A flyover so steep that TxDOT says it must be destroyed and replaced was partially demolished with explosives Saturday morning.
The demolition is part of a $124.2 million construction project on I-35 from Rundberg Lane to U.S. 290 East. The project includes three new flyovers, reconstruction of the St. Johns Avenue Bridge, extended entrance and exit lanes and other new infrastructure. The primary contractor on the project is J.D. Abrams. It hired American Demolition to take down the structures. American Demolition hired Dykon Explosives for a portion of the process.
Demolishing an elevated roadway with explosives requires special precautions. The explosives are wrapped with "blast mats" — railroad ties bolted together and strapped around the explosives. That gets wrapped in a synthetic fabric commonly used in construction. Then the whole thing is wrapped with chain-link fence. The goal is to muffle sound, direct the blast inward toward the concrete and contain debris.
TxDOT declined to reveal how much or what type of explosives were used.
"We're not really wanting to share that," TxDOT North Travis Engineer Victor Vargas said. "We don't need folks to know how much explosives it takes to demolish something like this."
A second implosion to demolish a remaining part of the flyover is scheduled for Saturday, May 15.
