PowerDigger 3D GPS system enables contractor to see excavation work underwater.
Last summer, M. Bowling Inc., Henderson, KY, excavated 130,000 cubic yards of earth to widen and deepen the Ohio River in preparation for a possible expansion of the John T. Myers Locks and Dam near Mt. Vernon, IN. Bowling was working under a $3.3-million subcontract to prime contractor Semper Tek-Intersteel Joint Venture, Lexington, KY.
The PowerDigger 3D GPS system was fitted to a Case CX240 excavator by JOB Rentals and Sales LLC, Jeffersonville, IN, a Leica Geosys terms dealer and leading Midwestern supplier of heavy construction equipment and GPS systems. JOB Rentals rented the excavator to M. Bowling Inc. The PowerDigger played a key role in fine grading the river bottom, checking grade, and grooming a 3:1 slope on the river bank. Other excavators performed the heavy-duty excavation of the river bottom.
"The U.S. Army Corps of Engineers was checking grades as the contractor was digging underwater and after many checks and finding the PowerDigger system was so consistent on grade, they quit checking grades," said Mike Gall, sales representative, Leica Geosystems Machine Control Division.
"There's no guesswork involved with the PowerDigger system," said Brandon Bowling, the project superintendent. "And there's no over-excavation - that's a huge advantage right there."
Bowling estimates that the PowerDigger system sliced two weeks from the 26-week project schedule, by providing one-time assurance of grades achieved and eliminating wasted movement of work barges from place to place on the river.
"Furthermore, the PowerDigger system eliminated the need to continually measure the newly-excavated depth of the river bottom," Bowling said. "Without the GPS system, a survey crew would need to take a john boat into the river and use a tape measure or sounding equipment to check grades. You would need two workers full-time to check grades."
Bowling said the PowerDigger 3D GPS system would also help finish grading the rip-rap stone to be placed along a 1,500-foot stretch of river bank and on two underwater dikes in the river. The dikes are used for current diversion.
"This PowerDigger system is the first one I've ever used," said Brandon Bowling. "It's a great system and has saved us a lot of money just on this job." 800.367.9453, leica-geosystems.us