Following Tuesday's tragic collapse of the Francis Scott Key Bridge in Baltimore, experts have spoken out about its quick and sudden collapse.
In the early hours of March 26, a cargo ship collided with the bridge - resulting in catastrophic damage and a desperate rescue operation.
As of this writing, officials have revealed that six individuals are still missing and are presumed dead. Two people have fortunately been rescued, with one of them in a critical condition.
The vessel involved in the collision, identified as the Dali, struck a pillar of the bridge approximately 30 minutes after embarking on its 27-day voyage to Sri Lanka while laden with cargo. The impact took place around 1:30AM on Tuesday morning.
The metal truss-style bridge at the center of this story was one of three ways to cross the Baltimore Harbor and saw around 31,000 vehicles cross it a day - that's a staggering 11.3 million vehicles a year.
Opening in 1977, the now-destroyed structure had four lanes and sat 185 feet above the Patapsco River. It spanned 1.6 miles (2.6 km).
What makes Tuesday's tragedy so startling is the speed at which the bridge collapsed after impact. Video footage shows the bridge crumbling into the freezing waters below. Now, experts have opened up about how and why the bridge's collapse unfolded this way.
Per The Independent, it is currently too soon in the investigation to understand exactly what happened, as we await more details to be released.
However, Ben Schafer - a structural engineering professor at Johns Hopkins University - told WTOP that he believes most bridges would collapse following the impact of a modern cargo ship.
"Fifty years into its design life and with its foundation, I don’t think there’s many bridges that are going to survive container ship head-on to one of its major supports directly as we saw this morning," Schafer said.
Schafer then commented on the bridge's design, saying: "It’s a sound bridge design and had been used in other locations [...] there’s no indications of problems with it over time."
These comments were echoed by Transportation Security Pete Buttigieg, who said on Tuesday that he is unaware of "a bridge that has been constructed to withstand a direct impact from a vessel this size".
Many experts have also noted that, despite the Francis Scott Key Bridge's modern design (constructed throughout the 1970s), cargo ships have continued to get bigger and bigger over the last 50 years.
And sadly, collisions like the one on Tuesday are becoming somewhat common.
In fact, Toby Mottram from the University of Warwick, revealed that there have been a total of 35 significant bridge collapses occurred following collisions with marine vessels from 1960 to 2015. As a result, bridges that are built today are constructed with such collisions in mind - with engineers developing a range of safety solutions to help protect modern structures.
Robert Benaim, a bridge designer and fellow of the Royal Academy of Engineering, told The Independent that these solutions come in many different forms. "These protections are either in the form of structural protections like ‘sacrificial dolphins’, which are made of steel and embedded in the seabed to stop or divert a ship," Benaim said.
"They can also be in the form of artificial islands; these are for very large ships and mean the ship will never reach the bridge pier itself."
Although experts and the public alike would expect the Francis Scott Key Bridge to have been built with some form of protection from collision, Lee Cunningham - a reader in structural engineering at the University of Manchester - echoes the sentiments of the other experts and says that these protections can only achieve so much.
"A vessel’s mass and velocity are key factors in the level of impact force generated and there is an economic and practical limit to what level of impact force can be designed for," Cunningham said. "Similarly, the direction of impact is also an important factor and design assumptions for this would likely be based on the position of the dedicated navigation channel."
Mottram agreed, adding: "It’s conceivable that the piers weren’t designed to withstand the magnitude of today’s ship impacts, as vessels like the ‘Dali’ weren’t navigating the Port of Baltimore during that era.
"Despite meeting regulatory design and safety standards of the 1970s, the Baltimore Key Bridge may not have been equipped to handle the scale of ship movements seen today."
Moving forward from Tuesday's tragedy, Schafer says there are definitely lessons to be learned.
"I do think if we’re going to have lessons learned, it’s going to be around that kind of port maintenance and the way we handle getting the ships in and out when it’s going through critical infrastructure like this," the professor said.
Our thoughts continue to go out to anybody impacted by this tragedy.
