sample prob 2

Combine

Combine

RELEASE 5

USER’S MANUAL

ENGINEERING DYNAMICS, INC.

2113 38TH STREET

KENNER, LOUISIANA 70065

U.S.A.

No part of this document may bereproduced in any form, in anelectronic retrieval system orotherwise, without the prior

written permission of the publisher.

Copyright © 1998 by

ENGINEERING DYNAMICS, INC.

Printed in U.S.A.

Combine

Combine

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TABLE OF CONTENTS

1.0 INTRODUCTION 1-1.......................................................................................................................1.1 OVERVIEW 1-1.........................................................................................................................1.2 PROGRAM FEATURES 1-1......................................................................................................

2.0 COMBINING ANALYSIS RESULTS 2-1.......................................................................................2.1 STATIC RESULTS 2-1..............................................................................................................2.2 DYNAMIC RESULTS 2-1.........................................................................................................2.3 STATIC AND EARTHQUAKE RESULTS 2-1........................................................................2.4 RESULTS FROM DISSIMILAR MODELS 2-2........................................................................2.5 SYMMETRIC-ANTISYMMETRIC ANALYSIS 2-2...............................................................2.6 EXTREME WAVE ANALYSIS RESULTS 2-2........................................................................2.7 EXTREME WIND RESULTS 2-2.............................................................................................

3.0 COMBINE INPUT FILE 3-1............................................................................................................3.1 COMBINE STANDARD INPUT LINES 3-1............................................................................3.2 COMBINE EXTREME WAVE INPUT 3-13..............................................................................

4.0 COMMENTARY 4-1........................................................................................................................4.1 SRSS COMBINATION METHOD 4-1......................................................................................4.2 COMPLETE QUADRATIC COMBINATION METHOD 4-1.................................................4.3 COMBINING STATIC AND SEISMIC RESULTS 4-2............................................................4.4 SPECTRAL RESPONSE ANALYSIS 4-2.................................................................................

4.4.1 Linear Systems 4-2............................................................................................................4.4.2 Transfer Function 4-4........................................................................................................4.4.3 Wave Height Spectral Density 4-5....................................................................................4.4.4 Spectral Response 4-6........................................................................................................

5.0 SAMPLE PROBLEMS 5-1...............................................................................................................5.1 SAMPLE PROBLEM 1 5-2........................................................................................................5.2 SAMPLE PROBLEM 2 5-5........................................................................................................5.3 SAMPLE PROBLEM 3 5-8........................................................................................................

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Combine

SECTION 1

INTRODUCTION

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1.0 INTRODUCTION

1.1 OVERVIEW

The Combine program is a utility program completely compatible with common solutionfiles from the SACS suite of programs. It allows the user to Combine static and/ordynamic results of the same model from various analyses into a single solution file. Theprogram has the ability to Combine results from dissimilar postfiles allowing results ofvarious construction stages to be interpreted and can also be used to perform symmetric-antisymmetric analysis.

1.2 PROGRAM FEATURES

Combine reads model physical data, deflections and internal loads from SACS commonsolution files. Some of the main features and capabilities of the program are:

1. Combine results from two solution files into one solution file.2. Create new load conditions by combining the results of existing basic load

conditions either linearly or by the SRSS method (square root of the sum of thesquares).

3. Combine dynamic modal responses by either the SRSS or Complete Quadratic(CQC) methods.

4. Combine static and earthquake analysis results.5. Format or unformat solution files, ie. convert UNIX or DOS binary solution file

into ASCII file, or convert ASCII file into UNIX or DOS binary file. 6. Combine results of analyses performed at various phases of construction by

allowing dissimilar solution files.7. Calculate extreme wave internal loads.8. Calculate internal loads for extreme wind.9. Obtain analysis results for an entire structure from the results of a partial model

by using symmetric and antisymmetric techniques.10. Supports unlimited number of load cases.11. Supports alpha numeric load case names.

Note: When combining results of 2 or more basic load cases, the loadcases need not be in the same solution file and the solution filesmay contain a different number of joints and/or members.

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Combine

SECTION 2

COMBINING ANALYSIS RESULTS

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2.0 COMBINING ANALYSIS RESULTSThe following sections contain a brief discussion on specifying combination proceduresfor various types of analysis results. For a discussion on the theory of the combinationtechniques, see the Commentary in Section 4 of this manual.

2.1 STATIC RESULTS

Results from static analyses can be combined by taking the algebraic sum(superposition), the sum of the absolute values, the square root of the sum of the squares(SRSS), or the largest value and adding the SRSS of the remaining values, by specifying'LIN', 'PEAK', 'RMS' or 'PRMS', respectively, on the LCOND input line.

The name of the new load case being created is specified in columns 7-10 on theLCOND line. Each contributing basic load condition is specified on the ensuing COMPinput lines along with its source* (Primary or Secondary file) and the load factor.

Note: When results of two solution files are being combined, one file isdesignated as the 'Primary file' and the other as the 'Secondaryfile' in the Combine runfile.

2.2 DYNAMIC RESULTS

In addition to the 'LIN', 'PEAK', 'RMS' and 'PRMS' methods, modal results can becombined using the Complete Quadratic Combination technique by specifying 'CQC' onthe LCOND input line.

The name of the new load case being created is specified in columns 7-10 on theLCOND line. The contributing modes, the source file** (usually Primary) and theappropriate modal participation factor, should be specified on the ensuing COMP inputline regardless of combination method. When specifying the 'CQC' method, the modalfrequency and percent damping should also be input on the COMP line.

Note: Normally, only one solution file is used when combining modalresults.

2.3 STATIC AND EARTHQUAKE RESULTS

Static analysis and seismic results can be combined assuming the earthquake axialstresses are either tensile or compressive by specifying 'PRST' or 'PRSC' respectively onthe LCOND line. In either case, all other stresses are assumed to have the same sign asthe corresponding static stress.

The name of the new load case being created is specified in columns 7-10 on theLCOND line. For a typical earthquake analysis, two combinations containing static plusseismic stresses, are made for each seismic basic load case, one combination withseismic axial loads assumed to be in tension and one with seismic axial loads assumed tobe in compression.

The solution file containing static results should be specified as the Primary solution file.The earthquake solution file should be specified as the Secondary solution file in theCombine runfile.

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2.4 RESULTS FROM DISSIMILAR MODELS

Solutions from models of different sizes (ie. number of joints and/or members) can becombined using the Combine program. This capability allows the analysis results ofstructures in various construction stages to be combined for evaluation.

2.5 SYMMETRIC-ANTISYMMETRIC ANALYSIS

Combine allows for the analysis of extremely large symmetric models utilizingsymmetric and anti-symmetric boundary conditions.

2.6 EXTREME WAVE ANALYSIS RESULTS

The extreme wave analysis results are generated by the Combine program. The transferfunction data must be created using Seastate, Wave Response, MORA or WAMIT andsupplied in the form of common solution files.

The spectral analysis option must be designated by ‘SP’ in columns 14-15 on theCMBOPT line.

Each direction is initiated by the DIRECT input line. The wave direction along with thedead load case location and load case number are designated in columns 7-14, 15 and 16-19, respectively. The load case factor and the axial load option are designated in columns20-26 and 27, respectively. For each wave direction, the load cases making up thetransfer function and the wave spectra for which to determine the extreme wave stressesare specified using LCAS and WSPEC input lines.

2.7 EXTREME WIND RESULTS

The Combine program may be used to Combine wind spectral results for extreme windand wind fatigue analyses.

