BIRMINGHAM, Ala (WIAT) – There’s new video circulating of the I-59/20 bridge project, but it’s not from the Alabama Department of Transportation. It’s actually coming from inside of the bridge.
The video first started making the rounds this week on Reddit. It shows construction workers standing inside of I-59/20.
“Each segment is hollow,” explained DeJarvis Leonard, East Central Region Engineer with ALDOT, “but it’s being supported by steel strands that go through the segments and oppose tensions to carry the weight of each span–which is span from each column to column. Between each one of those columns, the segments are opposed tension to carry the load.”
Leonard explained that this type of construction, as well as the bridge’s segmented design, is nothing new. However, he isn’t aware of a similar bridge in the immediate area.
“We’ve been able to cast the bridge during a time when they were actually demoing the bridge and other work,” he said. “By then being able to cast the bridge off-site, they were able to put it together so it eliminated the overall time-frame and downtime of the bridge.”
The segments are being cast in a yard near the airport. Leonard said it’s been going on for over a year–whereas the mainline bridges have only been closed for 6 months. Then, the parts are being assembled at the new I-59/20 site.
As for the bridge being hollow at certain parts, Leonard said that motorists shouldn’t be able to notice any difference. “Keep in mind that the part that you’re actually riding on is about 7 to 8 inches thick,” he said. “So that’s the normal thickness of a deck of a conventional bridge.”
According to ALDOT’s website, the segmental bridge design not only leads to faster construction time but should also help to reduce noise and vibrations.
“Overall, it’s going extremely well,” said Leonard. “We’re very pleased with the progress that the contractors are making, but we’re very confident at this point that we will make that deadline–14 months–and have traffic back on it before March of 2020.”