The Baltimore bridge disaster is what happens when 95,000 tons of modern cargo ship meets America's aging infrastructure, experts say

  • Baltimore's largest bridge collapsed after a cargo vessel, the Dali, crashed into it.

  • Experts told BI that a mechanical failure aboard the ship could have caused the crash.

  • The bridge was never built with modern container ships in mind.

The destruction of Baltimore's largest bridge early Tuesday morning has raised major questions about how such a disaster could have happened.

The National Transportation Safety Board said it has launched an investigation into the incident, in which a cargo vessel — the Dalicollided with one of the bridge's support beams, bringing it crashing down. It's unclear if there are any fatalities.

Much is still to be learned about what happened.

Both the FBI and the White House have said that nothing so far indicates nefarious intent or a terror attack. And Maryland Gov. Wes Moore said that "the preliminary investigation points to an accident," NBC News reported.

But what is clear is that one of modern shipping's largest vessels met with a bridge that was never meant to fend off such an impact, experts told Business Insider.

Henry Lipian, an expert at Introtech Accident Reconstruction and Forensics, said in a call with BI that while current information is limited, "the first thing that comes to mind to me is some kind of a mechanical failure, where either there's a problem with the steering of the ship or maybe a generator went out."

Lipian, who received specialist training in watercraft crash investigation during his time in the US Coast Guard, said this is more likely than "any mismanagement by the pilot or the captain."

Port pilots bring specialist knowledge of local waters and channels to guide visiting ships until they are out in open water.

The Maryland Association of Pilots was not available for comment on whether one of its pilots was in control of the Dali at the time of the collision.

Gov. Moore said in a news conference that the crew on the ship notified authorities they had lost power.

Moore told reporters that the ship was moving at a "very rapid speed" and that the mayday call stopped a greater disaster from occurring, with cars redirected away from the bridge.

He also said the bridge was "fully up to code" and had no structural issues.

An unclassified Cybersecurity and Infrastructure Security Agency report seen by ABC News said that the ship signaled to authorities that it had "lost propulsion" and was potentially going to crash.

A loss of propulsion would have had an effect on the rudder's ability to steer effectively, Lipian told BI. "If the rudder went out, now the ship's going to be at the mercy of the wind and the currents," he said.

The size of the vessel, even if it was moving slowly, would have created enormous kinetic energy, he said.

"There's no brakes on a ship," Lipian added. "You either have to reverse your engines or let it coast, and there's not enough time to drop any anchors."

A modern ship meets an old-school bridge

According to shipping publication Lloyd's List, the Dali is part of a modern generation of massive container ships with extended cargo capacity.

The ship is 300 meters long with a gross tonnage of roughly 95,000, according to the website

That wasn't common when the Francis Scott Key Bridge was first designed, Tim Broyd, a professor at University College London and a former president of the UK's Institution of Civil Engineers, told BI.

"Almost certainly when the bridge was designed, there was little to no consideration given to a hundred-thousand-ton ship hitting it," Broyd said.

But regardless of its age — construction on the bridge finished in 1977 — there's little chance it would have survived a head-on impact of this kind.

Instead of building bridges strong enough to withstand a direct impact from a ship like the Dali, engineers focus on deflecting a wayward vessel from its path.

This is achieved by putting structures in place around the bridge.

While it looks like some of these were in place around the structure, it is not clear what impact force they would have been designed for, David MacKenzie, Senior Technical Director of engineering and architecture consultancy COWI in the UK, told BI in an email.

In fact, engineers would struggle to design a bridge capable of stopping a ship as large as the Dali, Broyd said.

Newer bridges, built with heavier cargo ships in mind, may include larger gaps between the supporting piers, Broyd said. But "commercially, you can't make every bridge able to withstand a direct hit from a hundred thousand-ton vessel," he said.

"There's a balance between the amount of money you spend and the ability to withstand ever lower probability risks," he added.

Others see a much more worrying reality.

"This disaster reveals how exposed America's critical infrastructure is to sudden and devastating accidents as well as intentional destruction," said Rick Geddes, an infrastructure policy expert and director of the Cornell University Infrastructure Policy Program, in a statement seen by BI.

"Improved resilience should be on everyone's mind as aging infrastructure is rebuilt," he added. "Enhanced protection against ship-bridge collisions will certainly become more salient."

Broyd said that the fact that this collision happened at all points to a failure in the entire system of moving freight from the port down the river, rather than a flaw in the design of the bridge itself.

If it was indeed a mechanical failure that caused the Dali to crash, Lipian said, his next question would be to ask who was maintaining any systems that may have broken.

"Ships are very, very complicated machines," he said. "So in the future, there might be more information that we can glean in the human error part, like why did a mechanical condition fail?"

As Mark Richards director of NESTA consulting engineers, put it: "It's the full set of circumstances here, I think, which have led to the demise."

Correction: March 27, 2024 — An earlier version of this story misattributed quotes sent by COWI. These were from David MacKenzie, the senior technical director, not Lorna Wharton, the head of public affairs. MacKenzie's position about the strength of the structures in place to deflect the ship was also clarified. It is not clear what impact force they would have been designed for, he said. An earlier version of the story also misstated the weight of the vessel. The figure 95,000 refers to its gross tonnage; its weight in tons wasn't immediately clear.

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