Each load condition defined by the LCOND line represents one wind load and mustcontain the ‘WSP’ option. Each mode to be combined is designating using a COMP line.

Note: The Combine input file is generated automatically when executingspectral wind fatigue or extreme wind analysis.

Combine

SECTION 3

COMBINE INPUT FILE

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3.0 COMBINE INPUT FILE

3.1 COMBINE STANDARD INPUT LINES

The Combine program requires a Combine input file along with one or two SACScommon solution files. The table below shows the standard input lines for the Combineinput file.

INPUT LINE DESCRIPTION

TITLE Optional title information.

CMBOPT* Basic Combine analysis options.

LCOND* Specifies the load combination type

COMP* Specifies the contents of the combination

END* Designates the end of input data.

The following section contains the input lines that are applicable to the Combineprogram module for all combination techniques except for extreme wave analysis. Theinput lines for extreme wave are detailed in the following section.

Before creating the Combine input file, the user should be familiar with the basicguidelines for the use of input lines. These guidelines are located in the IntroductionManual.

Note: Required input lines are designated with an asterisk.

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TITLE COMBINE SAMPLE MODEL

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THE TITLE TO BE IN THE COMMON SOLUTION FILE IS ‘COMBINE SAMPLE MODEL’

COMBINE TITLE LINE

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DESCRIPTIVE TITLE INFORMATION

2)))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))) 78

COLUMNS COMMENTARY

LOCATION ALL TITLE LINES ARE ALWAYS PLACED IMMEDIATELY BEFORE THE ‘CMBOPT’ LINE.

(GENERAL) THE USER CAN PLACE AS MANY DESCRIPTIVE TITLE LINES AS REQUIRED IN THE DATA DECK. THE FIRST TITLE LINE IS PRINTED AS A HEADING AT THE TOP OF EACH OUTPUT PAGE. ALL TITLE LINES ARE LISTED AT THE BEGINNING OF THE PRINTED OUTPUT.

DESCRIPTIVE TITLE - INPUT LINE 1

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CMBOPT

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THE INPUT SOLUTION FILE IS UNFORMATTED (BINARY FORM). THE RESULTING OUTPUT FILE WILL BE IN UNFORMATTED FORM ALSO.

COMBINE OPTIONS LINE

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LINELABEL

FORMATTEDINPUTFILE

OPTION

FORMATTEDOUTPUT

FILEOPTION

SPECTRALANALYSIS

OPTION

SPECTRALUNITS

OPTION

JOINTACCELOPTION

MEANWIND

AVERAGINGTIME

LEAVE BLANK

CMBOPT

1))))) 6 8))))) 9 11))))12 14)))15 17)))18 20))21 37)42 43)))))))))))))))))))))))))) 80

DEFAULTS 600.0

ENGLISH SECS

METRIC SECS

COLUMNS COMMENTARY

(GENERAL) THIS LINE CONTROLS THE INPUT AND OUTPUT TYPE FOR THIS ANALYSIS.

( 1- 6) ENTER ‘CMBOPT’ ON THIS LINE. NO HEADER LINE IS REQUIRED.

( 8- 9) ENTER ‘FI’ IF THE INPUT POSTFILE(S) IS FORMATTED. NORMALLY ALL POSTFILES ARE UNFORMATTED, BUT THE OPTION TO FORMAT POSTFILES ENABLES THE USER TO TRANSFER THE FILES FROM ONE COMPUTER TO ANOTHER.

(11-12) ENTER ‘FO’ IF THE OUTPUT FILE IS TO FORMATTED.

(14-15) ENTER ‘SP’ THIS ANALYSIS IS A SPECTRAL COMBINATION.

(17-18) ENTER UNITS OPTION FOR SPECTRAL COMBINATION. ‘EN’ - ENGLISH ‘MN’ - METRIC WITH KILONEWTONS ‘ME’ - METRIC WITH KILOGRAMS

(20-21) ENTER ‘JA’ IF JOINT ACCELERATIONS ARE TO BE PRINTED. THIS OPTION IS ONLY VALID WITH THE SPECTRAL OPTION.

(37-42) FOR WIND SPECTRAL ANALYSIS, ENTER THE MEAN WIND SPEED AVERAGING TIME. THIS VALUE IS NORMALLY 600 SECONDS.

COMBINE OPTIONS LINE - INPUT LINE 2

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LCOND EQC1 PRSC SEISMIC W/AXIAL C

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OMPRESSION PLUS STATIC COMBINATION

LOAD CASE EQC1 WILL BE CREATED BY COMBINING RESULTS USING THE ‘PRSC’ METHOD. EARTHQUAKE MEMBER AXIAL LOADS WILL BE ASSUMED TO BE COMPRESSIVEWHILE ALL OTHER EARTHQUAKE LOADS WILL USE THE SIGN OF THE CORRESPONDINGDEAD LOAD CASE. A DESCRIPTIVE LABEL IS IN COLUMNS 18-80.

COMBINE LOAD CONDITION

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LINELABEL

LOADCONDITION

NAME

COMBINATIONTYPE

REMARKS

LCOND

1))))))))))) 5 7)))))))))10 14)))))))17 18))))))))))))))))))))))))))))))))))))) 80

DEFAULTS LIN

COLUMNS COMMENTARY

(GENERAL) THIS LINE CONTROLS THE CREATION OF OUTPUT LOAD CONDITIONS. EACH ‘LCOND’ CREATES ONE OUTPUT LOAD CASE WHICH WILL BE NUMBERED IN CONSECUTIVE ASCENDING ORDER. THIS DATA ALSO CONTROLS HOW THE CONTRIBUTING LOAD CASES WILL BE COMBINED TO FORM THE OUTPUT LOAD CASE.

( 1- 5) ENTER ‘LCOND’ ON THIS LINE. NO HEADER LINE IS REQUIRED.

( 7-10) ENTER LOAD CONDITION NAME.

(14-17) ENTER THE LOAD COMBINATION TYPE FROM THE FOLLOWING SELECTIONS:

‘LIN ‘ - ALGEBRAIC SUM (LINEAR) ‘PEAK’ - SUM OF ABSOLUTE VALUES ‘RMS ‘ - SQUARE ROOT OF THE SUM OF THE SQUARES ‘PRMS’ - PEAK OF THE LARGEST PLUS THE SQUARE ROOT OF THE

SUM OF THE SQUARES OF THE REST. ‘PRSC’ - USED IN COMBINING DEAD LOAD WITH A SPECTRAL

EARTHQUAKE ANALYSIS. THE EARTHQUAKE MEMBER LOADS WILL BE

COMBINED USING THE SIGN OF THE DEAD LOADS EXCEPT FOR

THE AXIAL LOADS WHICH WILL BE COMPRESSIVE. ‘PRST’ - SAME AS ‘PRSC’ EXCEPT THE EARTHQUAKE MEMBER

AXIAL LOADS WILL BE TENSION. ‘WSP’ - WIND SPECTRAL ANALYSIS. DYNAMIC AMPLIFICATION

FACTORS WILL AUTOMATICALLY BE CALCULATED.

NOTE: WHEN SPECIFYING TYPE ‘PRSC’ OR ‘PRST’, THE STATIC ANALYSIS POST FILE SHOULD BE SPECIFIED AS THE PRIMARY FILE AND THE EARTHQUAKE POST FILE AS THE SECONDARY FILE.

(18-80) ENTER ANY REMARKS TO INDENTIFY THIS LOAD CASE.

