The Baltimore Bridge collapsed so quickly

The Francis Scott Key Bridge: A Completely Constructed Iron Bridge with a Large Number of Steps, and its Failure to Fold Like Paper

Large steel structures may seem invulnerable, but steel, explains Knight, is relatively lightweight for its size. As soon as it is pushed or pulled the wrong way with enough force, it can fold like paper. The Francis Scott Key Bridge was a continuous bridge, meaning that it had a central section for over 300 meters. (Truss bridges use steel beams, arranged in triangular shapes, to support their load.) The central truss was made up of three horizontal stretches, known as spans, with two sets of supports holding these above the water. It was third biggest structure of its kind in the world.

Several people are missing, and the major US port is in a poor state, because of the collapse of the bridge. A rescue operation is underway. President Biden has called the disaster a “terrible accident.” Ship traffic is currently stuck on either side of the crash site, and a major roadway through Baltimore has been cut off.

“It’s a dreadful tragedy and something you hope never to see,” says David Knight, a bridge expert and specialist adviser to the UK’s Institution of Civil Engineers. He said he was not surprised at the way in which the bridge collapsed.

The Transportation Costs of a Roll on, Roll Off Ship: A Case Study on Baltimore, the East Coast, and the Northeastern Seaboard

This will be a special pain for the auto, farm equipment, and construction industries, because on the US East Coast, Baltimore handles the most “roll on, roll off” ships—an industry term for those designed to handle wheeled cargo. The port has the necessary equipment, workers with the correct training and a location that is close to the busy Eastern Seaboard and heavily farmland Midwest.

But the shipping picture will get more complicated the longer the disaster takes to resolve. Changes to the route and destinations of ships can add a great deal of time to a journey. If a ship is hauling a bunch of different cargoes for a bunch of different industries, a holdup along the way causes a lot of people to be screaming for their supplies.

“Everybody right now is saying, ‘We’re just going to reroute, it’s going to be fine,’” says Nada Sanders, an expert in supply chain management at Northeastern University. “If this lasts a while, it’s not going to be fine. It’s going to impact prices.”

The growth of boats is down to simple economics: The more goods you can cram onto a ship, the more you save on costs. “The amount of cargo has increased tremendously,” says Zal Phiroz, a supply chain analyst at UC San Diego. “This has been impacted to a great degree by Covid, and after Covid as well. The prices of things went up. Everything got through the roof.