In Baltimore, Ship Strike "Never Occurred to Anybody"; In Delaware, It Did

Nine years ago, in 2015, Delaware's bridge transport authority set aside $2.5 million to design new protective fenders for the Delaware Memorial Bridge. Tankers and boxships on the Delaware River were getting bigger, and the New Panama Canal could be bringing even larger ships to the Port of Wilmington. 

In the unlikely event of a ship strike on the Delaware Memorial Bridge's piers, one of these bigger vessels could hit with enough force to collapse the bridge, a Delaware River and Bay Authority spokesman told local media at the time. About 100,000 vehicles cross the eight-lane bridge every day, and it is vital to the region's economy. This was too much risk for the DRBA, and it looked at current highway code recommendations for guidance.

To deal with the risk, the DRBA hired consultants to design new protective bumpers of steel and rock (dolphins), and won a federal grant for $22 million to help pay for construction. The design spec for the new dolphins was intended to defend against a ship of up to 156,000 tonnes, moving at a speed of up to seven knots.

“[We've] come to the conclusion that these are the kind of protections that our bridges need,” Shekhar Scindia, a DRBA structural engineer, told Delaware Online in 2017. “Our complete preliminary design has been based on the calculations directed by the current code.”

They bundled the dolphin project into a large package of renovations, secured a permit from the Corps of Engineers, raised tolls on motorists, convinced two state governors to sign off on the cost, and issued bonds. (This was not easy: New Jersey's governor initially vetoed the toll hikes, and DRBA had to negotiate.)

Construction started on the eight protective steel-and-rock dolphins last year and should be done by 2025. The final cost will come to about $93 million.

“It never occurred to anybody”

In neighboring Maryland, state transportation officials appear to have never discussed the risk of a similar ship strike on the Francis Scott Key Bridge, two former highway agency officials told the Washington Post - even though the bridge faced a similar threat from similarly-sized ships. 

The idea of a ship hitting a pier on the Key Bridge “never occurred to anybody," a former senior transport official told the Post. In recent years, risk-management conversations about the Key Bridge focused on acts of terror, like truck bombs, reflecting the post-9/11 security planning of the era, the official said.

That may not have always been the case in years past. The risk of a ship strike was on the minds of Maryland's highway engineers in 1980, when a ship collapsed Florida's Sunshine Skyway Bridge. At the time, when the average vessel calling Baltimore was a fraction of the size of Dali, the Baltimore Sun quoted the state's top transport engineer saying that "a direct hit - it would knock [the bridge] down." 

On Tuesday, the Key Bridge was struck by the container ship Dali, a 150,000-tonne displacement container ship. She was about half-laden with cargo, lighter than full load, and was making eight knots when she slipped past the small dolphin on the bridge's southwest side. The ship hit a pier and the bridge collapsed within about 30 seconds, killing six and shutting down the ship channel with wreckage. The estimated cost of the casualty is in the range of $2-4 billion. 

This is approximately the same ship size, speed and outcome that Delaware authorities have been working to defend against at the Delaware Memorial Bridge since 2015. But even if Maryland transport officials had followed Delaware's lead, it is not clear that they could have done anything, engineering experts told the Washington Post. The center span on the Key Bridge is narrow, and installing protective dolphins or fenders would make it even narrower. 

"That’s a pretty tight channel,” a former state transport official told the Post. "You might actually create a hazard rather than mitigate one."

Cost is also a factor. Engineers have to work within a budget, and the outside risk of a vessel strike has to compete with all the other risks and costs in the transport system, like traffic safety improvements and roadway repairs. 

The National Transportation Safety Board - which first warned about the need for bridge pier protection in 1981 - is looking at the design of the Francis Scott Key Bridge as part of its investigation. It has asked the Key Bridge's operator for documents related to all four of its bridges, and will consider pier protection measures.