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: info@ttoolboxes.com
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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,
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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
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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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1-2
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
vi
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 Input Data for Analysis Using L1WIN
A.1-2 Summary of Results Using L1WIN
A.2-1 Summary of L2WIN Analysis Using L1WIN Designs
A.3-1 Summary of L2WIN Designs
A.4-1 Level 3 Confirmation of Level 2 Embedments
A-2
A.3
A-11
A-36
A-123
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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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1.0
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
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3.
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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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 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
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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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3.0
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
| Drag coeff = 0.7
| Lift coeff = 0.9
| Mass coeff = 3.29
| Wave crest = 0
degree
300.00 feet
feet
second
feet
feet
long
| Conc initial = 1
inches
| Conc final = 4
inches
| Conc increment =
0.125 inches
We Deliver
3-4
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
|
|
|
|
We Deliver
3-5
+-----------------------------------------------------------------------------------------------------------------------+
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
We Deliver
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
+---------------------------------------------------------------------------------------------------------------+
We Deliver
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.
We Deliver
3-8
FIGURE 3.2-1
We Deliver
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
We Deliver
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
We Deliver
| 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
3 - 11
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
|
+-----------------------------------------------------------------------------------------------------------------------+
|
|
|
We Deliver
3 - 12
|
|
SIG. BOTTOM VELOCITY
We Deliver
=
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
|
We Deliver
3 - 14
+-----------------------------------------------------------------------------------------------------------------------|
|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.
We Deliver
3 - 15
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
|
We Deliver
3 - 16
+-----------------------------------------------------------------------------------------------------------------------|
|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
3 - 17
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
3 - 18
+-----------------------------------------------------------------------------------------------------------------------|
|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
3 - 19
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
|
We Deliver
3 - 20
+-----------------------------------------------------------------------------------------------------------------------|
|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
3 - 21
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
|
We Deliver
3 - 22
+-----------------------------------------------------------------------------------------------------------------------|
|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.
We Deliver
3 - 23
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
|
We Deliver
3 - 24
+-----------------------------------------------------------------------------------------------------------------------|
|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.
We Deliver
3 - 25
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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3 - 26
+-----------------------------------------------------------------------------------------------------------------------|
|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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3 - 27
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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3 - 28
+-----------------------------------------------------------------------------------------------------------------------|
|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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3 - 29
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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3 - 30
+-----------------------------------------------------------------------------------------------------------------------|
|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 - 31
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 Nodal Report – 155 pages
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3 - 38
Example Page - Total Dynamic Beam Report – 318 pages
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3 - 39
Example Page - Total Dynamic Summary Report – 159 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-34
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).
C-2
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
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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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D-3
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.
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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.
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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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D-15
FIGURE D-6 PLOT SAFETY FACTORS
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D-16
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 e −n σ 2 cos(Θ − Θ 0 )
2 2
D
n =1
∞
=
Σ [ exp{(- 21 (θ - θ0 ) - 2 πk )2 / σD2}] / 2 π σ D
n =1
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) =
−
2
1

Θ

Θ
0
2
 σ 
 D 
2π σ D
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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E-8
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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E-10
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
We Deliver
! 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
We Deliver
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