They Saw the Cracks. Nobody Closed the Road.

The story

On 15 March 2018, at 1:46 in the afternoon, a new concrete pedestrian bridge at Florida International University collapsed onto SW 8th Street in Miami. Its main span had been moved into place five days earlier. One bridge worker and five people in cars waiting at a red light were killed.

In the weeks before, cracks had been growing at one joint of the truss, where diagonal member 11 met the deck. On the morning of the collapse, the people responsible met, judged that the cracks were not a safety concern, and work went ahead to retension a steel bar in that member. The road beneath stayed open.

The National Transportation Safety Board found that the probable cause was load and capacity calculation errors in the design of that joint. It also found that the failure to stop work and close the road contributed to the severity of the collapse. This film follows the record: the design, the review that missed the error, the cracks, and the decision on the last morning.

Sources

Primary sources are public records of U.S. federal agencies. Page references in the film refer to the printed page numbers of each report.

1. National Transportation Safety Board, Pedestrian Bridge Collapse Over SW 8th Street, Miami, Florida, March 15, 2018. Highway Accident Report NTSB/HAR-19/02, adopted 22 October 2019. Open ntsb.gov
2. NTSB, Illustrated Digest of the same report, SPC-20-02. Open ntsb.gov
3. NTSB, Preliminary Report, HWY18MH009. Open data.ntsb.gov
4. NTSB, Investigative Update 1, HWY18MH009. Open data.ntsb.gov
5. NTSB, Investigative Update 2, HWY18MH009. Open data.ntsb.gov
6. NTSB, Pedestrian Bridge Collapse Summary, public docket HWY18MH009. Open data.ntsb.gov
7. NTSB, Bridge Factors Group Chairman's Factual Report, public docket HWY18MH009. Open data.ntsb.gov
8. Federal Highway Administration (Holt, Graybeal), FIU Pedestrian Bridge Collapse Investigation: Assessment of Bridge Design and Performance, 12 September 2019. Docket attachment 73. Open data.ntsb.gov
9. FHWA Turner-Fairbank Highway Research Center, Factual Report for Concrete Interface Under Members 11 and 12, 23 September 2019. Docket attachment 74. Open data.ntsb.gov
10. FHWA, Assessment of the FIGG Factor of Safety Presentation, public docket HWY18MH009. Open data.ntsb.gov
11. NTSB Materials Laboratory, Study Report 19-043, surface roughness of the interface under members 11 and 12. Open data.ntsb.gov
12. NTSB, letter revoking the party status of the Occupational Safety and Health Administration, 20 June 2019. Open data.ntsb.gov
13. OSHA Directorate of Construction, Investigation of March 15, 2018 Pedestrian Bridge Collapse at Florida International University, Miami, FL, July 2019. Open osha.gov
14. U.S. Department of Labor, OSHA news release 18-1372-ATL, 18 September 2018. Open dol.gov
15. U.S. Department of Transportation, Office of Inspector General, correspondence CC2020006 on the firms involved with the FIU pedestrian bridge, 20 July 2020. Open oig.dot.gov

Documents from the NTSB public docket

Documents by the parties in the NTSB public docket. They are cited as evidence of what the parties wrote, not reproduced.

16. T.Y. Lin International for FIU, Pedestrian Bridge Design Criteria, June 2014. Docket attachment 12. Open data.ntsb.gov
17. Bolton, Perez and Associates, minutes of the meeting of 15 March 2018. Docket attachment 30. Open data.ntsb.gov
18. FIGG Bridge Engineers, minutes of the same meeting. Docket attachment 31. Open data.ntsb.gov
19. FIGG Bridge Engineers, presentation Temporary Construction Loading Condition, shown 15 March 2018. Docket attachment 32. Open data.ntsb.gov
20. AASHTO LRFD Bridge Design Specifications, 7th edition 2014 with 2015 interims, article 5.8.4.3, excerpt. Docket attachment 69. Open data.ntsb.gov
21. FIGG Bridge Engineers, party submission to the NTSB, 20 September 2019. Open data.ntsb.gov
22. FIGG Bridge Engineers, Factor of Safety presentation to the NTSB, 13 March 2019. Open data.ntsb.gov

Further

• NTSB investigation page HWY18MH009
• NTSB public docket HWY18MH009, all documents

Calculations marked "our calculation" in the film are our own, based on the values in these sources. They are not part of any official finding.

Corrections

Found an error? Send it with a source to contact@historiamachinae.com.