability Analysis Software 2.0

DESCRIPTION OF PROGRAM SUITE 2.1 Level 1 Stability Analysis – L1WIN 2.2 Level 2 Stability Analysis – L2WIN 2.3 Level 3 Stability Analysis – L3WIN

FIGURES 2.2-1 2.2-2 2.2-3 2.2-4 2.2-5 3.0

Bottom Velocity Amplitude Content During 4 Hour Storm Build-Up Bottom Velocity Amplitude Content During 3 Hour Design Storm Input/Output For WSIMQNU (Rev. 2) Input/Output For L3FORCE Input/Output For L3PIPDYN

EXAMPLE CASES 3.1 L1WIN Examples 3.2 L2WIN Examples 3.3 L3WIN Examples

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1-1 1-2

1-3 2-1 2-1 2-1 2-7

2-4 2-5 2-8 2-9 2-10 3-1 3-1 3-7 3-30

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FIGURES 3.1-1 Level 1 Pipeline On-Bottom Stability L2WIN Example Case Output File 3.2-1 PRCI Level 2 Stability Analysis L2WIN Example Case Output File 3.3-1 L3WIN Sample Input Deck 3.3-2 L3WIN Sample Input Deck L3WIN Example Case Output File Pipeline Dynamic Plot Case Lift & Drag Forces Case Velocity Case Statistical Plot Case Stress & Deflected Pipeline Configuration Case

3-2 3-3 3-8 3-9 3-31 3-32 3-33 3-42 3-43 3-44 3-45 3-46

APPENDIX A - Comparison of Results Using L1WIN, L2WIN, and L3WIN A.1 Design Using L1WIN (Traditional) A.1.1 Description A.1.2 Results A.2 Analysis Using L2WIN (State-of-the-Art Static) A.2.1 Description A.2.2 Results A.3 Design Using L2WIN A.3.1 Description A.3.2 Results A.4 Analysis Using L3WIN (State-of-the-Art Dynamic) Confirmation of Level 2 Embedments A.4.1 Description A.4.2 Results A.5 Sensitivity Analysis Using L3WIN A.5.1 Description A.5.2 Results

A-122 A-122 A-122 A-124 A-124 A-124

TABLES A.1-1 A.1-2 A.2-1 A.3-1 A.4-1

A-2 A.3 A-11 A-36 A-123

Input Data for Analysis Using L1WIN Summary of Results Using L1WIN Summary of L2WIN Analysis Using L1WIN Designs Summary of L2WIN Designs Level 3 Confirmation of Level 2 Embedments

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A-1 A-1 A-1 A-10 A-10 A-10 A-35 A-35 A-35

APPENDIX B - Installation and Running the Software B.1 Installing the Software B.1.1 PC Requirements B.1.2 Installation B.2 Operating the Software B.2.1 L1WIN B.2.2 L2WIN B.2.3 L3WIN Appendix B-1

B-1 B-1 B-1 B-2 B-3 B-4 B-5 B-6

APPENDIX C - L1WIN USERS MANUAL C.1 L1WIN Program Description C.2 L1WIN - Input Instructions C.2.1 Input File Description C.2.2 Level 1 Processor Moduleo C.2.3 Batched Input File Creation C.3 Output

C-1 C-2 C-2 C-3 C-4 C-6

FIGURES C-1 C-2

C-3 C-6

Example Input Deck - L1WIN View and Print Reports Screen

APPENDIX D - L2WIN - Users Manual D.1 L2WIN - Program Description D.2 L2WIN Input Instructions D.2.1 Input File Description D.2.2 Level 2 Processor Module D.3 Output D.3.1 Report Output D.3.2 Plot Output

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D-1 D-9 D-9 D-11 D-13 D-13 D-15

FIGURES D-1 D-2 D-3 D-4 D-5 D-6

Level 2 Build-Up Sea State Model Level 2 Program Logic Level 2 Pipe Embedment Logic Example Input Deck - L2WIN Input Screen for Level 2 Processor Module Plot Safety Factors

D-4 D-5 D-7 D-10 D-14 D-16

APPENDIX E - L3WIN Users Manual E.1 L3WIN - Program Description E.2 L3WIN Interface Description

E-1 E-17

FIGURES E-1 E-2 E-3 E-4

Geometric Layout of Pipeline and Nodes Ochi-Hubble Wave Spectrum in L3WIN Decomposition of irregular waves into single regular waves Plot of data base content, amplitudes and phases of the drag force as a function of the current ratio, a for KC = 40.

E-2 E-5 E-9 E-12

Fourier Coefficients for Regular Waves and Regular Waves with Steady Current

E-11

TABLES E-1

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SECTION 1.0 INTRODUCTION

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INTRODUCTION

As part of Project PR-178-01132, Kellogg Brown & Root, Inc. has for use with recent Microsoft Windows Operating Systems such as Windows 2000 and Windows XP modified previously existing PRCI software relating to pipeline on-bottom stability analysis. This manual provides a single reference document that describes the function and use of the PRCI's on-bottom stability analysis software. This software provides of three levels of analysis as shown in Table 1.0-1. The content of the three corresponding computer programs is discussed in the following paragraphs and illustrated in Figure 1.0-1. 1.

Level 1 Program "L1WIN" A Level 1 program, L1WIN (formerly L1STAB), was developed in PR-178-516 to provide a "traditional analysis" design tool. The tool incorporates traditional analysis methodology: • • •

frictional soil resistance, Morison-type hydrodynamic forces, and static analysis.

A Windows-based interface has been developed for this tool and the resulting program has been named L1WIN. 2.

Level 2 Program "L2WIN" Based on experience with the Level 3 soil model, a simplified analysis technique was developed and computerized in PR-178-517. The program was named L2STAB. A Windows-based interface has been developed for this tool and the resulting program has been named L2WIN. This approach is less computationally complex than the Level 3 software, and should be used as a primary analysis tool by design engineers. The program incorporates realistic hydrodynamic and soil resistance forces in a quasi-static analysis.

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ANALYSIS TYPE Level 1

Level 2

Simplified Static

Simplified Quasi-Static

PROGRAM NAME

COMMENTS

L1WIn

Program which performs a simplified analysis using ‘traditional’ methods.

L2WIn

Program which performs a static analysis based on: • Realistic hydrodynamic forces • Realistic pipe embedment calculated by quasi-static simulation of wave induced pipe oscillations

Wave Generation – Win Wave Wave kinematics for 3-D random seas based on PRCI Projects PR-162-157 and PR-175-420.

Level 3

Dynamic Time Domain with Wave Kinematics for 3-D Random Seas

L3WIn

Hydrodynamic Force Calculation – Win Force Generates wave forces based on a time history of wave kinematics (water particle velocities.)

Dynamic Simulation – Win Dynamic Pipe dynamics with external forces and a history dependent soil model based on PRCI Project PR-175-420.

TABLE 1.0-1 PRCI SUBMARINE PIPELINE ON-BOTTOM STABILITY ANALYSIS SOFTWARE

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Level 1 - Program L1WIN

Level 2 - Program L2WIN

Level 3 - Program L3WIN

* WINFORCE produces a series of wave forces on a stationary pipe. ** WINDYN performs a dynamic time domain analysis of a pipeline on the seabed. FIGURE 1.0-1 PRCI SUBMARINE PIPELINE ON-BOTTOM STABILITY ANALYSIS SOFTWARE We Deliver

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Level 3 Program Development "L3WIN" The programs in the previous Level 3 program suite, “WSIMQ”, “L3FORCE” and “L3PIPDYN,” have been combined and integrated with a top level program module to simplify input, execution and post processing. The resulting program, L3WIN, consists of a top level input and post processing module and an integrated timedomain dynamic simulation routine that incorporates random wave generation, hydrodynamic forces based on Fourier decomposition of results from numerous model tests, and soil models which include lateral earth pressure soil resistance as well as frictional soil resistance. Statistical analysis tools and post-processing interfaces have been developed to make use of the Level 3 analysis tool more powerful, more integrated, and easier to use.

The Windows-based interfaces provide the user with an interactive environment in which to develop the input file, and review the results of the analysis. This greatly reduces the need to reference input instructions in the User's Manuals. Examples of the input formats can be found in section 3.0, and further explanation of the programs can be found in the L1WIN, L2WIN and L3WIN User's Manuals in Appendices C, D and E, respectively. All of the computer programs discussed in this report are designed to be run in a Windows 2000, NT and XP operating environment on a personal computer. Although the core programs are written in Fortran, they are not presently structured to run on a mainframe system. The Level 1 and Level 2 programs (L1WIN and L2WIN) require minimal time to execute. The Level 3 program (L3WIN) requires a longer running time as well as correspondingly larger disk storage area. This is especially the case if many nodes are used in the simulation. The remaining sections of this report contain program descriptions, and example cases. Appendix A compares results using the software, and Appendix B describes hardware requirements, software installation procedures, and instructions for operating the programs. Appendices C through E contain input instructions.

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SECTION 2.0 DESCRIPTION OF PROGRAM SUITE

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DESCRIPTION OF PROGRAM SUITE

This section gives a brief description of each of the on-bottom stability analysis computer programs and their interfaces. Examples of the input formats can be found in section 3.0, and further explanation of the processors can be found in the L1WIN, L2WIN and L3WIN User's Manuals in Appendices C, D and E, respectively. 2.1

Level 1 Stability Analysis - L1WIN

Computer program L1WIN performs a very simple static pipeline stability analysis. The analysis is based on Airy wave theory and assumes either short or long crested waves. Maximum soil forces are calculated using an input friction factor and/or a soil cohesion force based on the pipe area in contact with the soil (based specified embedment). The inputs to L1WIN include pipe properties (diameter, wall thickness, corrosion coating thickness and density, and concrete coating thickness and density), environmental parameters (water depth, wave height, wave period, crest type, current), and soil characteristics (soil friction and/or embedment and cohesive soil strength). The user also inputs hydrodynamic force coefficients. Outputs include pipe weights, specific gravities, and safety factors against lateral and vertical movement for various concrete thicknesses. A detailed user manual for L1WIN is given in Appendix C. 2.2

Level 2 Stability - L2WIN

Computer program L2WIN forms the basis for the Level 2 design process. This quasistatic analysis program has been designed to take advantage of the results from the PRCI's hydrodynamic and pipe/soil interaction tests without a full dynamic simulation. A step-by-step description of the analysis conducted by L2WIN is as follows: 1.

Based on user inputs, the program calculates values for the design wave height spectral density function. The wave height spectral density function is then transformed to a bottom velocity spectral density function. The area under the bottom velocity spectrum is numerically integrated, and the significant bottom velocity is calculated. The peak frequency of the bottom velocity spectrum is determined.

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Maximum and minimum in-line hydrodynamic forces for the largest 200 waves contained in an assumed 4-hour long build-up sea state are calculated. The 4-hour long build-up period is considered to start with a zero wave height and to linearly increase with time to the design sea state wave height. The 200 largest waves are characterized by the five wave heights illustrated in Figure 2.2-1. More details on these calculations are discussed in Section 5.4.1. Wave forces for each of the five wave heights are calculated using the PRCI's hydrodynamic force calculation procedure and the associated data base of force coefficients.

3.

Based on the forces calculated in Step 2, a conservative estimate of pipe embedment at the end of the 4-hour storm build-up period is calculated. This estimate is obtained by subjecting the pipe to 200 small oscillations. The oscillations are limited in amplitude to be no larger than that which the wave forces can produce or 0.07 times the pipe diameter, whichever is smaller. To simulate the build-up sea state, the smaller waves shown on Figure 2.2-1 are considered first. Not all of the 200 oscillations necessarily produce pipe embedment. Only the waves that produce forces sufficient to overcome frictional resistance between the pipe and soil are considered to produce embedment. For each of the 200 waves, the in-line hydrodynamic force is reduced to account for the pipe embedment just prior to its application. The estimated pipe embedment and the available soil resistance force at the end of the build-up period are then saved for further processing. Pipe embedment and history dependent soil resistance are calculated using the PRCI's pipe/soil interaction model.

4.

Maximum and minimum in-line forces for the largest 50 waves during a subsequent 3-hour long design sea state are calculated as in Step 2 above. These 50 waves are characterized by the four different wave heights illustrated in Figure 2.2-2.

5.

Based on the forces calculated in Step 4 and the pipe embedment calculated in Step 3, the amount of additional pipe embedment that can be produced by the 50 largest waves in the design sea state is calculated in a fashion similar to that described in Step 4 for the storm build-up period. This embedment and the associated soil resistance force are saved for further processing.

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6.

Hydrodynamic forces for a complete wave cycle are calculated for four statistically meaningful wave induced bottom velocities which are expected in a 3-hour long design sea state. These wave induced bottom velocities are typical of the largest 135 waves expected during the design event, and have been selected to give designers a “feel” for how stable their pipeline designs are. Each statistical velocity has the possibility that some waves in the design event will exceed it.

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6.

Hydrodynamic forces for a complete wave cycle are calculated for four statistically meaningful wave induced bottom velocities that are expected in a 3-hour long design sea state. These wave induced bottom velocities are typical of the largest 135 waves expected during the design event and have been selected to give designers a "feel" for how stable their pipeline designs are. Each statistical velocity has the possibility that some waves in the design event will exceed it. The four bottom velocities, and, the most likely number of wave induced velocities exceeding each, are: U1/3 = 1.0 Us (135 exceedances) U1/10 = 1.27 Us (40 exceedances) U1/100 = 1.66 Us (4 exceedances) U1/1000 = 1.86 Us (0 exceedances)

7.

Using the soil resistance values obtained in Steps 3 and 5 and the hydrodynamic forces calculated in Step 6, the minimum factor-of-safety against lateral sliding is calculated for the pipe embedment at the end of the 4-hour long build-up period, and at the end of the 3-hour long design sea state. The factor of safety is calculated at one-degree intervals of wave passage for a complete 360-degrees from: Factor of Safety =

µ (Ws - FL (t)) + FH The minimum factor of safety is output FD (t) + FI (t)

for each of the four statistical waves assuming the two soil resistances calculated in Steps 3 and 5. The above procedure has been adopted after the results of typical analysis using the Level 3 dynamics software were used to calibrate and confirm that the results for pipe embedment are reasonable and that the results are conservative. Calibration of the Level 2 results to those of the Level 3 dynamic analysis are presented in Appendix A. A detailed user manual for L2WIN is given in Appendix D. 2.3

Level 3 Stability - L3WIN

The Level 3 suite consists of: a top level input and post processing module and a integrated time domain dynamic simulation routine that incorporates random wave generation and hydrodynamic forces based on Fourier decomposition of results from numerous model tests and soil models which include lateral earth pressure soil resistance We Deliver

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as well as frictional soil resistance. The integrated simulation routine incorporates the three original Level 3 program modules: L3WSIMQ, L3FORCE and L3PIPDYN. The user manual for L3WIN is given in Appendix E. The random wave generation routine (WinWave) calculates bottom water particle velocities based on airy wave theory and a set of randomly phased waves that are assigned different wave frequencies and directions. Wave energy is directionally spread using a wrapped normal distribution. Each component wave is assigned a direction based on a normal distribution in which the mean direction and standard deviation from the mean direction are user specified. Hydrodynamic force generation routine (WinForce) uses the generated bottom particle velocities and a state-of-the-art force formulation to calculate hydrodynamic drag and lift forces on a stationary pipeline. The calculation uses a Fourier summation to determine the wave forces. The coefficients for the Fourier summation are taken from a database developed from the model test results. The three database files of force coefficients (PRCWCU, PRCWCX AND PRCWU) that were developed for PRCI have been incorporated into the L3WIN program. The on-bottom pipeline dynamics simulation routine (WinDyn) models the pipeline as twodimensional finite beam elements. The program uses the hydrodynamic forces and a history dependent soil resistance model (developed for the PRCI in project PR-194-719) to dynamically model the wave/soil interaction. All elements are in a straight line and of equal length, but soil parameters, pipe parameters, boundary conditions, and applied loads can be varied along the pipe length. Pipeline displacements, embedment, instantaneous factors of safety and stresses are the main outputs. These can be obtained for several nodes as a function of time, or for the entire pipeline at specified time steps. The processes within the L3WIN are illustrated in Figures 2.2-3 through 2.2-5. A detailed user manual for L3WIN is given in Appendix E.

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SECTION 3.0 EXAMPLE CASES

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EXAMPLE CASES

The following section gives the input, output, and computer screens seen while running the sample cases contained on the program diskettes. This section is intended to familiarize the program user with what to expect as he uses the software. 3.1

Level 1 Examples

The L1WIN.EXE file is used to begin the processor module for the L1WIN software. LEVEL1 can be executed through Windows (from the Start button or Explorer) or from the DOS command line. If an input file already exists, the file name can be input on the first line of the processor interface and the file will be loaded. Figure 3.1-1 shows the sample input deck. Page 3-3 to 3-6 shows a copy of the output file created.

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FIGURE 3.1-1

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For

SUBMARINE PIPELINE STABILITY ANALYSIS

********************************************** Developed for A.G.A by Halliburton KBR ********************************************** Copyright 1988 by the American Gas Association Copyright 2002 by Pipeline Research Council International, Inc.

