Simulation of the Alfred P. Murrah Federal Building Collapse Due to Blast Loads

Many trials have been made to numerically simulate the Alfred P. Murrah Building bombing event using Finite Element Method. These trials were based on removal of one of the main supporting columns to investigate the generated internal forces and the possible deformations in other elements. However, these trials could not simulate real bomb explosion and automatic detection of the failed columns and floor slabs. Furthermore, the finite element analysis could not continue to model separation of failed elements, collision between structural elements till complete collapse. In this paper, a new technique, Applied Element Method (AEM), is used to simulate the collapse process of the Murrah Building. The bomb weight and location are considered in the simulation. Free-Field blast wave was assumed. The building dimensions, reinforcement and material properties were taken into account. The simulation shows real time analysis of the building performance since the blast occurs, failure of one of the supporting columns, and the failure of the supporting transfer girder till partial collapse of the structure. Two more cases were studied; the bomb was moved to the corner of the building and increasing reinforcement of the transfer girder to check building performance during these events. Results indicate that design firms, engineers, and insurance companies now can judge the safety of existing structures when subjected to extreme loads and to study the safety of proposed structures prior to their construction.