The crossing at Southwest 8th Street and 109th Avenue had long been a hazard. Seven lanes of traffic separated FIU's campus from student housing in Sweetwater, and the crosswalks were notoriously dangerous. A student had already been struck and killed trying to cross. The $14.2 million pedestrian bridge, funded by a $19.4 million federal TIGER grant from the U.S. Department of Transportation, was the answer -- a structure the university proudly proclaimed would last 100 years and withstand a Category 5 hurricane. Construction began in March 2016 with the main span assembled beside the highway using accelerated bridge construction, then swung into place across the roadway during a single weekend closure on March 10, 2018. A community gathered to watch the 950-ton span move into position. FIU tweeted that it was the first bridge in the world built entirely of self-cleaning concrete.

The bridge was styled to look like a cable-stayed structure with a dramatic pylon tower and high cables, but these were purely cosmetic. Structurally, it was a mono truss bridge -- self-supporting without the cables. The spans used what designers called a "re-invented I-beam concept," a novel concrete truss design invented specifically for this project. Concrete truss bridges are, as investigators later noted, "exceedingly rare." As of 2018, no other designs similar to the FIU bridge had been found anywhere in the world. The concrete walkway deck served as the bottom flange of a wide I-beam, with a concrete roof canopy functioning as the top flange. Between them, triangulated diagonal concrete struts formed the structural web. The design placed the walkway near ground level rather than atop the support structure. It was innovative, untested, and -- as the NTSB would determine -- fatally miscalculated.

Almost immediately after the main span was set in place on March 10, severe cracks appeared in the concrete at the north end of the bridge, where diagonal member 11 met the bridge deck. Consulting engineers photographed the damage. An FIU memo dated February 28 had already flagged cracking concerns from when the bridge was being assembled. On March 13 and 14, FIGG Bridge Engineers -- the Tallahassee-based firm behind the design -- developed a plan to re-tension the temporary post-tensioning rods. A meeting was scheduled for March 15 at a construction trailer on site. Two FIGG engineers inspected the span that morning, using a lift to examine the damage up close. The design-build team discussed the cracks for two hours. FIGG recommended expediting the pouring of the decorative pylon. At no point did anyone close the road beneath the span. Workers were actively re-tensioning the steel rods in diagonal member 11 when the bridge gave way at 1:47 PM.

The NTSB launched a 15-person go team the same day. Their investigation, which culminated in a public hearing on October 22, 2019, concluded that "load and capacity calculation errors made by FIGG Bridge Engineers, Inc." were the probable cause. The designers had overestimated the strength of the connection where diagonal member 11 and vertical member 12 met the bridge deck, and underestimated the load that connection would carry. The resistance to sliding between the truss and the walkway surface had been miscalculated. The connection was insufficient to prevent the truss from shearing along the deck, causing progressive cracking and ultimately total disconnection. OSHA cited five companies for seven violations. FIGG was found to have failed to recognize that collapse was imminent even while inspecting the bridge hours before it fell. The university, the NTSB noted, "had no professional engineers on its staff and relied solely on the expertise of its hired contractors." Eighteen civil lawsuits were filed. Munilla Construction Management filed for Chapter 11 bankruptcy and reached a $42 million settlement with victims' families.

The remnants of the collapsed bridge stood as a grim reminder until demolition began in September 2021. FDOT announced plans to rebuild the crossing with a new design -- a cable-stayed steel box girder bridge, this time using conventional construction methods with no experimental concrete truss concepts. Miami-based BCC Engineering finalized the design by November 2024, and construction is underway with a projected completion in fall 2026. The new bridge will carry the same purpose as the old one: getting students safely across Southwest 8th Street. But the lesson of March 15, 2018, is written into every specification. Innovation without verification, urgency without caution, and cracks without road closures cost six people their lives on a Thursday afternoon during spring break.