Run at 05/28/2003 16:21 Input source:C:\PRCI Stability\L1Win\PROJECT\CASE LIWIN.iL1,5/28/2003 4:21:34 PM DF 2.00-020206

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L1Win - PRCI OBS Level 1-Version 2.00-00

L1WIN EXAMPLE CASE

---------- Input Data ---------Run at 05/28/2003 16:21

Project title = L1WIN EXAMPLE CASE Subject = Friction = 0.7 Embedment = 0.00 inches

| Option = 1.00 | Wave angle = 90.00

Cohesive strength = 0.00 psf

| Water depth =

Pipe OD = 30 inches

| Wave height = 45

Wall thickness = 0.5 inches

| Wave period = 14.1

Corrosion coating = 0.15625 inches Density coating = 115 pcf

| Current = 1 ft/sec | Bndry current = 3

Density concrete = 190 pcf

| Bndry wave = 0.00

Density field joint = 0.00 pcf Cutback = 0 inches Taper angle = 0.00 degree Specific gravity = 0.00

| | | |

degree 300.00 feet feet second

feet feet Drag Lift Mass Wave

coeff coeff coeff crest

= = = =

0.7 0.9 3.29 0

long | Conc initial = 1 inches | Conc final = 4 inches | Conc increment = 0.125 inches

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L1Win - PRCI OBS Level 1-Version 2.00-00 L1WIN EXAMPLE CASE Run at 05/28/2003 16:21 +-----------------------------------------------------------------------------------------------------------------------+ | P I P E L I N E P R O P E R T I E S | +-----------------------------------------------------------------------------------------------------------------------+ | | | | PIPE OUTSIDE DIAMETER = 30.000 INCHES | PIPE WALL THICKNESS = 0.500 INCHES | | | | | CORROSION COATING THICKNESS = 0.15625 INCHES | CORROSION COATING DENSITY = 115.0 LBS/FT**3 | | | | | CONCRETE DENSITY = 190.0 LBS/FT**3 | FIELD JOINT DENSITY = 190.0 LBS/FT**3 | | | | | FIELD JOINT CUTBACK = 15.000 INCHES | TAPER ANGLE = 0.0 DEGREES | | | | +-----------------------------------------------------------------------------------------------------------------------+ | S O I L S P R O P E R T I E S | +-----------------------------------------------------------------------------------------------------------------------+ | | | SOIL FRICTION FACTOR = 0.70 | | | +-----------------------------------------------------------------------------------------------------------------------+ | H Y D R O D Y N A M I C P R O P E R T I E S | +-----------------------------------------------------------------------------------------------------------------------+ | | | | DRAG COEFFICIENT = 0.70 | LIFT COEFFICIENT = 0.90 | | | | | INERTIAL COEFFICIENT = 3.29 | WATER DEPTH = 300.0 FEET | | | | | WAVE HEIGHT = 45.00 FEET | WAVE PERIOD = 14.10 SECONDS | | | | | WAVE ANGLE OF ATTACK = 90.0 DEGREES | WAVE CREST TYPE = LONG | | | | | BOTTOM CURRENT NORMAL TO P.L.= 1.000 FEET/SECOND | | | | | | WAVE INDUCED BOTTOM PARTICLE | WAVE INDUCED BOTTOM PARTICLE | | VELOCITY NORMAL TO PIPE = 2.970 FEET/SEC. | ACCELERATION NORMAL TO PIPE = 1.324 FEET/SEC**2 | | | | | BOTT. BOUN. LAYER FOR CURR. = 3.000 FEET | BOTT. BOUN. LAYER FOR WAVES = 0.000 FEET | | | | | KUELEGAN CARPENTER W/O CONC. = 16.581 | CURRENT RATIO = 0.337 | | | |

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+-----------------------------------------------------------------------------------------------------------------------+ L1Win - PRCI OBS Level 1-Version 2.00-00

L1WIN EXAMPLE CASE

Run at 05/28/2003 16:21 +---------------------------------------------------------------------------------------------------------------+ | L O N G C R E S T E D W A V E S T A B I L I T Y A N A L Y S I S | +---------------------------------------------------------------------------------------------------------------+ |CONCRETE PIPE SUB. SPECIFIC PH.ANGLE PART. PART. DRAG LIFT INER. HORIZ. | VER. SAFETY FACT. | |THICKNESS WEIGHT GRAVITY THETA VELOC. ACCEL. FORCE FORCE FORCE S. FACTOR+---------+---------+ | (IN.) (LB/FT) (DEG.) (FPS) (FPS/SEC) (LB/FT) (LB/FT) (LB/FT) AT THETA |AT THETA MINIMUM | +---------------------------------------------------------------------------------------------------------------+ 1.000 -65.2 Pipe floats 1.125 -54.0 Pipe floats 1.250 -42.8 Pipe floats 1.375 -31.5 Pipe floats 1.500 -20.1 Pipe floats 1.625 -8.6 Pipe floats 1.750 3.0 1.01 85. 1.1 1.32 2.5 3.2 53.7 0.00 0.94 0.08 1.875 14.7 1.04 58. 2.4 1.12 11.8 15.1 46.4 0.00 0.97 0.39 2.000 26.4 1.06 37. 3.2 0.80 20.9 26.9 33.4 0.00 0.98 0.70 2.125 38.2 1.09 0. 3.8 0.00 29.6 38.0 0.0 0.01 1.01 1.01 2.250 50.2 1.12 14. 3.8 0.32 28.4 36.6 13.8 0.23 1.37 1.31 2.375 62.2 1.14 22. 3.6 0.50 26.7 34.4 21.7 0.40 1.81 1.61 2.500 74.2 1.17 28. 3.5 0.62 25.0 32.2 27.6 0.56 2.31 1.91 2.625 86.4 1.20 32. 3.4 0.70 23.7 30.5 31.6 0.71 2.83 2.21 2.750 98.7 1.22 36. 3.3 0.78 22.3 28.7 35.6 0.85 3.44 2.50 2.875 111.0 1.24 39. 3.2 0.83 21.2 27.2 38.6 0.98 4.07 2.79 3.000 123.5 1.27 42. 3.1 0.89 20.0 25.7 41.6 1.11 4.80 3.08 3.125 136.0 1.29 44. 3.0 0.92 19.3 24.8 43.8 1.23 5.49 3.37 3.250 148.6 1.31 46. 2.9 0.95 18.5 23.7 46.0 1.36 6.26 3.66 3.375 161.3 1.34 48. 2.9 0.98 17.7 22.7 48.2 1.47 7.11 3.94 3.500 174.1 1.36 49. 2.8 1.00 17.3 22.2 49.6 1.59 7.82 4.22 3.625 186.9 1.38 51. 2.7 1.03 16.5 21.2 51.7 1.70 8.83 4.50 3.750 199.9 1.40 52. 2.7 1.04 16.1 20.7 53.2 1.81 9.66 4.78 3.875 212.9 1.42 53. 2.7 1.06 15.7 20.2 54.6 1.92 10.53 5.06

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3-6

4.000 226.0 1.44 54. 2.6 1.07 15.4 19.7 56.0 2.02 11.45 5.33 +---------------------------------------------------------------------------------------------------------------+

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3-7

3.2

L2WIN Examples

The L2WIN.EXE file is used to begin the processor module for the L2WIN software. LEVEL2 can be executed through Windows (from the Start button or Explorer) or from the DOS command line. If an input file already exists, the file name can be input on the first line of the processor interface and the file will be loaded. Figure 3.2-1 shows a sample input deck. Pages 3-9 to 3-29 shows a copy of the output file created.

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3-8

FIGURE 3.2-1

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3-9

L2Win - PRCI OBS Level 2 - Version 2.00-00

For

SUBMARINE PIPELINE STABILITY ANALYSIS

********************************************** Developed for A.G.A by Halliburton KBR ********************************************** Copyright 1988 by the American Gas Association Copyright 2002 by Pipeline Research Council International, Inc.

Including new soil & hydrodynamic force formulations, Realistic forces & embedments.

Run at 05/29/2003 09:22 Input source:C:\PRCI Stability\L2Win\PROJECT\EXAMPLE CASE.iL2,5/29/2003 9:22:16 AM DF 2.00-020303

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3 - 10

L2Win - PRCI OBS Level 2 - Version 2.00-00 L2WIN EXAMPLE CASE

Run at 05/29/2003 09:22 ---------- Input Data ----------

Project title = L2WIN EXAMPLE CASE Subject = Soil type = 0 Sand Sand = 0.5000 fraction Embedment = 0.0000 in RIMBED = 0.68 RLMBED = 0.5000 RITRCH = 1.0000 RLTRCH = 1.0000 Pipe OD = 30 in Wall thickness = 0.5 in Corrosion coating = 0.15625 in Density coating = 115 pcf Density concrete = 190 pcf Density field joint = 0.0000 pcf Cutback = 0.000 in Taper anggle = 0.0000 degree Specific gravity = 0.0000 Pipe roughness = 0 (1) Concrete

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| | | | | | | | | | | | | | | | | |

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Water depth = 300 ft Current = 1 fps Boundary layer = 3 ft Input type = 0 (0) Spectral Use boundary layer = 1 (1) Yes Output option = 0 (0) Standard output Wave height = 45.0000 ft Peak period = 14.1000 second Spectral peakedness = 1.0000 Wave direction = 90.0000 degree Wave spreading = 30.0000 degree Directional spectrum = 0 (0) Uni-Modal Secondary direction = 90.0000 degree Secondary spreading = 30.0000 degree Maxing constant = 0.5000 Conc initial = 2.5 in Conc final = 3.5 in Conc increment = 0.125 in

L2Win - PRCI OBS Level 2 - Version 2.00-00 L2WIN EXAMPLE CASE Run at 05/29/2003 09:22 +-----------------------------------------------------------------------------------------------------------------------+ | P I P E L I N E P R O P E R T I E S | +-----------------------------------------------------------------------------------------------------------------------+ | | | | PIPE OUTSIDE DIAMETER = 30.000 INCHES | PIPE WALL THICKNESS = 0.500 INCHES | | | | | CORROSION COATING THICKNESS = 0.15625 INCHES | CORROSION COATING DENSITY = 115.0 LBS/FT**3 | | | | | CONCRETE DENSITY = 190.0 LBS/FT**3 | FIELD JOINT DENSITY = 190.0 LBS/FT**3 | | | | | FIELD JOINT CUTBACK = 15.000 INCHES | TAPER ANGLE = 0.0 DEGREES | | | | | SPECIFIC GRAVITY OF PRODUCT = 0.000 | PIPE ROUGHNESS = 1 | | | | +-----------------------------------------------------------------------------------------------------------------------+ | S O I L P R O P E R T I E S - S A N D Y S O I L | +-----------------------------------------------------------------------------------------------------------------------+ | | | RELATIVE DENSITY = 0.5 | | | | FRICTION FACTOR = 0.6 | | | +-----------------------------------------------------------------------------------------------------------------------+ | W A V E S P E C T R A L P R O P E R T I E S | +-----------------------------------------------------------------------------------------------------------------------+ | | | | SIG. WAVE HEIGHT = 45.00 FEET | PEAK PERIOD = 14.10 SECONDS | | | | | WATER DEPTH = 300.0 FEET | LAMDA = 1.000 | | | | | WAVE ANGLE OF ATTACK = 90.0 DEGREES | WAVE SPREADING S.D. = 30.0 | | | | | BOTTOM CURRENT NORMAL TO P.L.= 1.000 FEET/SECOND | | | | | | BOTT. BOUN. LAYER FOR CURR. = 3.000 FEET | | | | | +-----------------------------------------------------------------------------------------------------------------------+ | C A L C U L A T E D B O T T O M S P E C T R A U S E D | +-----------------------------------------------------------------------------------------------------------------------+ | | |

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| |

SIG. BOTTOM VELOCITY

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=

2.179

FT/SEC.

| |

3 - 13

ZERO CROSSING PERIOD

=

14.947

SECONDS

| |

L2Win - PRCI OBS Level 2 - Version 2.00-00 L2WIN EXAMPLE CASE Run at 05/29/2003 09:22 +-----------------------------------------------------------------------------------------------------------------------+ | L E V E L 2 P I P E L I N E S T A B I L I T Y - R E S U L T S | |-----------------------------------------------------------------------------------------------------------------------+ | CONCRETE THICKNESS, IN = 2.50 | | SUBMERGED WEIGHT, LB/FT = 74.25 | | SPECIFIC GRAVITY = 1.17 | | | | AFTER AFTER | | EMBEDMENT 4 HR ADD. | | & SOIL STORM 3 HR | | RESISTANCE BUILDUP STORM | | ---------------------------------- ------- -----| | NO. OF WAVES ADDING EMBED. = 75 50 | | PREDICTED EMBEDMENT , IN = 2.0 2.6 | | PASSIVE SOIL RESISTANCE, LB/FT = 61.1 84.2 | | MAX. FRICTION (NO LIFT), LB/FT = 44.5 44.5 | | MAX. TOTAL SOIL FORCE | | (NO LIFT), LB/FT = 105.6 128.7 | | | | NOTES: = | | 1. P. RESIST.(NO EMBED), LB/FT = 18.0 | | 2. INITIAL EMBEDMENT, IN = 0.8 | | 3. MAX. EMBEDMENT ALLOWED, IN = 6.9 |

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+-----------------------------------------------------------------------------------------------------------------------| |STATISTIC|VELOCITY |KUELEGAN |PH. ANGLE| PART. | PART. | DRAG | LIFT | INER. | HORIZ. | VER. SAFETY FACT. | | BOTTOM |AMPLITUDE|CARPENTER| THETA | VELOC. | ACCEL. | FORCE | FORCE | FORCE |S. FACTOR+---------+---------+ |VELOCITY |(FT/SEC) | /ALPHA | (DEG.) |(FT/SEC) |(FPS/SEC)| (LB/FT) | (LB/FT) | (LB/FT) |AT THETA |AT THETA | MINIMUM | +---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+ | STABILITY AT END OF 4 HR STORM BUILDUP | | U(SIG.) | 2.18 | 11./0.40| 33. | 2.7 | 0.50 | 13.0 | 61.9 | 21.4 | 1.99 | 1.20 | 1.20 | | | | | | | | | | | | | | | U(1/10) | 2.77 | 14./0.31| 50. | 2.6 | 0.89 | 19.8 | 86.7 | 38.2 | 1.05 | 0.86 | 0.85 | | | | | | | | | | | | | | | U(1/100)| 3.62 | 18./0.24| 44. | 3.5 | 1.06 | 45.4 | 109.4 | 45.3 | 0.67 | 0.68 | 0.64 | | | | | | | | | | | | | | |U(1/1000)| 4.05 | 21./0.21| 47. | 3.6 | 1.25 | 55.0 | 127.6 | 53.4 | 0.56 | 0.58 | 0.56 | | POTENTIAL FOR STABILITY AT END OF ADDITIONAL 3 HR STORM | | U(SIG.) | 2.18 | 11./0.40| 33. | 2.7 | 0.50 | 12.9 | 60.7 | 21.1 | 2.71 | 1.22 | 1.22 | | | | | | | | | | | | | | | U(1/10) | 2.77 | 14./0.31| 50. | 2.6 | 0.89 | 19.5 | 85.0 | 37.8 | 1.47 | 0.87 | 0.87 | | | | | | | | | | | | | | | U(1/100)| 3.62 | 18./0.24| 44. | 3.5 | 1.06 | 44.8 | 107.2 | 44.8 | 0.94 | 0.69 | 0.66 | | | | | | | | | | | | | | |U(1/1000)| 4.05 | 21./0.21| 47. | 3.6 | 1.25 | 54.3 | 125.1 | 52.8 | 0.79 | 0.59 | 0.57 | +---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+ NOTES: 1. At the end of the 4 hour storm buildup period, a lateral factor-of-safety greater than 1.0 for the U 1/1000 bottom velocity indicates a very stable pipe. However, a lighter pipe may also be stable. 2. At the end of the additional 3 hour storm period, a lateral factor-of-safety greater than 1.0 for the U1/1000 bottom velocity indicates that the pipe has the potential to become stable during the 3 hour storm and most likely is for many Level 3 storm realizations. However, this is not always the case, since the calculations for checking stability at the end of the 3 hours assume the pipe has not broken out of the soil during the entire 3 hours. 3. A pipe which is stable in the U 1/100 velocity at the end of the 4 hour storm build-up, and is also stable in the U 1/1000 velocity at the end of the 3 hour storm, is stable. 4. If there is a large difference in weight coating required to meet both criteria in note 3 it is recommended that a Level 3 analysis be performed to determine stability. 5. In a 3 hour storm period, there is approximately 1 occurence of the U 1/1000 bottom velocity and 10 occurences of bottom velocity whose average is the U 1/100 velocity.

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L2Win - PRCI OBS Level 2 - Version 2.00-00 L2WIN EXAMPLE CASE

Run at 05/29/2003 09:22 +-----------------------------------------------------------------------------------------------------------------------+ | L E V E L 2 P I P E L I N E S T A B I L I T Y - R E S U L T S | |-----------------------------------------------------------------------------------------------------------------------+ | CONCRETE THICKNESS, IN = 2.63 | | SUBMERGED WEIGHT, LB/FT = 86.42 | | SPECIFIC GRAVITY = 1.20 | | | | AFTER AFTER | | EMBEDMENT 4 HR ADD. | | & SOIL STORM 3 HR | | RESISTANCE BUILDUP STORM | | ---------------------------------- ------- -----| | NO. OF WAVES ADDING EMBED. = 38 50 | | PREDICTED EMBEDMENT , IN = 2.0 2.7 | | PASSIVE SOIL RESISTANCE, LB/FT = 64.5 92.2 | | MAX. FRICTION (NO LIFT), LB/FT = 51.9 51.9 | | MAX. TOTAL SOIL FORCE | | (NO LIFT), LB/FT = 116.4 144.0 | | | | NOTES: = | | 1. P. RESIST.(NO EMBED), LB/FT = 21.0 | | 2. INITIAL EMBEDMENT, IN = 0.9 | | 3. MAX. EMBEDMENT ALLOWED, IN = 7.6 |

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+-----------------------------------------------------------------------------------------------------------------------| |STATISTIC|VELOCITY |KUELEGAN |PH. ANGLE| PART. | PART. | DRAG | LIFT | INER. | HORIZ. | VER. SAFETY FACT. | | BOTTOM |AMPLITUDE|CARPENTER| THETA | VELOC. | ACCEL. | FORCE | FORCE | FORCE |S. FACTOR+---------+---------+ |VELOCITY |(FT/SEC) | /ALPHA | (DEG.) |(FT/SEC) |(FPS/SEC)| (LB/FT) | (LB/FT) | (LB/FT) |AT THETA |AT THETA | MINIMUM | +---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+ | STABILITY AT END OF 4 HR STORM BUILDUP | | U(SIG.) | 2.18 | 11./0.40| 33. | 2.7 | 0.50 | 13.1 | 62.4 | 21.7 | 2.27 | 1.38 | 1.38 | | | | | | | | | | | | | | | U(1/10) | 2.77 | 14./0.31| 51. | 2.6 | 0.90 | 18.8 | 87.3 | 39.3 | 1.11 | 0.99 | 0.98 | | | | | | | | | | | | | | | U(1/100)| 3.62 | 18./0.24| 44. | 3.5 | 1.06 | 45.7 | 111.1 | 46.0 | 0.70 | 0.78 | 0.74 | | | | | | | | | | | | | | |U(1/1000)| 4.05 | 20./0.21| 46. | 3.7 | 1.23 | 56.2 | 127.7 | 53.3 | 0.59 | 0.68 | 0.64 | | POTENTIAL FOR STABILITY AT END OF ADDITIONAL 3 HR STORM | | U(SIG.) | 2.18 | 11./0.40| 33. | 2.7 | 0.50 | 12.9 | 61.0 | 21.4 | 3.13 | 1.42 | 1.42 | | | | | | | | | | | | | | | U(1/10) | 2.77 | 14./0.31| 49. | 2.7 | 0.88 | 19.6 | 85.7 | 37.7 | 1.62 | 1.01 | 1.01 | | | | | | | | | | | | | | | U(1/100)| 3.62 | 18./0.24| 44. | 3.5 | 1.06 | 45.1 | 108.5 | 45.3 | 1.02 | 0.80 | 0.76 | | | | | | | | | | | | | | |U(1/1000)| 4.05 | 20./0.21| 46. | 3.7 | 1.23 | 55.4 | 124.9 | 52.6 | 0.85 | 0.69 | 0.65 | +---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+ NOTES: 1. At the end of the 4 hour storm buildup period, a lateral factor-of-safety greater than 1.0 for the U 1/1000 bottom velocity indicates a very stable pipe. However, a lighter pipe may also be stable. 2. At the end of the additional 3 hour storm period, a lateral factor-of-safety greater than 1.0 for the U1/1000 bottom velocity indicates that the pipe has the potential to become stable during the 3 hour storm and most likely is for many Level 3 storm realizations. However, this is not always the case, since the calculations for checking stability at the end of the 3 hours assume the pipe has not broken out of the soil during the entire 3 hours. 3. A pipe which is stable in the U 1/100 velocity at the end of the 4 hour storm build-up, and is also stable in the U 1/1000 velocity at the end of the 3 hour storm, is stable. 4. If there is a large difference in weight coating required to meet both criteria in note 3 it is recommended that a Level 3 analysis be performed to determine stability. 5. In a 3 hour storm period, there is approximately 1 occurence of the U 1/1000 bottom velocity and 10 occurences of bottom velocity whose average is the U 1/100 velocity.

