CFVR1324 - Biaxial Bending + Axial force checking according to ACI 318

check a reinforced concrete beam subjected to Biaxial Bending + Axial force according to ACI 318

A fixed beam which has a I reinforced concrete section is subjected to an axial compression force of 212.46 Mp, a bending moment of 20 m*Mp on the Z axis direction, and a bending moment of 15 m*Mp on the Y axis direction.
The aim of the example is to obtain the check criterion according to ACI 318.

Element types used in the model: BEAM4

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

Reinforced Concrete

ACI 318

Model Statistics
Number of elements	4
Number of nodes	5
Number of civil materials	2
Number of cross sections	1
Number of shell vertices	0

Log file: CFVR1324.DAT

   FINISH
  ~CFCLEAR,,1
   NomFile='CFVR1324'
 /TITLE,%NomFile%, Biaxial Bending + Axial force checking according to ACI 318

! -------------------------------------------------------------------------------------
! Initial data
! -------------------------------------------------------------------------------------
! CivilFEM SETUP
 ~UNITS,BIN
 ~CODESEL,,ACI

 ! Parameters
  Ec_ACI=3820000 ! Psi
  
! Preprocessor
  /PREP7

! Material Definition
 ~CFMP,1,LIB,CONCRETE,ACI,fc_3500
 ~CFMP,1,USER
 ~CFMP,1,ACI_C   ,Ec      ,,  Ec_ACI,7,0,0
 ~CFMP,2,LIB,REINF,ACI,fy_70000
 
 FINISH
 ~UNITS,,LENG,M
 ~UNITS,,TIME,S
 ~UNITS,,FORC,MP
 /PREP7
! Element Type Definition
  ET,1,Beam4                            ! Element Type 1: 3D Beam

! Cross-section definition
 ~CSECDMS,1,I,1,0.6,0.15,0.5,0.2,0.3,0.15
! Reinforcement definition
 ~RNFDEF,1,1,2,2,0,0.046,0.5120E-2
 ~SECMDF,1,STRPROP,ASEC,,7  
! Beam & Shell property
 ~BMSHPRO,1,BEAM,1,1,,,4,1,0,,Beam property

! Model Construction
  N,1                                   ! Nodes input
  N,5,5
  FILL,1,5
  E,1,2                                 ! Elements input
  EGEN,4,1,1,1
  D,1,ALL                               ! Boundary conditions

/SOLU
  M1=20				   ! 144.62 Kip*ft bending moment
  M2=15		           ! 108.46 Kip*ft bending moment
  H=-212.46            ! 528.36 Kip axial force
  F,5,FX,H
  F,5,MZ,M1
  F,5,MY,M2
  SOLVE               ! Calculation

/POST1

! Postprocessor
  ~CFSET,,1,1       ! Read first load step

! Biaxial Bending + Axial force checking according to ACI 318
  ~CHKCON,3DB

!--------------------------------------------------------------------------------------
! DATA CHECK
!--------------------------------------------------------------------------------------
! Data comparison number
  NComp = 2
  NComp_ch = 0

! Matrix 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) = 'CRTC2D_I'
  LABEL(2,1) = 'CRTC2D_J'

! Correct values
  VALUE(1,1)=1.59
  VALUE(2,1)=1.59 

! Comparison
 ~PLLSCON,CRT_TOT
 *GET,VALUE(1,2),ELEM,4,ETAB,CFETAB_I
 ~PLLSCON,CRT_TOT
 *GET,VALUE(2,2),ELEM,4,ETAB,CFETAB_J

! Warning and error tolerances
  TOLER( 1, 1)= 5.0E-02 $ TOLER( 1, 2)= 5.0E-02
  TOLER( 2, 1)= 5.0E-02 $ TOLER( 2, 2)= 5.0E-02

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

Results

Label	Target	CivilFEM	Ratio	Tolerance
CRTC2D_I	1.59	1.5703	1.012	0.05
CRTC2D_J	1.59	1.5703	1.012	0.05

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CFVR1324 - Biaxial Bending + Axial force checking according to ACI 318

check a reinforced concrete beam subjected to Biaxial Bending + Axial force according to ACI 318

Results