Minnesota Bridge Conditions Were Extensively Documented

This article looks at the documentation involved in the structural evaluations of the I-35W Bridge collapse in Minneapolis, Minnesota. While there are extensive documents covering needed repairs for the bridge, which could in turn lead to an answer for why the bridge collapsed, these documents could not be examined immediately after the disaster as resources were being placed into rescue efforts. A video recording of the incident will also be used in evaluating what might be the cause of the accident. The bridge, designed for a 50 year life span and built from steel multibeam approach spans with concrete slab approach spans, was due to be replaced in 2020. While the bridge received poor marks and was deemed functionally obsolete in 1990, no cracks were found in the main truss nor were the bridge deemed unsafe. The Minnesota Department of Transportation had hired a San Francisco-based firm in 2003 to conduct tests on the robustness of the bridge and to locate cracking. Engineers at that time believed that the bridge could sustain even the loss of the floor truss without a full collapse.