JACKSONVILLE, Fla. – The National Transportation Safety Board had a stern warning this week for agencies that oversee bridges near ports: Evaluate your bridge’s safety.
The Dames Point Bridge in Jacksonville was among the 68 bridges flagged by the NTSB in a report released Tuesday as we approach the one-year mark of the Francis Scott Key Bridge collapse in Baltimore.
During the early hours of March 26, 2024, the “Dali” container vessel struck one of the piers of the Key Bridge, causing the bridge to collapse and killing six construction workers.
The NTSB’s investigation into the bridge collapse found that if the Maryland Transportation Authority had done a vulnerability assessment of the Key Bridge, it would have realized the bridge’s risk level for collapse was nearly 30 times above acceptable levels.
Because of that, the NTSB is urging similar bridges near ports that might be a risk of being hit by a large vessel to be proactive.
“Frankly, we’ve been sounding the alarm on this since the tragedy occurred, and in testimony before the house Transportation and Infrastructure Committee last April. We need action. Public safety depends on it,” said NTSB Chairman Jennifer Homendy.
The Dames Point Bridge, which is owned by the Florida Department of Transportation, was built in 1989 -- before new guidance was developed in 1991 for assessing the risk of bridge collapses from vessel strikes.
It’s also one of the bridges that hasn’t had a vulnerability assessment based on recent vessel traffic.
The only other Florida bridge that made the NTSB’s list is the Sunshine Skyway Bridge across Tampa Bay, which was built in 1986.
So how can the FDOT make sure the bridges are safe from collapse?
The NTSB said the bridges need to follow guidelines set by the American Association of State Highway and Transportation Officials (AASHTO).
Those guidelines check the vulnerability of bridges based on:
- The kinds of vessel traffic passing under the bridge
- How fast the vessels are going
- How the vessels are loaded
- How the vessels navigate the channel and any intersecting channels
- How deep the water is
- Environmental conditions
- Bridge geometry
- Pier protection systems
- The lateral capacity of bridge piers
Using that data, the guidelines help officials calculate the risks for the bridge related to:
- How often vessels are going under the bridge
- How likely it is that a vessel will go off course
- How likely it is that a vessel will hit a bridge pier
- The probability of the bridge collapsing if there is a collision
- Whether dolphins, islands or other protective structures will help if there’s a collision.
The NTSB called for a team from the Federal Highway Administration, the U.S. Coast Guard, and the Army Corps of Engineers to help with the risk evaluations and plans to fix any issues identified in the evaluations.
Homendy acknowledged that a bridge with a high risk of vulnerability isn’t guaranteed to collapse if it’s hit by a large vessel, but she also warned that bridges with lower risk aren’t guaranteed to be safe from collapse either.
