As larger, faster container ships began plying the Delaware River in recent years, transportation officials feared the possibility that one would go off course and repeat, or worsen, what happened in 1969, when a tanker truck collided. against the Delaware Memorial Bridge. and caused significant damage.
Thus, work began last year on a $93 million project to build eight enormous cylinders that would stand guard in front of the bridge pillars to protect a system that transports tens of thousands of vehicles a day.
“The tankers and freighters of 1950 are not the tankers and freighters of today,” said James Salmon, spokesman for the Delaware River and Bay Authority.
The Tuesday morning collapse of the Francis Scott Key Bridge in Baltimore after a freighter the size of nearly three football fields crashed into it, claiming the lives of six people, has raised questions about whether similar disasters could occur elsewhere. places.
But the work on the Delaware Memorial Bridge reflects the fact that some maritime and transportation experts have been reflecting for some time on the dangers of new ships of cargo trapped under decades-old bridges.
The problem is that there are no easy answers, in part because the ships continue to grow.
Michael Rubino, retired chief pilot of the Port of Los Angeles, said the air currents (the distance between the water and the highest point of a boat) of some newer boats have become so large that some boats need fold their antennas. and masts to pass under a bridge.
“People don’t realize how huge these ships are,” he said.
Joseph Ahlstrom, a SUNY Maritime College professor, ship captain and commissioner of the New York state pilot board, said commercial ships have grown so much in recent years that they are much more likely to cause damage to infrastructure such as bridges. .
“This is going to affect them,” he said of a modern ship and the danger it represents to a bridge like the one in Baltimore.
“It’s going to take him down, and that’s what happened.”
Only case?
Many transportation officials say it’s difficult to draw parallels with the Key Bridge because what happened in Baltimore appeared to be a very unusual event:
a confluence of factors at the worst possible time.
When the ship, the Dali, passed through the port without a tug attached to it, it experienced a “total blackout” and lost control, then crashed into a dock that had small protective barriers.
The situation with the Key Bridge is “unique,” said Jim Tymon, executive director of the American Association of State Highway and Transportation Officials, which represents state transportation departments.
“This is not something we can really make a comparison with.”
Still, officials with the National Transportation Safety Board said Wednesday that they were not only examining the protection system around the Key Bridge, but were also seeking records about the protections around other bridges in Maryland.
Aimless ships have long been seen as a risk to bridges, particularly after a freighter crashed into the Sunshine Skyway Bridge in Tampa Bay, Florida, in 1980, killing 35 people.
After that disaster, Maryland officials acknowledged that the Key Bridge, opened in 1977, could be brought down by a direct hit.
But they said the concrete barriers that had been installed on the river were intended to divert or slow down an out-of-control boat.
Therefore, the final contact could only be an “indirect hit,” John Snyder, director of engineering for the state Toll Facilities Administration, told the Baltimore Sun at the time.
As part of rebuilding in Tampa Bay, officials prioritized protecting against a future disaster.
They built a network of large concrete islands, called dolphinswhich could absorb the impact of a runaway ship.
Since then, officials across the country have increasingly focused on strategies to improve shields around bridges.
“Some modern bridges around the world, especially after the Tampa incident in 1980, have been designed with different features to mitigate impacts and protect their piers,” US Transportation Secretary Pete Buttigieg.
“Right now, I think there’s a lot of debate among the engineering community about whether any of those features could have played any role in a situation like this.”
Efforts to improve bridges are often slowed due to the large number of state and federal government entities involved, the often glacial pace of funding and the construction time required for such large-scale projects.
Still, some places have seen results.
In Minnesota, a ship pushing 12 barges crashed into a Union Pacific railroad bridge near St. Paul, Minnesota, in 2017, damaging a century-old pier.
A protection system was later built around the new dock.
In New York, the Bayonne Bridge was raised 64 feet (about seven stacked shipping containers) in 2019 to accommodate increasingly larger ships docking at container ports in New Jersey and Staten Island.
In Long Beach, California, the new Gerald Desmond Bridge was raised 15 meters in 2020.
And in New Orleans, officials have installed a sophisticated oceanographic system, courtesy of the National Oceanic and Atmospheric Administration, to transmit vertical clearance to ships approaching two bridges to avoid collisions.
The technology will soon be installed on five more bridges along the Mississippi River, and “we actually received notice of funding availability Monday morning,” said Matt Gresham, head of government relations for the Port of New Orleans.
In Delaware, officials wanted the bridge to be able to support modern vessels, so they came up with a design that could support vessels even larger than the Dali.
It was funded in part by the federal government.
The final product will include eight cylindrical islands, each 24 meters in diameter, reinforced with 540 tons of steel and filled with tens of thousands of cubic meters of sand, stone and boulders.
The piles will be buried 14 meters deep in the river bed.
But even if solutions like the one in Delaware are implemented, the work is not done.
Hyun-Joong Kim, an assistant professor of civil engineering at Liberty University who has studied dolphin protection systems around bridges, said vulnerabilities around bridges should be reviewed periodically to ensure that protection systems, many of which which were installed decades ago, are capable of handling modern threats.
“If they see much larger ships coming and going, maybe they need to review the risk assessment,” he said.