Design Errors Cited in Florida Bridge Collapse Report

Source: Florida International University

The National Transportation and Safety Board (NTSB), has a released an investigative update on the bridge collapse at Florida International University (FIU) on March 15, 2018, in which six people died and eight others were injured when the 174-foot bridge collapsed.

Eight vehicles were crushed in the collapse, with seven of those vehicles being occupied at the time.

Since the first investigative update was issued on August 9, 2018, new information on the bridge design has been developed and additional forensic examination/evaluation of the bridge structural components has been completed.

The new update says design errors made were in the design of the northernmost nodal region of the span where two truss members were connected to the bridge deck, and that the errors resulted in:

  • Overestimation of the capacity (resistance) of a critical section through the node, comprised of diagonal member 11 and vertical member 12, and
  • Apparent underestimation of the demand (load) on that same critical section.

The design review was conducted by the Federal Highway Administration’s Office of Bridges and Structures, in support of NTSB’s ongoing investigation of the collapse. The Federal Highway Administration is a party to the investigation.

The Turner-Fairbank Highway Research Center in McLean, Va., conducted numerous tests and examinations of concrete and steel samples taken from the fallen bridge.

The concrete and steel specimens tested by Turner-Fairbank Highway Research Center personnel met the minimum requirements specified in the project’s build plans, the update says, adding, that concrete core specimens from the bridge deck and bridge canopy met the compression requirements in the project plans.