The pedestrian bridge that collapsed at Florida International University Thursday was the largest of its kind in Florida to use a new construction process designed to reduce road closures, overnight shifts and costs.
But as I-Team Investigator Adam Walser learned from a longtime bridge designer, new techniques can also bring new risks.
“People depend on our work,” said retired structural engineer Gautam Ghosh. “And if something goes wrong it can be devastating.”
Ghosh has spent four decades designing bridges.
His firm Jacobs Engineering was called in to provide a solution after the Selmon Crosstown Expressway collapsed in 2004.
The same firm that designed the FIU pedestrian bridge, FIGG Bridge Engineers, paid the Tampa Expressway authority $750,000 to settle a lawsuit related to issues with the Selmon Expressway Project.
In 2012, the state of Virginia fined FIGG $28,000 after part of a bridge under construction fell onto railroad tracks, injuring workers.
In a statement, a FIGG spokesperson described the FIU bridge collapse as “unprecedented” and vowed to “fully cooperate with authorities in reviewing what happened and why.”
Ghosh says FIGG was using a new technique called accelerated bridge construction, or A.B.C.
“it would not tie up much time. It could be done fast, economically basically. Traffic could be flowing,” said Ghosh.
Ghosh says that A.B.C. has been used successfully to build highway overpasses, including some along I-4 in Central Florida.
“Typically, our bridges over highways are a shorter span,” Ghosh said.
Most A.B.C. built bridges cross about four lanes of traffic and are around 70 feet long.
The FIU bridge was 174-feet long and weighed nearly 2,000,000 pounds.
Investigators are now reviewing the engineering, design, construction and safety of the project.
“Safety should always be the paramount aspect of any construction,” said Ghosh.
Ghosh says witness accounts point to possible problems with the anchoring system, but it's too soon to guess what happened.
He says there will be lessons learned, as there are in all construction-related tragedies.
“It's a learning opportunity. I wish we didn't have to learn this way,” Ghosh said.
Ghosh says the public should feel confident now using the Selmon Expressway since those original flaws have long since been corrected and the Florida DOT regularly inspects to make sure there are not any new concerns.
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