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CFVR8010 - Strip-footing collapse

Bearing capacity of a strip footing on a Mohr-Coulomb medium

This example is the 3-D version of CFVR8009 example, being completely analogous to it. For a complete description refer to that example.

Element types used in the model: SOLID186,TARGE170,CONTA174

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

The example cannot be launched on an educational license.
KEYWORDS
Materials
Geotechnics
Material Models

Model Statistics
Number of elements 347
Number of nodes 2556
Number of civil materials 1
Number of cross sections 0
Number of shell vertices 0

Log file: CFVR8010.DAT


  FINISH
  ~CFCLEAR,,1
  NomFile='CFVR8010'
  /TITLE, %NomFile%, Strip-footing collapse
  
  PI = ACOS(-1)

! ----------------------------------------------------------------------
! Initial data
! ----------------------------------------------------------------------
  ~UNITS,SI
  /PREP7

  IFLOW = 0 !!1      ! type of flow law
  EMOD  = 1.E10  ! elasticity modulus
  NU    = 0.48   ! Poisson's ratio
  PHI   = 20.    ! friction angle
  COH   = 490.E3 ! cohesion
  PSI   = 10     ! dilation angle
  HYP   = 0.05*COH/TAN(PHI*PI/180) ! hyperbolicity parameter
  NTINC = 50*4     ! number of time increments
  U0    = -0.002 ! prescribed displacement of the footing

! ----------------------------------------------------------------------
! Model definition
! ----------------------------------------------------------------------

  ! Materials

  ~CFMP,1,LIB,SOIL,,CL
  ~CFMP,1,SOIL,EXST,,EMOD
  ~CFMP,1,SOIL,NUXYST,,NU
  ~CFMP,1,SOIL,KPLA,,2
  ~CFMP,1,SOIL,KMCSP,,1
  ~CFMP,1,SOIL,PHIMCEFF,,PHI
  ~CFMP,1,SOIL,CMCEFF,,COH
  ~CFMP,1,SOIL,DELEFF,,PSI
  ~CFMP,1,SOIL,HYP,,HYP
  ~CFMP,1,SOIL,IFLOW,,IFLOW

  ! Element types

  ET,1,SOLID186
  *IF,IFLOW,EQ,1,THEN
    KEYOPT,1,5,1
  *ENDIF

  ET,2,TARGE170
  KEYOPT,2,2,1
  ET,3,CONTA174
  KEYOPT,3,2,0
  KEYOPT,3,12,4

  ET,4,MESH200
  KEYOPT,4,1,7

  ! Geometry
  
  K,1,0.,0.
  K,2,5.,0.
  K,3,5.,5.
  K,4,.5,5.
  K,5,0.,5.
  L,1,2
  L,2,3
  L,3,4
  L,4,5
  L,5,1
  AL,1,2,3,4,5

  VEXT,1,,,0.,0.,1.

  ! Meshing

  TYPE,4
  ESIZE,0.4
  AMESH,1

  NSEL,S,LOC,X,-0.001,1.
  NSEL,R,LOC,Y,4.,5.001
  NREFINE,ALL,,,2
  NSEL,ALL

  TYPE,1
  EXTOPTE,ACLEAR,1
  EXTOPT,ESIZE,1
  VSWEEP,1,1,2

  *GET,TMP,NODE,,NUM,MAXD
  ND0 = TMP + 1
  N,ND0,0.,6.,0.5 ! pilot node to impose displacement of the footing
  TMP  = ND0 + 1
  TMP1 = ND0 + 2
  TMP2 = ND0 + 3
  TMP3 = ND0 + 4
  NKPT,TMP,5
  NKPT,TMP1,4
  NKPT,TMP2,9
  NKPT,TMP3,10

  REAL,2
  TYPE,2
  TSHAP,PILO
  E,ND0
  TSHAPE,QUAD
  E,TMP,TMP1,TMP2,TMP3

  TYPE,3
  ASEL,S,,,6
  NSLA,S,1
  ESLN,S
  ESURF

  ASEL,ALL
  NSEL,ALL
  ESEL,ALL
  
  ! Loads

  DA,1,UZ
  DA,2,UZ
  DA,3,UY
  DA,4,UX
  DA,7,UX
  D,ND0,UX
  D,ND0,UY,U0
  D,ND0,UZ
  D,ND0,ROTX
  D,ND0,ROTY
  D,ND0,ROTZ
  
!-----------------------------------------------------------------------
! DATA CHECK
!-----------------------------------------------------------------------
! Data comparison number
  NCOMP    = 1
  NCOMP_CH = 0

! Array dimensions
  *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) = 'Collapse factor'

! Warning and error tolerances
  !TOLER(1,1) = 0.23 $ TOLER(1,2) = 0.23
  !TOLER(1,1) = 0.76 $ TOLER(1,2) = 0.76
  !TOLER(1,1) = 0.9  $ TOLER(1,2) = 0.9  ! 6% = 0.06
  TOLER(1,1) = 15.0 * 0.06 $ TOLER(1,2) = 15.0 *0.06

! Correct values
!-----------------------------------------------------------------------
 
  VALUE(1,1) = 15.

! Obtained values
!-----------------------------------------------------------------------
  /SOLU

  AUTOTS,OFF
  NSUBST,NTINC
  *IF,IFLOW,EQ,1,THEN
    NROPT,UNSYM
  *ELSE
    NROPT,FULL
  *ENDIF
  NEQIT,50

  ERESX,NO
  OUTRES,ALL,NONE
  OUTRES,NSOL,5
  OUTRES,ESOL,5
  OUTRES,RSOL,5

  SOLVE

  *GET,TMP,NODE,ND0,RF,FY
  VALUE(1,2) = -2*TMP/(1.*COH)

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



Results

LabelTargetCivilFEMRatioTolerance
Collapse 15 14.2381.051 15


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