We Deliver

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L2Win - PRCI OBS Level 2 - Version 2.00-00 L2WIN EXAMPLE CASE

Run at 05/29/2003 09:22 +-----------------------------------------------------------------------------------------------------------------------+ | L E V E L 2 P I P E L I N E S T A B I L I T Y - R E S U L T S | |-----------------------------------------------------------------------------------------------------------------------+ | CONCRETE THICKNESS, IN = 2.75 | | SUBMERGED WEIGHT, LB/FT = 98.69 | | SPECIFIC GRAVITY = 1.22 | | | | AFTER AFTER | | EMBEDMENT 4 HR ADD. | | & SOIL STORM 3 HR | | RESISTANCE BUILDUP STORM | | ---------------------------------- ------- -----| | NO. OF WAVES ADDING EMBED. = 26 50 | | PREDICTED EMBEDMENT , IN = 2.1 2.8 | | PASSIVE SOIL RESISTANCE, LB/FT = 71.6 99.6 | | MAX. FRICTION (NO LIFT), LB/FT = 59.2 59.2 | | MAX. TOTAL SOIL FORCE | | (NO LIFT), LB/FT = 130.8 158.8 | | | | NOTES: = | | 1. P. RESIST.(NO EMBED), LB/FT = 24.0 | | 2. INITIAL EMBEDMENT, IN = 1.0 | | 3. MAX. EMBEDMENT ALLOWED, IN = 8.3 |

We Deliver

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+-----------------------------------------------------------------------------------------------------------------------| |STATISTIC|VELOCITY |KUELEGAN |PH. ANGLE| PART. | PART. | DRAG | LIFT | INER. | HORIZ. | VER. SAFETY FACT. | | BOTTOM |AMPLITUDE|CARPENTER| THETA | VELOC. | ACCEL. | FORCE | FORCE | FORCE |S. FACTOR+---------+---------+ |VELOCITY |(FT/SEC) | /ALPHA | (DEG.) |(FT/SEC) |(FPS/SEC)| (LB/FT) | (LB/FT) | (LB/FT) |AT THETA |AT THETA | MINIMUM | +---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+ | STABILITY AT END OF 4 HR STORM BUILDUP | | U(SIG.) | 2.18 | 11./0.40| 33. | 2.7 | 0.50 | 13.1 | 62.8 | 22.0 | 2.66 | 1.57 | 1.57 | | | | | | | | | | | | | | | U(1/10) | 2.77 | 14./0.31| 49. | 2.7 | 0.88 | 19.4 | 88.3 | 38.7 | 1.34 | 1.12 | 1.12 | | | | | | | | | | | | | | | U(1/100)| 3.62 | 18./0.24| 44. | 3.5 | 1.06 | 46.0 | 112.4 | 46.5 | 0.77 | 0.88 | 0.83 | | | | | | | | | | | | | | |U(1/1000)| 4.05 | 20./0.21| 46. | 3.7 | 1.23 | 56.5 | 128.7 | 54.0 | 0.65 | 0.77 | 0.73 | | POTENTIAL FOR STABILITY AT END OF ADDITIONAL 3 HR STORM | | U(SIG.) | 2.18 | 11./0.40| 33. | 2.7 | 0.50 | 12.9 | 61.4 | 21.7 | 3.53 | 1.61 | 1.61 | | | | | | | | | | | | | | | U(1/10) | 2.77 | 14./0.31| 50. | 2.6 | 0.89 | 18.6 | 86.2 | 38.7 | 1.87 | 1.15 | 1.14 | | | | | | | | | | | | | | | U(1/100)| 3.62 | 18./0.24| 44. | 3.5 | 1.06 | 45.3 | 109.9 | 45.9 | 1.09 | 0.90 | 0.85 | | | | | | | | | | | | | | |U(1/1000)| 4.05 | 20./0.21| 46. | 3.7 | 1.23 | 55.7 | 125.8 | 53.2 | 0.91 | 0.78 | 0.74 | +---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+ NOTES: 1. At the end of the 4 hour storm buildup period, a lateral factor-of-safety greater than 1.0 for the U 1/1000 bottom velocity indicates a very stable pipe. However, a lighter pipe may also be stable. 2. At the end of the additional 3 hour storm period, a lateral factor-of-safety greater than 1.0 for the U1/1000 bottom velocity indicates that the pipe has the potential to become stable during the 3 hour storm and most likely is for many Level 3 storm realizations. However, this is not always the case, since the calculations for checking stability at the end of the 3 hours assume the pipe has not broken out of the soil during the entire 3 hours. 3. A pipe which is stable in the U 1/100 velocity at the end of the 4 hour storm build-up, and is also stable in the U 1/1000 velocity at the end of the 3 hour storm, is stable. 4. If there is a large difference in weight coating required to meet both criteria in note 3 it is recommended that a Level 3 analysis be performed to determine stability. 5. In a 3 hour storm period, there is approximately 1 occurence of the U 1/1000 bottom velocity and 10 occurences of bottom velocity whose average is the U 1/100 velocity.

We Deliver

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L2Win - PRCI OBS Level 2 - Version 2.00-00 L2WIN EXAMPLE CASE

Run at 05/29/2003 09:22 +-----------------------------------------------------------------------------------------------------------------------+ | L E V E L 2 P I P E L I N E S T A B I L I T Y - R E S U L T S | |-----------------------------------------------------------------------------------------------------------------------+ | CONCRETE THICKNESS, IN = 2.88 | | SUBMERGED WEIGHT, LB/FT = 111.03 | | SPECIFIC GRAVITY = 1.24 | | | | AFTER AFTER | | EMBEDMENT 4 HR ADD. | | & SOIL STORM 3 HR | | RESISTANCE BUILDUP STORM | | ---------------------------------- ------- -----| | NO. OF WAVES ADDING EMBED. = 26 50 | | PREDICTED EMBEDMENT , IN = 2.1 2.9 | | PASSIVE SOIL RESISTANCE, LB/FT = 76.2 104.6 | | MAX. FRICTION (NO LIFT), LB/FT = 66.6 66.6 | | MAX. TOTAL SOIL FORCE | | (NO LIFT), LB/FT = 142.8 171.2 | | | | NOTES: = | | 1. P. RESIST.(NO EMBED), LB/FT = 27.0 | | 2. INITIAL EMBEDMENT, IN = 1.1 | | 3. MAX. EMBEDMENT ALLOWED, IN = 9.0 |

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+-----------------------------------------------------------------------------------------------------------------------| |STATISTIC|VELOCITY |KUELEGAN |PH. ANGLE| PART. | PART. | DRAG | LIFT | INER. | HORIZ. | VER. SAFETY FACT. | | BOTTOM |AMPLITUDE|CARPENTER| THETA | VELOC. | ACCEL. | FORCE | FORCE | FORCE |S. FACTOR+---------+---------+ |VELOCITY |(FT/SEC) | /ALPHA | (DEG.) |(FT/SEC) |(FPS/SEC)| (LB/FT) | (LB/FT) | (LB/FT) |AT THETA |AT THETA | MINIMUM | +---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+ | STABILITY AT END OF 4 HR STORM BUILDUP | | U(SIG.) | 2.18 | 11./0.40| 34. | 2.7 | 0.51 | 12.5 | 63.3 | 22.9 | 2.97 | 1.76 | 1.75 | | | | | | | | | | | | | | | U(1/10) | 2.77 | 14./0.31| 50. | 2.6 | 0.89 | 18.4 | 88.9 | 39.8 | 1.54 | 1.25 | 1.24 | | | | | | | | | | | | | | | U(1/100)| 3.62 | 18./0.24| 44. | 3.5 | 1.06 | 46.3 | 114.0 | 47.1 | 0.82 | 0.97 | 0.93 | | | | | | | | | | | | | | |U(1/1000)| 4.05 | 20./0.21| 45. | 3.7 | 1.21 | 57.7 | 128.6 | 53.8 | 0.68 | 0.86 | 0.81 | | POTENTIAL FOR STABILITY AT END OF ADDITIONAL 3 HR STORM | | U(SIG.) | 2.18 | 11./0.40| 34. | 2.7 | 0.51 | 12.3 | 61.9 | 22.6 | 3.84 | 1.79 | 1.79 | | | | | | | | | | | | | | | U(1/10) | 2.77 | 14./0.31| 50. | 2.6 | 0.89 | 18.2 | 86.9 | 39.2 | 2.07 | 1.28 | 1.27 | | | | | | | | | | | | | | | U(1/100)| 3.62 | 18./0.24| 44. | 3.5 | 1.06 | 45.6 | 111.5 | 46.5 | 1.13 | 1.00 | 0.95 | | | | | | | | | | | | | | |U(1/1000)| 4.05 | 20./0.21| 45. | 3.7 | 1.21 | 56.9 | 125.8 | 53.0 | 0.95 | 0.88 | 0.83 | +---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+ NOTES: 1. At the end of the 4 hour storm buildup period, a lateral factor-of-safety greater than 1.0 for the U 1/1000 bottom velocity indicates a very stable pipe. However, a lighter pipe may also be stable. 2. At the end of the additional 3 hour storm period, a lateral factor-of-safety greater than 1.0 for the U1/1000 bottom velocity indicates that the pipe has the potential to become stable during the 3 hour storm and most likely is for many Level 3 storm realizations. However, this is not always the case, since the calculations for checking stability at the end of the 3 hours assume the pipe has not broken out of the soil during the entire 3 hours. 3. A pipe which is stable in the U 1/100 velocity at the end of the 4 hour storm build-up, and is also stable in the U 1/1000 velocity at the end of the 3 hour storm, is stable. 4. If there is a large difference in weight coating required to meet both criteria in note 3 it is recommended that a Level 3 analysis be performed to determine stability. 5. In a 3 hour storm period, there is approximately 1 occurence of the U 1/1000 bottom velocity and 10 occurences of bottom velocity whose average is the U 1/100 velocity.

We Deliver

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L2Win - PRCI OBS Level 2 - Version 2.00-00 L2WIN EXAMPLE CASE

Run at 05/29/2003 09:22 +-----------------------------------------------------------------------------------------------------------------------+ | L E V E L 2 P I P E L I N E S T A B I L I T Y - R E S U L T S | |-----------------------------------------------------------------------------------------------------------------------+ | CONCRETE THICKNESS, IN = 3.00 | | SUBMERGED WEIGHT, LB/FT = 123.47 | | SPECIFIC GRAVITY = 1.27 | | | | AFTER AFTER | | EMBEDMENT 4 HR ADD. | | & SOIL STORM 3 HR | | RESISTANCE BUILDUP STORM | | ---------------------------------- ------- -----| | NO. OF WAVES ADDING EMBED. = 12 50 | | PREDICTED EMBEDMENT , IN = 2.0 2.9 | | PASSIVE SOIL RESISTANCE, LB/FT = 75.5 108.1 | | MAX. FRICTION (NO LIFT), LB/FT = 74.1 74.1 | | MAX. TOTAL SOIL FORCE | | (NO LIFT), LB/FT = 149.6 182.2 | | | | NOTES: = | | 1. P. RESIST.(NO EMBED), LB/FT = 30.0 | | 2. INITIAL EMBEDMENT, IN = 1.2 | | 3. MAX. EMBEDMENT ALLOWED, IN = 9.7 |

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+-----------------------------------------------------------------------------------------------------------------------| |STATISTIC|VELOCITY |KUELEGAN |PH. ANGLE| PART. | PART. | DRAG | LIFT | INER. | HORIZ. | VER. SAFETY FACT. | | BOTTOM |AMPLITUDE|CARPENTER| THETA | VELOC. | ACCEL. | FORCE | FORCE | FORCE |S. FACTOR+---------+---------+ |VELOCITY |(FT/SEC) | /ALPHA | (DEG.) |(FT/SEC) |(FPS/SEC)| (LB/FT) | (LB/FT) | (LB/FT) |AT THETA |AT THETA | MINIMUM | +---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+ | STABILITY AT END OF 4 HR STORM BUILDUP | | U(SIG.) | 2.18 | 11./0.40| 34. | 2.7 | 0.51 | 12.5 | 64.0 | 23.2 | 3.11 | 1.93 | 1.93 | | | | | | | | | | | | | | | U(1/10) | 2.77 | 14./0.31| 50. | 2.6 | 0.89 | 18.0 | 90.1 | 40.4 | 1.64 | 1.37 | 1.36 | | | | | | | | | | | | | | | U(1/100)| 3.62 | 18./0.24| 50. | 3.2 | 1.17 | 40.7 | 120.6 | 52.8 | 0.83 | 1.02 | 1.01 | | | | | | | | | | | | | | |U(1/1000)| 4.05 | 20./0.21| 44. | 3.8 | 1.18 | 59.0 | 129.1 | 53.7 | 0.67 | 0.96 | 0.89 | | POTENTIAL FOR STABILITY AT END OF ADDITIONAL 3 HR STORM | | U(SIG.) | 2.18 | 11./0.40| 34. | 2.7 | 0.51 | 12.3 | 62.4 | 22.9 | 4.11 | 1.98 | 1.98 | | | | | | | | | | | | | | | U(1/10) | 2.77 | 14./0.31| 50. | 2.6 | 0.89 | 17.7 | 87.8 | 39.8 | 2.25 | 1.41 | 1.40 | | | | | | | | | | | | | | | U(1/100)| 3.62 | 18./0.24| 49. | 3.2 | 1.15 | 41.2 | 117.0 | 51.2 | 1.21 | 1.06 | 1.04 | | | | | | | | | | | | | | |U(1/1000)| 4.05 | 20./0.21| 44. | 3.8 | 1.18 | 58.1 | 125.9 | 52.8 | 0.97 | 0.98 | 0.91 | +---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+ NOTES: 1. At the end of the 4 hour storm buildup period, a lateral factor-of-safety greater than 1.0 for the U 1/1000 bottom velocity indicates a very stable pipe. However, a lighter pipe may also be stable. 2. At the end of the additional 3 hour storm period, a lateral factor-of-safety greater than 1.0 for the U1/1000 bottom velocity indicates that the pipe has the potential to become stable during the 3 hour storm and most likely is for many Level 3 storm realizations. However, this is not always the case, since the calculations for checking stability at the end of the 3 hours assume the pipe has not broken out of the soil during the entire 3 hours. 3. A pipe which is stable in the U 1/100 velocity at the end of the 4 hour storm build-up, and is also stable in the U 1/1000 velocity at the end of the 3 hour storm, is stable. 4. If there is a large difference in weight coating required to meet both criteria in note 3 it is recommended that a Level 3 analysis be performed to determine stability. 5. In a 3 hour storm period, there is approximately 1 occurence of the U 1/1000 bottom velocity and 10 occurences of bottom velocity whose average is the U 1/100 velocity.

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L2Win - PRCI OBS Level 2 - Version 2.00-00 L2WIN EXAMPLE CASE

Run at 05/29/2003 09:22 +-----------------------------------------------------------------------------------------------------------------------+ | L E V E L 2 P I P E L I N E S T A B I L I T Y - R E S U L T S | |-----------------------------------------------------------------------------------------------------------------------+ | CONCRETE THICKNESS, IN = 3.13 | | SUBMERGED WEIGHT, LB/FT = 135.99 | | SPECIFIC GRAVITY = 1.29 | | | | AFTER AFTER | | EMBEDMENT 4 HR ADD. | | & SOIL STORM 3 HR | | RESISTANCE BUILDUP STORM | | ---------------------------------- ------- -----| | NO. OF WAVES ADDING EMBED. = 12 50 | | PREDICTED EMBEDMENT , IN = 1.7 2.8 | | PASSIVE SOIL RESISTANCE, LB/FT = 69.6 109.0 | | MAX. FRICTION (NO LIFT), LB/FT = 81.6 81.6 | | MAX. TOTAL SOIL FORCE | | (NO LIFT), LB/FT = 151.2 190.6 | | | | NOTES: = | | 1. P. RESIST.(NO EMBED), LB/FT = 33.0 | | 2. INITIAL EMBEDMENT, IN = 1.3 | | 3. MAX. EMBEDMENT ALLOWED, IN = 10.4 |

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+-----------------------------------------------------------------------------------------------------------------------| |STATISTIC|VELOCITY |KUELEGAN |PH. ANGLE| PART. | PART. | DRAG | LIFT | INER. | HORIZ. | VER. SAFETY FACT. | | BOTTOM |AMPLITUDE|CARPENTER| THETA | VELOC. | ACCEL. | FORCE | FORCE | FORCE |S. FACTOR+---------+---------+ |VELOCITY |(FT/SEC) | /ALPHA | (DEG.) |(FT/SEC) |(FPS/SEC)| (LB/FT) | (LB/FT) | (LB/FT) |AT THETA |AT THETA | MINIMUM | +---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+ | STABILITY AT END OF 4 HR STORM BUILDUP | | U(SIG.) | 2.18 | 11./0.40| 35. | 2.7 | 0.53 | 12.0 | 65.0 | 24.3 | 3.09 | 2.09 | 2.09 | | | | | | | | | | | | | | | U(1/10) | 2.77 | 14./0.31| 50. | 2.6 | 0.89 | 17.7 | 91.7 | 41.2 | 1.63 | 1.48 | 1.47 | | | | | | | | | | | | | | | U(1/100)| 3.62 | 18./0.24| 50. | 3.2 | 1.17 | 41.2 | 123.3 | 53.9 | 0.81 | 1.10 | 1.09 | | | | | | | | | | | | | | |U(1/1000)| 4.05 | 20./0.21| 48. | 3.6 | 1.27 | 55.3 | 136.8 | 58.5 | 0.61 | 0.99 | 0.96 | | POTENTIAL FOR STABILITY AT END OF ADDITIONAL 3 HR STORM | | U(SIG.) | 2.18 | 11./0.40| 35. | 2.7 | 0.53 | 11.8 | 63.0 | 23.8 | 4.29 | 2.16 | 2.16 | | | | | | | | | | | | | | | U(1/10) | 2.77 | 14./0.31| 51. | 2.6 | 0.90 | 16.8 | 88.5 | 41.0 | 2.38 | 1.54 | 1.52 | | | | | | | | | | | | | | | U(1/100)| 3.62 | 18./0.24| 48. | 3.3 | 1.13 | 42.6 | 118.3 | 51.2 | 1.28 | 1.15 | 1.13 | | | | | | | | | | | | | | |U(1/1000)| 4.05 | 20./0.21| 50. | 3.5 | 1.31 | 51.6 | 134.4 | 59.2 | 0.99 | 1.01 | 0.99 | +---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+ NOTES: 1. At the end of the 4 hour storm buildup period, a lateral factor-of-safety greater than 1.0 for the U 1/1000 bottom velocity indicates a very stable pipe. However, a lighter pipe may also be stable. 2. At the end of the additional 3 hour storm period, a lateral factor-of-safety greater than 1.0 for the U1/1000 bottom velocity indicates that the pipe has the potential to become stable during the 3 hour storm and most likely is for many Level 3 storm realizations. However, this is not always the case, since the calculations for checking stability at the end of the 3 hours assume the pipe has not broken out of the soil during the entire 3 hours. 3. A pipe which is stable in the U 1/100 velocity at the end of the 4 hour storm build-up, and is also stable in the U 1/1000 velocity at the end of the 3 hour storm, is stable. 4. If there is a large difference in weight coating required to meet both criteria in note 3 it is recommended that a Level 3 analysis be performed to determine stability. 5. In a 3 hour storm period, there is approximately 1 occurence of the U 1/1000 bottom velocity and 10 occurences of bottom velocity whose average is the U 1/100 velocity.

