The vulnerability of the Francis Scott Key bridge to a vessel collision was almost 30 times above the acceptable risk threshold for critical or essential bridges when it was run over last year by the M/V Dali container container ship, announced the National Transportation Board on Thursday.
According to the agency, the Maryland (MDTA) transport authority never calculated the risks to the structure of the almost 50 -year -old steel arc, as recommended by the specifications of the Aashto Guide of 1991 and 2009, even as container vessels that used the deep draft channel underlying the port of Baltimore, continuing to grow in size and in number.
The impact of Dali with one of the main piles of support of the bridge in the early hours of March 26, 2024, resulted in the sinking of the main interval, killing six construction workers and blocking the channel for more than two months with approximately 50,000 tonnes of debris.
If MDTA performed the evaluation, NTSB President Jennifer Homendy told an informative press session: “They could have identified strategies proactively to reduce the risk of collapse and loss of lives associated with a collision of the boat with the bridge.”
The NTSB also recommends Evaluations of vulnerability for 68 other bridges Cross navigable water in 13 states. During the investigation of the key bridge, The agency identified the other bridges as a lack of an evaluation of current collision vulnerability. The Agency has issued an urgent recommendation to the owners of the bridges to calculate the annual collapse rate of these structures, by calculating Aashto Method II.
The bridges, all built before the initial version of the AASHTO orientation in 1991, also include the Golden Gate and Coronado bridges in California; the Long Huey bridge in Louisiana; the Brooklyn and Verrazano Narrows bridge in New York; and the Florida Sunshine Skyway bridge, which was built to replace a collapsed structure with an impact of the boat.
If the calculations indicate that a bridge has a level of risk above the Aashhto threshold, NTSB recommends the owners to develop and implement a comprehensive risk reduction plan for their structures. Expressing the hope that the number of vulnerable bridges will be reduced, Homenday said that his agency would continue with Pont and FHWA owners to ensure that they follow the recommendation.
“We look forward to actions,” he said. “Public safety depends on it.”
MDTA added that he is actively evaluating the wharf protection systems, operating changes and traffic procedures on the bridge of the Bay of Chesapeake in Annapolis.
Lack of evaluation
Homendy said that his agency needed FHWA assistance to develop data to perform his own Aashhto Method II ASSESSMENT OF THE KEY PONT, as MDTA failed or could not provide NTSB key information on ship traffic, channel geometry and depth, dock protection systems and final side side capacity.
“There is no reason why [MDTA] He should not have done it before, ” said Homenday to perform the evaluation. He added that, while Maryland officials have collaborated with the research, it was surprised that the vulnerability of the key bridge was so high. In addition to determining the general risk of the bridge to collapse, NTSB found that Moll 17, which Dali reached, was 15 times above the acceptable risk section, based on Arase orientation.
In a statement, MDTA counteracted that the collapse and loss of life “was the only fault of the Dali and the serious negligence of its owners and operators who have benefits above security.” The MDTA Declaration said that, as with other North -American bridges, the key bridge “was approved and allowed by the federal government and fulfilling these permits”, and that for the last 50 years, “hundreds of thousands of passed ships under the key bridge without incidents”.
As NTSB’s investigation into Key Bridge’s incident continues, Homendy said that the agency has published about 40 documents related to the investigation with his public deposit, including the fact of a fact report and bridge interviews. Additional materials will be added in the coming weeks, including Dali’s Voyage data recorder and voice transcripts; Engineering, Nautical Operations and Feds of the Anchorage; and other studies. Homendy said that the agency will begin to develop its findings and its potential cause and safety recommendations, in order to launch the final report this fall.
In the meantime, Kiewit Infrastructure Co. It is found in the first phase of $ 73 million of a progressive design construction contract for a 2 -mile replacement replacement on the key bridge, with the $ 1.7 billion replacement structure estimated currently planned for the fall of 2028.
