Florida International University has released time-lapse videos of its pedestrian bridge being installed and collapsing on a busy road — the public’s closest view yet of the deadly accident and the days leading up to it.
Clearly seen on the videos are at least four workers standing atop the bridge moments before it fell. The workers were using a jack to re-tension, or tighten, the steel rods that ran through a crucial concrete support truss at the bridge’s north end. Their actions may have caused the bridge — which was already developing alarming cracks — to come crashing down.
Who ordered the construction crew up there — and why — remains unclear. That information may be contained in documents that the Miami Herald is suing to acquire.
The six time-lapse videos are constructed from a series of still photos taken by FIU cameras from various angles between March 1 and March 19. They show the 950-ton span being raised across Southwest Eighth Street on March 10 and then collapsing on March 15, killing six people. After that, the footage captures workers clearing away the rubble.
The images provide the closest view to date of the bridge coming down. Previously, the public has seen only grainy surveillance camera and brief dashcam footage.
The new videos — delivered to the Herald in response to a public records request — reveal more details about the work performed on the doomed bridge in the days before its collapse.
The $14.3 million bridge had been built on the side of Southwest Eighth Street, also known as Tamiami Trail, in a process known as accelerated bridge construction that made prolonged street closures unnecessary. On March 10, the bridge was lifted into place over the road by two special transporters set toward the center of the span.
The placement of the transporters meant that the ends of the span — designed to rest on pylons once the bridge was in place — would tend to sag under their own weight while being moved. To counteract that sag, the bridge’s designers added steel support rods into two diagonal support pieces at the span’s north and south ends.
Documents show those rods were tensioned, a technical term for tightening, before the move to provide added support to the bridge ends while up in the air. The rods were then de-tensioned, or loosened, once the span was resting on the pylons, because the added support was not needed at that point.
Workers seen in the new videos are shown de-tensioning the north and south ends on March 10.
Then, on March 15, workers clamber back on top of the bridge. They are shown attaching a jack to a concrete support at the bridge’s north end. But the support — apparently unbeknownst to the construction crew — had not been designed to withstand the stress placed upon it, independent experts who studied the bridge’s plans told the Herald earlier this summer. The seeming design error likely doomed the bridge to catastrophic failure, the experts said.
Large cracks had begun forming in the area around that support in the days before the collapse, a potentially ominous warning of what was to come. Still, an engineer from FIGG Bridge Group, which designed the bridge, did not believe the cracks signaled a threat to the span’s structural integrity, according to a voice message the engineer, W. Denney Pate, left with a Florida Department of Transportation official two days before the collapse.
On the morning of March 15, FIGG employees met with FIU officials, representatives from general contractor Munilla Construction Management and an FDOT consultant to discuss the cracks.
FDOT has refused to release records that might show what was decided at that two-hour meeting and why. But it ended with the workers climbing on top of the span to re-tension it. Two of three westbound lanes were closed to traffic to accommodate a crane needed in the work. Five eastbound lanes were left open.
At 1:47 p.m., as the workers stood atop the critically weakened structure, the bridge fell down, crushing five motorists underneath. One worker, Navaro Brown, 37, of subcontractor Structural Technologies, also died. At least two other employees of the Maryland-based firm were injured. (A spokesman for the firm did not return a phone call.)
First responders who rushed to the scene found the men lying on top of or near the rubble.
It’s not clear why the workers were re-tensioning the bridge, although it may have been an attempt to close up the alarming cracks. Notably, the videos do not appear to show workers performing similar work at the south end of the bridge on March 15.
“The design was better at the south end than at the north end,” said David Beck, a structural engineer who has extensively examined the bridge’s design plans. “There was clearly concern about what was happening at the north end.”
No serious cracks in the bridge’s south end have been reported so far.
Given the available information, Beck believes that de-tensioning the north end rods worsened concrete damage in the under-designed support, which connected the bridge’s canopy with its deck. Then, when workers came back five days later and started putting tension back into the damaged concrete, “it was like pulling a trigger and going bang,” Beck said.
