Engineers who inspected a pedestrian bridge at Florida International University (FIU) just hours before it collapsed, killing six people, failed to recognize the danger posed by multiple growing cracks in the structure, the Occupational Safety and Health Administration (OSHA) said in a report about the accident.
The FIU bridge collapsed on March 15, 2018, five days after construction crews set part of it in place over SW 8th St.
OSHA’s report details a spectrum of problems, ranging from an unsound design by Tallahassee-based FIGG Bridge Engineers that triggered the structure’s failure, to inadequate oversight of the project by two engineering and consulting firms and FIGG’s misguided efforts to close the widening cracks, which further weakened an already overstressed joint and triggered the collapse.
The report contains multiple texts and emails from crew members to engineers expressing alarm over the cracks in the structure, which continued to grow in number and size. One supervisor who OSHA said was “visibly disturbed” by the situation took pictures of the cracks, saying the bridge “cracked like hell.”
Despite the “sense of urgency” expressed by construction crews, Tallahassee-based FIGG Bridge Engineers failed to recognize the gravity of the situation. According to OSHA, FIGG engineers even inspected it the day it collapsed but said the cracks did not pose any safety concerns.
In addition to its poor response to the bridge cracks, OSHA also said that the bridge design was structurally “deficient” and poor oversight of the bridge project by engineering consultants violated Florida Department of Transportation requirements.
FIU was constructing the pedestrian bridge to connect the university campus to the Sweetwater community on the opposite side of SW 8th Street, where thousands of university students live. Students on foot currently have to risk crossing multiple lanes of traffic, which has led to the death of at least one FIU student.
When it fell onto the busy street below, the bridge consisted of a single concrete truss spanning approximately 174 feet and weighing approximately 930 tons. An adjoining span of concrete truss was to be constructed next over the canal to make a continuous bridge of 289 feet.
Engineers designed the bridge using Accelerated Bridge Construction techniques that allowed the construction to be performed quicker and cheaper without closing the streets for long periods of time. Bridge components were built off-site and then transported to FIU for installation.
According to OSHA, “the magnitude of the cracks warranted that SW 8th Street be immediately closed, and the concrete truss be shored and supported at multiple intermediate locations to reduce the loads [on the weakened sections] until final evaluations were done and remedial measures implemented.”
The heavy structure collapsed onto SW 8th Street as motorists were waiting under the bridge at a stoplight. Five motorists and one construction worker were killed. Another worker sustained permanent disabling injuries.
In a statement to CNN, FIGG said it disagrees with OSHA’s conclusions, arguing the accident report is “factually inaccurate and incomplete, and includes errors and flawed analyses.” The company did not say why it failed to close the street below to traffic or take other precautionary measures as the cracks in the bridge worsened daily.
The National Transportation Safety Board (NTSB) continues to investigate the bridge collapse.