On Thursday, March 15, 2018, about 1:46 p.m., a partially constructed pedestrian bridge crossing an eight-lane roadway in the city of Miami, in Miami-Dade County, Florida, experienced a catastrophic structural failure in the nodal connection between truss members 11 and 12 and the bridge deck. The 174-foot-long bridge span fell about 18.5 feet onto SW 8th Street, which consists of four through travel lanes and one left-turn lane in the eastbound direction, and three through travel lanes in the westbound direction. Two of the westbound lanes below the north end of the bridge were closed to traffic at the time of the collapse; however, one westbound lane and all five eastbound lanes were open.
The pedestrian bridge was under construction as part of the Florida International University University City Prosperity Project. On the day of the collapse, a construction crew was working on retensioning the post-tensioning rods within member 11, connecting the bridge canopy and the deck at the north end. About 1:46 p.m., a video camera on a construction pickup truck traveling east, approaching the bridge, recorded the collapse sequence. The video showed the blowout of the concrete north of truss member 12, and the truss losing geometric stability. Eight vehicles that were located below the bridge were fully or partially crushed, seven of which were occupied. One bridge worker and five vehicle occupants died. Five bridge workers and five other people were injured.
We determined that the probable cause of the Florida International University (FIU) pedestrian bridge collapse was the load and capacity calculation errors made by FIGG Bridge Engineers, Inc., (FIGG) in its design of the main span truss member 11/12 nodal region and connection to the bridge deck. Contributing to the collapse was the inadequate peer review performed by Louis Berger, which failed to detect the calculation errors in the bridge design. Further contributing to the collapse was the failure of the FIGG engineer of record to identify the significance of the structural cracking observed in this node before the collapse and to obtain an independent peer review of the remedial plan to address the cracking. Contributing to the severity of the collapse outcome was the failure of MCM; FIGG; Bolton, Perez and Associates Consulting Engineers; FIU; and the Florida Department of Transportation to cease bridge work when the structure cracking reached unacceptable levels and to take appropriate action to close SW 8th Street as necessary to protect public safety.
We made safety recommendations to the Federal Highway Administration, the Florida Department of Transportation, the American Association of State Highway and Transportation Officials, and FIGG Bridge Engineers, Inc.
