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A1 Kiwi Cutters & Drillers Ltd not only work in New Zealand - we have recently sent operators to assist in a large dam project in Columbia, please download the attached story board for more information on this exciting project.

Delegats, one of New Zealand's top wine makers, recently acquired new office space on the ground and first floor of a building in central Auckland. The main contractor, Stanley Group Ltd, was given the job of refurbishing both floors before Delegats employees moved in. This included the installation of a curved staircase and ellipse-shaped viewing area to the floor below.

To aid in the installation of both the staircase and ellipse, sections of the floor had to be cut out in specific shapes. The ellipse was approximately 4 meters (13 feet) in diameter and the curved staircase was 6 meters (19.5 feet) long by 1.5 meters (5 feet) wide. The structure of the floor consisted of double-T beams with a concrete slab on top, ranging from 150 to 350 millimeters (6 to 13.8 inches) in thickness. Due to other occupants in the building, all work had to be completed outside of normal working hours.

Stanley Group enlisted the help of CSDA member A1 Kiwi Cutters & Drillers Ltd of Auckland, New Zealand, to perform the required cutting work. "We were chosen because not only did we have 3-phase equipment in the form of hydraulic hand saws, ring saws and a bar saw along with an electric floor saw, but also because we had the experience and team to be able to carry out the work in the timeframe specified," said Penny Simons, joint owner of the concrete cutting firm.

Concrete cutting was the chosen method to create the specified openings, as it was the only way to protect the structural integrity of the building. Electrically powered machinery was also the favorable choice, due to the fact that this type of equipment is quieter than gas-powered machinery and can be operated inside the building. This way, cutting work could be performed without disturbing residents in surrounding apartments. As both the staircase and ellipse have curved edges, a satisfactory way to achieve the desired cuts was to use a hydraulic bar saw. This saw was able to easily navigate throught the varying thicknesses of the slab.

An alternative method of cutting the concrete slab to create the openings was suggested; however, the use of jack hammers to break through the floor was deemed too loud and the vibrations too destructive for the building. Diamond tools were decided to be a better choice, as they are flexible and versatile enough to cut to over 350 millimeters (13.8 inches) deep where necessary. This type of equipment also cuts with almost no vibration, and is able to get close to vertical surfaces. Once all plans had been drawn out and approved for the cutting work, the team from A1 Kiwi Cutters & Drillers got to work.

The first task was to draw an outline to mark the cut for the ellipse opening, after which an operator used the bar saw to score the outline. The contractor then used an electric CC1800 floor saw from Diamond Products to split the cut section into smaller, more manageable pieces. This cutting work took six hours, and the pieces created each measured 500 by 500 millimeters (19.5 by 19.5 inches) and weighed 50 kilograms (110 pounds). These pieces were then removed from site by a demolition team. The whole underside of the slab was supported using a crash deck while the ellipse was being created. This crash deck consisted of a series of support scaffolding and boards that were positioned immediately below the slab to prevent pieces from dropping and trapping the blade or chain.

As the cutting team moved closer to the scored outline of the opening, the floor saw was swapped for a Husqvarna hydraulic hand saw and ring saw to cut and remove the remaining area of concrete. Once again, the slab was cut into several smaller pieces so that it could be easily removed from the work area. This cutting work continued until 150 millimeters (4 inches) remained before the contractor reached the scored outline. At this point, the bar saw was utilized to achieve a smooth curve on the final finished edge. This finish was achieved by repeatedly plunging the bar saw while the cutting work around the ellipse was performed. It took a team of three a total of nine hours to cut and remove the pieces of concrete slab from the work area to form the elliptical opening.

The cutting contractor then prepared to cut the required opening for the curved staircase. The same methods were applied to the cutting of this opening as the ellipse shape, scoring the outline before dissecting the area that was to be removed into manageable sections. The opening for the curved staircase covered a larger area than the ellipse opening, approximately 6 by 1.2 meters (19.6 by 4 feet) at its widest point, therefore it took the cutting team from A1 around six hours to completely section off and remove the cut pieces.

During the course of the work, the team from A1 were wary of slurry building up on the floor of the concrete sawing work and spilling to the floor below. All slurry and waste material was controlled and collected using wet vacuums on the floor below. Any debris from the cutting work was removed and disposed of by qualified demolition contractors.

To create the openings for Delegats, A1 Kiwi Cutters & Drillers used a Core Cut CC1800, 20-horsepower electric floor saw from Diamond Products, a Husqvarna K2500 hydraulic hand saw and K3600 ring saw, and an 11.5-horsepower ICS hydrualic bar saw. A Numatic twin-motor wet vacuum was used to collect slurry.

One of the main concerns this CSDA member had on the job was to control noise. Any noise created from the cutting and removal of the concrete slab had to be kept to an absolute minimum, especially as the work took place in the evenings as residents lived in the adjacent buildings. In addition, the team had to contend with a reletively tight working space and closely monitor the removal of debris and slurry. A great deal of thought was dedicated to the setup of a support structure for the floor and for the collection of debris and cut sections. A combination of training, experience and the right equipment ensured that this phase of the building project was completed without any problems.

In order to protect operators and other employees against any falls from height once the openings had been created, a series of 1-meter (3.3-foot) safety barriers were erected. In addition, all personnel in or around the work area were required to wear personal protective equipment, including steel toe-capped boots, ear defenders, eye protection and work gloves.

The cutting team from A1 Kiwi Cutters and Drillers Ltd cut and removed approximately 11 metric tons (12 tons) of concrete slab from the floor of the Delegats building over the course of three six-hour shifts, working from 7:00 PM to 1:00 AM each shift. The project finished ahead of the scheduled time frame, and due to the success of the cutting work the contractor has developed a healthy relationship with the general and demolition contractors.

Unfortunately, the team from A1 were not able to sample the wine after successful completion of the job. Simons commented, "I believe they make great wine, but being from Manchester, England, I'm happier with a cold beer after work!" The real reward for the contractor, however, was achieving a satisfactory result from a challenging project, and the company took great pride in its work when the finished area was unveiled in the middle of 2009.

Company Profile
Established in 2005, A1 Kiwi Cutters & Drillers Ltd merged with Access Concrete Cutting in 2008 to become one of the biggest concrete cutting companies in Auckland, New Zealand. The company joined CSDA in 2009 and is also a member of the New Zealand association (NZCSDA). A1 Kiwi Cutters & Drillers have 14 operators and 10 trucks. The company offers the concrete cutting services of bar sawing, grinding, core drilling, slab sawing, ferroscanning, hand sawing, ring sawing, wall sawing, wire sawing and floor polishing and preparation.