DUNDALK, Md. — It was the first question many of us asked when we saw the video of the Francis Scott Key Bridge collapse, and it's a question that is still unanswered: how does something like this happen? And, could it happen again?
Answering those questions requires examining the structure of the Key Bridge, a task the National Transportation Safety Board says it will do as part of its investigation.
Governor Wes Moore initially described the bridge as "up to code," shortly after its collapse on Tuesday morning.
The last time the bridge was inspected was May 2023, according to the Federal Highway Administration's National Bridge Inventory. It was rated in "fair" condition, right in between "good" and "poor." Last year, nearly half of all U.S. Bridges found themselves in the fair category, according to an analysis of the inventory's database by the American Road and Transportation Builders Association.
Specifically, in the inspection report, the pier protection system was rated as "in place and functioning."
Ben Schafer, structural engineering expert at Johns Hopkins, described the protection system in place on the key bridge as "pretty modest,” based on what he’s seen.
“The bow line of the ship was much higher than that protection. So it wouldn't really make any stop for a cargo ship. Something like a small fishing vessel or pleasure cruise wouldn't be able to hit the piers directly. But no significant system directly at the piers that’s evidenced."
However, Schafer doubts that any U.S. bridges that have been built, or even could be built, would be able to withstand a blow from a massive cargo ship. He described the event not as a bridge that collapsed, but as a bridge that was destroyed by a ship "nearly as big as the bridge itself."
"Could we build a Fort Knox, you know, a nuclear bunker in front of every bridge? It's structurally possible but it's not economically feasible. And so even in the most extreme bridge protection systems that we see, at this point, I remain unconvinced that in a similar incident, they would perform successfully," Schafer said.
During a White House press briefing today, Department of Transportation Secretary Pete Buttigieg said, "It's difficult to overstate the impact of this collision. It's not just as big as a building, it's really as big as a block - 100,000 tons all going into this pier, all at once."
Buttigieg pointed to the 1980 collapse of the Sunshine Skyway in Tampa, Florida, saying that since that collapse, many modern bridges have been designed with more protective structures in place.
"Right now there’s a lot of debate taking place in the engineering community about whether any of those features could have had any role in a situation like this,” he said.
For example, the Skyway bridge now has parts called “dolphins.” Other bridges have features called “fenders,” which can be thought of as similar to a bumper for your car.
"In the event that you have a ship or a vessel go off course, they're there to effectively protect the structure from a collision like the one we saw in Baltimore,” Zacharay Haber, assistant professor of structural engineering at the University of South Florida and former researcher for the Federal Highway Administration, said.
But so far it’s unclear whether any design features could have prevented this. That will be a question for the NTSB to answer.
NTSB Chair Jennifer Homendy said on CNN this morning, when asked about the apparent lack of fenders, "Yes, I've seen the pictures. Again, we’ll want to look at everything that the – on the structure of the bridge, on the design of the bridge, and then we’ll have further information to share [...] We will look at fenders. We will look at areas that should have been in place to prevent this type of destruction from occurring. That will be part of our investigation here."
During the White House briefing today, Buttigieg said of the NTSB investigation, “If they discover or determine anything that should be considered in the regulation, inspection, design, or funding of bridges in the future. we will be ready to apply those findings.”
During a Wednesday evening press conference, the NTSB said the Key Bridge is a "fracture-critical," bridge. Think of it like a three-legged stool; if one piece goes, they all go. Homendy said this is no longer the preferred method to build bridges. There are more than 17,000 fracture-critical bridges in the U.S.
Homendy also said during that presser that the NTSB has not yet had a chance to review the latest 2023 inspection report that rated the bridge in "fair" condition, but they will.
Investigators will also request and review all inspection reports for the Key Bridge from the past decade, as well as information on pier protection systems for all MDTA-owned bridges. There are four.
