$93M modernization project to protect Delaware Memorial Bridge from ship crashes
| January 22, 2024
A $93 million project aims to update a system that protects the Delaware Memorial Bridge against ships crashing into one of its two towers.
Work on the project began in July and is set to wrap up in September 2025.
Though the dual spans of the Delaware Memorial Bridge, one of which dates back to 1951 and the other to 1968, have been updated throughout the years to support the upward of 100,000 vehicles that cross the bridge daily, the existing protection system is outdated.
“The current protection systems at the bridge’s tower structures are original to the spans built in the 1950s and 1960s, and today’s ships are much bigger and much faster than those of that era,” said authority spokesman James Salmon. “If we were building a brand-new bridge, this type of collision protection system would be required for permitting to proceed.”
The updated system will consist of eight cylinders filled with compressed stone and sand, each measuring 80 feet in diameter.
Four cylinders will be installed at the piers supporting the eastern towers and four will be installed to protect the western towers as a barrier against a ship in the event of a crash. The original system consisted of fenders that functioned similarly to the cylinders being installed now, but they were designed to withstand less force.
The new infrastructure is designed to protect the bridge from a vessel crash in the range of 120,000 deadweight tonnage traveling at a speed of approximately seven knots, according to R. E. Pierson Construction, the general contractor for the project.
“Our goal is to take preemptive measures to prevent a commercial vessel from striking one of the bridge towers, which could cause significant damage to the bridge infrastructure and disruptions to interstate travel,” Thomas J. Cook, executive director of the authority, said in a statement.
Bridge strikes have happened before
Ships crashing into the Delaware Memorial Bridge, which connects Pennsville, N.J., and New Castle, Del., are uncommon but not unprecedented.
In July 1969, the tanker Regent Liverpool struck the bridge, requiring extensive repairs that would have cost around $7 million in today’s dollars.
“You hope an event like that never happens again, but you want to be prepared, be proactive, and have the proper protections in place so that this important structure can continue to serve the general public,” Salmon said.
Commuters and other drivers using the bridge will not find their route affected by the construction of the new protection system. All of the construction is occurring on the Delaware River itself so it will not affect traffic.
The project’s funding is derived from two main sources: revenue generated from the Delaware Memorial Bridge’s tolls and a grant from the U.S. Department of Transportation. The Better Utilizing Investment to Leverage Development grant is covering $22.25 million of the construction costs.
It will take approximately three months to complete construction of each cylinder. A temporary pier was installed to transport construction personnel and materials to and from barges on the river.
The barges at the construction site will carry cranes to install long wick drains into the river bottom, which function like straws, enabling water to travel to the surface as the 80-foot-diameter cylinders are filled with sand and stone.
As the soft material is compressed by the weight, the water contained within the cylinder is squeezed out and up.
The project was announced in January but construction did not begin until July to accommodate the needs of certain fish.
“We had a delay in the early going due to the spawning season of the sturgeon fish prevalent in the Delaware River, so we weren’t able to proceed until after July 1,” Salmon said. “Now we’ve started and the project is on schedule.”