PROGRESSIVE COLLAPSE MECHANISM ANALYSIS ON SPATIAL COMPOSITE FRAME WITH CFST COLUMNS BASED ON ABAQUS PARAMETRIC MODELING

摘要

Based on the script programming interface of ABAQUS/Standard finite element platform,concrete-filled steel tube(CFST)spatial frame parametric modeling script Auto-frame was developed by Python language.It is very convenient to develop spatial composite frame with RC slabs through input frame geometry information,so the parametric modeling script Auto-frame can improve the efficiency of modeling.The material constitutive model of steel and core concrete used our research groups developed the iFiberLUT,and used-defined material model based on the subroutine UMAT provided by ABAQUS used Fortran language.The material constitutive model has been verified by others' experimental results.This paper established a finite element(FE)model of 9-story spatial frame with CFST columns based on nonlinear fiber beam-column element theory to study the collapse mechanism based on Pushdown analytical method.The results show that the mechanism of progressive collapse includes beam mechanism and catenary mechanism under different removal columns cases except corner column destroyed,which only contained catenary mechanism.The catenary mechanism is offered by the beam axial force of upper level floor.