Questions raised over piers supporting Baltimore bridge

Collapse might have been averted if piers were adequately fitted with fenders, say experts

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NEW YORK - The Francis Scott Key Bridge in Baltimore suffered a near-total collapse after a large container ship appeared to strike a critical component, known as a pylon or pier, and much of the structure above it plummeted into the water below, according to several engineers who have reviewed footage of the incident.

Without the pier, they said, it was impossible for other components of the bridge to assume the load and keep the bridge standing.

The piers on a bridge act as a kind of leg and are known as "non-redundant" parts of a bridge's structure. If a pier is somehow taken out, there is nothing to compensate for the missing structural support, and a collapse of the bridge is all but inevitable, most of the analysts said.

Yet the collapse in Baltimore on March 26 might have been avoided, some of the engineers said, if the piers were adequately equipped with blocking devices with a self-explanatory name: fenders.

In bridge engineering, fenders can be anything from simple pyramids of rocks piled around the pylons to major concrete rings padded with slats of wood, designed to shield the bridge's supports from damage by water or collisions.

It is not clear whether any such protection built around the bridge's piers would be sufficient to guard against even a glancing hit from a 95,000 gross-ton container vessel.

The Maryland Transportation Authority did not immediately respond to a request for comment on the design of the piers, or whether any fenders were installed around them.

At a news conference on the afternoon of March 26, the chair of the National Transportation Safety Board, Ms Jennifer Homendy, said protective structures would be a part of the investigation into the bridge's collapse.

"There are some questions about the structure of the bridge - protective structure around the bridge or around the piers to make sure there isn't a collapse," she said, responding to a reporter's question.