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L2Win - PRCI OBS Level 2 - Version 2.00-00 L2WIN EXAMPLE CASE

Run at 05/29/2003 09:22 +-----------------------------------------------------------------------------------------------------------------------+ | L E V E L 2 P I P E L I N E S T A B I L I T Y - R E S U L T S | |-----------------------------------------------------------------------------------------------------------------------+ | CONCRETE THICKNESS, IN = 3.25 | | SUBMERGED WEIGHT, LB/FT = 148.59 | | SPECIFIC GRAVITY = 1.31 | | | | AFTER AFTER | | EMBEDMENT 4 HR ADD. | | & SOIL STORM 3 HR | | RESISTANCE BUILDUP STORM | | ---------------------------------- ------- -----| | NO. OF WAVES ADDING EMBED. = 12 50 | | PREDICTED EMBEDMENT , IN = 1.8 2.8 | | PASSIVE SOIL RESISTANCE, LB/FT = 74.9 112.5 | | MAX. FRICTION (NO LIFT), LB/FT = 89.2 89.2 | | MAX. TOTAL SOIL FORCE | | (NO LIFT), LB/FT = 164.0 201.7 | | | | NOTES: = | | 1. P. RESIST.(NO EMBED), LB/FT = 36.1 | | 2. INITIAL EMBEDMENT, IN = 1.3 | | 3. MAX. EMBEDMENT ALLOWED, IN = 11.0 |

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+-----------------------------------------------------------------------------------------------------------------------| |STATISTIC|VELOCITY |KUELEGAN |PH. ANGLE| PART. | PART. | DRAG | LIFT | INER. | HORIZ. | VER. SAFETY FACT. | | BOTTOM |AMPLITUDE|CARPENTER| THETA | VELOC. | ACCEL. | FORCE | FORCE | FORCE |S. FACTOR+---------+---------+ |VELOCITY |(FT/SEC) | /ALPHA | (DEG.) |(FT/SEC) |(FPS/SEC)| (LB/FT) | (LB/FT) | (LB/FT) |AT THETA |AT THETA | MINIMUM | +---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+ | STABILITY AT END OF 4 HR STORM BUILDUP | | U(SIG.) | 2.18 | 11./0.40| 35. | 2.7 | 0.53 | 12.0 | 65.4 | 24.6 | 3.41 | 2.27 | 2.27 | | | | | | | | | | | | | | | U(1/10) | 2.77 | 13./0.31| 50. | 2.6 | 0.89 | 17.2 | 92.4 | 41.7 | 1.84 | 1.61 | 1.60 | | | | | | | | | | | | | | | U(1/100)| 3.62 | 18./0.24| 49. | 3.2 | 1.15 | 42.6 | 124.3 | 53.7 | 0.93 | 1.20 | 1.18 | | | | | | | | | | | | | | |U(1/1000)| 4.05 | 20./0.21| 52. | 3.4 | 1.34 | 50.0 | 142.0 | 62.9 | 0.70 | 1.05 | 1.03 | | POTENTIAL FOR STABILITY AT END OF ADDITIONAL 3 HR STORM | | U(SIG.) | 2.18 | 11./0.40| 35. | 2.7 | 0.53 | 11.8 | 63.5 | 24.2 | 4.55 | 2.34 | 2.33 | | | | | | | | | | | | | | | U(1/10) | 2.77 | 13./0.31| 51. | 2.6 | 0.90 | 16.4 | 89.3 | 41.6 | 2.56 | 1.66 | 1.65 | | | | | | | | | | | | | | | U(1/100)| 3.62 | 18./0.24| 48. | 3.3 | 1.13 | 42.9 | 120.1 | 51.9 | 1.37 | 1.24 | 1.22 | | | | | | | | | | | | | | |U(1/1000)| 4.05 | 20./0.21| 50. | 3.5 | 1.31 | 51.9 | 136.3 | 60.0 | 1.07 | 1.09 | 1.07 | +---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+ NOTES: 1. At the end of the 4 hour storm buildup period, a lateral factor-of-safety greater than 1.0 for the U 1/1000 bottom velocity indicates a very stable pipe. However, a lighter pipe may also be stable. 2. At the end of the additional 3 hour storm period, a lateral factor-of-safety greater than 1.0 for the U1/1000 bottom velocity indicates that the pipe has the potential to become stable during the 3 hour storm and most likely is for many Level 3 storm realizations. However, this is not always the case, since the calculations for checking stability at the end of the 3 hours assume the pipe has not broken out of the soil during the entire 3 hours. 3. A pipe which is stable in the U 1/100 velocity at the end of the 4 hour storm build-up, and is also stable in the U 1/1000 velocity at the end of the 3 hour storm, is stable. 4. If there is a large difference in weight coating required to meet both criteria in note 3 it is recommended that a Level 3 analysis be performed to determine stability. 5. In a 3 hour storm period, there is approximately 1 occurence of the U 1/1000 bottom velocity and 10 occurences of bottom velocity whose average is the U 1/100 velocity.

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L2Win - PRCI OBS Level 2 - Version 2.00-00 L2WIN EXAMPLE CASE

Run at 05/29/2003 09:22 +-----------------------------------------------------------------------------------------------------------------------+ | L E V E L 2 P I P E L I N E S T A B I L I T Y - R E S U L T S | |-----------------------------------------------------------------------------------------------------------------------+ | CONCRETE THICKNESS, IN = 3.38 | | SUBMERGED WEIGHT, LB/FT = 161.29 | | SPECIFIC GRAVITY = 1.34 | | | | AFTER AFTER | | EMBEDMENT 4 HR ADD. | | & SOIL STORM 3 HR | | RESISTANCE BUILDUP STORM | | ---------------------------------- ------- -----| | NO. OF WAVES ADDING EMBED. = 12 30 | | PREDICTED EMBEDMENT , IN = 1.9 2.7 | | PASSIVE SOIL RESISTANCE, LB/FT = 80.4 113.1 | | MAX. FRICTION (NO LIFT), LB/FT = 96.8 96.8 | | MAX. TOTAL SOIL FORCE | | (NO LIFT), LB/FT = 177.2 209.9 | | | | NOTES: = | | 1. P. RESIST.(NO EMBED), LB/FT = 39.2 | | 2. INITIAL EMBEDMENT, IN = 1.4 | | 3. MAX. EMBEDMENT ALLOWED, IN = 11.6 |

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+-----------------------------------------------------------------------------------------------------------------------| |STATISTIC|VELOCITY |KUELEGAN |PH. ANGLE| PART. | PART. | DRAG | LIFT | INER. | HORIZ. | VER. SAFETY FACT. | | BOTTOM |AMPLITUDE|CARPENTER| THETA | VELOC. | ACCEL. | FORCE | FORCE | FORCE |S. FACTOR+---------+---------+ |VELOCITY |(FT/SEC) | /ALPHA | (DEG.) |(FT/SEC) |(FPS/SEC)| (LB/FT) | (LB/FT) | (LB/FT) |AT THETA |AT THETA | MINIMUM | +---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+ | STABILITY AT END OF 4 HR STORM BUILDUP | | U(SIG.) | 2.18 | 11./0.40| 36. | 2.6 | 0.54 | 11.4 | 65.7 | 25.5 | 3.73 | 2.45 | 2.44 | | | | | | | | | | | | | | | U(1/10) | 2.77 | 13./0.32| 51. | 2.6 | 0.90 | 16.2 | 92.6 | 42.9 | 2.06 | 1.74 | 1.72 | | | | | | | | | | | | | | | U(1/100)| 3.62 | 18./0.24| 49. | 3.2 | 1.15 | 42.8 | 125.8 | 54.4 | 1.05 | 1.28 | 1.27 | | | | | | | | | | | | | | |U(1/1000)| 4.05 | 20./0.22| 51. | 3.4 | 1.32 | 51.7 | 142.9 | 62.8 | 0.80 | 1.13 | 1.11 | | POTENTIAL FOR STABILITY AT END OF ADDITIONAL 3 HR STORM | | U(SIG.) | 2.18 | 11./0.40| 36. | 2.6 | 0.54 | 11.2 | 64.1 | 25.1 | 4.71 | 2.52 | 2.51 | | | | | | | | | | | | | | | U(1/10) | 2.77 | 13./0.32| 51. | 2.6 | 0.90 | 15.9 | 90.3 | 42.2 | 2.68 | 1.79 | 1.76 | | | | | | | | | | | | | | | U(1/100)| 3.62 | 18./0.24| 48. | 3.3 | 1.13 | 43.2 | 122.0 | 52.7 | 1.42 | 1.32 | 1.30 | | | | | | | | | | | | | | |U(1/1000)| 4.05 | 20./0.22| 50. | 3.5 | 1.31 | 52.3 | 138.5 | 60.9 | 1.12 | 1.16 | 1.14 | +---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+ NOTES: 1. At the end of the 4 hour storm buildup period, a lateral factor-of-safety greater than 1.0 for the U 1/1000 bottom velocity indicates a very stable pipe. However, a lighter pipe may also be stable. 2. At the end of the additional 3 hour storm period, a lateral factor-of-safety greater than 1.0 for the U1/1000 bottom velocity indicates that the pipe has the potential to become stable during the 3 hour storm and most likely is for many Level 3 storm realizations. However, this is not always the case, since the calculations for checking stability at the end of the 3 hours assume the pipe has not broken out of the soil during the entire 3 hours. 3. A pipe which is stable in the U 1/100 velocity at the end of the 4 hour storm build-up, and is also stable in the U 1/1000 velocity at the end of the 3 hour storm, is stable. 4. If there is a large difference in weight coating required to meet both criteria in note 3 it is recommended that a Level 3 analysis be performed to determine stability. 5. In a 3 hour storm period, there is approximately 1 occurence of the U 1/1000 bottom velocity and 10 occurences of bottom velocity whose average is the U 1/100 velocity.

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L2Win - PRCI OBS Level 2 - Version 2.00-00 L2WIN EXAMPLE CASE

Run at 05/29/2003 09:22 +-----------------------------------------------------------------------------------------------------------------------+ | L E V E L 2 P I P E L I N E S T A B I L I T Y - R E S U L T S | |-----------------------------------------------------------------------------------------------------------------------+ | CONCRETE THICKNESS, IN = 3.50 | | SUBMERGED WEIGHT, LB/FT = 174.06 | | SPECIFIC GRAVITY = 1.36 | | | | AFTER AFTER | | EMBEDMENT 4 HR ADD. | | & SOIL STORM 3 HR | | RESISTANCE BUILDUP STORM | | ---------------------------------- ------- -----| | NO. OF WAVES ADDING EMBED. = 12 30 | | PREDICTED EMBEDMENT , IN = 1.9 2.7 | | PASSIVE SOIL RESISTANCE, LB/FT = 86.2 116.3 | | MAX. FRICTION (NO LIFT), LB/FT = 104.4 104.4 | | MAX. TOTAL SOIL FORCE | | (NO LIFT), LB/FT = 190.6 220.7 | | | | NOTES: = | | 1. P. RESIST.(NO EMBED), LB/FT = 42.3 | | 2. INITIAL EMBEDMENT, IN = 1.5 | | 3. MAX. EMBEDMENT ALLOWED, IN = 12.3 |

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+-----------------------------------------------------------------------------------------------------------------------| |STATISTIC|VELOCITY |KUELEGAN |PH. ANGLE| PART. | PART. | DRAG | LIFT | INER. | HORIZ. | VER. SAFETY FACT. | | BOTTOM |AMPLITUDE|CARPENTER| THETA | VELOC. | ACCEL. | FORCE | FORCE | FORCE |S. FACTOR+---------+---------+ |VELOCITY |(FT/SEC) | /ALPHA | (DEG.) |(FT/SEC) |(FPS/SEC)| (LB/FT) | (LB/FT) | (LB/FT) |AT THETA |AT THETA | MINIMUM | +---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+ | STABILITY AT END OF 4 HR STORM BUILDUP | | U(SIG.) | 2.18 | 10./0.40| 36. | 2.6 | 0.54 | 11.4 | 66.1 | 25.9 | 4.05 | 2.63 | 2.62 | | | | | | | | | | | | | | | U(1/10) | 2.77 | 13./0.32| 51. | 2.6 | 0.90 | 15.7 | 93.3 | 43.4 | 2.28 | 1.87 | 1.84 | | | | | | | | | | | | | | | U(1/100)| 3.62 | 17./0.24| 48. | 3.3 | 1.13 | 44.2 | 126.7 | 54.2 | 1.16 | 1.37 | 1.35 | | | | | | | | | | | | | | |U(1/1000)| 4.05 | 19./0.22| 51. | 3.4 | 1.32 | 51.9 | 144.5 | 63.6 | 0.90 | 1.20 | 1.19 | | POTENTIAL FOR STABILITY AT END OF ADDITIONAL 3 HR STORM | | U(SIG.) | 2.18 | 10./0.40| 37. | 2.6 | 0.55 | 10.7 | 64.4 | 26.1 | 4.95 | 2.70 | 2.68 | | | | | | | | | | | | | | | U(1/10) | 2.77 | 13./0.32| 52. | 2.6 | 0.92 | 15.0 | 90.7 | 43.4 | 2.85 | 1.92 | 1.88 | | | | | | | | | | | | | | | U(1/100)| 3.62 | 17./0.24| 48. | 3.3 | 1.13 | 43.5 | 123.8 | 53.5 | 1.51 | 1.41 | 1.38 | | | | | | | | | | | | | | |U(1/1000)| 4.05 | 19./0.22| 50. | 3.5 | 1.31 | 52.6 | 140.4 | 61.8 | 1.19 | 1.24 | 1.21 | +---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+ NOTES: 1. At the end of the 4 hour storm buildup period, a lateral factor-of-safety greater than 1.0 for the U 1/1000 bottom velocity indicates a very stable pipe. However, a lighter pipe may also be stable. 2. At the end of the additional 3 hour storm period, a lateral factor-of-safety greater than 1.0 for the U1/1000 bottom velocity indicates that the pipe has the potential to become stable during the 3 hour storm and most likely is for many Level 3 storm realizations. However, this is not always the case, since the calculations for checking stability at the end of the 3 hours assume the pipe has not broken out of the soil during the entire 3 hours. 3. A pipe which is stable in the U 1/100 velocity at the end of the 4 hour storm build-up, and is also stable in the U 1/1000 velocity at the end of the 3 hour storm, is stable. 4. If there is a large difference in weight coating required to meet both criteria in note 3 it is recommended that a Level 3 analysis be performed to determine stability. 5. In a 3 hour storm period, there is approximately 1 occurence of the U 1/1000 bottom velocity and 10 occurences of bottom velocity whose average is the U 1/100 velocity.

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3.3

L3WIN Examples

The L3WIN.EXE file is used to begin the processor module for the L3WIN software. L3WIN can be executed through Windows (from the Start button or Explorer). Figures 3.3-1 and 3.3-2 are the sample input deck. 3-33 through 3-37 are the input data for the sample case. 3-38 through 3-44 are the output file for this sample case. These consist of Dynamic Nodel Report, Dynamic Beam Report, Dynamic Summary Report and the Statistical Summary Report.

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FIGURE 3.3-1

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FIGURE 3.3-2

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Example Page - Total Dynamic Beam Report – 318 pages

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APPENDIX A COMPARISON OF RESULTS USING L1WIN, L2WIN, and L3WIN

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APPENDIX A - COMPARISON OF RESULTS USING L1WIN, L2WIN, & L3WIN TABLE OF CONTENTS A.1

DESIGN USING L1WIN (TRADITIONAL) A.1.1 DESCRIPTION A.1.2 RESULTS

A.2

ANALYSIS USING L2WIN (STATE-OF-THE-ART STATIC) A.2.1 DESCRIPTION A.2.2 RESULTS

A.3

DESIGN USING L2WIN A.3.1 DESCRIPTION A.3.2 RESULTS

A.4

ANALYSIS USING L3WIN (STATE-OF-THE-ART DYNAMIC) A.4.1 DESCRIPTION A.4.2 RESULTS

A.5

SENSITIVITY ANALYSIS USING L3WIN A.5.1 DESCRIPTION A.5.2 RESULTS

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A.1

DESIGN USING L1WIN (TRADITIONAL)

A.1.1 DESCRIPTION Three pipe sizes (12-inch, 20-inch and 30-inch) were considered, all with 0.50-inch wall thickness. The pipes were assumed to be coated with 5/32-inch dope and wrap corrosion coating (115 lbs/ft3). They were assumed to be empty during the 100-year design event (i.e. gas pipelines). A concrete density of 190 lbs/ft3 was used for all cases, and field joints were assumed to be filled with quick set concrete of the same density. Friction factors of 0.4 and 0.7 were used in the L1WIN designs to represent the soil resistances for pipes on clay and sand, respectively. Two water depths were selected so that wave forces would be felt at the seabed - 200 foot and 300 foot. Two analysis approaches (Cases A and B) were selected for the study: Case A:

representing the "typical" approach in the traditional design, where the design wave height is the significant wave height.

Case B:

using the DnV 1976 approach where 0.70 times the maximum wave height is used. This effectively reduces wave induced bottom velocities by 30%, per the 1976 DnV code.

A total of 24 cases have been performed using the traditional design method. Table A.1-1 summarizes all the assumed input data used in the analyses for both cases A and B. A.1.2 RESULTS A range of concrete thicknesses was analyzed for each case in order to determine the design concrete thickness for which the horizontal factor-of-safety is equal to 1.0. A summary of the resulting concrete thicknesses is shown in Table A.1-2.

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A.2

ANALYSIS USING L2WIN (STATE-OF-THE-ART STATIC)

A.2.1 DESCRIPTION To evaluate the results between L1WIN and L2WIN, the same inputs and assumptions used in the traditional design approach L1WIN are considered to perform the state-of-theart static L2WIN analyses. The summary of input data for this study is presented in Table A.2-1 taking the design concrete thicknesses resulted from L1WIN as benchmarks. For each case of pipe on clay, undrained shear strengths of 20, 50, and 80 psf were utilized to represent a range of very soft to medium soils, whereas relative densities of 0.10, 0.30 and 0.50 were used for loose to dense sands. A total of 72 (24 X 3) cases were analyzed using L2WIN. A.2.2 RESULTS Important results from L2WIN analyses are given in Table A.2-1. Pipe embedment and factors-of-safety of U(1/100) and U(1/1000) after 4-hour storm build-up and additional 3hour storm are listed. Also, plots of the Factor-of-Safety predicted by L2WIN are presented to illustrate the significant differences between the two design approaches.

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A.3

DESIGN USING L2WIN

A.3.1 DESCRIPTION In this study, using the same sea state as in L1WIN Case A, state-of-the-art static L2WIN analyses were performed to determine the required concrete thickness for the three previous pipe sizes resting on the same soil stiffnesses as in Section A.2. A range of concrete thicknesses were selected for each case in order to locate the desired concrete thickness for pipeline stability. Thirty-six (36) cases were considered in this study and are summarized in Table A.3-1. A.3.2 RESULTS Thirty six (36) plots based on the outcome of the analyses were produced, showing concrete thicknesses versus factors-of-safety of U(1/100) after 4-hour build-up, and of U(1/1000) after an additional 3-hour storm. These plots indicate at what concrete thickness the pipe becomes stabile. That is at what point does both U(1/100) and U(1/1000) reach a Factor-of-Safety of 1.0. The second group of plots (12 figures) shows the difference in concrete required using L1WIN case A and B designs, and L2WIN designs. The required concrete is presented as a function of soil strength for each pipe size and water depth.

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A.4

ANALYSIS USING L3WIN (STATE-OF-THE-ART DYNAMIC) CONFIRMATION OF LEVEL 2 EMBEDMENTS

A.4.1 DESCRIPTION To verify the embedments calculated by L2WIN a series of L3WIN analyses were made with a 30-inch pipe to simulate the build-up sea state. The same soil conditions and design sea state as mentioned in earlier sections were used, and the concrete thicknesses were based on the original L1WIN designs. (Reference: Section A.1). A.4.2 RESULTS Table A.4-1 shows the results of pipe build-up embedments for both L2WIN and L3WIN analyses. The results are remarkably consistent and illustrate that the L2WIN embedment predictions are reasonably accurate and conservative for most cases.

