The FIU pedestrian bridge collapsed on March 15, 2018, because of calculation errors in its original design. The National Transportation Safety Board determined that FIGG Bridge Engineers made critical mistakes in calculating the loads and capacity of a key connection point in the bridge’s structure. Those errors went undetected by every layer of oversight, and when cracks appeared in the days before the collapse, the engineering team misread them as cosmetic rather than catastrophic. Six people died and ten others were injured when the 950-ton concrete span fell onto SW 8th Street in Miami.
The Design Errors at the Core
The bridge used an unusual design: a single-span concrete truss that would eventually be supported by a cable-stayed tower. On the day it collapsed, the tower hadn’t been built yet, so the truss was bearing its own weight in a temporary configuration. The fatal flaw was in what engineers call the “nodal region” where two diagonal truss members (numbered 11 and 12) connected to the bridge deck at the north end. FIGG’s calculations underestimated the forces acting on this joint and overestimated its ability to handle them.
This wasn’t a subtle error buried in complex mathematics. The NTSB’s investigation found that the design firm got the basic load and capacity numbers wrong for the most critical connection in the structure. When the bridge was placed across the road on March 10, that joint was already under more stress than it could safely handle.
Two Weeks of Ignored Warnings
The bridge began showing visible distress almost immediately. When temporary supports were removed so the truss could bear its own weight, workers heard a loud popping sound. At least three employees from two different companies walked over to investigate and found cracks at the base of diagonal member 11, the same area that would later fail.
On February 28, the construction inspection firm forwarded photos of the cracks to the contractor, noting they needed “special attention.” FIGG responded on March 7 with a dismissive assessment: “No structural concern,” “Cracks expected,” “No concern.” This response would later become one of the most damning pieces of evidence in the investigation.
The situation worsened rapidly. On March 10, as the bridge was rotated into its final position over the road, new cracks appeared at multiple locations, concentrated around that same diagonal member 11 connection. By March 12, the contractor sent an urgent message stating “your immediate attention and response is required.” A superintendent who inspected the cracks that day noted they had gotten wider and larger. Photos taken on March 13 and 14 by the inspection firm documented deep diagonal cracks growing across the joint, longitudinal cracks running along member 11, and visibly widening fractures at the connection to the bridge deck. Each day brought worse photos than the day before.
Despite all of this, no one closed the road beneath the bridge. Traffic continued flowing under a structure that was actively breaking apart.
The Morning of the Collapse
FIGG’s lead engineer decided the fix was to re-tension steel rods running through diagonal member 11, restoring them to the tension levels they had held on March 10. The plan was developed remotely from FIGG’s office in Tallahassee on March 13 and 14. A meeting was scheduled for the morning of March 15 at the construction site, bringing together representatives from FIGG, FIU, the Florida Department of Transportation, the inspection firm, and the general contractor.
Immediately after that meeting, a post-tensioning crew began tightening two steel rods inside member 11, applying 280,000 pounds of force to each one. The idea was to squeeze the cracked concrete back together. Instead, the added force pushed the already overstressed joint past its breaking point. The crew had just finished the procedure and still had equipment attached when the concrete on the north side of member 12 blew out, the truss lost its geometric stability, and the entire span dropped onto the cars below.
The collapse took seconds. Eight vehicles were crushed. Five civilians in those cars and one construction worker on the bridge were killed.
Failures at Every Level of Oversight
The NTSB spread blame across nearly every organization involved in the project. At the top was FIGG’s flawed design. But the problems cascaded through a system that was supposed to catch exactly this kind of error.
Louis Berger, the firm hired to perform an independent peer review of the design, never checked the structural integrity of the bridge under different construction stages. This was a specific requirement under Florida Department of Transportation rules, and the firm simply didn’t do it. Had they performed this analysis, the calculation errors in the critical node would have been detectable before a single piece of concrete was poured.
FIGG’s own engineer of record failed to recognize what the growing cracks meant. Diagonal cracks widening daily at the exact joint where the truss connects to the deck are not cosmetic. They are signs of a shear failure in progress. The engineer never sought an independent review of the re-tensioning plan, treating it as a routine adjustment rather than an emergency intervention on a failing structure.
The NTSB also faulted the broader group of parties, including the contractor, the inspection firm, FIU, and the Florida Department of Transportation, for not closing the road. The cracking had reached what the board called “unacceptable levels,” and the basic precaution of keeping people out from under the bridge while it was being worked on was never taken. This failure didn’t cause the collapse, but it is the reason people died.
Legal and Financial Fallout
Lawsuits from the victims’ families and the injured were settled by 2022 for a combined $103 million. The settlements were paid by the engineering firms and other parties involved in the bridge’s design and construction. The litigation marked one of the largest infrastructure-related settlements in Florida’s history.
FIGG Bridge Engineers faced intense scrutiny, as the firm had previously been involved in other high-profile bridge projects. The case became a landmark example of how compounding failures in engineering oversight, from flawed calculations to rubber-stamp peer reviews to misread warning signs, can turn a design error into a fatal disaster.
The Replacement Bridge
FIU broke ground on a replacement pedestrian bridge at the same site in October 2024. The new bridge is expected to open in fall 2026, more than eight years after the collapse. The original bridge was intended to give students a safe way to cross the busy eight-lane road between campus and nearby housing, a stretch where a student had been killed by a car just months before the bridge project began.