Progressive collapse analysis of reinforced concrete in buildings L-shaped plan

One of the most important issues discussed structural passive defense is progressive collapse. Progressive collapse occurs the sudden destruction caused by the deliberate structural member by accidents or disasters, such as earthquakes and terrorist military or operational errors and downtime has spread to adjacent organs and extended downtime for the chain is ruining a part of or the entire structure. Structural performance by identifying the key elements (elements with the greatest potential for progressive collapse) will be upgraded and strengthened them. In this paper buildings with 4,7and 12 stories of reinforced concrete moment frame with resistant system has been selected L-shaped plan. To determine the key elements, different situations Delete columns plan, is considered. For the first time, the progressive collapse by two method of the sensitivity index and load factor was evaluated and structures have been analysised nonlinear static analysis (Push Down Analysis).From of the values of the bearing capacity of the structure, sensitivity index and the load balance corresponding to the target displacement, the load factor is calculated.The Element with the maximum of sensitivity as well as the lowest load factor as a key element in determining the progressive collapse. The results in this paper show that L-shaped concrete building plan corner columns is the greatest potential for progressive collapse. Moreover, the results indicate that the structures in height, has a better performance against progressive collapse