The U.S. National Transport Safety Board (NTSB) undertakes and shares excellent investigations - if you ever want a good example of openness and lessons, you should definitely look at their website.
What happened
On Thursday, March 15, 2018, 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.
One bridge worker and five vehicle occupants died. Five bridge workers and five other people were injured.
The investigation
The NTSB "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."
All of the information relating to this failure can be found on the NTSB website - including this illiustrated digest.
This video is a great walk-through and can be used for Lessons Learnt:
Comments