BEHAVIOR OF COMPOSITE STEEL I-GIRDER BRIDGES UNDER BLAST LOADS ABOVE BRIDGE SURFACE

In this paper, a simply supported composite steel I-girder bridge was studied to predict its behavior under blast loads. Abaqus nonlinear finite element analysis software was used to model the bridge. Bridge was loaded by blast loads, it's applied at mid-span and end span of bridge. The main parameters affecting the behavior of bridge under blast load above the surface are investigated such as explosive weight (W), the distance from the explosion source to bridge (R), and position of explosion. Based on the results, bridge collapse is directly proportional to the explosive weight and inversely proportional to the standoff distance. Reinforced concrete slab is more vulnerable to collapse in case of blast at mid-span than at span ends. Steel girders are more vulnerable to collapse in case of blast at span ends than at mid-span because of applied shear stress exceeds its shear capacity. In general, steel girder collapse is the main cause to the collapse of the bridge but the reinforced concrete slabs will not cause overall bridge collapse