Load and capacity calculation errors by FIGG Bridge Engineers, Inc., along with an inadequate peer review from Louis Berger, all contributed to the fatal collapse of a pedestrian bridge at the Florida International University last year, the National Transportation Safety Board (NTSB) has found.
Their determination, reached during a public board meeting held this week, placed probable cause in the companies’ hands and expanded fault to include the failures to exercise caution of MCM, Bolton Perez and Associates Consulting Engineers, FIU, and the Florida Department of Transportation (FDOT). The result of those failures was the collapse of a 174-foot bridge over Miami’s 8th Street, crushing eight vehicles in the process, killing six people and injuring 10 others.
“Errors in bridge design, inadequate peer review, and poor engineering judgment led to the collapse of this bridge,” NTSB Chairman Robert Sumwalt said. “The failure of all concerned parties, to recognize and take action on the threat to public safety presented by the significant observed bridge structure distress prior to the collapse, led to the tragic loss of life in this preventable accident.”
FIGG’s initial design was nonredundant because it only provided a singular load path. The company’s construction plans were inconsistently identified when intentionally roughened surfaces were needed to fulfill assumptions of the bridge design. There were also signs of premature concrete distress that offered a warning sign of impending failure that should have alerted FIGG and MCM. Louis Berger was not qualified by FDOT to conduct an independent peer review, and the department should have verified Louis Berger’s qualifications as part of their oversight of local agency program projects.
NTSB found that the concrete and steel materials used the construction of the bridge were not a contributing factor to the collapse.
In response to the tragedy and the ensuing investigation, the NTSB has delivered 11 safety recommendations to the Federal Highway Administration, FDOT, American Association of State Highway and Transportation Officials, and FIGG Bridge Engineers, Inc.