Left

CivilFEM Online Help

Right

CFVR4907 - PS 92: Seismic Analysis (design spectrum) Z-axis

Seismic Analysis on a 1 DOF beam according to PS 92

This example compares spectrum accelerations given by CivilFEM to accelerations obtained when solving on a 1 DOF beam and to the correct PS 92 spectum accelerations.
The model is 1 element beam with only 1 DOF, which direction the CivilFEM spectrum is set (the rest of the DOF are constrained). A different mass is applied at the free end of the beam for the beam period to be equal to the 20 CivilFEM spectrum points. After solving, the mass acceleration is obtained and compared to the CivilFEM spectrum acceleration and to the correct value. Therefore, this example checks the following results:

  • CivilFEM spectrum is defined correctly by comparing to the correct value
  • CivilFEM spectrum is applied correctly and response acceleration is equal to spectrum acceleration

Element types used in the model: BEAM4, MASS21

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
Seismic
PS 92

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: CFVR4907.DAT


   FINISH
  ~CFCLEAR,,1
  NomFile='CFVR4907'
  /TITLE, %NomFile%, PS 92: Seismic Analysis (design spectrum) Z-axis

! ----------------------------------------------------------------------
! Model definition
! ----------------------------------------------------------------------
! CivilFEM Setup: Code & Units
~UNITS,,LENG,CM
~UNITS,,TIME,S
~UNITS,,FORC,KP
~CODESEL,,,,,PS92
/PREP7
! Preprocessor
! ----------------------------------------------------------------------
! Materials: A-42
 ~CFMP,1,LIB,STEEL,EA,A42
! Modify density (Rho = 0)
 ~CFMP,1,USER
 ~CFMP,1,DatGen,RHO,,0
! Element Types
  ET,1,BEAM4   ! Type 1: 3D Beam
  ET,2,MASS21  ! Type 2: Mass
! Sections
 ~SSECLIB,1,1,1,1   !IPE 80
 ~BMSHPRO,1,BEAM,1,1,,,4,,0,,

! Nodes
  L = 10              ! L    : Bar length
  N, 1
  N,10,L

! Elements
  TYPE,1
  MAT ,1
  REAL,1
  EN,1,1,10
  EPLOT
! Parameters
  *GET,AR20,EX,1         		          ! Ex   : Elastic Modulus
  ~CFGET,AR22,SECTION,1,MECHPROP,A,,2     ! Area : Bar area
  ~CFGET,AR23,SECTION,1,MECHPROP,IZZ,,2   ! Izz  : Moment of inertia
  ~CFGET,AR24,SECTION,1,MECHPROP,IYY,,2   ! Iyy  : Moment of inertia

! Spectrum definition
  ~DEFSPEC,ALL,0.1*981,S2,DESIGN,1,5

  pi=3.141592654

! ----------------------------------------------------------------------
! DATA CHECK
! ----------------------------------------------------------------------
! Data comparison number
  NComp = 40
  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

*DO,ARG1,1,20
   /PREP7
   ~CFGET,AR26,SEISM,,SPEC,TH,,ARG1,2   ! Period
  ! Labels
   LABEL(ARG1,1) = 'Sa(%ARG1%)z'
   LABEL(20+ARG1,1) = 'Sa(%ARG1%)z'

   AR25=12*AR20*AR24/L**3      ! Bending rigidity around Y axis
   AR27=AR25*(AR26/(2*pi))**2  ! Mass applied at end
   R,2,0,0,AR27
   TYPE,2
   MAT, 1
   REAL,2
   EN,2,10
   FINISH
   /SOLU

 ! Solution
 ! ---------------------------------------------------------------------
 ! Displacements
   D,1,,,,,,ALL
   D,10,,,,,UX,UY,,ROTX,ROTY,ROTZ
   ~MODLSOL,1
   ~CMBMOD,NONE,NONE,HORIZONT,0,0.0001
 ! Query results
   *GET,ARG5,NODE,10,U,Z
 ! Correct values
   VALUE(20-ARG1+1,1)=ARG5*AR25/AR27 ! Acceleration
 ! Obtained values
   ~CFGET,VALUE(20-ARG1+1,2),SEISM,,SPEC,SDH,,ARG1,2	 ! Y components of design horizontal spectrum
   ~CFGET,VALUE(40-ARG1+1,2),SEISM,,SPEC,SDH,,ARG1,2	 ! Y components of design horizontal spectrum
   /PREP7
   ! CivilFEM gives the spectrum Normalized by gravity.
   ! To compare it must be changed to acceleration user units.
   VALUE(20-ARG1+1,2) = VALUE(20-ARG1+1,2)*981
   VALUE(40-ARG1+1,2) = VALUE(40-ARG1+1,2)*981
   EDELE,2
*ENDDO

