Design Flaw Caused Minnesota Bridge to Collapse

The media reported on Tuesday that investigators from the National Transportation Safety Board ("NTSB") have concluded that a design flaw caused last summer's collapse of a bridge in Minnesota, and that such flaw would not have been discovered during routine state inspections. The nature of the flaw related to steel structures known as gusset plates that connect the girders that supported the Minneapolis bridge. Investigators said the gusset plates used when the bridge was constructed in the 1960's were too thin to support the added weight caused by increased traffic and construction equipment and materials being used to perform renovations on the bridge at the time of the collapse.

During the construction project, sources said that state officials and contractors did not recalculate how the extra weight of the equipment and materials used might affect the gusset plates.

The collapse killed 13 people and injured over 100. 

A final NTSB report on the collapse is expected by the end of the year.

See media stories here (L.A. Times) and here (Washington Post)