The Coronado Bridge is listed as one of 68 bridges across the country that are at risk of collapse from a vessel collision and is in need of further evaluation.
The bridge provides primary access to Naval Air Station North Island, and is one of only two vehicle access routes. Its collapse would affect over 100,000 vehicles that cross the bridge daily, according to the Union Tribune, not to mention the large cargo ships and Navy vessels that routinely pass beneath the span.
The National Transportation Safety Board (NTSB) released a report on March 18 that found that the Coronado Bridge has never undergone a vulnerability assessment and therefore has an unknown level of risk of collapse if struck by a ship.
It also classified the bridge as serving as an important link in the Strategic Highway Network, which is an approximately 64,000 mile-long network of highways necessary for the deployment of military equipment and personnel.
This report was released as the NTSB investigates a containership collision with the Francis Scott Key Bridge in Baltimore, which happened about a year ago.
On March 26, 2024, a 984-foot-long cargo vessel was moving out of Baltimore Harbor when it experienced a loss of electrical power and propulsion, plowing right into a pier that supported the central span of the Francis Scott Key Bridge. A portion of the bridge caved in and as a result, six construction workers were killed.
The American Association of State Highway and Transportation Officials (AASHTO) established a mathematical risk model in 1991 that had been used on bridges built after that date; but the Francis Scott Key Bridge, which opened to the public in 1977, never received an assessment.
After its collapse, the NTSB conducted the AASHTO test and found that it was at above acceptable levels of risk at the time it was struck by the containership.
“We identified the need to safeguard bridges from vessel strikes as part of our ongoing investigation,” the NTSB reported.
Sixty-eight other bridges, including the Golden Gate Bridge and Brooklyn Bridge, have not received assessments either.
The NTSB urged the owners of the identified bridges to calculate the probability of a bridge collapse based on the risk threshold established by AASHTO.
The report states that neither the Federal Highway Administration nor the AASHTO can require a bridge owner to complete the vulnerability assessment if it was designed before 1991, and the owners might not even know their bridge is in need of evaluation.
“The 30 owners of 68 bridges over navigable waterways frequented by ocean-going vessels are likely unaware of their bridges’ risk of catastrophic collapse from a vessel collision and the potential need to implement countermeasures to reduce the bridges’ vulnerability,” states the report.
The NTSB recommends the tests be done with a team that includes members from the Coast Guard and the Corps of Engineers.
If the tests do reveal a higher than acceptable risk level, the NTSB suggests developing and implementing short and long term strategies to reduce probabilities of collapse.