Madeline Baró, a spokeswoman for FIU, did not respond to questions from the Herald about the time-lapse videos and why they were compiled. The videos range in length from five to 43 minutes. The Herald edited them into a single video showing the most relevant sections.
Public right to know
Immediately after the accident, the National Transportation Safety Board, a federal agency based in Washington, D.C., began investigating what caused the collapse.
Just as swiftly, reporters began asking for public records from FIU, the Florida Department of Transportation and the city of Sweetwater — the public entities that oversaw the bridge project — under the state’s broad Sunshine Law.
But NTSB officials ordered FIU, FDOT and Sweetwater not to release many records requested by media outlets, saying that doing so could imperil their investigation. In particular, NTSB has sought to prevent the release of records dating from after Feb. 19, roughly a month before the bridge fell down. The Herald is suing over the public-records block, including over documents withheld from the March 15 meeting.
Some records are being shared with the public, however, although usually after significant delays.
FIU released the time-lapse footage Tuesday as part of 652 emails requested by the Herald.
The email containing the videos was sent by John Cal, FIU’s associate vice president for facilities management, to Jorge Rivera, an employee of the Federal Highway Administration, on March 23.
“As you know, FIU provided live video coverage of the bridge construction via the Internet,” Cal wrote. “While that video was not recorded due to storage limitations, we did record periodic still photos with the intent of threading the photos into time lapse video. The accompanying link provides the time lapse videos from March 1-19, 2018.”
Cal then forwarded the email to FIU officials, including Carlos Castillo, the university’s general counsel, and Kenneth Jessell, its chief financial officer.
Rivera declined to comment when asked by phone why the videos had been sent to him. FHWA’s media office declined to comment. The federal agency is assisting the NTSB in its investigation.
Christopher O’Neil, a spokesman for the NTSB, declined to comment on the videos.
In June, the Herald asked FIU for emails concerning the bridge that were sent to or from FIU President Mark Rosenberg, administrator Tom Gustafson and Jessell, the CFO. FIU officials said the NTSB would have to sign off on releasing the emails. On Tuesday, after nearly three months of government review, FIU sent the emails to the Herald.
Most of the emails are condolences to Rosenberg on the tragedy. Some show FIU officials discussing how to respond to media inquiries and public records requests.
One message, from FIU geology professor Grenville Draper, summarizes the despondent mood around campus after the bridge — a symbol of the university’s ambitions for growth — collapsed.
“The pedestrian bridge was supposed to be [built] using ‘cutting edge’ technology, and we were all very excited and proud of it,” Draper wrote to Rosenberg a few hours after the disaster. “Now, in some ways it has become our ‘Titanic.’ ”
In May, FIU officials accidentally released photos showing hairline cracks forming at the north end of the bridge. The photos dated from late February. The university demanded that the Herald not publish the images. The newspaper did not comply, as it is not legally bound by the NTSB restrictions. Independent engineers told the Herald that the cracks were an early warning sign of a design flaw in the bridge.
Last week, the NTSB released more photos of cracks in the bridge dated March 13 and March 14. The cracks had grown significantly worse. But no action was taken to shut down the road before the bridge fell down on unsuspecting motorists.
The videos also feature a cameo from a crane that caused controversy online.
The crane had been used to lift the jack on top of the bridge’s north side for workers. But immediately after the bridge collapsed, the crane rumbled away, prompting Internet users to wonder if the lumbering contraption had somehow caused the accident. (Experts say that’s highly unlikely.)
A lawyer for the company, George’s Crane Service, said the operator needed to move his crane out of the way of emergency vehicles.
Miami-Dade police detectives believe the crane was an innocent bystander and say the operator simply drove the crane a short distance away, and then returned on foot to help.
But bystanders say the crane drove well away from the accident and vanished. The videos seem to support those accounts, as they show the crane retracting its arm and quickly disappearing from the frame.