US bridge collapse

In March, a cargo ship experiencing electrical difficulties crashed into one of the support pillars of the Francis Scott Key Bridge in Baltimore, US.

Dr Marina Bock, Lecturer in Structural Engineering at Aston University, said: “The Francis Scott Key Bridge is a metal truss bridge with a suspended deck, and from videos shown by the media it seems that the vessel hit a main pier of the bridge. The main piers rest on soil underwater and they are part of the foundations of the bridge.

“This type of bridge is not designed to redistribute loads in the event of a main pier collapsing and therefore videos show there is a progressive collapse of the bridge (bridge elements fail after other bridge elements had failed).

“Maybe if the vessel had hit a small section of the suspended deck the bridge would have been able to survive the collision, but not a main pier.”

The US National Transportation Safety Board and the FBI are investigating the incident, believing the cargo ship to have set off from port with an electrical fault.

Watch footage of the moment the bridge collapsed at: bit.ly/GuardianYT_Baltimorebridge

Image credit | Alamy