! Correct values
! ----------------------------------------------------------------------
 VALUE(40,1)= 13.01916
 VALUE(39,1)= 14.64925
 VALUE(38,1)= 16.63230
 VALUE(37,1)= 19.08261
 VALUE(36,1)= 22.16619
 VALUE(35,1)= 26.13204
 VALUE(34,1)= 31.36869
 VALUE(33,1)= 38.51187
 VALUE(32,1)= 48.66540
 VALUE(31,1)= 63.89720
 VALUE(30,1)= 68.23349
 VALUE(29,1)= 73.38913
 VALUE(28,1)= 79.64364
 VALUE(27,1)= 87.42696
 VALUE(26,1)= 97.44034
 VALUE(25,1)= 110.91976
 VALUE(24,1)= 130.29248
 VALUE(23,1)= 161.16594
 VALUE(22,1)= 220.72500
 VALUE(21,1)= 220.72500

! Warning and error tolerances
! ----------------------------------------------------------------------
   *DO,II,1,NComp
     TOLER(II, 1)= 0.1 $ TOLER(II, 2)= 0.1
   *ENDDO

! ----------------------------------------------------------------------
! Results Comparison
! ----------------------------------------------------------------------
  COMPARA.MAC

Results

LabelTargetCivilFEMRatioTolerance
Sa(1)z 220.73 220.721.000 0.1
Sa(2)z 220.72 220.721.000 0.1
Sa(3)z 161.23 161.231.000 0.1
Sa(4)z 130.34 130.341.000 0.1
Sa(5)z 110.96 110.961.000 0.1
Sa(6)z 97.477 97.4771.000 0.1
Sa(7)z 87.46 87.461.000 0.1
Sa(8)z 79.674 79.6741.000 0.1
Sa(9)z 73.417 73.4171.000 0.1
Sa(10)z 68.259 68.2591.000 0.1
Sa(11)z 63.921 63.9211.000 0.1
Sa(12)z 48.684 48.6841.000 0.1
Sa(13)z 38.526 38.5261.000 0.1
Sa(14)z 31.38 31.381.000 0.1
Sa(15)z 26.142 26.1421.000 0.1
Sa(16)z 22.175 22.1751.000 0.1
Sa(17)z 19.09 19.091.000 0.1
Sa(18)z 16.639 16.6391.000 0.1
Sa(19)z 14.655 14.6551.000 0.1
Sa(20)z 13.024 13.0241.000 0.1
Sa(1)z 220.72 220.721.000 0.1
Sa(2)z 220.72 220.721.000 0.1
Sa(3)z 161.17 161.231.000 0.1
Sa(4)z 130.29 130.341.000 0.1
Sa(5)z 110.92 110.961.000 0.1
Sa(6)z 97.44 97.4771.000 0.1
Sa(7)z 87.427 87.461.000 0.1
Sa(8)z 79.644 79.6741.000 0.1
Sa(9)z 73.389 73.4171.000 0.1
Sa(10)z 68.233 68.2591.000 0.1
Sa(11)z 63.897 63.9211.000 0.1
Sa(12)z 48.665 48.6841.000 0.1
Sa(13)z 38.512 38.5261.000 0.1
Sa(14)z 31.369 31.381.000 0.1
Sa(15)z 26.132 26.1421.000 0.1
Sa(16)z 22.166 22.1751.000 0.1
Sa(17)z 19.083 19.091.000 0.1
Sa(18)z 16.632 16.6391.000 0.1
Sa(19)z 14.649 14.6551.000 0.1
Sa(20)z 13.019 13.0241.000 0.1


Contains proprietary and confidential information of Ingeciber, S.A.