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Emeritus Professor Toby Mottram on the Baltimore Key Bridge collapse

Emeritus Professor and Structural Engineer Toby Mottram said:

“Historically, there have been instances where sections of bridge structures collapsed following collisions with marine vessels. Between 1960 and 2015 there have been 35 major bridge collapses worldwide due to ship or barge collisions.

Regarding today's Baltimore Key Bridge incident, the speed of the 'Dali' ship at the time of impact remains unknown. With an overall length of 300 meters and a width of 48.2 meters, the significant momentum of this massive cargo vessel, especially when laden with cargo, would have been considerable upon impact with the reinforced concrete pier.

It's evident that the pier couldn't withstand the impact energy, leading to its failure and subsequent collapse of the steel truss and reinforced concrete deck superstructure. The extent of the damage to the bridge superstructure appears disproportionate to the cause, a matter for future investigation.

When the steel truss road bridge was designed and built in the 1970s (opened in 1997), there likely wasn't a requirement to consider disproportionate collapse and structural integrity. 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. However, modern navigation technologies should have prevented the ship from striking the pier. Investigating what failed on the ship to cause the fatal impact will be a priority.

The social and economic repercussions of this disaster are anticipated to be significant and prolonged.”

Tue 26 Mar 2024, 11:25 | Tags: engineering, United States