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A.5

SENSITIVITY ANALYSIS USING L3WIN

A.5.1 DESCRIPTION Based on the L2WIN designs (Ref.: Plots in Section A.3), four (4) cases were selected to assess the sensitivity of pipe movement to concrete thickness. Three hour simulations were made using L3WIN and a single element pipe model. These cases are summarized in Table A.5-1. A.5.2 RESULTS The movement results are also presented in Table A.5-1, and show that the L2WIN results predict fairly well when pipe movement will occur.

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APPENDIX B INSTALLING AND RUNNING THE SOFTWARE

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APPENDIX B - INSTALLING AND RUNNING THE SOFTWARE B.1

INSTALLING THE SOFTWARE B.1.1 PC Requirements B.1.2 Installation

B.2

OPERATING THE SOFTWARE B.2.1 L1WIN B.2.2 L2WIN B.2.3 L3WIN

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B.1

Installing the Software

B.1.1 PC Requirements To install and run the PRCI pipeline stability software, the following minimum PC requirements are necessary; 1)

486 / 66 MHz PC

2)

16 Mb of RAM;

3)

NT, 2000 and XP

4)

Hard disk with approximately 47 megabytes of free disk space. Plus the disk space for storing case input and output files.

5)

256-color display with 1024 x 768 resolution

6)

CD-ROM drive (for installation)

B.1.2 Installation Use the following steps to install the software; 1)

Start Windows and close any open applications

2)

Insert the “PRCI Pipeline Stability Analysis Software Suite” CD-ROM into your CD-ROM drive.

3)

Click the Start Button and select Run.

4)

Type: [CD Drive]:\setup.exe or select “\setup.exe” on the CD-ROM using the “Window Explorer” feature and press enter.

5)

Follow the instructions on the screen

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The installation file will create the following directory structure;

PRCI Stability L1WIN Project L2WIN Project L3WIN Project

The contents in each subdirectory: Please see Appendix B-1. B.2

Operating the Software

There are (3) Levels of PRCI applications. Namely Level 1 (L1WIN), Level 2 (L2Win) and Level 3 (L3WIN).

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B.2.1 Level 1 The Level 1 application may be accessed by selecting the “L1WIN.exe” from “L1WIN” subdirectory. The Level 1 main form will be displayed as follows:

The Level 1 User’s Manual may be found from selecting the Help/Help Topic Menu.

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B.2.2 Level 2 The Level 2 application may be accessed by selecting the “L2WIN.exe” menu from “L2WIN” subdirectory. The Level 2 main form will be displayed as follows: The Level 2 User’s Manual may be found from selecting Help/Help Topic Menu.

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B.2.3 Level 3 The Level 3 application may be accessed by selecting the “L3WIN.exe” menu from “L3WIN” subdirectory. The Level 3 main form will be displayed as follows:

The Level 3 User’s Manual may be found from selecting the Help/Help Topic Menu.

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Appendix B-1

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APPENDIX C L1WIN– LEVEL 1 - USERS MANUAL

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C.1

L1WIN – LEVEL 1 - PROGRAM DESCRIPTION

L1WIN is a Kellogg Brown & Root (KBR) developed computer analysis tool. It calculates the static stability of an untrenched pipeline against lateral and vertical displacement under wave and current loading. Drag, lift, and inertial forces are considered along with the restraining effect of either cohesive or noncohesive soils. This restraining effect is dependent on the soil friction factor and pipe submerged weight for noncohesive soils, and on the cohesive shear strength and pipe embedment depth for cohesive soils. Any embedment will also reduce the exposed drag area. The program makes the following basic assumptions: •

Airy wave theory and the Morison force formulation apply.

•

A cohesive soil retains its restraining force on the pipe when lift force exceeds the pipe weight.

In open sea and when analyzing hurricane type storms, the short-crested wave approach may be applicable since wave energy will be multi-directional. The direction of wave approach and the component of steady current normal to the pipeline are specified for each analysis. When short-crested theory is used, the force is averaged along the wave front under the crest. The average is taken between the two still waterline crossings of the crest assuming a sine wave for the crest height. Averaging the force in this manner accounts for change in forces along the pipe length, treating the pipeline as a body rather than as a point. Long crested theory is generally applicable when crest lengths are much longer than the pipe length structurally rigid from adjacent pipe, and in areas where the waves have been aligned by shoaling into parallel rays (i.e., near shore where shoali ng occurs or in long fetch driven seas). After reading the input data, the program calculates the wavelength. The wave is then stepped over the pipeline in 10 increments. The pipe stability is checked at each step, and the minimum value of horizontal stability is found. The corresponding water particle motions and forces are saved. The results are then printed.

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C.2

L1WIN – LEVEL 1 – INERFACE DESCRIPTION

C.2.1 L1WIN – LEVEL 1 - Menu Description The users interface for the L1WIN program consists of: File management, Input editor, Program control and Post processing modules. These are broken down into four (4) menu items: File, Run, Report and Help. See Figure C-1 L1WIN Input Form. File Menu

The file menu accesses the file management and program termination functions. The file system uses a project name convention. Project files may be saved under the default “Projects” sub-directory, or at an arbitrary location on the users drives or network.

New

Creates a new file based on program defaults. A default file name, “Untitled” is assigned. The project input must be edited (see the Edit menu item) and saved to a project file before it can be run.

Open

Open an existing project file.

Save AS … Save the existing project file as a different file. Delete

Delete a project file and the associated files. Program will prompt to close any active project before allow to delete a project file.

Exit

Close the active project and quit the program.

Run Menu

Execution once the data has been input.

Run project Run the active project with the input (note input forms must be complete.) Report Menu Output

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Open, view and/or print an existing report. Opens a “View & Print Reports” form that allows viewing and printing of any project report files. “View & Print reports” form has a button options to CLOSE or CANCEL the print reports form, to PRINT ALL REPORTS for the selected project, PRINT the selected report for the selected project and VIEW the selected report for the selected project. There are arrow keys (up and down) that allow changing the VIEW SIZE (zoom feature).

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Option Menu

Controls the operation when the project under execution.

Date stamp When Date stamp menu is checked, the date and time of execution is printed on all output pages. Help Menu Help topic

Provide online helps documents and other information. Opens a “L1Win Help” form that consists of a table of content and list of the topic to be viewed. The “L1Win Help” form may be resized by dragging the frame of the form.

About L1Win Short description of the L1Win application.

Figure C-1 L1WIN Input Form C.2.2 L1WIN - Input Form The input form of the user interface consists of three basic areas. The input area, the message area and the data range area. The information for the input area is used to provide data to run project. The message area provides the information of the input data status. As the cursor moves to each new field the data range area display the description, minimum, maximum and default values of the input field. The information within the pair of the square brackets [ ] is the data item name used in previous (DOS) version. The input area is subdivided into five (5) groups namely: Title, Soil Properties, Pipe Properties, Hydro Properties and Concrete thickness ranges. See Figure C1.

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Title

(optional) allows input of two 80-column lines of arbitrary alphanumeric data. The two lines of title description will be printed on all output pages for identification.

Soil Properties

Defines the soil properties.

Friction

Soil to Pipe Lateral Friction Factor.

Embedment

Pipe Embedment into Soil (in)

Cohesive

Soil Cohesive Shear Strength (psf) May be used in Conjunction with Friction, or Not input For Cohesionless Soil

Pipe Properties

defines the physical characteristics of the pipeline.

Pipe OD

Steel Outside Diameter (in)

Wall thickness

Pipe Wall Thickness (in)

Corrosion coating

Thickness of Corrosion Coating (in)

Density coating

Density of Corrosion Coating (pcf). Defaults to 120 pcf

Density concrete

Density of Concrete Coating (pcf). Defaults to 160 pcf

Density field joint

Density of Field Joint Coating (pcf). Defaults to Density concrete

Cutback

Concrete Coating Cutback (in). Default to 15 inches.

Taper angle

Taper Angle of Concrete (degree) From the Radial Direction

Specific gravity

Specific Gravity of Product (relative to fresh water, 62.4 lb/ft3 )

Hydro Properties

Defines the hydrodynamic parameters to be used in the analysis.

Option

Currently only one (1) option is provided. This field is set to 1.00 and is disable to edit.

Wave angle

Wave Angle of Propagation Relative to the Pipeline (perpendicular to pipe is 90°) (degree)

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Water depth

Water Depth (feet)

Wave height

Wave Height (feet)

Wave Period

Wave Period (second)

Current

Current Velocity normal to Pipeline (ft/sec)

Bndry current

Boundary Layer Height for Current (feet)

Bndry wave

Boundary Layer Height for Waves (feet)

Drag coeff

Coefficients of Drag

Lift coeff

Coefficients of Lift

Mass coeff

Coefficients of Mass

Type of wave crest Select one of the option “Long”, “Short” or “Both” Wave Crest. Defaults to “Long”. Concrete thickness ranges

Defines the concrete coating thickness to be analyzed.

Conc initial

First Concrete Thickness (inches)

Conc final

Last Concrete Thickness (inches)

Conc increment

Concrete Thickness Increment (inches)

Note: L1Win makes a series of run starts from “Conc initial”, then with a uniformly increasing amount of “Conc increment” until the “Conc final” is achieved.

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C.3

OUTPUT The output file can be viewed by clicking the Report Menu that Open a “View & Print Reports” form that allows viewing and printing of any project report files. “View & Print reports” form has a button options to CLOSE the print reports form, to PRINT ALL REPORTS for the selected case, PRINT THIS REPORT for the selected report of the selected case, PRINT THIS PAGE for the current page of the selected report and VIEW the selected report of the selected case. There are arrow keys (up and down) that allow changing the VIEW SIZE (zoom feature). See Figure C-2 VIEW & PRINT REPORTS

FIGURE C-2 VIEW & PRINT REPORTS Close

Close the View & Print Report form and return to the Main form.

Cancel

Close the View & Print Report form and return to the Main form.

Print All Reports

Print all reports of the selected project.

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Print This Report

Print the current report of the selected project.

Print This Page

Print the current page of the selected project.

View Command

View and refresh the display of the selected project.

View Size Command

Change the font size of the display.

Project Command

A drop down list for project selection, if more than one project may be selected.

Select Report Command A drop down list for report selection, if more than one report may be selected Path

Shows the current drive/path of the report located.

Beside the standard Vertical and Horizontal scroll bars, a set of special navigation button is provided to navigate on the displayed report à Move to first page of the report à Move to previous page of the report à Move to next page of the report à Move to last page of the report à Move to the page specified from the “Move to Page “input box (see below). Enter the page number and press the OK button or Cancel if the move is not wanted.

L3Win outp ut includes the drag, lift, and inertial forces acting on the pi9pe at the moment of least stability. The phase location of the wave and the corresponding particle velocities and accelerations normal to the pipe at that point are also printed.

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The explanation of the output table heading: Concrete thickness Pipe sub. weight carried Specific gravity Ph. ang le theta stability occurs. Part. Veloc.

Concrete thickness Pipe submerged weight, including any product being Specific gravity of the line in seawater, including product is being carried. Phase angle of the wave, where minimum horizontal

Sum of normal wave and current velocities, acting at pipe depth for the phase angle. Part. Accel. Normal particle acceleration acting at the pipe depth for the phase angle. Drag force Drag force for the above velocity. Lift force Lift force for the above velocity. Iner force Inertial force for the above acceleration. Horiz S. factor at theta Minimum horizontal safety factor encountered (corresponds to above phase a ngle). It is the quotient of the available soil resistance divided by the sum of the horizontal forces. Ver. Safety Fact. At theta Vertical safety factor corresponding to above phase angle. Quotient of the pipe weight divided by the lift force. Ver. Safety Fact. Minimum Minimum vertical safety factor under the wave, often not at the above phase angle.

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APPENDIX D L2WIN – LEVEL 2 - USERS MANUAL

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D.1

L2WIN – LEVEL 2 - PROGRAM DESCRIPTION

Computer program L2WIN forms the basis for the Level 2 design process. This quasistatic analysis program has been designed to take advantage of the results from the PRCI's hydrodynamic and pipe/soil interaction tests. Whereas the Level 3 dynamic analysis program requires careful development of the input, L2WIN is easy to use. A step-by-step description of the analysis conducted by L2WIN – LEVEL 2 program is as follows: 1.

Based on user inputs, the program calculates values for the design wave height spectral density function. The wave height spectral density function is then transformed to a bottom velocity spectral density function. The area under the bottom velocity spectrum is numerically integrated, and the significant bottom velocity is calculated. The peak frequency of the bottom velocity spectrum is determined.

2.

Maximum and minimum in-line hydrodynamic forces for the largest 200 waves contained in an assumed 4-hour long build-up sea state are calculated (the 4hour long build-up period is considered to start with a zero wave height and to linearly increase with time to the design sea state wave height). The 200 largest waves are characterized by the five wave heights illustrated in Figure 2.2-1 (see Section 2.2). Wave forces for each of the five wave heights are calculated using the PRCI's new hydrodynamic force calculation procedure and the associated database of force coefficients.

3.

Maximum and minimum in-line forces for the largest 50 waves during a subsequent 3-hour long design sea state are calculated as in Step 2 above. These 50 waves are characterized by the four different wave heights illustrated in Figure 2.2-2 (see Section 2.2)

4.

Based on the forces calculated in Step 2, a conservative estimate of pipe embedment at the end of the 4-hour storm build-up period is calculated. This estimate is obtained by subjecting the pipe to 200 small oscillations. The oscillations are limited in amplitude to be no larger than that which the wave forces can produce, or 0.07 times the pipe diameter, whichever is smaller. To simulate the build-up sea state, the smaller waves shown on Figure D-1 are considered first. Not all of the 200 oscillations necessarily produce pipe embedment. Only the waves which produce in-line forces sufficient to overcome frictional resistance between the pipe and soil are considered to produce embedment. For each of the 200 waves, the in-line hydrodynamic force is reduced to account for the pipe embedment just prior to its application. The estimated pipe embedment and the available soil resistance force at the end of the build-up period is then saved for further processing. Pipe embedment and history We Deliver

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dependent soil resistance are calculated using the PRCI's new pipe/soil interaction model. 5.

Based on the forces calculated in Step 3 and the pipe embedment calculated in Step 4, the amount of additional pipe embedment that can be produced by the 50 largest waves in the design sea state, is calculated in a fashion similar to that described in Step 4 for the storm build -up period. This embedment and the associated soil resistance force is saved for further processing.

6.

Hydrodynamic forces for a complete wave cycle are calculated for four levels of bottom velocity which are expected in a 3-hour long design sea state. The four bottom velocities are: U1/3 U1/10 U1/100 U1/1000

7.

= = = =

1.0 Us 1.27 Us 1.66 Us 1.86 Us

Using the soil resistance values obtained in Steps 4 and 5 and the hydrodynamic forces calculated in Step 6, the minimum factor-of-safety against lateral sliding is calculated for the pipe embedment at the end of the 4-hour long build-up period, and at the end of the 3 -hour long design sea state. The minimum factor of safety is calculated from: Factor of Safety =

µ ( W s - F L (t)) + F H F D (t) + F I (t)

The factor of safety is calculated at 1-degree intervals of wave passage for a complete 360-degrees.

The above procedure was adopted after the results of typical analysis using the Level 3 dynamics software were used to calibrate and confirm that the results for pipe embedment are reasonable and that the results are conservative. Calibration of the Level 2 results to those of Level 3 dynamic analysis are presented in Appendix A.4. The pipe embedment developed by the "assumed recent wave history" in steps 2 through 4 above is computed using conservative assumptions which include the following: 1.

no pipe embedment is considered to have occurred until just prior to the design storm,

2.

a short, 4-hour storm build-up period is assumed to precede the design storm during which some pipe embedment is allowed to occur,

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3.

the significant wave height during the build-up period starts at a zero wave height and increases linearly with time to the significant wave height of the design storm (see Figure D-1),

4.

the pipe is considered to undergo only very small oscillations, and thus does not embed as far as it might otherwise.

The Level 2 software provides a better estimate of pipe embedment than static calculations which do not consider the effect of pipe movement, but it does not overestimate the embedment. With these additional features, the Level 2 analysis provides realistic estimates of both hydrodynamic and soil resistance forces during the design sea state. Other assumptions specific to the Level 2 analysis tool are as follows; 1.

Wave induced near sea bed water particle velocities are assumed to have a Rayleigh distribution (ie. similar to the wave height distribution).

2.

Bottom velocity amplitudes are based on a 3-hour storm duration with input spectral parameters.

3.

Soil resistance is based on the PRCI's pipe/soil interaction model which includes a frictional resistance (dependent on the normal force applied to the soil) and a passive soil resistance (dependent upon pipe embedment and independent of instantaneous pipe normal force).

4.

Pipe embedment at the end of the storm build-up period is based on 200 small amplitude cyclic oscillations. The amplitude of the oscillations is limited by the hydrodynamic forces expected from a rapidly developing build-up sea state model.

5.

Subsequent pipe embedment during the design storm is estimated using 50 small amplitude cyclic oscillations of the pipe. The amplitude of these oscillations is also limited by the hydrodynamic force contained in the storm.

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FIGURE D-1 LEVEL 2 BUILD-UP SEA STATE MODEL EMPLOYED TO PREDICT PIPE EMBEDMENT

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FIGURE D-2 LEVEL 2 PROGRAM LOGIC

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These last two assumptions describe the basis for the soil resistance, and detail the conservative estimate of both number and magnitude of oscillations expected to embed the pipe just before the design sea state is encountered. Figure D-3 shows the logic for determining pipe embedment at the end of the b uild-up sea state. Following is a summary of the data requirements; PIPE DATA 1. 2. 3. 4. 5. 6. 7. 8.

Uncoated outside diameter Steel wall thickness Corrosion coating thickness Concrete coating thicknesses to check for stability Concrete coating density Concrete cutback length for field joint Field joint density Pipe roughness

All of these pipe data are used to calculate pipe submerged weight, volume, and drag diameter. These three calculated values are required to determine hydrodynamic and soil resistance forces.

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FIGURE D-3 LEVEL 2 PIPE EMBEDMENT LOGIC

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ENVIRONMENTAL DATA 1. 2. 3. 4. 5. 6. 7. 8.

Significant wave height of design storm Peak period of design storm Mean direction of waves in design storm Standard deviation of wave spreading Near seabed current velocity (perpendicular to pipeline) Soil type (sand or clay) Soil characteristic parameter (Relative density for sands, or undrained shear strength for clays) Reduction factors for partial burial and/or trenches (if any).

These environmental data, along with the pipe data, are used to; 1) 2)

Estimate pipe embedment due to design storm build -up; and Check stability of the pipeline for four statistical wave and current loadings on the pipeline (Us , U1/10 , U1/100, and U1/1000).

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D.2

L2WIN – LEVEL 2 - INPUT INSTRUCTIONS

D.2.1 L2WIN – Menu Description The users interface for the L2WIN – LEVEL 2 program consists of: file management, input editor, program control and post processing modules. These are broken down into four (4) menu items: File, Run, Report and Help. See Figure D-4 L2WIN Input Form. File Menu

The file menu accesses the file management and program termination functions. The file system uses a project name convention. Project files may be saved under the default “Projects” sub-directory, or at an arbitrary location on the users drives or network.

New

Creates a new file based on program defaults. A default file name, “Untitled” is assigned. The project file input must be edited (see the Edit menu item) and saved to a project file before it can be run.

Open

Open an existing project file.

