The National Transportation Safety Board’s Oct. 8 release of documents related to its FIU bridge collapse investigation raises questions but provides no definitive conclusions about why the partially built structure suddenly crashed to the ground on March 15, 2018, killing six. The last official word on the cause of the fatal collapse will have to await the agency’s final report, scheduled to be released on Oct. 22.

However, notable among the Oct. 8 release of interview transcripts, newly released photos and dozens of other items are two separate reports submitted by the project’s lead contractor, MCM, and the bridge’s design engineer, FIGG Bridge Engineers. The respective “party submission” reports, provided to NTSB as part of the agency’s investigatory process, offer dueling accounts, with each pointing responsibility at the other party.

For example, FIGG asserts that contractors failed to communicate specifics of cracking on the bridge structure. MCM’s report to NTSB counters that argument with details of emails and other communications to FIGG—and other project team members—noting the cracking’s severity.

In an Oct. 8 press release, FIGG  touted the conclusions reached by Wiss, Janney, Elstner Associates (WJE)—whom FIGG hired—that the collapse resulted from “a failure by contractors to conform to the final bridge design plans and comply with state of Florida construction requirements.”

The Tallahassee, Fla.-based bridge engineer specified that the “probable cause,” based upon WJE’s findings, was that “the construction joint at the north end of the main span between the truss members and the bridge deck was not roughened as required.”

FIGG added, “This failure to meet the construction specification requirements was not noticed by either the contractor’s quality control personnel or by the construction inspectors under contract to FIU.”

Critically, FIGG asserts that MCM and other firms on site had become aware of changes in the cracks that were occurring on the bridge in the days preceding the collapse, but failed to communicate these developments to FIGG personnel.

“There is no indication that MCM, BPA (Bolton, Perez & Associates) or other project participants who were on-site during this time actively observing the cracking expressed concern with the safety of the span suspended over SW 8th Street or suggested that the road should be closed until the situation was resolved,” FIGG’s report states.

Account Disputed By MCM Submission

Contacted by ENR, MCM did not offer a further statement but instead pointed to its own submission to the NTSB, which rebuts FIGG’s version of events with extensive details of its communications to the bridge designer.

For example, days before the collapse, MCM reports emailing new photos of the cracking to FIGG, along with this message: “Following our previous emails regarding the noted cracks, and as witnessed on site by FIGG as part of the movement/erection support, attached please find photos depicting the cracks developed prior [to] and post [of] the span 1 erection and/or destressing of truss members 2 and 11.

“It is our opinion,” the MCM email continued, “that some of these cracks are rather large and/or of concern; therefore, please review and comment as promptly as possible and advise if there is a required course of action to remedy or address these right away.”

MCM further asserts to NTSB that FIGG’s design manager, Dwight Dempsey, communicated back to the contractor that the engineer “did not see this as a safety issue.”

Meeting Minutes

Minutes of a FIGG-led meeting held on-site the morning of the collapse, released by FDOT in May, back up MCM’s contention that the bridge’s designers saw “no safety concern” from the cracks. The record of that March 15 meeting showed, for example, that a slide from FIGG’s presentation stated: “After about an hour of review and evaluation, FIGG had conducted sufficient supplemental/independent computations to conclude that there is not any concern with safety of the span suspended over the road.”

Nevertheless, citing the analysis by WJE, FIGG contends that the blame rests squarely with construction contractors, stating: "Contrary to incomplete prior accident updates, the design of the UniversityCity Pedestrian Bridge at Florida International University was neither the proximate cause, nor a contributing cause, of the construction accident. If, however, the various parties constructing the bridge, inspecting the construction, or moving the bridge into position, fail to comply with (plans, specifications, and requirements), then even a safe design will be compromised.”

The NTSB is scheduled to release its report on the tragedy’s probable cause in a public meeting to be held at 9:30 a.m. on Oct. 22. The meeting will be available via live webcast.