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Baltimore Bridge collapse highlights need to protect critical foundations

A potential legal angle when it comes to liability payments has not been raised directly, but will surely be in the minds of lawyers likely to be tied up in the courts for many years with the Dali case, is whether the collapse of Baltimore’s Key Bridge was at least in part the result of a failure to better protect the piers holding up the spans over shipping channels, given the growth in the average size of container ships over the past 40 years.

The Bridge was fully within the construction code.

However, there are an estimated 16,800 span bridges in the US which are “fracture critical” – meaning that, if one portion of the bridge collapses, all of it is likely to come down.

US Transportation Secretary Pete Buttigieg said on Wednesday that the Key Bridge “was simply not made to withstand a direct impact on a critical support pier from a vessel that weighs about 200m pounds.”

While that assertion is impossible to deny, several engineers pointed out that it dodged the question as to whether there were safety measures that could have prevented the allision in the first place (e.g., tugs as well as a pilot) or mitigated the crush of the impact to keep the foundation intact (e.g., a protective dolphin ring around the piers).

The Key Bridge was opened in 1977, which was three years before a similar vessel crash into the Sunshine Skyway Bridge in Tampa Bay, Florida killed 35 people. That event caused bridge designers to implement better protections for foundation piers, but no retrospective rules were brought into play. It seems certain that, if the Key Bridge had been built four years later, or the Skyway crash had been four years earlier, then the design of the Key Bridge would have been different.

One question that might be raised in courts therefore could be “why was there no retrofit for the Key Bridge?”

Structural engineers talking about the case agree that, until the National Transportation Safety Board finalizes its investigation into the disaster, it will be impossible to say whether retrofitted dolphins could have prevented the collapse – given the facts that it was a mid-to-large container ship making seven knots at the time of the direct hit on the pier.