Save AS … Save the existing project file as a different file. Delete

Delete a project file and the associated files. Program will prompt to close any active project before allow to delete a project file.

Exit

Close the active project and quit the program.

Run Menu

Execution once the data has been input.

Run project Run the active project with the input (note input forms must be complete.) Report Menu

Open, view and/or print an existi ng report.

Output

Opens a “View & Print Reports” form that allows viewing and printing of any project report files. “View & Print reports” form has a button options to CLOSE or CANCEL the print reports form, to PRINT ALL REPORTS for the selected project, PRINT the selected report for the selected project and VIEW the selected report for the selected project. There are arrow keys (up and down) that allow changing the VIEW SIZE (zoom feature).

Plot

Opens a “Plot Safety Factors” form that allows viewing a plot of Factor of safety and Embedment to Concrete thickness.

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Option Menu

Controls the operation when the project under execution.

Date stamp When Date stamp menu is checked, the date and time of execution is printed on all output pages. Help Menu Help topic

Provide online helps documents and other information. Opens a “L2WIN Help” form that consist of a table of content and list of the topic to be viewed. The “L2WIN Help” form may be resized by dragging the frame of the form.

About L2WIN Short description of the L2WIN application.

Figure D-4

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L2WIN Input Form

D-10

C.2.2 L2WIN - Input Form The input form of the user interface consists of three basic areas. The input area, the message area and the data range area. The information for the input area is used to provide data to run project. The message area provides the information of the input data status. As the cursor moves to each new field the data range area display the description, minimum, maximum and default values of the input field. The information within the pair of the square brackets [ ] is the data item name used in previous (DOS) version. The input area is subdivided into six (6) groups namely: Title, Soil Properties, Pipe Properties, Hydro Properties, Wave and Concrete thickness ranges. See Figure D-4 L2WIN Input Form. Title

(optional) allows input of two 80-column lines of arbitrary alphanumeric data. The two lines of title description will be printed on all output pages for identification.

Soil Properties

defines the soil properties.

Soil type

Select option to identifying soil type: Sand (cohesionless soil) or Clay (cohesive soil). An input box display the soil type selected (Sand/Clay) with a default value. Make sure to change the appropriate value for the project

Sand/Clay

Soil parameter by which soil is characterized, if SAND parameter is relative density of soil (fractions), if CLAY parameter is cohesive strength of soil (psf)

Embedment

Pipe embedment if pipe embedment is to be input rather than calculated. Embedment = 0 if program is to calculate Embedment Embedment > 0 if input value is to be used (in)

RIMBED

In-line Force Reduction Multiplier at 0.5 Embedment

RLMBED

Lift Force Reduction Multiplier at 0.5 Embedment

RITRCH

In-line Force Reduction Multiplier due to Trench Effects

RLTRCH

Lift Force Reduction Multiplier due to Trench Effects

Pipe Properties

defines the physical characteristics of the pipeline.

Pipe OD

Steel Outside Diameter (in)

Wall thickness

Pipe Wall Thickness (in)

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Corrosion coating

Thickness of Corrosion Coating (in)

Density coating

Density of Corrosion Coating (pcf) Defaults to 120 pcf

Density concrete

Density of Concrete Coating (pcf) Defaults to 160 pcf

Density field joint

Density of Field Joint Coating (pcf) Defaults to Density concrete

Cutback

Concrete Coating Cutback (in). Default to 15 inches.

Taper angle

Taper Angle of Concrete (degree) From the Radial Direction

Specific gravity

Specific Gravity of Product (relative to freshwater, 62.4 lb/ft3 )

Pipe Roughness

Select option of Pipe Roughness: (1) Concrete - Concrete coating, (2) Roughened - Roughened concrete coating (hard bio-fouling) or (3) Very rough - Very rough pipe (soft bio-fouling).

Hydro Properties

Defines the hydrodynamic parameters to be used in the analysis.

Water depth

Water Depth (feet)

Current

Current Velocity normal to Pipeline (ft/sec)

Boundary layer

Boundary Layer Height for Current (feet)

Input type

Select option of Input type: (0) Spectral - the input SPECTRAL parameters are used to determine bottom conditions, or (1) Wave height & Period - the input wave height and period are taken as the near seabed significant oscillatory velocity and peak period, respectively

Use Boundary layer Select option of Use boundary Layer: (0) no or (1) yes Output option

Wave

Select option of Output: (0) Standard output - standard output report or (1) Standard output with plot - standard output report with plot output file for force traces Defines the wave parameters to be used in the analysis.

Wave height

Significant Wave Height (feet)

Peak period

Peak Wave Period (second)

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Spectral peakedness

Peakedness parameter LAMBDA in Ochi-Hubble spectrum

Wave direction

Mean direction of wave propagation (deg) 90? is perpendicular to pipeline

Wave speading

Standard deviation of wave spreading (deg) used in wrapped normal spreading function

Directional spectrum

Select option of directional spectrum: (0) Uni-Modal unimodal directional spectrum or (1) Bi-Modal bimodal directional spectrum. Addition input for BiModal spreading is required if selected.

Bi-Modal Spreading Secondary direction Secondary mean direction for wave spreading (deg) Secondary spreading

Secondary standard deviation of wave spreading (deg)

Mixing constant

Mixing constant for bimodal wave spreading

Concrete thickness ranges

defines the concrete coating thickness to be analyzed.

Conc initial

First Concrete Thickness (in)

Conc final

Last Concrete Thickness (in)

Conc increment

Concrete Thickness Increment (in)

Note: L2WIN makes a series of run starts from “Conc initial”, then with a uniformly increasing amount of “Conc increment” until the “Conc final” is achieved. D.3

OUTPUT

D.3.1 Report output The output file can be viewed by clicking the Report Menu that Open a “View & Print Reports” form that allows viewing and printing of any project report files. “View & Print reports” form has a button options to CLOSE the print reports form, to PRINT ALL REPORTS for the selected case, PRINT THIS REPORT for the selected report of the selected case, PRINT THIS PAGE for the current page of the selected report and VIEW the selected report of the selected case. There are arrow keys (up and down) that allow changing the VIEW SIZE (zoom feature). See Figure D-5 VIEW & PRINT REPOSTS. We Deliver

D-13

FIGURE D-5 VIEW & PRINT REPORTS

Close

Close the View & Print Report form and return to the Main form.

Cancel

Close the View & Print Report form and return to the Main form.

Print All Reports

Print all reports of the selected project.

Print This Report Print the current report of the selected project. Print This Page

Print the current page of the selected project.

View

View and refresh the display of the selected project.

View Size

Change the font size of the display.

Project

A drop down list for project selection, if more than one project may be selected.

Select Report A drop down list for report selection, if more than one report may be selected. We Deliver

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Path

Shows the current drive/path of the report located.

Beside the standard Vertical and Horizontal scroll bars, a set of special navigation button is provided to navigate on the displayed report à Move to first page of the report à Move to previous page of the report à Move to next page of the report à Move to last page of the report à Move to the page specified from the “Move to Page “input box (see below). Enter the page number and press the OK button or Cancel if the move is not wanted.

D.3.1 Plot output The Plot file can be viewed by clicking the Report / Plot Menu that Open a “Plot Safety Factor” form that allows viewing and printing of the plot of Factor of Safety and Embedment. “Plot Safety Factory” form has button options to CLOSE or PRINT (plot) the selected project. The upper graph is factory of safety and the lower graph is the corresponded embedment. Press either left or right mouse button inside the graph area activate a small yellow text window shows the curve values (x, y) at the mouse location. See Figure D-6 Plot Safety Factors.

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FIGURE D-6 PLOT SAFETY FACTORS

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APPENDIX E L3WIN USERS MANUAL

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E.1

L3WIN - PROGRAM DESCRIPTION

Currently, the program can simulate a design storm for up to 101 nodal points. The geometric layout of the pipeline and nodes is shown in Figure E-1. The program consists of top level, user interface for data input, program control, viewing of output and plotting of results and three core program modules: WINWAVE, the Random Wave Generation module; WINFORCE, the Hydrodynamic Force module; and WINDYN, the dynamic simulation module. The Random Wave Generation module WINWAVE simulates water-particle velocity time series that result from wave motion at the sea surface. The time series are simulated at grid points on the sea floor that correspond to the pipeline route. The velocity time series simulated at each pipe node is passed to the hydrodynamic force module. Plot output of the velocities is available and can be referenced to check the simulation output. Based on user input of coated pipe diameter, pipe roughness, current velocity, etc., and the output velocity time series, the WINFORCE program module produces a time series of hydrodynamic drag and lift force at each pipe node. The main assumption behind the program is that the Fourier expansion of the measured drag and lift forces in regular waves, as determined during the PRCI model tests (project PR-170-185), can be used to calculate the forces associated with the individual waves in irregular waves when taking into account the effect of the flow history, the so called "wake effect". The forces are computed for a stationary pipe which is fully exposed (no partial burial). The force time series are passed to the dynamic simulation module. The dynamic simulation module, WINDYN, solves for the dynamic response of the pipe string in the time domain. The pipe model is two dimensional (lateral displacement and rotations in the plane of the lateral displacements). The program uses force time series as the forcing function. Soil resistance forces are calculated based on the PRCI soil model (see Section 4.8). Forces, pipe movements and stresses are output on a timestep-bytimestep basis to both output files and as a database for the post processor. E.1.1 Random Wave Generation Directional Wave Spectra Model The directional wave (sea surface) spectral density, S(f,Θ) is a function of frequency, f, and direction, Θ; and is expressed as the product of two parametric quantities, frequency spectral density, S(f), and D(Θ), the directional spreading function : S(f,Θ) = S(f) D(Θ)

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E-1

FIGURE E-1

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Geometric Layout of Pipeline and Nodes

E-2

where: S(f) = sea surface frequency spectral density D(Θ) = spreading function at frequency, f and by definition, 2π

∫ D(Θ ) dΘ = 1.0 0

This involves a substantial simplification because S(f,Θ) is taken as separable (i.e., the spreading function, D(Θ), is actually only a function of Θ and not of f) over the frequencies where substantial wave energy is present. This assumption is reasonable for wave periods affecting submarine pipelines. Frequency Spectral Density A three parameter generalization of the Pierson-Moskowitz-Bretschneider formula (Ochi and Hubble, 1977) is used for S(f), and the wrapped-normal directional density (Mardia, 1972; Borgman, 1979) is used for D(Θ). This characterizes the sea surface with five input parameters. The original Ochi-Hubble formulation contains six parameters. However the high frequency component contributes little to the pipeline motion and has, therefore, been deleted, eliminating three terms. The formulation of the three-parameter spectral density developed by Ouchi and Hubble is expressed as a one-sided function of radian frequency. This formula may be modified to the two-sided function of cycles-per-second frequency, for -∞ < f < ∞, to obtain,

S(f) =

4 4 2[(4λ + 1) f /4 ] λ σ 2 e - (4λ +1)(f 0/ f ) / 4 0 Γ ( λ )|f |4λ +1

where Γ(λ) is the complete gamma function. By the definition of a two-sided spectral density, the variance of the sea surface elevations is given by

σ2 = ∫

∞ S(f)df = 2 ∫ ∞ 0 S(f)df ∞

The spectral function has a maximum (denoted by S) at f = f0 . This may be verified by differentiating the spectra and setting the derivative equal to zero. Consequently, an expression for S may be obtained by setting f equal to f0

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S =

2[(4λ + 1) / 4 ]λ 2 -(4 λ + 1)/4 σ e Γ ( λ )|f 0 |

This formula depends on three parameters, f0 , σ2 , and λ. The parameters f0 and σ2 have direct geometric interpretations. The parameter f0 is the frequency at which the spectra reaches its maxima. The variance, σ2 , is the area under the spectral density in (-∞, ∞) or twice the area under S(f) in (o, ∞). This leaves λ as a fitting parameter to force the function to have maximum height of S. Lambda, λ, is a mathematical parameter measures which the width of the spectral density function, S(f).and is a function of another more intuitive or geometric parameter called the effective width of the spectrum. Consider the diagram in Figure E-2. The area under the spectral density from (o, ∞) is σ2 /2. The height of the spectra at f=f0 is S(f0 ). The effective width is defined to be the width of the rectangle which is S(f0 ) tall and which equals the area under S(f). The Ochi- Hubble function can represent fairly well many spectral shapes. Very narrow spectra (small δ) give large values of λ. Very broad spectra (large δ) give small values of λ. If λ = 1, the function becomes a form of the Pierson-Moskowitz-Bretschneider spectral density. Directional Spreading Function There are two options available for obtaining the directional spectrum of the sea surface that is needed in the simulation: •

The directional spectrum is generated by using an Ochi-Hubble spectral density function S(f), and a wrapped normal spreading function D(Θ). In this case, values of Co (mean direction) and rD (standard deviation) are read from the input file. (Default)

•

This is similar to Option 0 except D(Θ) is considered to be a mixture of two wrapped normals with a mixing constant applied. In this case, values of Θ, and rD for each normal are read from the input file. (an Advanced Option)

Various spreading function formulas such as the von Mises, the generalized cosinesquared (Borgman, 1978), and the wrapped- normal function can all represent, with about the same accuracy, the spreading function for waves where the function is unimodal and roughly symmetric. Thus, it appears reasonable to use the formula which is most tractable mathematically. The wrapped-normal matches this criteria and is used in the current version of L3WIN.

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OCHI-HUBBLE WAVE SPECTRUM in L3WIN (Double Sided)

S η (f) =

4 4 2[(4λ + 1) f /4 ]λ σ 2 e -(4λ +1)(f o / f ) /4 o Γ (λ )|f |4λ +1

Γ(λ) = Gamma Function Note: For λ = 1, the Ochi- Hubble spectrum is a Pierson-Moskowitz type spectrum ∞

σ = 2 ∫ S η ( f )df = Variance of sea surface elevation 2

0

σ=Standard deviation of water surface elevation H s = 4σ f o = Peak Frequency Tp = 1 f o = Peak Period

Sη(f)

fo FIGURE E-2

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f Ochi Hubble Wave Spectrum

E-5

The wrapped-normal formula may be expressed in two mathema tically equivalent forms.

∞ D( Θ) =

1 + 2π

Σ

2 2 e − n σ D 2 cos(Θ − Θ 0 ) n =1

∞ =

Σ n =1

2 1 [ exp{(- ( θ - θ0 ) - 2 πk )2 / σ }] / 2 π σ D 2 D

If σD < π/3, as is usually the case for storm waves, the second formula (in the exponential form) will have only one term in the summation which is not essentially zero. Thus, the spreading function would then become

e D( Θ) =

−

1 2

 Θ - Θ 0  σ   D  2π σ D

2

providing Θ is restricted to the interval (Θ0 -π, 00 +π). The wave energy is being spread over the various angles by what is functionally equivalent to a normal probability density with standard deviation, σD. In the unimodal option (default), the wrapped normal spreading function is used for D(Θ). The vector of directional spreading values are computed from parametric input based on a central direction, H0 , (direction toward which the waves are traveling) and a directiona l standard deviation, σD. The standard deviation can be directly compared with the corresponding parameter in the usual normal probability density. That is about 2/3 of the energy is contained between Θ0 -σD and Θ0 +σD. The bi- modal option (an advanced feature) is very similar to the unimodal option, except that two wrapped normal spreading functions at each frequency are used. D(Θ) = a D1 (Θ) + (1 - a) D2 (Θ) Here "a" is a selected constant, O < a < 1, and Dj(Θ) are each wrapped normal spreading functions with their own sets of Θ0 and σD values. Input Parameters The values of S(f) and D(Θ) are developed in the program as two vectors NF and NT long, respectively. Here NF denotes number of frequencies and NT is the number of theta values. Frequency is expressed in cycles per second, or Hertz, and Θ is in degrees.

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The frequency increment is DF, representing ∆f, and the angle increment is DR, standing for ∆Θ. The number of terms in the simulated wave time sequence is N. As an advanced option, this value can input directly (rather than generated by the pre-processor) and must be an integer power of 2, (i.e. N=2K). If not, the value is rounded down to the next lowest integer power of 2. The time increment, DT, can also be directly input, and since DT=1.0/(N*DF); this also fixes the frequency internal, DF. The aforementioned relation is required by the fast Fourier transform algorithm used in the simulation. The cut-off frequency, FC, can also be input. Given the cut-off frequency, FC, and the frequency interval, DF, the number of frequencies, NF is defined. NF = (DF) (FC) The value of NF must satisfy two requirements. The values of NF and DF must be selected so that : (1) S(F,Θ) is negligible (close to zero) for f > NF*DF, and (2) NF must be less than half of N, where N is the length, or number of terms, in the time series of wave properties being simulated. For stability of the fast fourier transform applied in the wave generation module, the product of M, DT and FC must be less than 4095.5 to ensure convergence. This is satisfied automatically with values chosen by the pre-processor, but must be enforced if the values are input. As an advanced option, the number of theta values, DT, can be directly input. The values of DT and NT are chosen so that NT* DT is a full circle, 360°. The default option sets DT to the maximum value allowed by the program, 24. Other input parameters are covered in sufficient detail in the input instructions.

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E.1.2 Hydrodynamic Force Calculation Decomposition of Irregular Waves By decomposing a time series of bottom wave velocities in irregular waves into zeroupcrossing and zero-downcrossing half- wave cycles it is possible to define local wave parameters, such a the KC-number and the Current ratio, a, see Figure E-3. The halfwave cycle is by no means sinusoidal. It is, however, treated as a regular wave with an amplitude equal to the maximum absolute value of the observed velocity during the corresponding upcrossing or downcrossing half-wave cycle, and with a wave period equal to twice the half- wave period. The non-dimensional wave parameters are thus calculated as: 2 • | U w1| • T1 / 2 Uc KC1 = , α1 = D |U w1| KC 2 = .

.

KCn =

2 • | Uw2 | • T2 / 2 , D .

.

2 • |Uwn | • Tn / 2 , D

α2 =

Uc |U w2 |

. αn =

Uc |Uwn |

where n is the total number of half-wave cycles, Uw the maximum wave velocity, T/2 the half- wave period, and Uc is the steady current, which is assumed constant for all n. The steady current, Uc applied when calculating the local current ratio, α, is the mean current over one pipe diameter. This value may either be given directly (default) or it may be calculated based on an assumed logarithmic velocity profile. In the present version a procedure is included which is based on the calculations performed by the Current Complex Model (PRCI PR-169-186). In this case the bottom friction must be given as input in terms of a drag coefficient in addition to the steady current at a reference level 1 m above the sea bed. Force Calculation The hydrodynamic forces during the first part of half period No. 2 are mainly determined by the reversal of the wake created in the previous half period, No. 1. The properties of this wake are determined by the parameters associated with half period No. 1, and the forces in the first part of half period No. 2 are then those associated with a regular wave corresponding to half wave No. 1. For the remainder of half period No. 2, the flow (and hence the forces) correspond to those associated with the regular wave defined by the parameters of half period No. 2, i.e. KC2 = U2 •T2 /D and α 2 = Uc/U2 .

