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CFVR8652 - AISC15: Chapter E Design of Members for Compression.

Compression check according to AISC/ASD15 - BUILT-UP COLUMN WITH A SLENDER WEB

A built-up column is subjected to a compression force.
The column of 15ft of length is pinned top and bottom in both axes.
The aim of the example is to obtain the compression criterion according to AISC15 (LRFD/ASD). REFERENCE: Volume 1: Design Examples Version 15.1 EXAMPLE E.2 BUILT-UP COLUMN WITH A SLENDER WEB

Element types used in the model: BEAM188

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
Steel
Code Checking/Design
AISC15

Model Statistics
Number of elements 1
Number of nodes 2
Number of civil materials 1
Number of cross sections 1
Number of shell vertices 0

Log file: CFVR8652.DAT


 FINISH
 ~CFCLEAR,,1
 NomFile='CFVR8652'
 /TITLE, %NomFile%, AISC15: Compression Check 
!--------------------------------------------------------------------------------------
! Model definition
!--------------------------------------------------------------------------------------
! CivilFEM Setup: Code & Units
  ~UNITS,,LENG,IN
  ~UNITS,,TIME,S
  ~UNITS,,FORC,KIPS! in, sec, Kips
  ~CODESEL,AISC15

! Parameters
  P  = -420		! Axial force kips

/PREP7
! Preprocessor
! --------------------------------------------------
! Materials
 ~CFMP,1,LIB,STEEL,ASTM,A572Gr50  ! ASTM A572 Grade 50
 
! Element Types
  ET,1,188  ! Type 1: 3D Beam
  
! Cross Section Built-up
  H  = 17
  TW = 0.25
  BF = 8
  TF = 1
  D  = 15
  
  ~SSECDMS,1,I,1,H ,TW, BF, TF,, D   

! member property: effective length = 15 ft
  ~MEMBPRO,1,AISC15,ALL,15.00*12,1.00,1.00,1.000,1.000,15.00*12,  
   
! Beam & Shell Property
  ~BMSHPRO,1,BEAM,1,1,,,188,1,0,,Beam 1
  
! Nodes
  N,1
  N,2,,2
  
! Elements
  SECNUM,1
  REAL,1
  E,1,2  

  /SOLU
! Solution
! --------------------------------------------------
! Constrains
  D,1,ALL
  
! Apply Load
  F,2,FY,P
  
! Solve
  SOLVE
  
  /POST1
! Postprocessor
! --------------------------------------------------
! Read results
  ~CFSET,,1                ! First load case
  
! Checking
 ~CHKSTL,COMPRESS,Z,LRFD   
 ~CHKSTL,COMPRESS,Z,ASD 
 
 !--------------------------------------------------------------------------------------
! DATA CHECK
!--------------------------------------------------------------------------------------
! Data comparison number
  NComp = 6
  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) = 'FCR'
  LABEL(2,1) = 'PN'
  LABEL(3,1) = 'FE'
  LABEL(4,1) = 'CLS_COMP'
  LABEL(5,1) = 'CRT_LRFD'
  LABEL(6,1) = 'CRT_ASD'

! Correct values
  VALUE(1,1)=28.9   ! Flexural buckling stress (Spec. Eq. E3-2) 
  VALUE(2,1)=555    ! Nominal Compressive Strength (Spec. Eq. E7-1) 
  VALUE(3,1)=38.3   ! Elastic  critical  buckling  stress (Spec. Eq. E3-4) 
  VALUE(4,1)=2.00   ! web is slender
  VALUE(5,1)=0.84   ! LRFD CRITERION   420/(0.90*555)
  VALUE(6,1)=1.26   ! ASD CRITERION    420/(555/1.67)

! Comparison

~CFSET,1   ! LRFD 
 ~CFGET,VALUE(1,2),ELEMENT,1,RESULT,FCR,I 
 ~CFGET,VALUE(2,2),ELEMENT,1,RESULT,PN,I 
 ~CFGET,VALUE(3,2),ELEMENT,1,RESULT,FE,I 
 ~CFGET,VALUE(4,2),ELEMENT,1,RESULT,CLS_COMP,I
 ~CFGET,VALUE(5,2),ELEMENT,1,RESULT,CRT_TOT,I
 
~CFSET,2  ! ASD 
 ~CFGET,VALUE(6,2),ELEMENT,1,RESULT,CRT_TOT,I

! Warning and error tolerances
*DO,JJ,1,6
 TOLER(JJ,1)= 0.04*VALUE(JJ,1) $ TOLER(JJ,2)= 0.04*VALUE(JJ,1)
*ENDDO
  
!--------------------------------------------------------------------------------------
! Results comparison
!--------------------------------------------------------------------------------------
  COMPARA.MAC

 

Results

LabelTargetCivilFEMRatioTolerance
FCR 28.9 28.91.000 1.156
PN 555 553.371.003 22.2
FE 38.3 38.1771.003 1.532
CLS_COMP 2 21.000 0.08
CRT_LRFD 0.84 0.843310.996 0.0336
CRT_ASD 1.26 1.26750.994 0.0504


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