Oklahoma Statewide Vessel Collision Risk Assessment

On May 26, 2002, the I-40 Webbers Falls Bridge over the Arkansas River was struck by a tugboat towing a series of barges. The impact rocked the bridge, sending a 580-ft section of the interstate, along with multiple cars and trucks, into the river below. Fourteen people perished in the tragic event. Both the Public and Oklahoma Department of Transportation (ODOT) officials demanded to know how this could happen. And could it happen again to other bridges in the area? To begin answering these tough questions, ODOT sought the input of an experienced bridge engineering firm. 

For the emergency collapse investigation, Modjeski and Masters (M&M) first determined barge collision loads, and created finite element models for in-depth analysis. In addition, our engineers evaluated materials samples and testing data from the affected span to determine probable collapse mechanisms. We then provided ODOT with documentation detailing the initial cause and the sequence of events leading up to the bridge collapse. To answer the question of whether this could happen to other bridges, M&M completed a statewide vessel collision vulnerability study. This study included structural and risk analyses for 12 bridge crossings, including vessel and waterway data collection, and vessel collision load calculations. As a result, our technical staff provided ODOT with recommendations for bridge protection systems and accident prevention measures. ODOT has remained proactive in preventing a repeat of the Webbers Falls incident. As active partners, M&M designed pier protection systems for four of the 12 study area bridges.