Although not commonly occurring, collisions of heavy vehicles with highway overpass bridge columns have happened in the past and resulted in catastrophic structural failures that paralyze traffic on both the overpass and the highway below. A study that was conducted at South Dakota State University performed risk assessment and developed mitigation strategy for vehicular collision with bridge columns on South Dakota interstate highways. Since the collision force is dependent upon the stiffness of the structure and the approach speed of the crashing truck, a finite element (FE) dynamic analysis was performed in the study to evaluate the collision forces resulting from two different truck sizes crashing into a prototype bridge bent at three different approach speeds (55 mph, 65 mph, 75 mph). This paper covers the FE simulation that was performed using computer software. The results indicate that the 600-kip vehicular collision force specified by AASHTO is a reasonable estimate for the load demand induced by an 80,000 lb. tractor-trailer crashing into a bridge column at an approach speed not exceeding 55 mph.
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