The GOMACO GT-3600 slipforms curb and gutter radii with a stringless system. The contractor would normally handform the radii and average only two completed islands per day. With the GT-3600 and stringless system, they can easily complete eight radii in a single workday.
Ida Grove, Iowa -- Stringless curb and gutter is here! The GOMACO GT-3600 curb and gutter machine with Leica PaveSmart 3D can slipform all profiles of curb and gutter without the use of stringline. Stringless curb and gutter is not limited to straight sections only, it can also slipform radii as tight as 18 inches (457 mm) with the GOMACO GT-3600.
The PaveSmart 3D system for curb and gutter is an optional plug and play software program available on GOMACO equipment. Additional hardware is required for the stringless system. The GT-3600, for example, is equipped with a prism on the rear mast, which a Total Station uses for height control, and also a GPS receiving disc on the front mast, which is used for machine orientation. Or, the GPS unit can be switched over for a second Total Station if the area doesn’t allow GPS reception.
Data provided by the project engineer is converted into a surface model. The surface model is uploaded into the Leica computer. The data can be imported from almost any CAD system. The Leica computer is then interfaced with the GOMACO G21 or optional G22 controller on the GT-3600. When it’s time to start slipforming, the operator simply opens up a map of the project on the Leica computer and chooses where he wants to go. The computer has a toggle switch or touch-screen interface, so it’s just a matter of pressing a button to chose where to pave. The GT-3600 is then moved into position. The Total Station takes measurements off predetermined reference points to orientate its position. Then, it’s aimed at the prism on the machine and along with the GPS, begins the tracking process. The operator only has to look at the Leica computer to know that the GT-3600 is positioned correctly to begin the curb and gutter pour.
“The Leica system is connected to the GT-3600’s G21 or G22 control system via the CAN (Controlled Access Network) cables, which are an integral part of each machine that GOMACO produces,” Kevin Klein, GOMACO’s Vice President of Engineering/Research and Development, said. “The Leica system contains the design file for the project which the contractor is building. As the Leica instruments track the machine, the exact position of the machine is sent to the Leica computer and that exact position is then compared to the project design file. From there, the Leica system places any relevant steering and grade control information onto the CAN line for the G21/G22 control system to capture and use in steering the machine, as well as maintaining the proper elevation. The operator can focus on control of the travel speed of the machine, controlling the vibration, and concrete delivery. The machine controller will take care of steering and grade, by monitoring the inputs from the 3D control system. However, I am sure the operator is very busy monitoring the system and under a lot of pressure. Pulling tight radii can be very tricky.”
When an island is finished, the operator simply goes back to the map in the Leica computer, and chooses where he wants to go to next. Or, for example, if an area isn’t ready for paving yet, the grade isn’t prepared or some other factor, they can go anywhere else on the job site. They are no longer dependent on stringline to dictate when and where they work.
GOMACO Corporation (www.gomaco.com) is the worldwide leader in concrete construction equipment with headquarters in Ida Grove, Iowa. GOMACO equipment will slipform concrete streets and highways, airport runways, curb and gutter, sidewalks and recreational trails, safety barrier, bridge parapet, and irrigation canals. Support equipment includes grade trimmers, concrete placers, concrete placer/spreaders, and texturing and curing machines. We also offer equipment to finish flat slabs, bridges, and slopes. GOMACO will consult on equipment for large or unique concrete paving projects. GOMACO products are offered through a worldwide distributor network for local sales, parts and service expertise.