# MN I-35W Bridge Collapse was Design Error



## PRR 60 (Nov 14, 2008)

Despite the conventional wisdom that the collapse of the I-35W bridge in Minneapolis was the result of aging and neglected infrastructure, the NTSB has determined the actual cause to be more fundamental. Steel gusset plates - the plates used to connect the large bridge beams together - were designed too small for the loads. They should have been about twice as thick as they were designed. The collapse was then caused by construction loads - loads well within the stated capability of the bridge - that fractured one of the plates resulting in the rapid failure of multiple additional plates and collapse.

Minneapolis Star Tribune 11/14/08


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## PetalumaLoco (Nov 14, 2008)

I thought this was publicized not long after the collapse?


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## PRR 60 (Nov 14, 2008)

PetalumaLoco said:


> I thought this was publicized not long after the collapse?


It was. Relatively early in the process, the undersized gussets were discovered. But now it gains status as being the official cause per the NTSB. The report is to be issued today.


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