'Risk Of Collapse' Evaluation Ordered For Chicago-Area Bridge

ILLINOIS — As the National Transportation Safety Board continues its investigation into the deadly collapse of the Francis Scott Key Bridge in Maryland, the safety administration has identified numerous bridges that are also at risk of collapse should a vessel collide with them.

As a result of the investigation, the NTSB is recommending that 68 bridges — including one in the Chicago region — undergo a vulnerability assessment to determine the risk of collapse. The NTSB this week released a report on the March 2024 Maryland incident that documented dozens of other bridges across the nation they say have "unknown levels of risk of collapse" from vessel collisions.

In the Chicago region, the Chicago Skyway Calumet River Bridge in Chicago is recommended to undergo a risk assessment. The NTSB classified the Calumet River bridge as "critical/essential."

The bridge, owned by Skyway Concession Company LLC, was built in 1958.

According to the bridge's website, the bridge spans the Calumet River and Calumet Harbor, which is a main harbor for industrial ships. The 1/2-mile long steel truss bridge is also known as the "high bridge."

The City of Chicago used to operate and maintain the Skyway until 2005, when Skyway Concession Company LLC assumed operations under a 99-year operating lease, according to the bridge website.

The NTSB is recommending the bridge owners calculate the annual frequency of collapse for the structures using the Method II calculation from the American Association of State Highway and Transportation Officials.

If a bridge exceeds that risk threshold, it is considered high risk, according to NTSB. The owners must inform the NTSB whether the probability of collapse is above the threshold.

"Today’s report does not suggest that the 68 bridges are certain to collapse. The NTSB is recommending that these 30 bridge owners evaluate whether the bridges are above the AASHTO acceptable level of risk. The NTSB recommended that bridge owners develop and implement a comprehensive risk reduction plan, if the calculations indicate a bridge has a risk level above the AASHTO threshold," the NTSB said.

A date by which the assessments must be complete was not immediately clear.