CREATE LOAD CONDITION - INPUT LINE 3A

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LCOND T001 RMS

COMP PTEST 1.00

COMP SOP01 2.00

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LOAD CASE T001 WILL CONSIST OF THE SQUARE ROOT OF THE SUM OF THE SQUARESOF 100 PERCENT OF LOAD CASE ‘TEST’ FROM THE PRIMARY SOLUTION FILE AND 200 PERCENT OF LOAD CASE ‘OP01' OF THE SECONDARY SOLUTION FILE.

LOAD CONDITION COMPONENT

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LINELABEL

SOURCE OFCONTRIBUTING

LOADCASE

CONTRIBUTINGLOAD

CONDITION

LOAD CASEFACTOR

SYMMETRIC-ANTISYMMETRIC MODEL SIGN CHANGES MODAL PARAMETERS

LEAVE BLANKROT.MOM.

XAXIS

ROT.MOM.

YAXIS

ROT.MOM.

ZAXIS

DEFL.FORCE

XAXIS

DEFL.FORCE

YAXIS

DEFL.FORCE

ZAXIS

ALLSTRESSES

FREQUENCY(HZ)

DAMPINGRATIO

(PERCENT)

COMP

1))) 4 6 7))))10 11))))22 25))31 26 27 28 29 30 31 32)))43 44)))55 56)))80

DEFAULTS

COLUMNS COMMENTARY

(GENERAL) THIS LINE DESIGINATES THE CONTRIBUTION OF AN INPUT LOAD CASE.

( 1- 4) ENTER ‘COMP’ ON THIS LINE. NO HEADER LINE IS REQUIRED.

( 6 ) ENTER THE LOAD CONDITION SOURCE: ‘P’ - PRIMARY FILE ‘S’ - SECONDARY FILE ‘C’ - PREVIOUS COMBINATION REPEAT THIS LINE FOR EACH LOAD CASE CONTRIBUTION.

( 7-10) ENTER THE NAME OF THIS CONTRIBUTING LOAD CASE.

(11-22) ENTER THE FACTOR TO MULTIPLY THIS LOAD CASE. DEFAULT IS 1.0.

(25-31) IF HALF OF A SYMMETERIC STRUCTURE HAS BEEN MODELED, THESE SIGN CHANGES CAN BE USED TO SIMULATE THE OMITTED HALF OF THE STRUCTURE.

( 25 ) ENTER ‘1' TO CHANGE SIGN ON ROTATIONS AND MOMENTS ABOUT THE X AXIS.

( 26 ) ENTER ‘1' TO CHANGE SIGN ON ROTATIONS AND MOMENTS ABOUT THE Y AXIS.

( 27 ) ENTER ‘1' TO CHANGE SIGN ON ROTATIONS AND MOMENTS ABOUT THE Z AXIS.

( 28 ) ENTER ‘1' TO CHANGE SIGN ON DEFLECTIONS AND FORCES IN THE X DIRECTION.

( 29 ) ENTER ‘1' TO CHANGE SIGN ON DEFLECTIONS AND FORCES IN THE Y DIRECTION.

( 30 ) ENTER ‘1' TO CHANGE SIGN ON DEFLECTIONS AND FORCES IN THE Z DIRECTION.

( 31 ) ENTER ‘1' TO CHANGE SIGN ON ALL STRESSES.

(32-55) FOR ‘CQC’ COMBINATIONS OR WIND SPECTRAL ANALYSIS (WSP) ENTER THE MODAL FREQUENCY AND DAMPING RATIO FOR THIS MODAL CONTRIBUTION.

LOAD CONDITION COMPONENTS - INPUT LINE 4A

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END

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THE LINE DESIGNATES THE END OF INPUT DATA.

END OF DATA

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LINELABEL

LEAVE THIS FIELD BLANK

END

1))))) 3 4)))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))) 80

DEFAULT

ENGLISH

METRIC

COLUMNS COMMENTARY

GENERAL THIS LINE IS THE LAST CARD OF THE INPUT FILE.

( 1- 3) ENTER ‘END’.

END LINE - INPUT LINE 7

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3.2 COMBINE EXTREME WAVE INPUT

The Combine program may be used to determine extreme wave stresses. The transferfunction loading must be supplied in the form of a common solution file(s). The tablebelow shows the input lines for an extreme wave analysis.

INPUT LINE DESCRIPTION

TITLE Optional title information.

CMBOPT* Basic Combine analysis options.

DIRECT* Specifies the wave direction

LCAS* Designates load cases used for transfer function

WSPEC Specifies wave spectra

SPEC Specifies user defined spectra

END* Designates end of input

The following section contains the input lines that are applicable to extreme waveanalysis. Before creating the Combine input file, the user should be familiar with thebasic guidelines for the use of input lines. These guidelines are located in theIntroduction Manual.

Note: Required input lines are designated with an asterisk.

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TITLE COMBINE SAMPLE MODEL

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THE TITLE TO BE IN THE COMMON SOLUTION FILE IS ‘COMBINE SAMPLE MODEL’

COMBINE TITLE LINE

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DESCRIPTIVE TITLE INFORMATION

2)))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))) 78

COLUMNS COMMENTARY

LOCATION ALL TITLE LINES ARE ALWAYS PLACED IMMEDIATELY BEFORE THE ‘CMBOPT’ LINE.

(GENERAL) THE USER CAN PLACE AS MANY DESCRIPTIVE TITLE LINES AS REQUIRED IN THE DATA DECK. THE FIRST TITLE LINE IS PRINTED AS A HEADING AT THE TOP OF EACH OUTPUT PAGE. ALL TITLE LINES ARE LISTED AT THE BEGINNING OF THE PRINTED OUTPUT.

DESCRIPTIVE TITLE - INPUT LINE 1

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CMBOPT

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THE INPUT SOLUTION FILE IS UNFORMATTED (BINARY FORM). THE RESULTING OUTPUT FILE WILL BE IN UNFORMATTED FORM ALSO.

COMBINE OPTIONS LINE

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LINELABEL

FORMATTEDINPUTFILE

OPTION

FORMATTEDOUTPUT

FILEOPTION

SPECTRALANALYSIS

OPTION

SPECTRALUNITS

OPTION

JOINTACCELOPTION

MEANWIND

AVERAGINGTIME

LEAVE BLANK

CMBOPT

1))))) 6 8))))) 9 11))))12 14)))15 17)))18 20))21 37)42 43)))))))))))))))))))))))))) 80

DEFAULTS 600.0

ENGLISH SECS

METRIC SECS

COLUMNS COMMENTARY

(GENERAL) THIS LINE CONTROLS THE INPUT AND OUTPUT TYPE FOR THIS ANALYSIS.

( 1- 6) ENTER ‘CMBOPT’ ON THIS LINE. NO HEADER LINE IS REQUIRED.

( 8- 9) ENTER ‘FI’ IF THE INPUT POSTFILE(S) IS FORMATTED. NORMALLY ALL POSTFILES ARE UNFORMATTED, BUT THE OPTION TO FORMAT POSTFILES ENABLES THE USER TO TRANSFER THE FILES FROM ONE COMPUTER TO ANOTHER.

(11-12) ENTER ‘FO’ IF THE OUTPUT FILE IS TO FORMATTED.

(14-15) ENTER ‘SP’ THIS ANALYSIS IS A SPECTRAL COMBINATION.

