Giant Foam Blocks Keep Bridge Approaches From Settling
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JOHNSON COUNTY (CBS 11 NEWS) - That bump on the road is never good. But on some roads, it's unavoidable. Engineers say natural settling of dirt under highways and roads create bumps and cracks in the asphalt. It is especially true for approaches to bridges and repairs for that can be costly.
"Bridges are a natural funneling point for traffic, they are expensive to construct and are usually very specialized structure," TxDOT spokesperson Val Lopez told CBS 11 News. The agency spends approximately $7 million each year to fix and maintain bridge approaches on a system of highway with more than 50,000 bridges across the state.
The point where the road meets the bridge is often prone to settling and thus the bump or a technical term "the bump at the end of the bridge." Motorist notice it at both ends of the bridge. There is a solution to the problem and it's being developed in the civil engineering department at UT-Arlington.
Dr. Anand Puppala and his team with the help of TxDOT have installed hundreds of giant 6 feet by 3 feet specialized Styrofoam blocks under the road on Highway 67 in Johnson County.
"This is hundred times lighter than soil," Dr. Puppala told us. The idea is the less weight, less compression of native soil and therefore less settling of the roadway. Theoretically that would mean less bump.
So far it appears to be working. The blocks have been in place for the last three years. The team measures road settlement every month. Before the foam blocks went in -- TxDOT told us the settling was about an inch and year. Meaning repeated repairs. Since Dr. Puppala and his team installed the blocks, the settlement is about an inch and a half in three years.
Dr. Puppala says the giant Styrofoam blocks are much easier to install, saving time and money and traffic nightmares. It's still just a test, paid for with a state grant, but foam may be on track to smoothing things out for drivers across the state.
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