18 Years Later: Remembering the I-35W Bridge Collapse

(KNSI) — Eighteen years ago today, August 1st, the Interstate 35W bridge over the Mississippi River in Minneapolis collapsed during evening rush hour, plunging everyone and everything on it into the water and onto the banks below.

A total of 13 people were killed and 145 others were injured.

The National Transportation Safety Board conducted a thorough investigation into what happened, blaming the collapse on a design flaw with the gusset plates. Those plates are used to join members of steel trusses and connect bracing members to adjacent beams and girders. At the time of the failure, the span was carrying heavy traffic, construction equipment, materials and workers and the undersized plates couldn’t handle all of the extra weight on the deck.

The bridge was already deemed “structurally deficient,” but was still considered safe for traffic.

A new bridge was built to replace the collapsed span and opened to traffic in September 2008, incorporating advanced safety features and monitoring systems.

The disaster prompted nationwide scrutiny of America’s aging infrastructure and led to increased federal funding for bridge inspections and repairs. The Highway 23/DeSoto Crossing over the river in St. Cloud was found to have a similar design to the 35W bridge and was demolished a year after the collapse. The new bridge, renamed the Granite City Crossing, was built on the same site and opened in 2009.

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