Feds say engineers didn’t heed alarms before bridge collapse

In a damning new report, federal work-safety investigators conclude that engineers in charge of design and construction of the ill-fated Florida International University pedestrian bridge should have shut down Southwest Eighth Street because of growing cracks in the structure, but failed to recognize the span was in danger of imminent collapse due to design errors.

The 115-page report by the Occupational Safety and Health Administration, obtained Tuesday by the Miami Herald, finds plenty of blame to spread around for the collapse of the bridge last year while under construction.

The report details a catalog of errors ranging from a “deficient” design by Tallahassee-based FIGG Bridge Engineers that led to structural failure, to inadequate oversight by two engineering consulting firms that were supposed to act as a backstop on design and construction, Louis Berger and Bolton Perez and Associates, and a fatal attempt by FIGG to close the cracks that triggered the collapse.

The 930-ton span fell onto the roadway as motorists were waiting under the bridge at a stoplight. Six people were killed, including one construction worker. Another worker was permanently disabled.

The OSHA report also faults the bridge contractor, Munilla Construction Management (MCM), for not exercising “independent judgment with regard to implementing necessary safety measures” after FIGG engineers dismissed concerns over the growing cracks during a meeting on the morning of the March 15, 2018, collapse. The report, prepared by Mohammad Ayub, director of OSHA’s office of engineering services, concludes that the road should have been closed “immediately” and the bridge shored up to prevent collapse.

The OSHA report is the first time federal investigators have stated unequivocally that the roadway should have been closed in response to the cracking on the bridge, one of the principal points of public concern after the catastrophic accident.

The report also dings FIU and the Florida Department of Transportation, which oversaw the project but did not have direct involvement in design or construction, for not stepping in and demanding that FIGG’s conclusions on the morning of the collapse be reviewed by independent experts — something they had the ability to do, according to OSHA. Both had representatives at the meeting.

FIU declined to comment, cit

ing an open investigation by the National Transportation Safety Board. That agency’s report into the cause of the collapse is expected later this year.

The document also confirms that the collapse was triggered by FIGG’s sending work crews to re-tension internal support cables at the critical structural connection where the cracks appeared, and that the task was a misguided effort to close the widening gaps. That, OSHA concluded, was a fatal error. The retensioning further weakened a structural joint at the north end of the span that was already severely overstressed and failing because of a design error by FIGG that made it too weak to hold up the bridge. The additional stress caused by the re-tensioning led to the collapse, OSHA concluded.

“FIU, FDOT and MCM did not insist that all computations performed by FIGG, including FIGG’s recommendation to re-tension the PT bars, be peer reviewed. They deferred to FIGG’s conclusions, and failed to apply their own judgment and judiciousness, even though FDOT, BPA and MCM have extensive experience in bridge and concrete construction,” OSHA said in its report.

Louis Berger, and BAP did not immediately respond to requests for comment. In a statement released Tuesday night, FIGG called the OSHA report “factually inaccurate and incomplete.” It also said the report included “flawed analyses” and did not “Include an evaluation of many important factors pertinent to the construction process leading up to the accident.”

FIGG comes in for an unusually blunt thrashing by OSHA. The agency’s investigators conclude that FIGG and its chief design engineer, W. Denney Pate, failed to design the bridge properly, then compounded the error by not raising an issue over an inadequate review by Louis Berger of that design. FIGG also failed to take the growing cracks seriously enough to investigate their cause or seek a second, independent opinion on whether they represented a safety hazard, OSHA said.

But the report notes that Pate and his team were sufficiently concerned to ask MCM to hurry up construction of the bridge’s back end, a connector leading from the cracking north end of the completed span to Sweetwater. That back span would have provided sufficient additional structural strength to support the failing connection, the independent experts consulted by the Herald said.