(17-18) ENTER UNITS OPTION FOR SPECTRAL COMBINATION. ‘EN’ - ENGLISH ‘MN’ - METRIC WITH KILONEWTONS ‘ME’ - METRIC WITH KILOGRAMS

(20-21) ENTER ‘JA’ IF JOINT ACCELERATIONS ARE TO BE PRINTED. THIS OPTION IS ONLY VALID WITH THE SPECTRAL OPTION.

(37-42) FOR WIND SPECTRAL ANALYSIS, ENTER THE MEAN WIND SPEED AVERAGING TIME. THIS VALUE IS NORMALLY 600 SECONDS.

COMBINE OPTIONS LINE - INPUT LINE 2

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DIRECT 90.0 P 1 B

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THE DIRECTION IS 90.0 DEGRESS. THE DEAD LOAD CASE IS IN THE PRIMARYSOLUTION FILE AND IS LOAD CASE NUMBER 1. TWO LOAD CASES ARE TO BE CREATED, ONE WITH AXIAL TENSION AND ANOTHER WITH AXIAL COMPRESSION ASDESIGNATED BY ‘B’ IN COLUMN 27.

DIRECTION HEADER LINE

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LINELABEL

DIRECTION

DEAD LOAD CASE

REMARKSLOADCASE

SOURCE

LOADCASE

NUMBER

LOADCASE

FACTOR

AXIALLOAD

OPTION

DIRECT

1)))))) 6 7))))))14 15))))))27 16))))19 20))))26 27 28))))))))))))))))))))))))) 80

DEFAULTS P 1.0 B

DEGREES

DEGREES

COLUMNS COMMENTARY

(GENERAL) THIS LINE INDICATES THAT A NEW DIRECTION IS BEGINNING FOR SPECTRAL COMBINATION. FOLLOWING THIS LINE, THE TRANSFER FUNCTION FOR THIS DIRECTION IS DEFINED BY A SERIES OF ‘LCAS’ LINES WHICH ARE THEN IN TURN FOLLOWED BY THE ‘WSPEC’ LINES FOR THIS DIRECTION. A SIMILAR SET OF DATA IS INPUT FOR EACH DIRECTION DESIRED.

( 1- 6) ENTER ‘DIRECT’ ON THIS LINE. NO HEADER LINE IS REQUIRED.

( 7-14) ENTER THE DIRECTION FOR THIS SET OF DATA. THIS IS USED ONLY FOR TITLING PURPOSES.

( 15 ) ENTER THE SOURCE OF THE DEAD LOAD CASE. ‘P’ - PRIMARY FILE ‘S’ - SECONDARY FILE ‘C’ - PREVIOUS COMBINATION

(16-19) ENTER THE DEAD LOAD CASE NUMBER.

(20-26) ENTER THE FACTOR FOR THE DEAD LOAD CASE.

( 27 ) SELECT THE TYPE OF AXIAL LOAD TO BE USED IN COMBINING WITH THE DEAD LOAD CASE.

‘C’ - COMPRESSION ‘T’ - TENSION ‘B’ - BOTH (CREATES 2 LOAD CASES FOR EACH SPECTRUM)

DIRECTION HEADER - INPUT LINE SET 3B

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LCAS 62.0 11.0 R+IP 58 P 59

LCAS 51.2 10.0 R+IP 60 P 61

LCAS 41.4 9.0 R+IP 62 P 63

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THE WAVE HEIGHT AND PERIOD ARE SPECIFIED ALONG WITH THE COMBINATION TYPE ‘R+I’ IN COLUMNS 20-22. FOR THIS SAMPLE, PAIRS OF LOAD CASES WERE USED TO DESCRIBE THE REAL AND IMAGINARY ROOTS OF THE TRANSFER FUNCTION.

TRANSFER FUNCTION LOAD CASE HEADER

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LINELABEL

WAVEHEIGHT

WAVEPERIOD

LOADCOMB.

OPTION

1ST CONTRIBUTING LOAD CASE 2ND CONTRIBUTING LOAD CASE 3RD CONTRIBUTING LOAD CASE 4TH CONTRIBUTING LOAD CASE

LEAVEBLANKLOAD

CASESOURCE

LOADCASE

NUMBER

LOADCASE

FACTOR

LOADCASE

SOURCE

LOADCASE

NUMBER

LOADCASE

FACTOR

LOADCASE

SOURCE

LOADCASE

NUMBER

LOADCASE

FACTOR

LOADCASE

SOURCE

LOADCASE

NUMBER

LOADCASE

FACTOR

LCAS

1) 4 6<)12 13<)19 20)22 23)34 24)27 28)34 35)46 36)39 40)46 47)58 48)51 52)58 59)70 60)63 64)70 71)80

DEFAULTS STD P 1.0 P 1.0 P 1.0 P 1.0

FT SECS

M SECS

COLUMNS COMMENTARY

(GENERAL) THIS LINE DESIGINATES THE CONTRIBUTION OF INPUT LOAD CASES TO THE TRANSFER FUNCTION. EACH LCAS DATA AND CONTINUATION LINES DESCRIBE ONE POINT ON THE TRANSFER FUNCTION FOR A DIRECTION.

( 1- 4) ENTER ‘LCAS’ ON THIS LINE. NO HEADER LINE IS REQUIRED.

( 6-12) ENTER THE WAVE HEIGHT THAT WAS USED TO CREATE THIS TRANSFER FUNCTION POINT.

(13-19) ENTER THE WAVE PERIOD FOR THIS TRANSFER FUNCTION POINT. THE TRANSFER FUNCTION MUST BE DESCRIBED IN ORDER OF DESCENDING WAVE PERIODS.

(20-22) ENTER THE TYPE OF LOAD COMBINATION IS TO BE USED IN CREATING THIS TRANSFER FUNCTION POINT. THE CHOICES ARE:

‘STD’ - LINEAR LOAD CASE ADDITIONS ‘R+I’ - REAL AND IMAGINARY LOAD CASES (REQUIRES 2 LOAD LINES) ‘SIN’ - SINUSOIDAL LOAD CASES (REQUIRES 2 LOAD CASES) ‘SRC’ - SEARCH (FINDS MAX. AND MIN. FROM SPECIFIED LOAD LINES)

( 23 ) ENTER THE SOURCE OF THIS LOAD CASE. ‘P’ - PRIMARY FILE ‘S’ - SECONDARY FILE ‘C’ - PREVIOUS COMBINATION

(24-27) ENTER THE LOAD CASE NUMBER FOR THIS CONTRIBUTION.

(28-34) ENTER THE FACTOR FOR THIS LOAD CASE.

(35-46) ENTER DATA FOR 2ND LOAD CASE IF NEEDED.

(47-58) ENTER DATA FOR 3RD LOAD CASE IF NEEDED.

(59-70) ENTER DATA FOR 4TH LOAD CASE IF NEEDED.

REPEAT THIS LINE FOR ADDITIONAL LOAD CASES IF NEEDED. THE WAVE HEIGHT, WAVE PERIOD, AND COMBINATION TYPE FIELDS MUST BE LEFT BLANK FOR THE ADDITION LINES.

REPEAT THIS LINE FOR ALL TRANSFER FUNCTION POINTS FOR THIS DIRECTION.

