Posted: October 7, 2016
Last modified: January 19, 2017
Building new bridges or revamping old ones for the I-4 Ultimate project often requires huge machines that can stretch across more than 100 feet of freshly poured concrete and smooth out the uneven surface with a slow, steady motion.
In some ways, they are like giant, automated trowels or squeegees, taking 100-foot-long strokes with pinpoint precision and turning thick, heavy concrete into smooth roadway surface.
The work often requires lane closures to keep motorists safe, so the I-4 Ultimate team usually performs the tasks at night when traffic is lighter. As a result, most commuters and residents rarely see the big machines in motion.
Called bridge deck finishers or deck screeds, they can weigh more than 10,000 pounds and may take two days to assemble and test on the bridges. The apparatus includes augers and drum rollers attached to an overhead truss, which moves ahead slowly to flatten out the 8-inch-deep, wet concrete.
Throughout the 21-mile reconstruction project, the I-4 Ultimate team will use this process to revamp, reconstruct or build anew more than 140 bridges, said Chris Dubois, Area 3 Project Manager for SGL – the design-build joint venture of Skanska Granite and Lane for the I-4 Ultimate project.
In addition to safety, working at night offers other benefits. “We usually don’t have to worry about rain late in the evening,” said Kevin Moynihan, Area 3 Construction manager for SGL. “And the cooler evening temperatures help the concrete cure evenly.”
While parts of the process are highly automated and mechanized, the team still relies on old-fashioned methods to ensure the concrete cures evenly during a seven-day period. They seal the smoothed surface, spread burlap on top and periodically wet it down until the curing process is complete.