A New Design to Prevent Progressive Collapse of Reinforced Concrete Buildings
Abnormal loads that include bombing, gas explosions and vehicle collision can cause a column failure leading to a partial or a complete progressive collapse of the building. This study presents a new approach to provide alternate load paths to redistribute the residual loads and prevent the potential progressive collapse of reinforced concrete buildings in case of column failure. It is proposed to transfer the residual loads upwards above the failed column of the reinforced concrete buildings by vertical cables hanged at the top to a hat steel braced frame seated on the top of the building which in turn redistributes the residual loads to the adjacent columns. The vertical cables are connected to the ends of beams in existing buildings or embedded in columns in new constructions. In order to investigate the validity of the new proposed design method, a nonlinear dynamic analysis is used following the alternate path method (APM) recommended by GSA (2003) guidelines. The investigations are conducted for a ten storey reinforced concrete building designed according to Australian Standard AS3600 (2001). The structure is simulated using ANSYS 11.0 finite element software. The simulation results of the example building show that the presented method of using vertical cables and hat steel braced frame is efficient in absorbing the loss of a ground floor column and preventing the progressive collapse of the building.