The 950-ton portion of bridge intended to connect Florida International University students with a nearby city collapsed just days after it was installed using a speedy and unique construction method advanced by the school.
Touted as an “instant bridge,” workers installed the 174-foot span at Southwest Eighth Street and Southwest 109th in a single day. They utilized Accelerated Bridge Construction or modular construction methods for the hours-long installation on March 10.
Community members came out in droves to witness the bridge swing into place and experts heralded it as a “milestone” at the time, according to a university press release.
Professor Amjad Aref, a researcher at the University of Buffalo’s Department of Civil, Structural and Environmental Engineering, warned the new method comes with several risks, particularly in the early stages of construction.
“The idea is that you can build small- to mid-size bridges very quickly, sometimes within hours,” Aref said. “But until all the pieces are put together to transmit the loads safely to the foundations, these bridges may suffer disproportionate or full collapse due to instability.”
MCM Construction and FIGG Bridge Design collaborated on the $14.2 million cable bridge, intended to provide a safer route for students and staff traveling between campus and Sweetwater. The university estimates some 4,000 students reside in the nearby city.
The pedestrian chunk of the overall 320-foot bridge was prefabricated next to Tamiami Trail and then moved into position using gantry cranes, according to the MCM website. It marked the largest pedestrian bridge move by way of Self-Propelled Modular transportation in United States history.
The construction company in a statement said it was “devastated” by the “catastrophic collapse and loss of life,” adding it intends to conduct a full investigation into the matter.
Pennsylvania-based FIGG Engineering in a separate statement said “nothing like this has ever happened before” within in its 40-year history.
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A group of volunteer bridge engineering experts in 2010 gathered at Florida International University and established the Accelerated Bridge Construction University Transportation Center — a hub intended to facilitate research on the snappy construction method.
They believe the technique will “reduce societal costs of bridge construction by reducing the duration of work zones, focusing special attention on preservation, service life, construction costs, education of the profession, and development of a next-generation workforce fully equipped with ABC knowledge.”
The collection of experts first nabbed federal funding for their efforts in 2013 and then again in December 2016 for its efforts to “make the country’s aging bridges safer.”
“With accelerated bridge construction, we are able to replace or retrofit bridges without affecting traffic, while providing safety for motorists and workers who are on site,” ABC Director Atorod Azizinamini said when the funding was announced. “The result is more durable bridges.”
The Department of Transportation also footed the bill for the so-called “instant bridge,” also referred to as the FIU-Sweetwater bridge. The project additionally includes self-cleaning sidewalks and a plaza complete with benches, tables and Wi-Fi.
Both students and staff at Florida International University have long called for a bridge at the high-traffic intersection, where pedestrians currently have to cross seven lanes of traffic to get to campus, the Miami Herald.
The elevated walkway was slated to open in 2019 before it crashed down on workers and cars traveling below Thursday afternoon.