Going the Distance
Diamond Cutter Completes 12 Rounds at Water Treatment Plant
The City of Philadelphia’s Water Department had a problem. As part of the department’s clean water tank expansion project, the underground storage basins at one of its treatment plants had to be modified to allow water to flow from one basin to another at a higher volume than before. This required the creation of 12 large 42-inch-diameter openings through a concrete basin wall that tapered out from 28 to 36 inches thick at the marked locations. Core drilling was ruled out due to limited access, so an alternative solution was needed.
The Water Department began service in 1801 and supplies water service to approximately 1.7 million people in the City of Philadelphia and a portion of Bucks County. Baxter Water Treatment Plant is situated next to the Delaware River in the northeast of Philadelphia. The plant contains two water basins measuring approximately 500 feet in length and 300 feet wide and it was determined that a series of openings was necessary to create the required rate of flow between them.
Philadelphia Water Department employed general contractors A.E. Kelly Group, LLC of Berlin, New Jersey and A.P. Construction, Inc. of Philadelphia for the main expansion project, and these companies began looking for bids to complete the basin openings. CSDA member Concrete Cutting Systems, Inc. of Philadelphia was selected. The concrete sawing and drilling contractor devised a plan to create 12 cylindrical openings spaced 15 feet apart without the use of diamond core bits.
“The basins had limited access so we could not fit any large machinery or saws down there,” Dave Nevrotski, owner of Concrete Cutting Systems. “Attempting to get a 42-inch-diameter core drill bit and associated barrels into the basins would have been almost impossible, so we chose to use a circular wire saw setup instead. It was by far the best choice, as the equipment could be taken down into the basins and assembled once down there.”
Access was certainly a factor on this job. The contractor had only a 3-foot-wide door opening to access the basins and there was a 10-foot drop to the floor below. Any tools and equipment had to be rigged to an overhead anchor point and lowered down, so the weight of all items had to be considered too. Operators had ladder access to the basin.
Not only was the wire saw the best choice in terms of accessibility to the work area, but it also provided superior speed, production and finish compared to alternatives like jackhammering. A hydraulic power unit supplied by Husqvarna Construction Products was delivered to the jobsite along with the Tyrolit circular wire saw and the team from Concrete Cutting Systems got to work.
With all 12 opening locations marked, the first task was to create a series of smaller 4-inch-diameter holes through the center of each one. These holes were used to mount the circular wire saw and allowed operators to pass a 10-foot length of diamond wire from one side of the wall back to the other to make a complete loop. The top feed hole, measuring just 1 inch in diameter, was made at the top of each marked location so that the wire could be fed back and return through the wire saw system. A Shibuya TS252 core drill fitted with 1-inch and 4-inch-diameter bits from DITEQ Corporation was used to core through the basin walls to a depth of around 30 inches. Each center hole took 30 minutes to complete, while the smaller 1-inch holes took 10 minutes.
Once the equipment was properly mounted and the diamond wire was looped through the concrete basin wall via the access holes, wire sawing commenced. The saw was built with hydraulic actuated rotation, allowing it to perform a push cut through a full 360-degree rotation and create the circular shape. The diamond wire saw operator monitored progress, adjusting speed and tension as the saw went through its first 180 degrees and the tapered wall increased in thickness from 28 to 36 inches. Further adjustments were made as the saw completed its remaining 180 degrees of rotation and the wall thickness returned to 28 inches. Concrete Cutting Systems completed a 42-inch-diameter circular cut in 1.75 hours, which included setup and takedown time.
The cutting contractor then moved the equipment along to the next marked location and repeated this process, completing 12 circular wire saw cuts in total. Concrete cores each measured 137 cubic feet in volume and 27.5 square feet of wire sawing was completed to create them. The 4,400-pound cores were rigged by Concrete Cutting Systems and pulled out from the cut, then removed from the basin by the general contractor’s forklift via the roof hatch opening. All wire sawing work was completed on time and within budget over eight shifts by two operators and helpers.
“The only concern we had going into this job was moving everything safely in and out of the basin of the treatment plant. The rigging system in the roof of the tank had to hold all of our heavy hydraulic equipment. To mitigate any potential failures in the rigging, we triple-anchored with 5,000-pound power bolts,” said Pat Salemno, technician for Concrete Cutting Systems. “Once we were down in the basin, we used wet cutting techniques to eliminate dust and had everyone use the appropriate PPE for the work environment.”
“Circular wire sawing the dozen 42-inch-diameter and 36-inch-thick openings at Baxter Water Treatment Plant was an extremely successful and satisfying job for us,” commented Nevrotski. “The total combined years of experience held by our crew gave us confidence that the job could be done well and to the satisfaction of the customer, while our choice of quality concrete sawing tools and equipment gave us the means to execute our plan without any problems,” he added.
Coming from the “fighting city” of Philadelphia, the home of movie icon Rocky Balboa, this CSDA member knows how important it is to go the distance—especially when there are 12 tough rounds of wire sawing to complete. Diamond tools provide the speed, efficiency and low levels of noise and debris necessary for cutting contractors to succeed in all types of projects, much like the wire sawing work done at Baxter Water Treatment Plant.
Concrete Cutting Systems, Inc. has been a CSDA member for six years and is based in Philadelphia, Pennsylvania, with a support location in Pittsburgh. The company has been in business since 1995, has 60 employees, 48 trucks and offers the services of core drilling, wall sawing, wire sawing, flat sawing, selective demolition, joint sealing and slurry collection.
A.E. Kelly Group, LLC
Sawing and Drilling Contractor:
Concrete Cutting Systems, Inc.
Methods Used: Wire Sawing