In March of 2018, an under construction pedestrian bridge on Florida International University’s (FIU) campus collapsed onto an open street below, killing 6 and injuring several others. Roughly 19 months after the tragedy occurred, the National Transportation Safety Board (NTSB) has released their final findings.
What Happened?
To help us understand the sequence of events, the NTSB released the video below last week, laying out the facts of the incident:
The NTSB’s Findings
The NTSB determined that the probable cause of the fatal bridge collapse was due to load and capacity calculation errors by FIGG Bridge Engineers, Inc. They also determined that a contributing factors were an inadequate peer review by Louis Berger, FIGG’s engineer of record’s failure to realize the significance of the concrete cracking prior to the collapse, and FIGG’s failure to obtain an independent peer review for how to address the cracking issue.
In addition to the causes of the collapse, the NTSB also determined that there were several factors that contributed to the severity of the collapse. They named FIGG, MCM, Bolton Perez and Associates Consulting Engineers, FIU, and the Florida Department of Transportation (FDOT) specifically for failing to close the street before the collapse.
In total, the NTSB made 30 findings, including the fact that FIGG’s design was nonredundant and only provided a singular load path, the concrete and steel materials used were not a factor in the collapse, the restressing of member 11 should have been independently reviewed prior to implementation, and that Louis Berger was not qualified by the FDOT to conduct an independent peer review and FDOT should have verified that. All 30 findings can be found on this 7-page abstract of the findings.
Many of these findings also line up with OSHA’s 115-page report on the incident, which was published in June of 2019.
NTSB Safety Recommendations
Any good investigation should have a plan of attack to prevent the same thing from happening again. As part of the report, the NTSB has issued 11 total recommendations spread across 4 different entities, including the Federal Highway Administration, the FDOT, the American Association of State Highway and Transportation Officials, and FIGG Bridge Engineers, Inc.
FDOT received the most recommendations, six in all, including the need to revise their Plans Preparation Manual to tighten up their independent peer review requirements, adding a requirement to immediately close the road below if structural cracks are found on bridges, and adding information about redundancy in structures to their design guidelines.
The Final Report
The full report of the NTSB’s investigation is expected to be released within the next few weeks. Until then, you can also watch the 3-hour long public board meeting the NTSB held on Tuesday, October 22 below.
Full story: Load, Capacity Calculation Errors, Inadequate Peer Review Led to Pedestrian Bridge Collapse | NTSB
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