Various Approaches for Mitigating Progressive Collapse of Asymmetrical RC Building

Abstract

The failure of structural members under blast, impact, wind pressure and earthquake is highly dynamic phenomenon. One of the mechanisms of failure during such event is referred to as “Progressive Collapse”. In the present study progressive collapse potential of 4-storey and 10-storey asymmetrical concrete framed building is evaluated. Linear static and dynamic analysis is performed by following the General Service Administration and Department of Defense guidelines for evaluating progressive collapse potential. Modeling, analysis and design of the buildings are performed using SAP2000 for five different threat-independent column removal conditions by following the alternate load path method. It is observed that demand capacity ratio (DCR) in beams and columns are exceeding the allowable limit for all the cases. This indicates the building considered for study is having high potential of progressive collapse. To reduce the potential of progressive collapse various approaches for mitigation of the progressive collapse are presented in this paper. Three different approaches like providing bracing at floor level, moderate increase in the size of beam at all the storey level and major increase the size of beam at bottom storey level are studied. Comparison between all the three approaches is presented for building taken into study. Among all the three approaches, bracing at floor level emerges as the most effective and economic approach for mitigating the potential of progressive collapse.