TRANSFER FUNCTION LOAD CASE - INPUT LINE 4B

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DIRECT 90.0 P 1 B

LCAS 62.0 11.0 R+IP 58 P 59

LCAS 51.2 10.0 R+IP 60 P 61

LCAS 41.4 9.0 R+IP 62 P 63

WSPEC PM7.0 12.0 0.25

WSPEC PM5.0 8.0 0.53

WSPEC PM3.0 4.0 0.22

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FOR THE 90 DEGREE DIRECTION, THREE WAVE SPECTRA WERE USED TO DETERMINE THE WAVE EXTREMES.

WAVE SPECTRAL DENSITY SPECIFICATION

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LINELABEL

WAVESPECTRUM

TYPE

WAVE SPECTRUM PARAMETERS JONSWAP PARAMETERS

PROBABILITYLEVEL OF

EXCEEDANCE

SINGLE ORDOUBLE

AMPLITUDEOPTION

LEAVE THIS FIELD BLANKSIGNIF-ICANTWAVE

HEIGHT

DOMINANTPERIOD

“GAMMA” “C”

WSPEC

1)))) 5 11)))12 13<))))))19 20<)))))26 34<))))40 41<)))47 48<)))))56 57)))))58 59))))))))))))80

DEFAULT PM 3.3 1.525 99.9 SA

ENGLISH FT SEC %

METRIC M SEC %

COLUMNS COMMENTARY

GENERAL THIS LINE IS USED IF AND ONLY IF A SPECTRAL ANALYSIS IS BEING DONE. IT IS USED TO DESIGNATE THE FORM OF THE WAVE HEIGHT SPECTRAL DENSITY FUNCTION.

( 1- 5) ENTER ‘WSPEC’.

(11-12) ENTER THE TYPE OF SPECTRUM TO BE USED FOR THE WAVE HEIGHT SPECTRAL DENSITY FUNCTION. CHOOSE FROM BETWEEN THE FOLLOWING;

‘PM’...PIERSON-MOSKOWITZ SPECTRUM. THIS IS THE DEFAULT. ‘JS’...JONSWAP SPECTRUM. ‘US’...USER DEFINED SPECTRUM

(13-19) ENTER THE ‘SIGNIFICANT WAVE HEIGHT’ FOR THIS SPECTRUM. FOR USER DEFINED SPECTRUM, THIS VALUE SQUARED WILL BE USED TO MULTIPLY THE INPUT SPECTRUM. ALSO FOR USER DEFINED SPECTRUM, THIS VALUE DEFAULTS TO 1.0.

(20-26) ENTER THE ‘DOMINANT PERIOD’ FOR THIS SPECTRUM. FOR USER DEFINED SPECTRUM, THIS VALUE WILL BE USED TO MULTIPLY THE INPUT SPECTRUM. ALSO FOR USER DEFINED SPECTRUM, THIS VALUE DEFAULTS TO 1.0.

(34-47) ENTER THE VALUES OF THE PARAMETERS ‘GAMMA’ AND ‘C’ REQUIRED TO FULLY DEFINE THE JONSWAP SPECTRUM IF ‘JS’ IS IN COLS. 11-12.

(48-56) ENTER THE PROBABILITY LEVEL OF EXCEEDANCE. THIS IS THE PROBABILITY THAT THE QUANTITY CALCULATED WILL NOT BE EXCEEDED BASED ON A RAYLEIGH PROBABILITY DISTRIBUTION.

(57-58) THE RESULTS GENERATED BY THE COMBINE PROGRAM CAN EITHER BE SINGLE AMPLITUDE OR DOUBLE AMPLITUDE. THE SPECTRA ENTERED IS ASSUMED DOUBLE AMPLITUDE. IN MOST CASES, FOR A EXTREME WAVE ANALYSIS, THE SINGLE AMPLITUDE RESULTS ARE ARE DESIRED.

WAVE SPECTRAL DENSITY SPECIFICATION - INPUT LINE 5

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1 2 3 4 5 6 7 8 9 10111213141516171819202122232425262728293031323334353637383940

WSPEC 1 US7.0 10.0 0.45

SPEC 17.0 0.1 12.5 22.1

SPEC 4.0 1.85 3.0 0.45

41424344454647484950515253545556575859606162636465666768697071727374757677787980

10.0 43.8 5.0 5.62

2.0 0.05

A USER DEFINED WAVE SPECTRUM WILL BE USED. TO USE THIS LINE, ‘US’MUST BE SPECIFIED IN COLS. 11-12 ON THE WSPEC CARD.

USER DEFINED SPECTRUM

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LINELABEL

USER DEFINED SPECTRAL DATA

LEAVEBLANK

1ST POINT 2ND POINT 3RD POINT 4TH POINT

PERIODSPECTRAVALUE

PERIODSPECTRAVALUE

PERIODSPECTRAVALUE

PERIODSPECTRAVALUE

SPEC

1))) 4 9<))))))16 17<))))24 25<)))))32 33<))))40 41<)))))48 49<))))56 57<)))))64 65<))))72 73))))80

DEFAULTS

ENGLISH SECS FT**2/HZ SECS FT**2/HZ SECS FT**2/HZ SECS FT**2/HZ

METRIC SECS M**2/H SECS M**2/H SECS M**2/H SECS M**2/H

COLUMNS COMMENTARY

GENERAL THIS LINE DEFINES THE USER SPECTRUM. FOR THOSE CASES WHERE A PIERSON-MOSKOWITZ OR JONSWAP SPECTRUM DEFINITION IS NOT SATISFACTORY, THE USER CAN DEFINE A PARTICULAR SPECTRUM WITH UP TO 100 POINTS USING 4 VALUES PER RECORD AND UP TO 25 RECORDS. THESE RECORDS FOLLOW THE WSPEC RECORD WITH THE ‘US’ OPTION.

( 1- 4) ENTER ‘SPEC’

( 9-16) ENTER THE PERIOD OF THE FIRST POINT OF THE WAVE SPECTRUM. PERIODS MUST BE ENTERED IN DESCENDING ORDER. A PERIOD OF ZERO SHOULD NOT BE ENTERED.

(17-24) ENTER THE WAVE SPECTRUM VALUE IN TERMS OF WAVE HEIGHT SQUARED / HERTZ.

(25-40) ENTER THE SECOND POINT.

(41-56) ENTER THE THIRD POINT.

(57-72) ENTER THE FOURTH POINT.

USER DEFINED SPECTRUM - INPUT LINE 6

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1 2 3 4 5 6 7 8 9 10111213141516171819202122232425262728293031323334353637383940

END

41424344454647484950515253545556575859606162636465666768697071727374757677787980

THE LINE DESIGNATES THE END OF INPUT DATA.

END OF DATA

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LINELABEL

LEAVE THIS FIELD BLANK

END

1))))) 3 4)))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))) 80

DEFAULT

ENGLISH

METRIC

COLUMNS COMMENTARY

GENERAL THIS LINE IS THE LAST LineOF THE INPUT FILE.

( 1- 3) ENTER ‘END’.

END LINE - INPUT LINE 7

Combine

3-28

Combine

SECTION 4

COMMENTARY

Combine

Combine

4-1

rRMS ' r 21%r 2

2%r 23 ...%r 2

n

Dij '8 .i.j (.i%r.j)r

3/2

(1&r 2)2% 4.i.jr(1%r 2)% 4(.i2%.j

2)r 2

Dij '8.2(1%r)r 3/2

(1&r 2)2% 4.2r(1%r)2

4.0 COMMENTARY

4.1 SRSS COMBINATION METHOD

The square root of the sum of the squares combination method, usually called the SRSSor RMS method, is used to Combine analysis results that are not correlated and are notdirection dependent. The RMS result is taken as:

4.2 COMPLETE QUADRATIC COMBINATION METHOD

The application of two-dimensional methods to the three-dimensional dynamic analysishas resulted in the use of combination procedures that assume that only responses in thesame direction as the load occur. The contribution of modal responses orthogonal to theload are usually not considered.

