NTSB determines likely cause of FIU pedestrian bridge collapse

Load and capacity calculation errors, inadequate peer review led to collapse, agency says

October 23, 2019
Florida International University bridge collapse

The National Transportation Safety Board (NTSB) determined during a public board meeting held this week that the probable cause of the Florida International University (FIU) pedestrian bridge collapse in March 2018 was due to load and capacity calculation errors made by designer FIGG Bridge Engineers Inc.

The agency said that consultant Louis Berger's inadequate peer review also contributed to the collapse, as it failed to detect FIGG's calculation errors in its design of a main span truss member nodal region and connection to the bridge deck. NTSB also said the FIGG engineer of record’s failure to identify the significance of structural cracking observed in this node before the collapse, and failure to obtain an independent peer review of the remedial plan to address the cracking, further contributed to the collapse.

The FIU bridge collapse killed six people and injured 10 others on March 15, 2018 near the city of Sweetwater, Florida. Upon its collapse, the 174-ft-long, 950-ton span fell onto traffic on SW 8th Street, crushing eight vehicles under the structure. Six out of the eight lanes of roadway were open to traffic at the time.

During this week's board meeting, NTSB said the failure of FIGG, MCM, Bolton Perez and Associates Consulting Engineers, FIU, and the Florida DOT (FDOT) to halt bridge work and close SW 8th Street to protect public safety contributed to the severity of the collapse outcome.

“Errors in bridge design, inadequate peer review, and poor engineering judgment led to the collapse of this bridge,” NTSB Chairman Robert Sumwalt said in a statement. “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.”

Over the summer, the Occupational Safety and Health Administration released its own investigative findings of the collapse, the conclusions of which largely placed blame with FIGG as designer of the bridge as well. Earlier this month, NTSB released 6,300 pages of documents connected to its investigation of the collapse.

Among the 30 key findings in its investigation, NTSB found that the rate of premature concrete distress was clear evidence the structure was progressing toward failure and should have alerted FIGG and MCM to the origin of the distress.

Based on its investigation of the bridge collapse, NTSB issued 11 safety recommendations in total, with one issued to the Federal Highway Administration, five issued to FDOT, three issued to the American Association of State Highway and Transportation Officials, and two issued to FIGG Bridge Engineers Inc.



Related Articles

Bayonne Bridge project wins top civil engineering award from ASCE
Image: Port Authority of N.Y./N.J.
The Bayonne Bridge Navigational Clearance project has been awarded the top project honor from the American Society of Civil Engineers (ASCE). On…
March 31, 2020
Gov. Mario M. Cuomo Bridge in New York; 2020 Prize Bridge Awards
The Gov. Mario M. Cuomo Bridge in New York was one of the major spans recognized in the 2020 Prize Bridge Awards. Image: New York State Thruway Authority
The American Institute of Steel Construction (AISC) and the National Steel Bridge Alliance (NSBA) recently announced the winners of the 2020 Prize…
February 21, 2020
Marc Basnight Bridge, Dare County, North Carolina
The Marc Basnight Bridge in North Carolina won the Main Span more than 150 ft award in the transportation category. Image: PCI
The Precast/Prestressed Concrete Institute (PCI) recently announced its annual PCI Design Awards for 2020.  Judges awarded 25 projects and five…
February 06, 2020
Gov. Hogan announces Chesapeake Bay Bridge completion for summer 2020
Gov. Hogan announces Chesapeake Bay Bridge completion for summer 2020. Image: Office of Gov. Hogan
Gov. Larry Hogan this week announced that all lanes at the Chesapeake Bay Bridge in Maryland will be open this summer as deck work on the westbound…
January 30, 2020