Pennsylvania Warned of Design Flaw Cited in Minneapolis Bridge Collapse

January 2008

The National Transportation Safety Board (NTSB) has recommended that Pennsylvania and other states inspect the gusset plates of bridges similar in design to the one that collapsed in Minneapolis in August, killing 13 people and injuring more than 100. PA has 54 deck truss bridges, the most in the nation.

Included are the Highland Park Bridge, the Homestead Grays Bridge, and the Rankin Bridge, all of which are located in the Pittsburgh area. Their gusset plates – flat steel pieces with rivets to connect steel beams – should be one-inch thick, but those on the Minneapolis bridge were only half an inch thick. The NTSB recommended that owners of the designated bridges reevaluate the structures’ plates before making any enhancements to them.

The Federal Highway Administration (FHA) may expand the scope of the recommendation, and the Pennsylvania Department of Transportation has vowed to follow the FHA’s orders. No problems were found with Pennsylvania’s truss bridges during an investigation conducted immediately after the Minneapolis collapse. Of the 54 truss bridges, 21 are located in Allegheny County.