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FIGURE E-3

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Decomposition of irregular waves into single regular waves

E-9

In PR-170-185 it was found that the Fourier decomposition method was superior in predicting the hydrodynamic forces associated with regular waves (with or without steady current). This method is therefore applied to calculate the forces corresponding to the single half regular waves. The force model reads in analytical format: t' < t < t' + 0.25 T2 /2 : 5 2 1 F = ρ D U • {Co 1 + ∑ Cn1 • cos n(ω 2 t + φ n1)} 1 2 1

t' + 0.25 T2 /2 < t < t' + T2 /2: 5 2 1 F = ρ D U • {Co 2 + ∑ Cn2 • cos n(ω 2 t + φ n2)} 2 2 1

Here t' is the time for the zero-crossing at the start of half period No. 2. Co1 , C11 .... C51 , and Φ o1 , Φ11 .... Φ51 are the Fourier coefficients and phases related to the force associated with the regular wave defined by KC1 and α1 . Similarly, Co2 , C12 .... C52 and Φ12 , Φ22 ... Φ 52 are those associated with the force determined by the second half wave. ω2 is the cyclic frequency of the half period No. 2, i.e. ω2 = 2π/T2 . In summary, the forces in the half period No. 2 are in the first 25 per cent of the time found as those associated with a regular wave flow defined by the parameters of the previous half period (No. 1) and for the latter 75 per cent of the time by the forces associated with the present half wave (No. 2). The equations given above apply to the in- line drag force and the lift force components, with different sets of coefficients and phases. The total in- line force is found by adding the inertia term,

2 F I = π ρ D C M ⋅ a(t), taking CM = 3.29. 4 In the PR-170-185 project it was demonstrated that this force prediction model yields accurate time series for in- line as well as lift forces.

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Data Base In the present version, the data base contains Fourier coefficients for relative pipe roughness, k/d = 10-3 , 10-2 and 5*10-2 and for test conditions as outlined in Table E-1 below. KC

Current Ratio: α u

Number

0.10

2.5

1

4.5

1

5.0

1

10

1

12

1

15

1

17

1

20

1

25

1

30

0.16

0.32

0.48

0.64

0.80

0.96

1.20

1.60

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

40

1

1

1

1

1

1

1

1

50

1

1

1

1

1

1

1

55

1

60

1

1

1

1

1

1

65

1

70

1

1

1

1

1

75

1

80

1

100

1

120

1

140

1

160

1

Table E-1

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Fourier Coefficients for Regular Waves and Regular Waves with Steady Current E-11

The content of the data base is illustrated in Figure E-4 below, showing a plot of the Fourier coefficients and phases.

Figure E-4

Plot of data base content, amplitudes and phases of drag force as a function of the current ratio,α for KC = 40.

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Within the ranges listed in Table E-1, linear interpolation has been applied. For local KC-numbers and current ratios beyond these ranges various extrapolation routines have been adopted as follows: a.

Extrapolation beyond max. KC for α = 0

Drag: for KC > 160 CDi, φDi = CDi, φ Di for KC = 160 Lift: for KC > 160 CLi, φLi = CLi, φLi for KC = 160 b.

Extrapolation beyond min. KC for α = 0

Drag: for KC = 0 CDi, φDi = 0 Linear interpolation is used between CDi, φ Di at KC = 2.5 and CDi, φ Di at KC = 0. Lift: for KC < 2.5 CLi, φLi = CLi, φLi for KC = 2.5 c.

Extrapolation beyond max. KC for α > 0

Drag: Estimates have been made on CDi, φ Di for KC = 100 and 160 based on results for α = 0. Linear interpolation is then performed between KC = 70, 100 and 160. for KC > 160 CDi, φDi = CDi, φ Di for KC = 160 Lift: A similar approach is made for CLi, φ Li

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d.

Extrapolation beyond min. KC for α > 0

Estimates have been made on CDi, φ Di for KC = 2.5 and 5 based on results for α = 0 for KC = 0 CDi, φDi = 0 Linear interpolation is then used between CDi, φ Di at KC = 2.5 and CDi, φ Di at KC = 0 For 2.5 \ KC \ 10 linear interpolation is used. Lift: Estimates have been made on CLi, φ Li for KC = 2.5 and 5 based on results for α = 0 for KC < 2.5 CLi, φLi = CLi, φLi FOR KC = 2.5 For 2.5 \ KC \ 10 linear interpolation is used. e.

Extrapolation beyond max. α > for given KC

Drag: CDO = CD (1/2 + α 2 ) CD1 = C D (2α) CD2 = 1/2 CD CD3 = C D4 = CD5 = 0

for α > 2.0 for α > 3.0 for α > 3.0 for α > 3.0

Where CD is the drag coefficient found from the least-squares-fit analysis of the model tests at α = max. α. Linear interpolation is used between max. α given in Table E-1 and α = 2 and 3, respectively, as given above. For α > max. α in Table E-1 φ Di = φ Di at max. α. Lift: A similar approach is made for CLi, φ Li, i.e.: CL0 = C L (1/2 + α2 ) for α > 2.0 CLi = CL (2α) for α > 3.0 CL2 = 1/2 CL for α > 3.0 CL3 = C L4 = CL5 = 0 for α > 3.0 Where CL is the lift coefficient found from the least-squares- fit analysis of the model tests at α = max. α. For α > max. α in Table E-1 φ Li = φ Li at max. α.

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E.1.3 Pipe Dynamics Simulation Basically L3PIPDYN solves the Euler-Bernoulli equation for bending of a uniform beam under tension. Finite beam elements (with cubic shape functions) are used to model the pipeline, and the Newmark numerical integration scheme is use to integrate the nonlinear equations of motion. At each time step an interactive procedure is used to satisfy dynamic equilibrium. Specifically, the Euler-Bernoulli equation...

EIu"" - T e u" + Cu& + m && = q a (x,t) + q s (s,t) + qh (x,t) is reduced to .. . [M]{U} + [C]{U} + [K]{U} = {R} where:

[M] is the inertia matrix [C] is the proportional damping matrix [K] is the stiffness matrix {U} is the vector of nodal deflections {R} is the resultant load vector

and solved at each incremented timestep using the Newmark method [K]{Ut+Dt } = {Rt+Dt } where:

[K] is the effective stiffness matrix = [K] + a1 [M] + a2 [C] {Ut+Dt } is the vector of nodal deflections at time t+Dt {Rt+Dt } is the resultant load vector at time t+Dt a1 , a2 are integration constants.

An interative procedure known as "Successive substitution" is used at each timestep until convergence is reached at each timestep. [K i]{Ui+1 } = {Ri} where the superscript i denotes the "i"th iteration. The program was originally developed during project PR-175-420, and the details of the program can be found in the final report for that project. The basic programming is the same; however, many modifications regarding the hydrodynamic and soil models have been incorporated. See Section 3.5 and 4.8 in Volume 1 and F.1 in Volume 2 for details of the hydrodynamic and soil models now incorporated in L3PIPDYN.

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Convergence Criteria The convergence parameter at the kth iteration, GK(I), is defined as NC ∑ [ U K (I, J) - U K-1 (I, J) ]2 G K (I) = [

J=1

1

NC*|U max (I)|

]2

where: I = degree of freedom (D.O.F.), NC = number of nodes, UKmax = maximum of deflection at iteration K in D.O.F. I, UK(I,J) = deflection of node J in D.O.F. I Convergence is assumed when : GK(I) < EPS for I = 1, 2

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E.2

L3WIN - INTERFACE DESCRIPTION

E.2.1 L3WIN - Menu Description The users interface for the L3WIN program consists of: file management, a top level input editor, program control and post processing modules. These are broken down into five (5) menu items: File, Edit, Run, Report and Plot.

File Menu

The file menu accesses the file management, printing and program termination functions. The file system uses a case name and case numbering convention. This allows a case or project name to be designated with multiple cases grouped easily under one identifiable case name. Case numbers may be set sequentially or arbitrarily depending upon the user. Case files may be saved under the default “Projects” sub-directory, or at an arbitrary location on the users drives or network.

New Case

Creates a new case file based on program defaults. The case file input must be edited (see the Edit menu item) before it can be run.

Open Case

Open an existing case file.

Save AS …

Save the existing case file as a different file.

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Delete Case

Delete any case and associated files. Program will prompt to close any active case before allowing to delete a case.

Print Report

View and print any report file (see Report Menu).

Exit

Close active cases and quit the program.

Edit Menu

Activates the input form for the present case (note a case must be active). For details on the input form, see Section E.2.2 below.

Run Menu

Provides program status and execution once the data has been input.

Status

Lists case files status information and any warning or error messages

Case

Run the existing case with the input (note input forms must be complete.)

Statistical

Run the case multiple times with several (up to 10) independent analysis with different random seeds for the wave generation module (different realizations of the design storm.) Limited statistical information is retained for these cases (runs) for comparison in report and plots (lateral and vertical factors of safety, position, stress and embedment.)

Special

Run an existing case with limited changed information. This allows the user to change information that is not required for the wave generation or hydrodynamic force modules and re-run the case without re-generating the design storm and associated hydrodynamic force time series. A common use of this feature is to re-run a pipe with a slightly different submerged weight (without changing pipe O.D. or drag O.D. (coating thickness).

Report Menu

Open, view and/or print an existing report. Opens a “Print Reports” form that allows viewing and printing of any case report files. “Print reports” form has a button options to CLOSE the print reports form, to PRINT ALL REPORTS for the selected case, PRINT THIS REPORT for the selected report of the selected case, PRINT THIS PAGE for the current page of the selected report and VIEW the selected report of the selected case. There are arrow keys (up and down) that allow changing the VIEW SIZE (zoom feature). There are also input areas that allow selection of the case, report file and changing path to select different cases.

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Plot Menu

Controls the generation, viewing and printing of output data plots.

Velocity Plot Opens a plot window and displays the velocity time series output from the random wave generation module. Shown in the center of the plot is a bar indicating the magnitude of the contribution of the steady current velocity. The plot window will automatically scale and break the plot up into a number of pages to ensure adequate resolution of the time series (note if resolution is not desirable the same data may also be plotted through the PLOT\Pipeline Dynamic menu item.)

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The velocity plot window has button options to CLOSE the plot window, view the PREVIOUS and NEXT page of the time series plot, PRINT the current page of the time series plot and PRINT ALL pages of the time series plot. There is also an input area for selection of the node at which to display the time series.

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HydrodynamicOpens a plot window and displays the raw (static pipe) lift and drag forces output from the hydrodynamic force module at top half of the page and a velocity time series plot on the bottom half of the page. This plot is useful to illustrate the velocities and the resultant hydrodynamic forces. The plot window will automatically scale and break the plot up into a number of pages to ensure adequate resolution of the time series (note if resolution is not desirable the same data may also be plotted through the Plot \ Pipeline Dynamic menu item.) The Hydrodynamic Plot window has button options to CLOSE the plot window, view the PREVIOUS and NEXT page of the time series plot, PRINT the current page of the time series plot and PRINT ALL pages of the time series plot. There is also an input area for selection of the node at which to display the time series.

Pipeline Dynamic Opens a Dynamic Plot selection window that controls the data to be shown on the plot, scope (time series) of the plot, the desired number of pages for scaling of the plot and the node for which the data is to be plotted. The Dynamic Plot selection window has: Select curves to be drawn : a button menu to select which data time series are to be drawn from: Position, Fluid Velocity, Pipe Embedment, Total Soil Resistance, Modified (with pipe moving)

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Lift and Drag Forces, Unmodified (static pipe) Lift and Drag Forces, Vertical and Lateral Factors of Safety. A second button selection box will appear in front of the selected time series to allow specification of the primary plot (y-) axis. Plot Format : X- axis (Plotting Time Period) : Specifies the start and end times for the plot (in mmm:ss format). Defaults to the entire time series. Y-axis: Controls the automatic y-axis scaling to either the maximum and minimum of the entire time series or the maximum and minimum of the selected time interval. Number of page : Sets the number of pages to scale the selected time series plot. DRAW Button : Generates the plot and opens a Dynamic Plot window to view and print the resulting plot selection. There is an input area for selection of the Node at which to display the time series. CHECK ALL and UNCHECK ALL Buttons : Selects and deselects (respectively) all data time series to be plotted. Factor of Safety Cap : Factors of safety get large as the lift and drag forces reverse (when force is zero, the instantaneous factor of safety goes to infinity.) Thus, the user can specify a cap on the maximum value of factor of safety to be displayed to obtain the desired resolution of the data. CHANGE COLOR Button : Allows the user to change the plotted color of the plot selected as the primary plot (in the curve selection area.)

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The dynamic plot window (opened once the DRAW button has been selected) has button options to CLOSE the plot window, view the PREVIOUS and NEXT page of the time series plot, PRINT the current page of the time series plot and PRINT ALL pages of the time series plot.

Stress and Deflected Plot Opens a plot window to display the stress and deflected configuration output data. These data series are ‘snap shots’ of the instantaneous stress and deflected position of the entire model at selected times. These times are specified in the input form Output Control tab under the Plot Times selection. These configurations can be either displayed as a animated series (where the program flips through the plots to create a ‘movie’), or as individual snapshots. The animation or display times are selected in an input form at the top of the page. START ANIMATION or PRINT Button : This button will begin the animation if the Animation option is selected or will print the present plot if a time series is selected. Time Display : For the Animation option, the current time is displayed for each slide in the animation.

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Animation Delay : The rate of the animation can be controlled from 6.25 (very fast) to 3200 (rather pedestrian). Zoom : There is a input form to control the Zoom of the plot from 25% to 100%. This controls the scaling of the pipe deflection during an animation.

Statistical

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Opens a plot window and displays the statistical summary data in a plot format. The statistical summary plot consists of: • Minimum Lateral Factor of Safety • Minimum Vertical Factor of Safety • Maximum Position • Final Embedment • Maximum Stress.

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for all nodes and (for a statistical summary) for all analysis. This plot is automatically formatted onto a single page or multiple pages depending upon internal criteria.

The statistical plot window has button options to CLOSE the plot window, view the PREVIOUS and NEXT page of the statistical plots, PRINT the current page of the plot and PRINT ALL pages of the statistical plots. E.2.2 L3WIN - Input Form The input form of the user interface (accessed with the EDIT menu item) consists of three basic input pages and two advanced input pages. The input pages are separated by category of input: Case Definintion, Soil, Wave and Current, Output Control, Parameters & Simulation Time, Boundary Condition. The information for these input pages is used for all program modules.

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CASE DEFINITION Tab

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This input tab defines the case title, simulation duration, unit system, pipe properties (size, weight, length, etc.) and water depths.

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Case Title

Allows input of two 80 column lines of arbitrary alphanumeric data.

Simulation Duration

Total duration for the dynamic simulation of the design storm. Based on limitations of the Random Wave Gene ration module, durations can be up to 1000 cycles (based on peak period).

Unit

Default units for the input and output can be selected as either ‘English’ (pounds, feet and inches), or ‘Metric’ (kilograms, meters and millimeters). Toggling the selection will convert the units between the selections. Note: all internal calculations are done in English units with the results converted for input and output.

Pipeline Parameters Outer Diameter (Steel)

Pipeline (steel) outer diameter (in inches or millimeters.) May be input using the Pipe Weight Calculator option (see description below.)

Wall Thickness (Steel)

Pipeline (steel) wall thickness (in inches or millimeters.) May be input using the Pipe Weight Calculator option (see description below.)

Drag Diameter (coated O.D.)

Total diameter including all coatings (corrosion, weight, etc.) (but not including embedment.) May be input using the Pipe Weight Calculator option (see description below.)

In Air Weight

Average total weight of the pipeline (including all coatings and contents) in air per unit length of pipe. May be input using the Pipe Weight Calculator option (see description below.)

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Submerged Weight

Average total submerged weight of the pipeline (including all coatings and contents) per unit length of pipeline. May be input using the Pipe Weight Calculator option (see description below.)

Internal Pressure

Internal pressure, assumed constant along the pipeline axis. (Defaults to zero.)

Young’s Modulus

Young's modulus of elasticity. The program uses the default values of 30x106 psi or 20.68x1010 N/m2 depending on the units.

Pipe Roughness

Characteristic pipe roughness (three choices): • Smooth concrete, • Hard fouling on pipe (barnacles), or • Soft fouling (marine growth), used in the hydrodynamic drag calculations.

Pipeline Length

Total length of pipeline to be analyzed. If only a section of pipe is to be analyzed for stability (similar to a Level 2 analysis) a unit length of pipeline (a one foot or one meter segment of pipe) is sufficient.

Number of Pipe Nodes

Number of nodal points in the finite element model (maximum value for NC is 101, i.e. 100 elements.) If only a section of pipe is to be analyzed for stability (similar to a Level 2 analysis) a two node model (single element) is sufficient.

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Water Depth Parameters

Water depth at End 1 and End 2 of the pipe.

Pipe Weight Calculator

Activates a simple pipe calculation routine which accounts for pipe weight, coatings, field joints, water absorption into the concrete and internal contents to yie ld: Outer Diameter (steel), Wall Thickness (Steel), Drag Diameter (coated O.D.), In Air and Submerged Weights and Specific Gravity of Pipe w/ Product

Pipe Size Outer Diameter (Steel)

Pipeline (steel) outer diameter (in inches or millimeters) with scrollable list based on API 5L.

Wall Thickness (Steel)

Pipeline (steel) wall thickness (in inches or millimeters) with scrollable list based on API 5L.

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Corrosion Coating

Coating Thickness and Density with scrollable lists and densities of some common coating materials.

Concrete

Coating Thickness and Density with scrollable lists and three common concrete densities.

Field Joint

Field Joint Thickness and Density with scrollable lists and two common field joint materials. Defaults to no field joint material.

Other Steel Density

Scrollable list with three common steel density values. The first value (489.535 pcf or 7841.685 kg/m3 ) is a best fit of API 5L values for pipe weights.

Field Joint Cutback Length

Scrollable list with common concrete cutback lengths (from each end of pipe).

Pipe Joint Length

Average pipe joint length.

% Water Absorption

Amount (in percent) of Water Absorption into the concrete coating.

SG of Product

Allows specification of internal contents for either liquid (S.G. based on fresh water density, 62.4 pcf (999.52 kg/m3 )) or gas (S.G. based on air density, 0.07 pcf.(1.1 kg/ m3 ))

Calculated Results Drag Diameter (coated O.D.)

The total O.D. of the pipe with all coatings. The Drag Diameter is calculated as: Drag Diamete

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=

Outer Diameter (steel)

Corrosio

+

Coating Thicknes

+

Concrete Coating Thicknes

In Air Weight

The in-air weight is calculated as the average total of the pipe weight, coating weight, concrete coating weight without field joints and with water absorption, field joint weight and the internal contents (product weight.) The ratio of field joints and concrete coating is specified with the cutback length and pipe joint length.

Submerged Weight

The submerged weight is calculated as the in-air weight minus the buoyancy of the coated pipe (Drag O.D.) in seawater with a density of 64.0 pcf (1025.1 kg/m3 .)

Specific Gravity of Pipe w/ Product

The specific gravity is presented for information purposes only. The specific gravity is calculated as ratio of the in-air weight of the pipe to buoyancy force.

CALC Button

The CALC button must be selected to output results.

PASTE Button

Results from the pipe weight calculator may be pasted into the PIPE PROPERTIES section of the input by using the PASTE button.

CANCEL Button

The analysis may be canceled without pasting the information into the PIPE PROPERTIES section of the input by selecting the CANCEL button.

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SOIL, WAVE & CURRENT Tab

This tab defines the soil conditions, current and wave parameters and sets the random seed (for the Random Wave Generation module.)

Soil Resistance Number of Soil Resistance Groups

The soil conditions can be varied over the length of the pipeline. The user may input up to a maximum of 10 different soil groups.

Beginning Node

Beginning node number for the soil group.

Ending Node

Ending node number for the soil group.

Soil Type

Sand soil and clay soil models are available. The User Soil models may be selected if the Advanced feature is enabled and the User Supply Soil Model routine is selected (see below.)

Sandy Soil Relative Density

Relative density (DR in fractions) of the sandy soil.

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Clay Soil Shear Strength

Undrained shear strength, Su, (in psf or kg/m2 ), of the clay soil.

