Effect of Catenary Action on Reducing the Vulnerability of Steel Bending - Frame Structures versus Progressive Collapse

One of the most important issues in passive defense considerations is progressive collapse. For instant destruction of structural member due to different incidents such as deliberate or unexpected events, propagation of destruction to adjacent members and inability of building to achieve static alternative equilibrium conditions, progressive collapse occurs, which leads to partial or even total destruction. On the other hand, removing critical members in different buildings situations may have various progressive collapse potentials. Catenary action is a building rehabilitation mechanisms to achieve equilibrium alternative and stability of the structure. In this study, based on the sixth and tenth national building regulations and using vertical push nonlinear static analysis (Push-Down Analysis) and nonlinear dynamic time history analysis of steel bending frame structures, performance of the structure by removing columns in different locations and its effect on potential progressive collapse, are discussed. The results show that it has highest effect when a corner column is removed while it has lowest catenary action in building. Structural stability to achieve alternative equilibrium after columns removal, will improve by strengthening catenary action building performance.