Resistance of Flat-Plate Buildings against Progressive Collapse. II: System Response

Abstract

Using a macromodeling approach and alternate path method, dynamic and static analyses are performed to assess the progressive collapse resistance of a multistory reinforced concrete flat-plate building lacking structural integrity reinforcement in the slabs. Two loading scenarios, instantaneous removal of an exterior column and interior column, are considered. The dynamic analyses examine the potential of progressive collapse of the building, the dynamic demands on global and local nonlinear deformations, the effects of strain rate in materials, and the development of compressive membrane action. The effectiveness of an energy-based nonlinear static analysis procedure is examined for equivalently estimating the peak dynamic global and local responses caused by sudden column removal. The analyses indicate that older flat-plate buildings are vulnerable to progressive collapse; the combined effects from strain rate and compressive membrane action can significantly increase punching resistance; energy-based nonlinear static analysis can approximate the peak dynamic loading response especially for instantaneous exterior column removal.