Sustainability assessment of methods to prevent progressive collapse of RC flat slab buildings

Abstract

Previous studies have shown that RC flat slab buildings are highly vulnerable to progressive collapse because no beams could help redistribute the loads previously carried by the lost columns. The necessary strengthening methods should, therefore, be adapted to reduce the occurrence of progressive collapse. In this paper, the progressive collapse behaviour of five-storey R.C flat slab building is assessed by removing columns from the first-storey and dynamic analysis is conducted in compliance with GSA guidelines (2016). The results are analyzed in terms of vertical displacement and chord rotation at the location of removed columns and compared with the allowable limits as specified in DoD guidelines (2009). Different sized perimeter beams are used as strengthening methods to increase the progressive collapse resistance of the studied flat slab building. Since building strengthening uses structural elements that consume natural resources, sustainability criteria should be explicitly included in the strengthening requirements. These performance enhancement methods are then evaluated from structural, cost and environmental aspects and the results are examined. A strengthening alternative is then proposed which not only satisfy the progressive collapse code requirements but also requires less cost and emits less CO2 gas.