Progressive Collapse Analysis of Three-Dimensional Steel-Concrete Composite Building due to Extreme Blast Load

摘要

This paper investigated the behavior of three-dimensional (3D) steel-concrete building under external explosion considering the slab and connection rigidity. Most of the work carried out so far in the progressive collapse area followed the threat-independent alternate load path (ALP) methodology as a design guide. This study presents a simplified two-stage nonlinear dynamic analysis using Abaqus FE. The number of columns likely to be removed in progressive collapse due to blast is determined using a three-step restart analysis in the first stage. Collapse analysis of the entire building is carried out in the second stage, and the results were compared with nonlinear dynamic analysis of the ALP. The numerical model was validated with the data obtained from experimental works and the results showed good agreement. It was concluded that the ALP usually is not conservative; more columns may be eliminated under heavy explosion, and collapse analysis is required to capture the real behavior. The well-known failure criteria for yielding, fracture, and stability are not efficient enough, and the damage index criterion which basically depends on the global column behavior and its remaining axial capacity should be used.