A research team from UC Berkeley led by David Rempel, building on the success of an overhead drill press design, piloted a new solution for drilling into concrete during the seismic upgrade of Memorial Stadium at UC Berkeley. Workers taking part in the pilot reported a significant reduction in fatigue and back pain.
The new tool, called the Highway Drill Jig, aids construction workers who handle rock drills and rotary hammer drills that weigh anywhere from fifteen to forty-five pounds. These drills are employed on large scale projects such as highway bridges and large buildings, where workers will puncture up to 20,000 holes one to two feet deep into concrete.
"The rock drills used are pneumatic drills, similar to jack hammers," says Rempel, a professor of Medicine in the UCSF Division of Occupational and Environmental Medicine and director of the joint Berkeley and UCSF Ergonomics Program. "It's like holding a jack hammer at your waist and then forcing it into a concrete wall."
Existing drill methods are noisy and heavy, and they create large amounts of silica dust. The ergonomic design of the Highway Drill Jig solves some of these health risks. "We've been conducting laboratory studies measuring noise and dust at the Laborers Training Center in Pleasanton, California, and we've found that our method of dust containment reduces silica dust exposure to lower than NIOSH limits," says Rempel. "We're trying to decrease respiratory exposure, vibration exposure and the forces to the shoulder and back." An article publishing their results is in peer review.
The prototype device, developed in six months, was first tested on the new sound barriers installed along the San Raphael freeway in Marin County. "Laborers who used the device said they didn't want to go back to the previous method," said Rempel. "With the old method, workers were completely exhausted after a half day of work. Using the new device, they were able to work almost all day long without that same exhaustion."
The seismic renovation of Memorial Stadium represents the second test of the Highway Drill Jig. Rempel and colleagues will be recruiting 30 workers to compare the tool side-by-side their current methods. Outcomes measured are force, vibration, dust exposure and subjective feedback on pain. "This method is the way to go," said one worker surveyed. "No back pain." Another said, "I prefer the drill support. My hands and arms do not hurt at the end of the day."
Looking forward, Rempel says there are plans to use the Highway Drill Jig on an upcoming seismic upgrade of a Bay Area Rapid Transit station and on a bridge upgrade on Highway 13 in Oakland.
Collaborators on the Highway Drill Jig from the Ergonomics program include Research Assistant Maggie Robbins and Senior Development Engineer Alan Barr. Research partners are Webcor Builders, RM Harris Company and the Laborers International Union. Both research projects are funded by the Center for Construction Research and Training (CPWR) and The National Institute for Occupational Safety and Health.
Find this article and others online at http://coeh.berkeley.edu/bridges