The Maryland Transportation Authority failed to evaluate the Francis Scott Key Bridge for vulnerability and risk as a result of collision, the National Transportation Safety Board announced Thursday.
The March 26, 2024, collapse of the span could potentially have been prevented if the MDTA had reviewed the risk and taken corrective action, NTSB Chair Jennifer Homendy said during a press conference Thursday, nearly one year after the tragedy.
Homendy referred to an analysis provided by the American Association of State Highway and Transportation Officials created in 1991 as a result of the collapse of the Sunshine Skyway Bridge in Tampa, Florida, in 1980. AASHTO’s vulnerability assessment calculator for new bridges on the National Highway System evaluates the level of risk for collapse if a span were struck by a vessel.
Though the Key Bridge was finished in 1977, AASHTO says that its calculator is not just for new bridge construction and urges owners to evaluate existing spans constructed before the guidance.
But before the Key Bridge collapsed, Maryland officials had never performed the analysis, so the NTSB had to research the risk after the fact. The MDTA has still not assessed the nearby Chesapeake Bay Bridge, built in 1948, for risk, Homendy said.
“There’s no excuse,” Homendy said.
Upon assessing the span, the NTSB discovered the Key Bridge’s risk was nearly 30 times greater than the acceptable threshold for critical or essential bridges, Homendy said.
“We were very surprised that [the risk numbers] were high,” she said. “But it’s something MDTA could have known and should have known.”
Nationwide risk
In addition, Homendy said the NTSB recommends that the owners of 68 bridges across 19 states perform vulnerability assessments and take protective measures if necessary. The bridges were all constructed before the 1991 AASHTO guidance was established and have not undergone vulnerability assessment based on recent vessel traffic. Therefore, they have an unknown level of risk of collapse from a collision.
These spans include the Golden Gate Bridge in San Francisco, the Brooklyn Bridge in New York City and the new Sunshine Skyway Bridge.
She emphasized that singling out those bridges does not mean that they are automatically dangerous, merely that their risk needs to be calculated. By the same token, other bridges are not automatically safe from potential harm, Homendy said, as she cautioned vigilance.
The Key Bridge collapsed when the cargo ship Dali collided with one of the span’s piers. Had the analysis been performed, Homendy indicated that the MDTA could have invested in dolphins or other protections to drive fast-moving sea vessels away from the vital support for the bridge.
