Collapse mechanism of I-35W bridge in Minneapolis and evaluatiion of gusset plate adequacy

On August 1, 2007 at 6:05 PM, I-35W steel deck truss bridge over Mississippi River in Minneapolis catastrophically failed into the river resulting in the 13 people dead and more than 100 people injured. Determining the cause of the collapse is required to prevent bridge failures from similar causes. This paper attempted to reveal the cause of the I-35W bridge collapse using a finite element model. Firstly, an analysis of the bridge collapse mechanism specified that the failure of U10 gusset plate initially occurred and led to the collapse of entire span. Secondly, the result of calculating the stress in U10 gusset plate indicated that the gusset plate was likely to fracture under the loading and the structural conditions at the time of accident. Finally, an example of the method of preventing the bridge collapse was proposed.