Source: Getty Images

The Sweetwater University City Pedestrian Bridge collapse at Florida International University is the latest civil engineering failure making headlines around the world.

Figg Bridge Engineers discussed a crack that had formed on the new bridge hours before its demise, but “concluded there were no safety concerns and the crack did not compromise the structural integrity of the bridge.”

Despite these assertions it did collapse and caused six fatalities and further injuries. Vehicles were pancaked underneath the rubble, as the photograph here depicts.

Lead engineer on the project W. Denney Pate had sent a voice mail to the Transportation Department; he reported the “cracking” that was observed on the “north end” of the bridge. The voice mail was sent two days before the bridge came crashing down.

Pate did say, in his professional opinion, the cracking “from a safety perspective” was not something they were concerned about. The cracking did not indicate that a collapse would follow. The engineering firm even did a stress test a few days before the collapse. All tests performed failed to raise any urgent red flags.

A civil lawsuit has been filed for gross negligence, in an attempt to hold the design-construction firm to account. The bridge was a US$14.2 million project. The National Transportation Safety Board is currently investigating the case, and also keeping a close eye on other new bridges across the country.

How was the bridge made?

The doomed bridge in Florida was being designed and constructed using a method known as Accelerated Bridge Construction (ABC). The process makes use of prefabricated materials that are brought on-site and then assembled - the end product here was a pedestrian bridge.

In fact Florida International University has an entire center dedicated to the rapid bridge building practice: the Accelerated Bridge Construction University Transportation Center.

The ABC method, used for quicker bridge builds, is also renowned for its cost effectiveness. And the bridges are usually robust - a Category 5 hurricane shouldn’t have the capacity to take one down apparently. An added benefit: roads can remain open during the building process. It was this that proved fatal!

The ABC method has been proving popular around the world, but is now, understandably, receiving greater scrutiny. The National Transportation Safety Board in the US is currently investigating the case (and keeping a close eye on other new bridges across the country). The investigation will drill down into the specific methods used during an ABC build in an effort to determine what the exact cause or causes were for this catastrophic failure.

America needs to monitor current civil engineering structures whilst also focusing on the ‘in-need-of-maintenance’ infrastructure that has been receiving stark criticism in the last few months.

Earlier this year aging infrastructure in the US took center stage when data generated from the Department of Transportation revealed that more than 54,000 bridges in America are currently structurally deficient. The information suggested that one in three bridges is in need of repair, including three interstate highway bridges.

This is essentially good news for structural and civil engineers interested and experienced in bridge design, construction and maintenance and based in the US.

Works Cited
Dearen, Jason. “Rapid Building Technique Gets Scrutiny After Bridge Collapse.” Popular Mechanics, Popular Mechanics, 18 Mar. 2018, www.popularmechanics.com/technology/infrastructure/a19472387/rapid-building-technique/.
Self, Zac, and Associated Press. “Engineer Reported Cracking before Miami Pedestrian Bridge Collapsed.” 10News, 17 Mar. 2018, www.10news.com/news/engineer-reported-cracking-before-miami-pedestrian-bridge-collapsed.

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