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CFVR1905 - Steel checking according to British Standard 5950 1985

Lateral torsional buckling check of a simply supported steel beam.

A simply supported steel beam with I built-up shape section is subjected to a uniform load of 80 KN/m.
Determine the section class and total criterion according to BS 5950-85.

Element types used in the model: BEAM3

Needed CivilFEM Modules:
Geotechnical Module
Bridges and Civil Non Linearities Module
Advanced Prestressed Concrete Module

The example can be launched on an educational license.
KEYWORDS
Beam
Cross Section
Code Checking/Design
Steel
BS 5950-85

Model Statistics
Number of elements 6
Number of nodes 7
Number of civil materials 1
Number of cross sections 1
Number of shell vertices 0

Log file: CFVR1905.DAT


  FINISH
  ~CFCLEAR,,1
  NomFile='CFVR1905'
  /TITLE, %NomFile%, British Standard : Lateral Buckling

! -------------------------------------------------------------------------------------
! Initial data
! -------------------------------------------------------------------------------------
! CivilFEM Setup: Code & Units
  ~UNITS,,LENG,M
  ~UNITS,,TIME,S
  ~UNITS,,FORC,KN
  ~CODESEL,BS595085

/PREP7
! Materials
  ~CFMP,1,LIB,STEEL,BS5950,GrWR50B  ! GrWR50B

! Element types
  ET,1,Beam3 ! Element Type 1: 2D Beam

! Sections
~SSECDMS,2,I,1,0.44,6e-003,0.22,2e-002,3e-003

! Member properties
  L        = 6
  KLTXY    = 1
  KLTXZ    = 1
  KCXY     = 1.1
  KCXZ     = 1.1
  CteRob   = 0
  n        = 1
  m        = 1
  DL       = 0
  CFBUCKXY = 1
  CFBUCKXZ = 1
  CHCKAXIS = 0
  ~MEMBPRO,1,BS595085,ALL,L,KLTXY,KLTXZ,KCXY,KCXZ,CteRob,n,m,DL,CFBUCKXY,CFBUCKXZ,CHCKAXIS

! Beam properties
 ~BMSHPRO,1,BEAM,2,2,,,3,1,0

! Nodes
  N,1
  N,7,6
  FILL,1,7
! Elements
  E,1,2
  EGEN,6,1,1,1
! Boundary conditions
  D,1,,,,,,UX,UY
  D,7,,,,,,UY
! Plot
  /ESHAPE,1
  EPLOT

/SOLU
  P=80*1.5 ! 80 KN/m uniform distributed load
  SFBEAM,ALL,1,PRES,P
  SOLVE

/POST1
! Postprocessor
  ~CFSET,,1,1       ! Load first load case
! Plot bending moment MZ
  ~PLLSFOR,M,Z,-1
! Eurocode No.3 Check for lateral bending
  ~CHKSTL,BUCK_LAT
!--------------------------------------------------------------------------------------
! DATA CHECK
!--------------------------------------------------------------------------------------
! Data comparison number
  NComp = 9
  NComp_ch =  0

! Marix dim.
  *DIM,LABEL,CHAR,Ncomp,1
  *DIM,LABEL_CH,CHAR,Ncomp_ch,1
  *DIM,VALUE,,Ncomp,3
  *DIM,VALUE_CH,CHAR,Ncomp_ch,3
  *DIM,TOLER,,Ncomp,2

! Labels
  LABEL(1,1) = 'CLASS   '
  LABEL(2,1) = 'WEBCLASS'
  LABEL(3,1) = 'CRT_TOT '
  LABEL(4,1) = 'UNF_MOMT'
  LABEL(5,1) = 'MB      '
  LABEL(6,1) = 'LAMBDA  '
  LABEL(7,1) = 'LAMBDALT'
  LABEL(8,1) = 'LAMBDAL0'
  LABEL(9,1) = 'M       '

! Correct values
  VALUE(1,1)= 1
  VALUE(2,1)= 2
  VALUE(3,1)= 1.6738
  VALUE(4,1)= 540.
  VALUE(5,1)= 322.610
  VALUE(6,1)= 117.416
  VALUE(7,1)= 92.488
  VALUE(8,1)= 30.63
  VALUE(9,1)= 1

! Obtained values
 ~PLLSSTL,CLASS
  *GET,VALUE(1,2),ELEM,3,ETAB,CLASS_J
 ~PLLSSTL,WEBCLASS
  *GET,VALUE(2,2),ELEM,3,ETAB,CLASS_J
 ~PLLSSTL,CRT_TOT
  *GET,VALUE(3,2),ELEM,3,ETAB,CFETAB_J
 ~PLLSSTL,UNF_MOMT
  *GET,VALUE(4,2),ELEM,3,ETAB,CFETAB_J
 ~PLLSSTL,MB
  *GET,VALUE(5,2),ELEM,3,ETAB,CFETAB_J
 ~PLLSSTL,LAMBDA
  *GET,VALUE(6,2),ELEM,3,ETAB,CFETAB_J
 ~PLLSSTL,LAMBDALT
  *GET,VALUE(7,2),ELEM,3,ETAB,CFETAB_J
 ~PLLSSTL,LAMBDAL0
  *GET,VALUE(8,2),ELEM,3,ETAB,CFETAB_J
 ~PLLSSTL,M
  *GET,VALUE(9,2),ELEM,3,ETAB,CFETAB_J

! Warning and error tolerances
  TOLER( 1,1)= 1E-3 $ TOLER( 1,2)= 1E-3
  TOLER( 2,1)= 1E-3 $ TOLER( 2,2)= 1E-3
  TOLER( 3,1)= 1E-3 $ TOLER( 3,2)= 1E-3
  TOLER( 4,1)= 1E-3 $ TOLER( 4,2)= 1E-3
  TOLER( 5,1)= 1E-3 $ TOLER( 5,2)= 1E-3
  TOLER( 6,1)= 1E-3 $ TOLER( 6,2)= 1E-3
  TOLER( 7,1)= 1E-3 $ TOLER( 7,2)= 1E-3
  TOLER( 8,1)= 1E-2 $ TOLER( 8,2)= 1E-2  ! Rounding error accepted
  TOLER( 9,1)= 1E-3 $ TOLER( 9,2)= 1E-3

!--------------------------------------------------------------------------------------
! Results comparison
!--------------------------------------------------------------------------------------
  COMPARA.MAC

Results

LabelTargetCivilFEMRatioTolerance
CLASS 1 11.000 0.001
WEBCLASS 2 21.000 0.001
CRT_TOT 1.6738 1.67381.000 0.001
UNF_MOMT 540 5401.000 0.001
MB 322.61 322.611.000 0.001
LAMBDA 117.42 117.421.000 0.001
LAMBDALT 92.488 92.4881.000 0.001
LAMBDAL0 30.63 30.6321.000 0.01
M 1 11.000 0.001


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