Nobody likes being stuck in traffic. That had become a common occurrence, however, on the 4-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 400-feet-long, 3-feet-wide and 6-inch-deep 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.
JR RAMON’s demolition crews started with the outer section, using an 80,000-pound excavator with a pulverizer attachment to demolish the barriers. Next, 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.
JR RAMON president, Timothy Ramon, decided to purchase a new 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.
“The B120D allowed us to complete the inner section twice as fast as on the outer section while leaving the rebar undamaged,” Ramon said.
In addition to leaving the rebar untouched, the machine greatly increased productivity. Unlike workers with hand tools, 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 6 feet away, monitoring the work a safe distance from flying concrete as well as the 20-foot drop to the road below. Ramon said the setup saved him the three or four hours it would have taken in each section just to install tethers for workers.
JR RAMON 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.
Project Profile
Where: I-35, San Antonio
Demolition Contractor: JR RAMON
Task: Remove 1,050 tons of concrete bridge deck and rails
Machine: Brokk 120D with Atlas Copco SB 152 breaker