The Complete Quadratic Combination 'CQC' method on the other hand, accounts for thecross-correlation or coupling among responses of closely spaced modes. This methodrecognizes that when a particular mode responds, a secondary coupled response mayoccur from modes whose frequencies are closely spaced. The contribution of thesesecondary responses can be expressed as a coefficient which is a function of the modalfrequencies, structural damping ratios and the frequency content of the load.

Assuming that the periods of the structural modes are short compared to the earthquakeduration, and the earthquake spectrum is smooth over a wide range of frequencies, thecross-correlation coefficient between modal responses i and j, can be calculatedfrom:where r = Tj/Ti.

For constant modal damping, .i = .j = constant, the cross correlation coefficient can betaken as:

Note: For equal damping, modes with the same frequency (r = 1), willrespond equally regardless of direction (pij = 1).

Combine

4-2

Y(f)'H(f)X(f) (1)

Yi(f)'Hi(f)X(f) (2)

The CQC method is most applicable for symmetric structures with orthogonal modes ofnearly the same frequency. For systems in which the frequencies are well separated, theCQC method solution degenerates to that of the SRSS method.

4.3 COMBINING STATIC AND SEISMIC RESULTS

For an earthquake analysis, the design forces for a member are obtained by combininggravity, buoyancy and hydrostatic induced forces with the forces resulting fromearthquake ground motion. Because earthquake induced forces are cyclic in nature andhave no sense of direction associated with them, relative signs of these forces should beselected so that the most conservative condition results.

The 'PRST' and 'PRSC' combination methods are used to Combine seismic stresses withstatic stresses. For either method, member shear, bending and torsion stresses due toseismic ground motion are assumed to have the same sign as the corresponding staticstress. The seismic axial stress is assumed to be in tension for the 'PRST' method and incompression for the 'PRSC' method. The seismic stresses are then linearly combined withthe static stresses.

Note: Normally, this results in the creation of two static plus seismicload combinations to be used for code check purposes, for eachseismic load case.

4.4 SPECTRAL RESPONSE ANALYSIS

Spectral response analysis is used to account for the random nature of a confused sea in arational manner. The method assumes that there is a definable relation between waveheight and structural response, and that at any point the elevation of the sea above itsmean value is a stationary Gaussian random process.

4.4.1 Linear Systems

It is shown in standard references that linear systems whose properties do not changewith time can be characterized in the frequency domain by an expression of the form:

where: f = frequency.X(f) = Fourier transform of the excitation.Y(f) = Fourier transform of the response.H(f) = Transfer function.

The transfer function (also called the frequency response function) can be thought of asthe amplitude of the sinusoidal response when the excitation is a sinusoid of unitamplitude. Equation (1) can be extended to the case of many response functions to agiven excitation by interpreting the terms in a matrix sense. In subscripted notation it iswritten as:

Combine

4-3

Yi(f)Yj(f)'Hi(f)Hj(f)X2(f) (3)

YiYj'HiHjX2

(4)

Y 2i 'H 2

i X 2 (5)

SZ(f)'Z 2(f) (6)

y 2(t)'m4

0S(f)df (7)

YRMS ' m4

0H 2

i (f)Sh(f)df (8)

In equation (2) Y and H are Nx1 matrices (or N component vectors) and X is a scaler (ora 1x1 matrix). Taking the outer product of eq.(2) with itself results in the following:

If the excitation, x(t), is a random function of time, then its Fourier transform, X(f), isalso a random function, as are those of the responses, Yi(f). In this case equation (3) is arelation between random functions (note, however, that the transfer functions, Hi(f), arewell defined and not random).

The average value of a random variable, Z, is represented by the notation Z. The averageof both sides of equation (3) gives:

Including only the diagonal terms of this matrix equation yields:

For any random function defined in the frequency domain, Z(f), the function Z2(f) iscalled the power spectral density (or the mean-square spectral density) of the process andis designated by:

The mean-square value of a stationary random function of time, y(t), ( ie. a processwhose statistics do not change with time) is given by:

The square root of this is called the root-mean-square (RMS) value. Combining thisdefinition with equations (5), (6) and (7) yields the RMS value of the response of thesystem:

Combine

4-4

FRMSi' m

4

0H 2

i (f)Sh(f)df (9)

For spectral response analysis of offshore structures, the excitation is the elevation of thewater surface at a point as a function of time, h(t), and the responses of interest. Theresponse is defined as the difference between successive maximum and minimum peaksin the plot of versus time.

Thus if the spectral density of a particular seastate Sh(f), is known, and the transferfunction Hi(f) can be calculated, then the statistical RMS response for this particularseastate may be taken as:

4.4.2 Transfer Function

A transfer function defines the ratio of the cyclic response to wave height as a functionof frequency for a particular wave direction. If, for each frequency, the input to thesystem is a unit amplitude sinusoid of that frequency, then the steady state amplitude ofthe response is the transfer function at that frequency.

To generate a transfer function for a particular load case or wave direction, severalwaves of various frequencies (periods) are used to load the structure. These loads can betime history loads or real and imaginary components. The response of the structure iscalculated and the difference between the maximum and minimum response isdetermined for each wave.

Dividing these response ranges by one-half of the corresponding wave height producesresponses for waves of unit amplitude because wave height equals twice the waveamplitude for sinusoidal waves. The relationship between the response ranges of unitamplitude and the corresponding wave frequency for all waves considered is the transferfunction.

Combine

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SPM(F ()'5h 2

s To

161

(F ()5exp[&

54

(F ()&4]

SJ(F()'

SPM(F ()

Cexp6ln(exp[& (F (&1)2

2F2]>

SOH(f) 'B2j

2

f'1

[4(48f%1)B4f 4pf]

8f

'(8f)

h 2sf

(2Bf)48f%1

exp[&48f%1

4(fpf

f)4]

4.4.3 Wave Height Spectral Density

Wave height spectra are used to characterize the random behavior of waves statistically.From a wave spectrum, a wave height spectral density relating the probabilitydistribution at various frequencies can be developed. Three forms of wave heightspectral density functions are commonly used in the offshore industry, all of which areincorporated into the Combine program; they are:

A. PIERSON-MOSKOWITZ SPECTRUM (BRETSCHNEIDER'S FORM)

B. JONSWAP (JOINT NORTH SEA WAVE PROJECT) SPECTRUM

where:hs = Significant wave height, defined as the average height of the 1/3 highest

waves.To = Dominant wave period, the period for which S(f) is a maximum.F* = Dimensionless frequency, f/fo, where fo is the frequency corresponding to To.(, F and C are parameters characterizing the JONSWAP spectrum. The followingdefaults are built into the program:( = 3.3

R 0.07 for F*<1F = |F 0.09 for F*>1C = 1.525

C. OCHI-HUBBLE DOUBLE PEAK SPECTRUM

where:f = wave frequency8 = peakednesshs = significant wave heightfp = spectral peak frequency

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4-6

FRMSi' m

4

0H 2(f)(Si(f)df

p(s)'s

F2RMS

exp[&s 2

2(F2RMS

]

Fmax ' &2 ln(1 & 0.01PROB) ( FRMS

4.4.4 Spectral Response

The RMS stress for a particular wave spectrum can be calculated from the following:

Si(f) is the wave height spectral density and H(f) is the transfer function for the directionbeing considered.

