WASHINGTON (7News) — The Francis Scott Key Bridge collapse in Baltimore, Maryland highlighted the risk cargo ships passing beneath pose to aging American bridges. Before the disaster, federal engineers and state inspectors deemed the bridge’s protections ‘adequate.’
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A Design from Another Era
Built in the 1970s, the Key Bridge was originally designed to guard against smaller vessels. When the 100,000-ton cargo ship Dali struck a support column, the bridge collapsed due to its lack of structural redundancy — a critical design vulnerability known as “fracture critical.” More than 17,000 bridges across the United States share the vulnerability. Most of these fracture-critical bridges were designed and built between the 1950s and 1970s, according to Federal Highway Administration records. During this time, the interstate highway system was expanded and completed.
Local Concerns
Recent inspections show local bridges, including the Woodrow Wilson Bridge and the Chesapeake Bay Bridge, have ‘adequate’ protections against ship strikes. But, Baltimore’s bridge disaster has raised doubts about these assessments, revealing that many older bridges may not be up to current protection needs.
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“We have to start reevaluating because now with the Panama Canal width expansion, we’re getting PanaMex ships which are much bigger, much heavier,” bridge engineer and former American Society of Civil Engineers President Andy Herrmann told 7News.
The Panama Canal was expanded in 2016 and now allows the world’s largest vessels, Pana Max ships like the Dali, to reach the U.S. East Coast directly.
Maryland transportation officials said all current state bridge projects adhere to the latest safety standards and aim to eliminate fracture-critical bridges where feasible. However, retrofitting or rebuilding older bridges to meet today’s engineering standards can be prohibitively expensive. Estimates for rebuilding the Key Bridge exceed $1 billion. Physical constraints can make building structural redundancy impossible or difficult on some bridges.
“In some instances, it’s very hard,” Herrmann said.