Last week, a pedestrian bridge that connected Miami’s Florida International University and the city of Sweetwater, collapsed leaving six casualties and eight people injured. The main span of the bridge was put into place only five days before. And while families and the community mourn the victims, many questions arise on how this tragic accident could have been avoided.
Close to lunchtime last Thursday, March 15, 2018, people driving by Southwest Eighth Street, saw in horror as the 950-ton bridge span buckled. As CNBC reported, “Cracking had been reported in the concrete span in the days before and crews were performing what’s called “post-tensioning force” on the bridge when it flattened onto the busy highway.”
The pedestrian bridge, originally scheduled to open in 2019, cost $14.2 million. The project was a collaboration between MCM Construction, a Miami-based contractor, and FIGG Bridge Design, based in Tallahassee. FIGG led the iconic Sunshine Skyway Bridge project across Tampa Bay.
Safety is a top concern and priority in any construction project. And while there are strict safety regulations enforced in every construction project, one has to stop and wonder how this could have happened. Investigators are still trying to figure out what caused the bridge to crumble, but they are looking into a few things.
The Crack in the Bridge
Two days before the collapse, the lead engineer of FIGG left a voicemail in a Florida Department of Transportation (FDOT) landline. He said that said cracks had appeared on the bridge and were in need of repair. The message was not listened to until Friday because the employee was out on assignment.
In the voicemail, the engineer stated that they had observed a crack on “the north end of the span, the pylon end of that span we moved this weekend.” He continued, “from a safety perspective we don’t see that there’s any issue there, so we’re not concerned about it from that perspective,” the engineer said according to the transcript, “although obviously the cracking is not good and something’s going to have to be, ya know, done to repair that.”
Cue the FDOT saying that they did not know about the crack, and FIGG assuring that they did. At this point, all parties involved have agreed it’s too early to determine if the crack had anything to do with the collapse.
Loose Cables after Stress Test
A preliminary stress test is usually conducted by placing weights on the span to see how it responds. This test had just been completed on the Miami bridge right before it collapsed last Thursday.
Various accounts, including Sen. Marco Rubio who was at the scene moments before, commented that the cables were being tightened when the bridge collapsed. Some argue that traffic should have been stopped during the stress test. Others assure it wasn’t necessary.
At the moment, investigators are looking into the things mentioned here. They are also evaluating cement samples from the collapse and taking a closer look at the accelerated bridge construction technology used to build this bridge.