If a linear system is excited by a Gaussian random process, then the response will also bea where Gaussian process, thus having assumed system linearity and Gaussian excitation,the stress time histories are Gaussian at least to the order of our approximations. Further,if each response is assumed to be narrow banded, then the spectral density of theresponse is significant only over a narrow range of frequencies. Under these conditions

the stress range is a Rayleigh distributed random variable having a probability densityfunction given by:

where s is the response range and FRMS is the RMS value of the response range.

The maximum response may be calculated using the following:

Combine

SECTION 5

SAMPLE PROBLEMS

Combine

Combine

5-1

5.0 SAMPLE PROBLEMSThe structure shown below was used to demonstrate the various capabilities of theCombine program. Three separate Combine operations are illustrated:

1. The first sample problem illustrates the ability of the Combine program to createone solution file containing results from two separate solution files.

2. Sample Problem 2 illustrates the program's ability to Combine modal results

using the Complete Quadratic Combination technique.

3. Sample Problem 3 illustrates the program's ability to Combine earthquake andstatic results per API-RP2A guidelines.

Combine

5-2

5.1 SAMPLE PROBLEM 1

Two analyses were run for the same model with different support conditions. The resultswere combined into one solution file so that redesign could be done for the overallcritical condition.

The first solution file was designated as the primary solution file and contained resultsfor two load cases. The second solution file contained results for one load case and wasdesignated as the secondary solution file.

Below is the Combine input file for this sample problem followed by an explanation ofthe input lines used.

12345678901234567890123456789012345678901234567890123456789012345678901234567890

COMBINE SAMPLE PROBLEM 1CMBOPTLCOND LOAD CASE 1 OF SOLUTION FILE 1COMP P 1 1.0LCOND LOAD CASE 2 OF SOLUTION FILE 1COMP P 2 1.0LCOND LOAD CASE 1 OF SOLUTION FILE 2COMP S 1 1.0

A. The first line is a title line.

B. The CMBOPT is left blank.

C. The first LCOND line specifies that, by default, a linear combination is to beperformed when creating load case 1 (columns 14-17 left blank).

D. The COMP line specifies the following:

a. Load case one in the new solution file will consist of load case 1 of the primarysolution file ('P' in column 6 and '1' in column 10).

b. The load case factor is 1.0 as designated by '1.0' in columns 12-14.

E. The next LCOND line specifies that, by default, a linear combination is to beperformed when creating load case 2 (columns 14-17 left blank).

F. The ensuing COMP line specifies the following:

a. Load case two in the new solution file will consist of load case 2 of the primarysolution file ('P' in column 6 and '2' in column 10).


G. The last LCOND line specifies that a linear combination is to be performed whencreating load case 3 (columns 14-17 left blank).

H. The COMP line specifies the following:

a. Load case three in the new solution file will consist of load case 1 of thesecondary solution file ('S' in column 6 and '1' in column 10).

Combine

5-3


The following page contains the output listing for this sample problem.

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****** COMBINE PROGRAM OPTIONS ****** COMBINE SAMPLE PROBLEM 2

LOAD NUMB LOAD CASE DESCRIPTION UNIT ORIG FACTOR SIGN CHANGECASE COMB LC = ROT DEFL STRES XYZ XYZ

1 CQC X-DIRECTION RESPONSE 1 P 1 0.000 000 000 0 2 P 2 1.583 000 000 0 3 P 3 0.001 000 000 0 4 P 4 0.308 000 000 0 5 P 5 0.001 000 000 0 6 P 6 0.000 000 000 0 7 P 7 0.000 000 000 0 8 P 8 0.017 000 000 0 9 P 9 0.002 000 000 0 10 P 10 0.000 000 000 0

2 CQC Y-DIRECTION RESPONSE 1 P 1 0.000 000 000 0 2 P 2 0.001 000 000 0 3 P 3 1.583 000 000 0 4 P 4 0.001 000 000 0 5 P 5 0.308 000 000 0 6 P 6 0.000 000 000 0 7 P 7 0.000 000 000 0 8 P 8 0.002 000 000 0 9 P 9 0.017 000 000 0 10 P 10 0.000 000 000 0

3 CQC Z-DIRECTION RESPONSE 1 P 1 0.000 000 000 0 2 P 2 0.000 000 000 0 3 P 3 0.000 000 000 0 4 P 4 0.000 000 000 0 5 P 5 0.000 000 000 0 6 P 6 0.000 000 000 0 7 P 7 0.000 000 000 0 8 P 8 0.000 000 000 0 9 P 9 0.000 000 000 0 10 P 10 0.176 000 000 0

NUMBER OF FINAL LOAD CASES = 3

Combine

5-5


The following example illustrates the Complete Quadratic Combination technique.

The responses for ten modes are to be combined to create three load cases representingthe total response for the X, Y and Z directions respectively. Any cross-couplingbetween orthogonal modes is to be considered.

Below is the Combine input file used to create the solution file.

12345678901234567890123456789012345678901234567890123456789012345678901234567890

COMBINE SAMPLE PROBLEM 2 CMBOPTLCOND CQC X-DIRECTION RESPONSE

COMP P 1 0.2676E-04 0.11093E+01 0.05 COMP P 2 0.1583E+01 0.12512E+01 0.05 COMP P 3 0.1092E-02 0.12513E+01 0.05 COMP P 4 0.3080E+00 0.28624E+01 0.05 COMP P 5 -0.8988E-03 0.28626E+01 0.05 COMP P 6 -0.8665E-06 0.32961E+01 0.05 COMP P 7 -0.4582E-06 0.44839E+01 0.05 COMP P 8 0.1699E-01 0.51856E+01 0.05 COMP P 9 0.1758E-02 0.51857E+01 0.05 COMP P 10 -0.1025E-05 0.57600E+01 0.05 LCOND CQC Y-DIRECTION RESPONSE

COMP P 1 -0.2461E-04 0.11093E+01 0.05 COMP P 2 -0.1072E-02 0.12512E+01 0.05 COMP P 3 0.1583E+01 0.12513E+01 0.05 COMP P 4 0.9127E-03 0.28624E+01 0.05 COMP P 5 0.3080E+00 0.28626E+01 0.05 COMP P 6 0.1431E-05 0.32961E+01 0.05 COMP P 7 -0.2307E-07 0.44839E+01 0.05 COMP P 8 0.1728E-02 0.51856E+01 0.05 COMP P 9 -0.1688E-01 0.51857E+01 0.05 COMP P 10 0.1498E-06 0.57600E+01 0.05 LCOND CQC Z-DIRECTION RESPONSE

COMP P 1 -0.6543E-06 0.11093E+01 0.05 COMP P 2 -0.4092E-06 0.12512E+01 0.05 COMP P 3 -0.7652E-07 0.12513E+01 0.05 COMP P 4 -0.1212E-05 0.28624E+01 0.05 COMP P 5 0.2822E-08 0.28626E+01 0.05 COMP P 6 -0.1045E-05 0.32961E+01 0.05 COMP P 7 0.4767E-07 0.44839E+01 0.05 COMP P 8 0.1103E-05 0.51856E+01 0.05 COMP P 9 0.3179E-06 0.51857E+01 0.05 COMP P 10 0.1761E+00 0.57600E+01 0.05

The following is a detailed explanation of the input lines used.


