New Demolition Tool Cuts Construction Labor Costs

Traffic had become a common occurrence on the four-mile-long stretch between Loop 410 NE and Loop 410 S on I-35 in San Antonio. Texas Department of Transportation officials planned to remedy that with a four-year, $61.2 million project.

One section involved filling a gap between two parallel bridges to allow for the additional lanes and a new auxiliary lane. San Antonio-based demolition contractor JR RAMON came on board to remove rebar-reinforced concrete rails and three stretches of concrete bridge decks. The bridge deck concrete had to be removed without damaging the underlying rebar. Two of the stretches were on the inner sides of the bridges and one was on an outer section.

The demolition crews started with the outer section using an 80,000-pound excavator with a pulverizer attachment to demolish the barriers. They removed the outer bridge deck, using the excavator to weaken the deck before using hand tools to remove the concrete. The excavator made quick work of the concrete, but heavily damaged the rebar. Repairs set the project back several days and cost more than $100,000.

Remote-Controlled Demolition Machine Reduces Labor Costs

The company then purchased a diesel-powered, cordless Brokk 120D remote-controlled demolition machine specifically for the inner sections. Crews again used the excavator to remove the concrete rails, but then moved in with the Brokk machine to demolish the bridge deck concrete while avoiding the underlying rebar.

In addition to leaving the rebar untouched, the machine greatly increased productivity. The B120D didn’t fatigue, meaning the operator could work a 14-hour shift without tiring from the work and the Texas heat. This increased productivity, as well as safety, by eliminating mistakes and injuries caused by tired workers. The operator stood about six feet away, monitoring the work a safe distance, away from flying concrete as well as the 20-foot drop to the road below. The setup saves about three or four hours it would take in each section just to install tethers for workers.

The crews finished the inner section in just 1.5 days, including cleanup time. This reduced Ramon’s labor costs by 90 percent compared to the outer section, which took six days. This example of new technology will help save time and money on future construction projects.

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