Pipe Embedment

If positive, ZMAX represents the limiting pipe embedment into the soil; if negative, ZMAX represents the actual pipe embedment at the start of the run.

Inline Force Reduction due to Embedment

Maximum inline force reduction due to pipe embedment (0.313 clay, 0.68 sand.) See Volume 1, Section 3.5.5 and Figures 3.5.9

and 3.5.10 for more detailed information. Lift Force Reduction due to Embedment

Maximum lift force reduction due to pipe embedment (0.5 sand and clay) See Volume 1, Section 3.5.5 and Figures 3.5.9 and 3.5.10 for more detailed information.

Inline Force Reduction Due to Trench

Maximum inline force reduction due to trench geometry. See Volume 1, Section 3.5.5 and Figures 3.5.11 and 3.5.12 for more detailed information.

Lift Force Reduction Due to Trench

Maximum lift force reduction due to trench geometry. See Volume 1, Section 3.5.5 and Figures 3.5.11 and 3.5.12 for more detailed information.

Ochi-Hubble Wave Spectrum Significant Wave Height

Significant Wave Height (ft or m)

Peak Wave Period

Peak Wave Period (sec)

Peakedness Parameter LAMDA

Peakedness parameter LAMDA in OchiHubble spectrum

Wrapped Normal Directional Distribution Mean Direction of Wave Propogation

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Mean direction of wave propagation (deg) 90° is prependicular to pipeline

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Wave Spreading Standard Deviation

Standard deviation of wave spreading (deg) used in wrapped normal spreading function (1° min)

Current Parameters

Choice of two options for current calculation method: • Use input current as current for Force Simulation (recommended.) • Integrate Input Current Using Logrithmic Boundary Layer (use Seabed Roughness.)

Current Velocity

Steady current velocity normal to pipe (ft/sec or m/s)

Seabed Roughness

Seabed roughness (ft or m) for use in logarithmic boundary layer

Random Seed

Random Seed (used to generate random phase angles to assign each wave frequency)

User Supply Soil Model Routines

(ADVANCED option) User must supply the “SOILCON” and “SOILUSER” subroutines and “LINK” them properly before selection of this option. Otherwise, unpredictable results can happen. For further details see Section E.3.

Beginning Node

Beginning node number for the soil group. Should match the groups specified under Soil Resistance.

Ending Node

Ending node number for the soil group. Should match the groups specified under Soil Resistance.

Parameter 1 (to 4)

Value of the first user defined soil parameter across that soil group. Parameters do not have to be used. For further details see Section E.3.

Parameter 2

Value of the second user defined soil parameter across that soil group.

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Parameter 3

Value of the third user defined soil parameter across that soil group.

Parameter 4

Value of the fourth user defined soil parameter across that soil group.

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OUTPUT CONTROL Tab

Controls the frequency of the print and plot output.

Print Nodes Nbr of Nodes

The total number of nodes whose deflections, velocities, accelerations, and soil-resistance loads will be printed every ITPR time steps to the output file. This part of the output can be large for many time steps. For long simulation runs, this should be set to zero, suppressing this part of the output. MAXIMUM NUMBER OF NODES FOR OUTPUT is 50.

node list

List containing the nodes numbers whose deflections, velocities, accelerations, and soil-resistance loads are to be printed, every ITPR time steps.

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Print Beam Elements Nbr of Beams

The total number of beam elements whose dynamic loads and stresses will be printed every ITPR time steps to the output file. This part of the output can be large for many time steps. For long simulation runs, this should be set to zero, suppressing this part of the output. MAXIMUM NUMBER OF BEAMS FOR OUTPUT is 50.

node list

List containing the beam element numbers whose dynamic loads and stresses are to be printed, every ITPR time steps.

Plot Nodes Nbr of Nodes

The total number of nodes whose deflections embedment, forces, stresses, tension and factors of safety will be written to a plotfile every ITPR time steps, for plotting. This part of the output is recommended for long simulation runs whether or not plotting is planned. MAXIMUM NUMBER OF NODES FOR OUTPUT is 50.

node list

List containing the nodes whose deflections, etc. will be written to a plotfile every ITPR time steps.

Plot Times Nbr of Times

The total number of times at which the deflected configuration and stress configuration of the pipeline will be written on plotfile. This provides a series of instantaneous ‘snapshots’ of the pipe condition. The maximum value of NPT is 100.

time list

List containing the times at which the pipeline deflected configuration (deflection of all nodes) and stress configuration (stress of all beams) are to be written on plotfile.

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Print Control ITPR

A print control integer. ITPR is the number of time steps at multiples of which deflections, velocities, accelerations, soilresistance loads, beam element loads, and stresses are printed. Example: If ITPR = 4, and Dt = 0.25 sec, printing occurs at t = 1.0, 2.0, 3.0, ... sec.

print control

Three options for print output: • Printing occurs only at convergence (every ITPR time steps). • Results for pipeline deflections, velocities, accelerations, and soilresistance loads are printed at each iteration. • Minimal print (default) only history dependent information is printed at each wave 1/2 oscillation where embedment changes.

Print Half Wave Cycle

Two options for print output: • Printing is suppressed for 1/2 wave cycles. • History dependent information is printed at each wave 1/2 oscillation.

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PARAMETER & SIMULATION Tab

(ADVANCED Option) Controls the simulation times and timesteps for each analysis module, Bi-Modal Wave Spreading and Dynamic Simulation Parameters

Wave Time Series Number of Time Steps

List to specify the number of timesteps for the Random Wave Generation module (due to computational format should be 2 raised to a power with 8192 as the maximum)

Time Step Increments

Timestep Size for Random Wave Generation module (sec), N*DTIME = simulation time

Highest Frequency

High Frequency Cutoff (1/sec), highest frequency with non-negligible energy. N*DTIME*FC < 4095.5

for numerical stability.

Hydrodynamic Force Calculation Time Series

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Start Time

Start time for the Hydrodynamic Force module time series (min).

End Time

End time for the Hydrodynamic Force module time series (min).

Time Step Increment

Timestep Size for Hydrodynamic Force module (sec)

Pipe Dynamic Simulation Time Series Number of Time Steps

Number of timesteps for the Pipe Dynamic module.

Time Step Increments

Time step size (sec) used in the numerical integration (Newmark) method. If a negative value for DT is used, the program to select an appropriate value for DT. If DT = 0, or blank, the value of 0.25 sec will be used. The default (DT of -0.25 sec) is for the program to select an appropriate value.

Force Ramping Ramp Time

Time length over which forces are ramped to avoid transient effects. Default is 10 sec. Typically around Tp (wave period).

Build-up sea-state ramp

This parameter should be specified as greater than 12 if no ramping is desired (default). Otherwise, BUP divided by 12 is the wave height ratio by which hydrodynamic forces are scaled to simulate a building sea-state. Each 20- minute BUP is incremented by 1 until BUP equals 12.

Wave Spreading Parameters

Allows selection of: • No Bi-Modal Spreading (default) • Bi-Modal Spreading

Number of Angle Divisions

Number Angle Divisions for wrapped normal directional spreading (24 max) for both single and bi- modal spreading.

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2nd Direction

Secondary mean spreading (deg.)

direction

2nd Spreading Direction

Secondary standard deviation of wave spreading (deg)

Mixing Constant

Mixing constant spreading.

for

for

bimodal

wave

wave

Pipe Dynamic Simulation Parameters Integration DELTA NewMark’s

The parameter DELTA of the Newmark numerical integration method. The default value for DELTA is 0.5.

Convergence Tolerance

A tolerance parameter used to check for convergence. The default value is 0.0001. Note: Convergence is assumed when:

(G(I) - EPS (see definition of G(I); I = 1, 2) Maximum Iteration

Maximum number of iterations at a given time step. The default value for NIT is 10.

Damping ALPHA

Are the proportionality factors defining proportional, or classical damping, according to

[C] = ALPHA X [M] + BETA X [K] BETA

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This damping may be introduced to account for structural damping.

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BOUNDARY CONDITION Tab

(ADVANCED Option) Controls the boundary conditions: tension, fixity, external springs and the effects of external pressure.

Pipeline Tension

Choice of two options for calculation of pipeline tension: • The last node is fixed longitudinally and the tension is computed approximately using the stretch. • An end longitudinal spring is assumed (see Spring Constant field below) and the pipeline tension is determined as the product of spring constant times longitudinal deflection of the last node.

Spring Constant of Longitudinal End

Spring Constant in consistent units (lb/ft or N/m)

Initial Tension, Assumed Constant Along the Pipeline Axis

Tension in consistent units (lb or N.)

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Fixity Nbr of Fixity Nodes

Number of nodes with specified restraints, up to 10 maximum.

Node Number

Node number with specified restraints.

Translation

Free or Fixed at the specified node number in lateral direction and longitudinal direction.

Rotation

Free or Fixed at the specified node number in rotation in the horizontal plane (about zaxis.)

External Springs Number of External Spring Groups

The specification of external springs can be varied over the length of the pipeline. The user can enter up to a maximum of 10 external spring groups.

Beginning node number

Starting node for the external spring group.

Ending node number Ending node for the external spring group. Note: If ending node number zero (or blank) springs are added to beginning node number only. The nodal increment from beginning node to ending node is 1, that is, all nodes beginning with I and ending with L have spring additions with constants S1, S2. End this series with I = 0. Spring Constant

Spring constant of spring added to nodes of current external spring group, in degree of freedom 1 (lateral direction)

Rotational Spring Constant

Rotational spring constant (rotation in the horizontal plane (about z-axis)) of springs added to current external spring group.

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External Pressure due to Submergence

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Choice of two options for effect of external pressure: • The external pressure is used in computing actual pipeline compression and effective tension (default.) • The external pressure is not considered in the calculations of tension. Note that the pipeline is always considered effectively capped.

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E.3

User Soil Model

The L3WIN program has the capability to incorporate a user generated soil model. This soil model must be compiled and linked into the existing program. Outline subroutines are provided, although for detailed information on variable functions, the user should contact the maintenance contractor, Brown & Root Energy Services. For information on the pipe-soil interaction models implemented in L3WIN, see Volume 1, Section 4.8. E.3.1 Compiling and Linkage Operations The L3WIN program consists of source language written in Microsoft Visual Basic with some Microsoft system API calls and Digital Visual FORTRAN The L3WIN contain four (4) basic modules. A “CONTROL” module is written in Microsoft Visual Basic and three (3) FORTRAN modules WinWave, WinForce and WinDyna are written in Digital Visual FORTRAN language. The “CONTROL” module is to perform the system control, database management, data entry, reporting and plotting of results. The FORTRAN modules is invoked by the “CONTROL” module when the case input data has been checked whenever possible. The “CONTROL” module invokes the WinWave, WinForce and WinDyna in sequence and interrupt the processing if any error condition the module may have. The “CONTROL” module consists of Microsoft Visual Basic forms and modules and Microsoft system API calls. The Microsoft system API calls are used to shell the FORTRAN modules. The Microsoft Visual Basic 32 bit compiler is used to compile the “CONTROL” module. The FORTRAN modules are compiled with Digital Visual FORTRAN 32 bit compiler and execute under CONSOLE mode. E.3.2 User Supplied Soil Model Routines User may write his/her own soil model subroutines compile and linked into the L3WIN system. The module required to linked into is the WinDyna, a FORTRAN module. User must supply a “SOILCON” and a “SOILUSER” subroutines and link them properly into WinDyna module. Currently the WinDyna module is compiled and linked in CONSOLE mode and linked with a dummy “SOILCON” and “SOILUSER” . Since it is in CONSOLE mode, the user written routines is required to use the same compile and linker to link the user routines with the remain subroutines. The soil resistance model is assumed to be comprised of three component resistances (see Vol. 1, Fig. 4.8-2): • frictional resistance, based on some friction coefficient and the instantaneous submerged weight(mF N ); • passive soil resistance (or remaining soil resistance for lateral earth pressure and soil cohesion), based on soil and pipe properties; and • history dependent soil resistance, based on the history of pipe loading.

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The soil resistance is assumed linear with three defining points (see Vol. 1, Fig. 4.8-3) : • mobilization length (Y1 ) over which the soil resistance ramps up from zero to the sum of the frictional resistance and the passive resistance (mF N + FR), • distance to peak soil resistance (Y2), the distance from the origin to the peak historydependent soil resistance, and • distance to break out (Y3), the distance from the origin to break out (the point at which the history dependent component of the soil force is once again zero). At Y3 the soil force is again the same as at Y1. IMPORTANT! - since L3Win convert units into ENGLISH when invoke winDyna in FEET unit, hence all internal data values are in FEET and FEET related units. The "SoilCon" and "SoilUser" code must conform with FEET and FEET related units

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E.3.3 SOILCON The SOILCON subroutine will be called when Soil Resistance’s “Soil Type” is “User Soil” (type 3) is selected. SOILCON (similar to “SANDCON” and “CLAYCON” ) is called to setup soil properties for a given node. The SOILCON subroutine calling sequence are: subroutine soilCon ( n, userSoilParm, nvArray, vArray, ms g ) where: n userSoilParm nvArray

-

vArray

-

Msg

-

0 1 2 3 4 NOTE:

-

current node number - user data in parm1...parm4 of the node number (see E.2.1 User Supplied Soil Model Routines, Parameters) number of elements in vArray (i.e. number of data items passed from calling routine (equal to 11)) array contain data items from and return to the calling routine. is a text string returned by this routine to inform the caller routine the status of this routine. The first character of the msg must be a number (in string character) form 0 to 4 and followed by message, if any. The meaning of the number is: ok advisory warning error fatal nvArray must be same size as defined in Array and that equivalent to local variable (for easy usage). The calling routine will always set it to 11. The following code should be first part of you subroutine. The text after “!” are comments.

IMPLICIT REAL*8(A-H,O-Z) dimension userSoilParm(4) character*(*) msg dimension vArray(nvArray) dimension Array(11) integer n,mu ! Array is created with equivalence to variables for use without use of element number. equivalence (Array(01),dpipe), ! pipe diameter, ft INPUT ONLY (Array(02), ws), ! submerged weight, lb/ft INPUT ONLY (Array(03), amu), ! friction coefficient (by node) (0.6 - sand, 0.2 - clay) OUTPUT ONLY (Array(04), fr), ! passive soil resistance, lb/ft OUTPUT ONLY

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(Array(05), y1), (Array(06), y2), (Array(07), y3), (Array(08), a1), (Array(09), a2), (Array(10), a3), (Array(11), a4),

! mobilization length, ft (see Vol. 1, Fig. 4.8-3) OUTPUT ONLY ! distance to peak soil resistance, ft (see V-1, Fig. 4.8-3)OUTPUT ONLY ! distance to break out, ft (see Vol. 1, Fig. 4.8-3) OUTPUT ONLY ! soil constant (by node) to pass to SOILUSER OUTPUT ONLY ! soil constant (by node) to pass to SOILUSER OUTPUT ONLY ! soil constant (by node) to pass to SOILUSER OUTPUT ONLY ! soil constant (by node) to pass to SOILUSER OUTPUT ONLY

if(nvArray.ne.11) then msg='4 ERROR - SOILCON Array size not match' return endif ! copy vArray to local Array, so one can use variable name rather than array element number do i=1,nvArray Array(i)=vArray(i) enddo mu=amu ! userCon computation procedure start here ! ehUserDefault=0.1*dpipe !note dpipe is d2 when call … … … !store computed values back to vArray for calling routine use amu-mu do i=1,nvArray vArray(i)=Array(i) enddo msg=’0 No computation error’ return end

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! set message code

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E.3.3.1 SOILUSER The “UPDATE” subroutine calls The SOILUSER subroutine when Soil Resistance’s “Soil Type” is “User Soil” (type 3). The “UPDATE” subroutine calls “SOILS2” for sand soil and clay soil. The SOILUSER subroutine calling sequence are: subroutine soilUser(n,userSoilParm,nvArray,vArray,msg) where: n userSoilParm nvArray vArray

-

Msg

-

0 1 2 3 4 NOTE:

- ok -

current node number user data in parm1...parm4 of the node number number of elements in vArray (i.e. number of data items passed from calling routine) array contain data items from and return to the calling routine. is a text string returned by this routine to inform the caller routine the status of this routine. The first character of the msg must be a number (in string character) form 0 to 4 and followed by message, if any. The meaning of the number is: advisory warning error fatal nvArray must be same size as defined in Array and that equivalent to local variable (for easy usage). The calling routine will always set it to 33. The following code should be first part of you subroutine. The text after “!” are comments.

IMPLICIT REAL*8(A-H,O-Z) character*(*) msg dimension vArray(nvArray) dimension userSoilParm(4) dimension Array(27) integer ireset, mu equivalence (Array(01),d2), ! drag diameter of pipeline, ft INPUT ONLY (Array(02),ws), ! submerged weight of pipe, lb/ft INPUT ONLY (Array(03),fnv), ! instantaneous submerged weight of pipe (incl. lift), lb/ftINPUT ONLY (Array(04),fnvavg), ! average submerged weight of pipe (incl. lift), lb/ft INPUT ONLY (Array(05),zmax) ! maximum allowable pipe embedment, ft INPUT ONLY (Array(06),ymax), ! extreme maximum positio n from current halfcycle (ft)INPUT ONLY (Array(07),ymin), ! extreme minimum position from current halfcycle (ft)INPUT ONLY (Array(08),yh), ! YH=YMIN -YHO, (ft) INPUT ONLY

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(Array(09),amp), (Array(10),amp2), (Array(11),preamp), (Array(12),echeck), (Array(13),prefr), (Array(14),yho), (Array(15),amu), (Array(16),fr), (Array(17),zee), (Array(18),fh2), (Array(19),fhmax), (Array(20),y1), (Array(21),y2), (Array(22),y3), (Array(23),a1), (Array(24),a2), (Array(25),a3), (Array(26),a4), (Array(27),ireset),

! AMP=ABS(YH) (ft), INPUT ONLY ! AMP2=(YMAX-YMIN)/2.0, ft INPUT ONLY ! ‘amp2’ from previous halfcycle INPUT ONLY ! change in energy for this halfcycle, ft- lb INPUT ONLY ! ‘fr’ (passive soil resistance) from previous halfcycleINPUT ONLY ! instantaneous origin for soils model (ft) INPUT/OUTPUT ! friction coefficient (by node) passed from SOILCONINPUT/OUTPUT ! passive soil resistance, lb/ft INPUT/OUTPUT ! pipe embedment, ft OUTPUT ! history dependent soil resistance at current location, ‘Y’INPUT/OUTPUT ! maximum history dependent soil resistance at ‘Y2’ INPUT/OUTPUT ! mobilization length, ft (see Vol. 1, Fig. 4.8-3) INPUT/OUTPUT ! distance to peak soil resistance, ft (see V-1, Fig. 4.8-3)INPUT/OUTPUT ! distance to break out, ft (see Vol. 1, Fig. 4.8-3) INPUT/OUTPUT ! soil constant (by node) passed from SOILCON INPUT/OUTPUT ! soil constant (by node) passed from SOILCON INPUT/OUTPUT ! soil constant (by node) passed from SOILCON INPUT/OUTPUT ! soil constant (by node) passed from SOILCON INPUT/OUTPUT !?

if(nvArray.ne.27)then msg='4 ERROR - Array size not match' return endif ! copy vArray to local Array, so one can use variable name rather than array element number do i=1,nvArray Array(i)=vArray(i) enddo mu=amu ireset=reset !soilUser computation procedure here … … … … !store computed values back to Array amu=mu reset=ireset do i=1,nvArray vArray(i)=Array(i)

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enddo return end

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