The Miami bridge that COLLAPSED five days after it was installed

This bridge was five days old. It had been carried over an eight-lane road in Miami on a Saturday morning, in about six hours a span cast beside the highway and moved across in one piece, so the traffic below barely stopped. On 15 March 2018 it came down onto the lanes underneath. What makes this case different from almost every other collapse is that nobody was surprised by the cracks. They had been appearing for 19 days. They had been photographed by the contractor, the inspection firm and the university, measured, emailed, and put in front of the engineer legally responsible for the design. By the day it fell they were close to 2 cm wide about forty times wider than a concrete code allows. On the morning of the collapse, five organisations sat in a site trailer for two hours and discussed the exact joint that was about to fail. Then everyone went back to work, and the road stayed open. This episode takes the failure apart the way the NTSB did. Why a concrete truss with one load path was an unprecedented thing to build. What node 11/12 actually was, and why a cold joint between two concrete pours ended up holding the whole bridge. The two calculation errors a load underestimated by almost half, and a capacity inflated by the wrong load factor. The independent design check that was won by halving the fee and never looked at the nodes. And the chain of decisions in the last 48 hours: a voicemail nobody heard until the day after, a repair plan reviewed by nobody outside the firm that made the original mistake, and a road that everyone in that meeting had the authority to close. The NTSB's findings come in three tiers, and the order matters. The probable cause was the design error. The inadequate peer review and the engineer of record's judgement contributed to the collapse. And a separate sentence covers the deaths: contributing to the severity of the outcome was the failure of the contractor, the designer, the inspection firm, the university and the state transport department to stop work and close the street. A replacement is going up on the same spot now steel, genuinely cable-stayed, and built the slow way with the road closed. Six people died in this collapse. This video is about the engineering and the decisions, not the victims, and it contains no footage of the casualties. Chapters: 0:00 The bridge that was five days old 1:07 Why they wanted a bridge here 1:45 A bridge with no precedent 2:29 One path for the load 3:07 Six hours, 860 tonnes 3:42 Node eleven twelve 4:23 Two errors in one calculation 4:59 The $61,000 check 5:42 Nineteen days 6:15 It cracked like hell 6:52 What the cracks were saying 7:32 The voicemail 8:09 The nine o'clock meeting 8:59 One forty-six 9:39 What the investigation concluded 10:39 Who is allowed to stop the job? Sources: NTSB Highway Accident Report HAR-19/02, "Pedestrian Bridge Collapse Over SW 8th Street, Miami, Florida, March 15, 2018", adopted 22 October 2019 ntsb.gov NTSB investigation docket HWY18MH009 (released 8 October 2019) OSHA, "Investigation of March 15, 2018 Pedestrian Bridge Collapse at Florida International University, Miami, FL" (2019) osha.gov Institution of Civil Engineers Knowledge Hub, "Explainer: Florida International University footbridge collapse" (2025) Florida Department of Transportation press releases, 16 and 24 March 2018, including the transcript of the 13 March voicemail FIGG structural analysis presentation of 15 March 2018, released by FDOT Engineering News-Record and New Civil Engineer, October November 2019 US DOT Office of Inspector General, 19 January 2021 (FHWA debarment) Cao, El-Tawil & Agrawal, "Miami Pedestrian Bridge Collapse: Computational Forensic Analysis", Journal of Bridge Engineering 25(1), 2020 This video is an engineering explainer based on published investigation reports. It is not legal advice, and it is not a judgement about any individual's liability beyond what those reports state. #construction #engineering #bridges #collapse #miami