Revisit of I35W Bridge Collapse: A preliminary analysis at 2007 and conclusions today

August 1st of 2007, 6:05PM, the interstate highway I35W Bridge in the City Minneapolis, Minnesota, collapsed suddenly. The 8 traffic-lane, 1000-foot-long deck of the 1907-foot-long bridge fell into Mississippi River within seconds, resulted in 13 fatalities and 145 injuries. This paper is based on a report of a preliminary analysis of this disaster, which was submitted to the related administrative agencies at the September of 2007. By comparing the results in that report with the materials' evidences of National Safety Transportation Safety Board (NTSB) official investigation and recent in-depth analyses, it seems that the issues addressed in this earlier analysis may still have certain significance for the safety assessment of those similarly-structured steel bridges today. A bridge's service life is 75 years or longer. According to a NTSB's document, there are more than hundreds this kind of bridges still on service.