Engineering experts explain why Baltimore bridge collapsed after being hit by ship

BALTIMORE (TND) — The unbelievable collapse of a bridge in Baltimore has sparked a search for missing people, scrambled shipping routes, disrupted travel for tens of thousands of people in the surrounding areas and prompted a rush of resources to the region as government officials try to figure out what’s next.

The Francis Scott Key Bridge collapsed in stunning fashion early Tuesday morning when a cargo ship crashed directly into one of its support beams, causing the entire bridge to crumble around it and fall into the water below. Video captured of the crash showed the bridge falling into the water around the cargo ship, which caught fire and emitted black smoke into the area around it.

Investigators are still trying to piece together exactly what happened to cause the cargo ship to crash into the bridge, but have said it was moving at “very, very rapid speed.” Officials said that the ship issued a mayday call moments before the crash, giving authorities a chance to evacuate the bridge and stop cars from going across it. Maryland Gov. Wes Moore said the ship’s crew said they had lost power around the time the ship struck the bridge.

Moore and President Joe Biden both said Tuesday that there are no indications that the crash was intentional or tied to terrorist activity and it appeared to be an accident.

The National Transportation Safety Board was also investigating the crash on Tuesday.

The crash was a shocking incident for the area that will create significant logistical problems for commuters and shipping companies, as the bridge is located on the path to one of the busiest harbors in the country.

Reconstructing the bridge will also be a long and difficult task, which Moore described as a “long-term build.” In a Tuesday press conference, Biden said he expected the federal government to cover the costs of rebuilding the busy bridge and urged Congress to support efforts to fund the repairs.

“We’re going to get it up and running again as soon as possible,” Biden said. “Fifteen thousand jobs depend on that port, and we’re going to do everything we can to protect those jobs and help those workers.”

While bridges are built to withstand traffic riding over them and the current of the water beneath them, experts on bridge building say the results can be catastrophic when a pier is hit by the impact of a vessel the size of a cargo ship. Moore said during a Tuesday morning briefing that the bridge was “up to code.”

Darrell Kaminski, an assistant professor of practice in the University at Buffalo’s School of Engineering and Applied Sciences, said vulnerability to collisions is a factor when building bridges.

“If a large cargo ship impacts a pier, it may collapse, as we have seen. However, bridges can be designed to avoid collision, or to result in repairable damage,” he said.

There are also preventative measures and protective objects placed around the structural supports for bridges to prevent or minimize the damage of collisions, similar to concrete blocks frequently seen in parking lots to avoid cars hitting buildings. It wasn’t immediately clear what protective devices were in the water near the bridge or whether they would be able to avoid damage to a vital piece of the bridge’s support like the pier that was crashed into.

"The size of these cargo ships is just immense, so the real mechanism these days to avoid this is to put concrete fenders or or dolphins around the pier, so that the ship can never get there because it's just the mass of that ship is really more than you want to try to design a pier for," said Michael Chajes, professor of civil and environmental engineering at the University of Delaware.

Dr. Kim Roddis, professor emeritus of the Civil and Environmental Engineering Department at George Washington University, spoke with The National Desk Tuesday night about the incident.

Roddis said the bridge was inspected fairly recently, within the last two years.

"I do not think that there's any problem with the structure," Roddis said, noting she looked at the navigation charts for the Baltimore Harbor.

Roddis also addressed the infrastructure and transportation systems in place, mentioning that had the tug boats that assist ships in getting away from the docks stayed with the cargo ship until it is through the bridge, it may have prevented Tuesday's failure.

NTSB chairwoman Jennifer Homendy said the agency will look at the construction of the bridge, which was built in 1977, and whether that contributed to its collapse. Building standards and codes for bridges did not did not include potential impact, meaning that the Key Bridge was not built with being hit by a ship at the top of mind. It was also built at a time when cargo ships were significantly smaller than they are today.

"A bridge built in designed in the early '70s was not specifically designed with bridge impact in mind," Chajes said.