Memorial Bridge ‘dolphins’ designed to stop ships like Dali

Peter OsborneGovernment, Headlines


The Delaware River and Bay Authority is in the middle of a $95 million project that will stop ships bigger than the Dali from hitting the bridges. Photo by Delaware River and Bridge Authority.

Could it happen here?

That’s the question Delawareans have been asking since watching the horrific images of the Francis Scott Key Bridge collapsing after a cargo ship rammed it last month.

There are no guarantees, but efforts have been underway for 10 years to protect the Delaware Memorial Bridge from ships even larger than the Dali, which hit the Key Bridge March 26, and the state has been running bridge loss scenarios for years.

Drivers on and near the Delaware Memorial Bridge connecting Delaware and New Jersey can take some comfort from the huge cranes that are part of a $95 million project to update the system that protects against ships crashing into one of the spans.

Construction work on the Delaware Memorial Bridge project began in late July 2023 and is on target to be completed by September 2025. 

The Delaware River and Bay Authority (DRBA) is installing eight stone- and sand-filled “dolphin” cylinders, each of which measures 80 feet in diameter.  Two will be on each side of the bridge’s piers.

“This is a $95M insurance policy,” said Delaware River and Bay Authority  Public Information Officer James Salmon. “You never think you’ll have to use it. You hope it goes untouched, but you will be glad you have it if you need it.”

DRBA is a bi-state governmental agency that owns and operates the bridge, five airports and two ferry systems that connect New Jersey and Delaware.

Meanwhile, the Delaware Emergency Management Agency conducts annual Threat and Hazard Identification and Risk Assessments using different scenarios that test how they would impact the region and its options for responding. 

At least one focused on how the state would handle a collapse of a bridge like the Delaware Memorial Bridge or the large bridges spanning the Chesapeake & Delaware Canal in 2022, said Director & Homeland Security Advisor A.J. Schall.

In January 2017, DRBA had the Center for Homeland Defense and Security conduct a tabletop exercise involving a ship hitting the Delaware Memorial Bridge. 

The next year, the bridge had to shut down for more than six hours after a leak of ethlylene oxide from the neighboring Croda plant on the high-traffic Sunday evening after Thanksgiving.

The C&D Canal is a 14-mile sea-level ship canal connecting the Chesapeake Bay with the Delaware River. It includes six major automobile and railroad crossings, including the Summit Bridge, the St. Georges Bridge and the William V. Roth Jr. Bridge.

Bridges on the C&D Canal are maintained by the Army Corps of Engineers, which did not respond to requests for an interview.


The Delaware River and Bridge Authority is installing eight stone- and sand-filled “dolphin” cylinders, each of which measures 80 feet in diameter around the Delaware Memorial Bridge.

Memorial bridge dolphins

The Delaware Memorial Bridge project has been in the River and Bay Authority’s Capital Improvement Program for 10 years between design, permitting, federal funding and COVID, so planners are much further along than other states responding to what happened in Baltimore.

Still …

“It’s not necessary to accelerate our timeline,” Salmon said, noting that two of the eight piles have already been completed. “We have an ambitious construction schedule and we’re moving as fast and efficiently as we can. 

Salmon said DRBA still needs to deal with “some fishery restrictions during sturgeon reproduction season between mid-March and the end of June where you can’t drive piles but can do other things.”

The protection system is designed for a Neo-Panamax vessel, which is slightly larger than the Dali that hit the Key Bridge.

Our cells are designed to be sacrificial but will stop a ship from hitting the bridge,” Salmon said. 

RELATED STORY: DRBA’s $132.7 million budget includes bridge safety, airport expansion

The dolphins are made of 540 tons of steel, 15,000 cubic yards of sand, 140 yards of large stones and  4,000 cubic yards of large boulders at the top, with about 15 feet of the structure visible above the water.

They are designed to absorb the impact of the ship, preventing it from hitting one of the support towers or steering it away.

About 20 percent of the project is being funded by a U.S. Department of Transportation BUILD grant with the rest coming from bridge tolls generated by the more than 100,000 cars crossing the bridge each day.

The bridge spans were built in the 1950s and 1960s, and while they’ve been updated throughout the years to accommodate the vehicle traffic, the existing protection system hadn’t been updated, even though the ships passing under the bridge today are much larger and faster than those of that era, Salmon has previously said.

Ships crashing into the Delaware Memorial Bridge, which connects Pennsville, New Jersey, and New Castle, Delaware, 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.

All the construction is occurring on the Delaware River itself so it does not affect traffic.


The dolphin cylinders installed around the towers of the Delaware Memorial Bridge are designed to collapse and stop a ship headed toward a bridge support. Photo by Delaware River and Bay Authority.

Takeaways from Key Bridge

“All bridges are critical to our daily lives and are treated as so,” said DEMA’s Schall.

The scenarios created for mass-casualty events have included bridge ramming and tropical story closing the Roth Bridge. 

“The people in Baltimore brought their A games to what happened there and that’s what we want to do here,” he said. “You’re preparing for the unthinkable.”

Schall said he sat in on many of the meetings as Baltimore dealt with the Key Bridge collapse and will learn more once it releases its after-action report in a few weeks.

He says he learned a few things to apply to Delaware’s preparation for the unthinkable.

“We’re going to reprioritize [how we handle our] Business Emergency Operations Center,” which integrates local companies into the planning and improved communications in such areas as mass transportation, office schedules, outreach to other state agencies, and whether there’s a criminal presence in a given event. 

It’s “one area I want to make work even if we do not ‘need’ it as much as other states like Pennsylvania and Florida,” he said. “But I do feel vindicated a bit because we’ve done the bridge ramming scenario and learned where you become stressed.”

Schall said that while DEMA “learned more from COVID than the previous 50 years about delivering a unified message and communication to the public,” he also learned from “how Maryland did a great job on the tempo of its communications.”

Another major Delaware bridge is the Indian River Inlet Bridge (officially the Charles W. Cullen Bridge) that carries Delaware Route 1 over the Indian River Bay and the Atlantic Ocean.

 It is maintained by the Delaware Department of Transportation, which maintains most of Delaware’s 1,800 bridges. 

“All our bridges are in good shape,” said DelDOT Community Relations Coordinator Robin Bryson. “They’re inspected every two years and none of them handle large ships like the Delaware Memorial Bridge or the Roth Bridge and other C&D Canal bridges.”


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