B. The CMBOPT is left blank.

Combine

5-6

C. The first LCOND line specifies that a CQC combination is to be performed when

creating load case 1 ('CQC' in columns 14-17).

D. The ensuing COMP lines specify the following:

a. Load case 1 in the new solution file will consist of the modal responses for

modes 1 through 10 of the primary solution file ('P' in column 6 and the mode

number in columns 9-10).

b. The modal response factor of each mode is designated in columns 11-22.

c. The frequency of each mode is designated in columns 32-43.

d. A damping ratio of 0.05 is specified in columns 44-55 for each mode.

E. The LCOND and COMP lines are repeated for each load case.

Note: When executing an earthquake analysis using the DYNAMIC RESPONSE

module with a runfile created by the SACS Executive, the Combine

input files for CQC and/or RMS combinations are created

automatically. The Combine steps are executed automatically as

part of the earthquake analysis.

The following is the output for Sample Problem 2.

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COMBINE SAMPLE PROBLEM 2 DATE 22-NOV-1993 TIME 11:52:37 CMB PAGE 1

CMB VERSION I.D.012

****** COMBINE PROGRAM OPTIONS ****** COMBINE SAMPLE PROBLEM 2


1 CQC X-DIRECTION RESPONSE 1 P 1 0.000 000 000 0 2 P 2 1.583 000 000 0 3 P 3 0.001 000 000 0 4 P 4 0.308 000 000 0 5 P 5 0.001 000 000 0 6 P 6 0.000 000 000 0 7 P 7 0.000 000 000 0 8 P 8 0.017 000 000 0 9 P 9 0.002 000 000 0 10 P 10 0.000 000 000 0

2 CQC Y-DIRECTION RESPONSE 1 P 1 0.000 000 000 0 2 P 2 0.001 000 000 0 3 P 3 1.583 000 000 0 4 P 4 0.001 000 000 0 5 P 5 0.308 000 000 0 6 P 6 0.000 000 000 0 7 P 7 0.000 000 000 0 8 P 8 0.002 000 000 0 9 P 9 0.017 000 000 0 10 P 10 0.000 000 000 0

3 CQC Z-DIRECTION RESPONSE 1 P 1 0.000 000 000 0 2 P 2 0.000 000 000 0 3 P 3 0.000 000 000 0 4 P 4 0.000 000 000 0 5 P 5 0.000 000 000 0 6 P 6 0.000 000 000 0 7 P 7 0.000 000 000 0 8 P 8 0.000 000 000 0 9 P 9 0.000 000 000 0 10 P 10 0.176 000 000 0 NUMBER OF FINAL LOAD CASES = 3

Combine

5-8


The following example illustrates the ability to Combine static and seismic results usingthe 'PRST' and 'PRSC' features of the program.

A solution file containing the results for dead load, buoyancy and hydrostatic pressure,applied as a single load case, was created from a static analysis.

The earthquake solution file contains results representing the combined response for X-axis, Y-axis and Z-axis ground accelerations applied simultaneously. The results arecontained in one load case and have no direction associated with them.

The static and earthquake results will be combined so that member check and jointcheck can be performed. A total of four load cases, two for member check and two forjoint capacity check, containing both static and seismic stresses will be created. Formember check, one load case with all seismic axial stresses assumed to be tension andone load case with all seismic axial stresses assumed to be in compression will becreated. For joint check, both load cases will contain static stresses plus double theseismic stress. One load case will contain seismic axial stresses in tension, the other willcontain seismic axial stresses in compression.

Note: The sign of all other seismic stresses will be assumed to be thesame as the corresponding static stress. See the Commentary for acomplete discussion.

The following page contains the Combine input file used for this problem followed by adetailed description of each input line used.

12345678901234567890123456789012345678901234567890123456789012345678901234567890

STATIC + EARTHQUAKE CODE CHECK COMBINECMBOPTLCOND PRSC MEMBER CHECK STATIC + QUAKE COMPRESSIONCOMP P 1 1.0COMP S 1 1.0LCOND PRST MEMBER CHECK STATIC + QUAKE TENSIONCOMP P 1 1.0COMP S 1 1.0LCOND PRSC JOINT CHECK STATIC + QUAKE COMPRESSIONCOMP P 1 1.0COMP S 1 2.0LCOND PRST JOINT CHECK STATIC + QUAKE TENSIONCOMP P 1 1.0COMP S 1 2.0


B. The CMBOPT line is left blank.

C. The first LCOND line specifies that for load case 1, seismic axial stresses shall beassumed to be in compression ('PRSC' in columns 14-17).

D. The COMP lines specify the following:

Combine

5-9

a. Load case one in the new solution file will consist of load case 1 of the primarysolution file ('P' in column 6 and '1' in columns 10) and load case 1 of thesecondary solution file.

b. The load case factor for both load cases is 1.0 as designated by '1.0' in columns12-14.

E. The second LCOND line specifies that for load case 2, seismic axial stresses shall beassumed to be in tension ('PRST' in columns 14-17).

F. The COMP lines specify the following:

a. Load case two in the new solution file will consist of load case 1 of the primarysolution file ('P' in column 6 and '1' in column 10) and load case 1 of thesecondary solution file.

b. The load case factor for both load cases is 1.0 as designated by '1.0' in columns12-14.

G. The third LCOND line specifies that for load case 3, seismic axial stresses shall beassumed to be in compression ('PRSC' in columns 14-17).

H. The COMP lines specify that load case three in the new solution file will consist ofload case 1 of the primary solution file factored by 1.0 ('P' in column 6, '1' in column10 and '1.0' in cols 12-14), and load case 1 of the secondary solution file factored by2.0 ('P' in column 6, '1' in columns 10 and '2.0 in cols 12-14).

I. The last LCOND line specifies that for load case 4, seismic axial stresses shall beassumed to be in tension ('PRST' in columns 14-17).

J. The COMP lines specify that load case four in the new solution file will consist ofload case 1 of the primary solution file factored by 1.0 ('P' in column 6, '1' in column10 and '1.0' in cols 12-14), and load case 1 of the secondary solution file factored by2.0 ('P' in column 6, '1' in columns 10 and '2.0 in cols 12-14).

Note: When combining static and seismic results, the file containingstatic results must be designated as the Primary solution file andthe file containing seismic results must be designated as theSecondary solution file.

The following is the output for Sample Problem 3.

Com

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STATIC + EARTHQUAKE CODE CHECK COMBINE DATE 18-JAN-1993 TIME 09:51:45 CMB PAGE 1

CMB VERSION I.D.011

****** COMBINE PROGRAM OPTIONS ******

STATIC + EARTHQUAKE CODE CHECK COMBINE


1 PRSC MEMBER CHECK STATIC + QUAKE COMPRESSION

1 P 1 1.000 000 000 0

2 S 1 1.000 000 000 0

2 PRST MEMBER CHECK STATIC + QUAKE TENSION

1 P 1 1.000 000 000 0

2 S 1 1.000 000 000 0

3 PRSC JOINT CHECK STATIC + QUAKE COMPRESSION

1 P 1 1.000 000 000 0

2 S 1 2.000 000 000 0

4 PRST JOINT CHECK STATIC + QUAKE TENSION

1 P 1 1.000 000 000 0

2 S 1 2.000 000 000 0

NUMBER OF FINAL LOAD CASES = 4

sample prob 2

Documents

static results

extreme wave analysis

earthquake results

seismic results

dynamic results

extreme wind results

extreme wave input

spectral response analysis