Better Roads Digital Magazine
Issue link: http://read.dmtmag.com/i/239057
reference line – "virtual stringlines in the project coordinate system" – a reference point and a steering offset. Similar to a stringline, using a rectangular grid with stringless paving is suggested, but surveying is not necessary. The project can be modeled with as many or few details as needed for vertical, horizontal curves, transitions and super elevations. The model can represent existing stringline data, slab edges – i.e. "virtual slabs" – or any arbitrary offset (position and/or height). The future of stringless paving Steeves says eliminating the wire line on a jobsite creates safer working conditions for crews because they do not have to constantly step over it or manage the gates for the truck entrances, conventionally set up about every 600 to 800 feet. "Wireless technology allows trucks to come in ahead of the paver safety and back up a minimal distance," Steeves says. Minimizing backup increases paving efficiency, Steeves says. Using stringless technology increases the efficiency because the contractor can start paving as soon as the subgrade is verified instead of waiting for the paving pins to be set and for their own crews to set the stringlines. Such was the case with the Utah 1-15 Corridor Expansion project. Progressive contractors are more often than not asking counties and DOTs to create 3-D digital designs of their projects to be entered into the paving machine control systems, Steeves says. "In the future, most design work will be done on these digital programs," he says. "The way technology is advancing so rapidly, contractors are pushing DOTs to provide digital files." Stringless Paving: How it works back to total stations, giving them X, Y, Z positions. stations to computer on the paving machine. position in relation to a computer model of the new pavement. each of the four corners of the pan to achieve the correct pavement thickness, crossfall (cross-slope control monitored by sensor) and mainfall (forward and back slope control monitored by sensor). Smooth as glass. topconpositioning.com/mmgps-paving Better Roads January 2014 19