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A development plan for a luxury hotel and casino in Auckland, New Zealand, consisted of extra floors that include four VIP villas with gaming areas and VIP salons. In order to add these extra floors, a rooftop swimming pool needed to be removed.

SkyCity is one of Auckland’s biggest hotels, with over 340 rooms and views of the city’s harbor. One of the main draws of the hotel is the Sky Tower, a 328-meter-tall (1,076-foot) building that is the largest man-made structure in New Zealand. Visitors can dine in one of the tower’s restaurants or perform a 192-meter (630-foot) wire jump from the tower’s viewing platform. The VIP area development project was scheduled for completion in June 2011. This is so that the hotel will be prepared for a large volume of high-profile visitors arriving in September for the 2011 Rugby World Cup, an international tournament that features 20 teams and runs for two months.

The removal of the rooftop pool was scheduled for three weeks in February, and had to be done quickly to keep the project on track while keeping disruption of hotel operations to a minimum. The pool measured 13.3 meters (43.6 feet) long, 5.1 meters (16.7 feet) wide and had a depth ranging from 1.2 meters (3.9 feet) to 1.8 meters (5.9 feet). The concrete walls and floor of the pool were 250 millimeters (9.8 inches) thick. The general contractor for the project, Hyline Construction Ltd. of Auckland, began searching for a contractor that could take out the concrete pool without causing large amounts of vibration and noise that would disturb hotel guests.

A1 Kiwi Cutters & Drillers Ltd., a CSDA member based in Auckland, was contracted by Hyline to remove the pool. The plan devised by A1 Kiwi Cutters and approved by Hyline, called for the walls of the pool to be cut into 16 sections using a wall saw with diamond blades. It was specified that none of the cut sections could weigh more than 2.7 tons due to capacity of the crane on site. Each cut section would have two 132-millimeter-diameter (5.2-inch) holes core drilled into it so that lifting straps could be attached, then the section could be removed by the crane. Before the final cut was made on each section, the piece would be rigged for removal. The floor of the pool was to be cut into 14 sections using a floor saw, and a similar method was used to hold the weight of the cut piece before the final cut and removal. A1 Kiwi Cutters was responsible for the provision of machinery, labor and slurry control during all the cutting and drilling processes.

As the hotel was to remain fully operational during the work, wall sawing and diamond core drilling was the best choice. Wall sawing is much more quiet and efficient than demolition methods like jackhammering or the use of a wrecking ball. “This technique meant minimal disruption for the hotel staff and guests, as there would be less vibration, less debris and the cutting would not be as labor-intensive as breaking or wrecking,” said Penny Simons, co-owner of A1 Kiwi Cutters & Drillers Ltd.

The cutting contractor worked closely with Hilti New Zealand Ltd. and used a DS TS20-E wall saw to perform the majority of the cuts. The first step was to wall saw the internal perimeter where the pool walls met the pool floor. The cuts were made 50 millimeters (2 inches) above the joint and were completed in five hours. It was then time to core drill the 132-millimeter-diameter (5.2-inch) holes for the lifting straps. Two holes were cored per section using a Hilti DD200 core drill. The final part of the pool job involved vertical wall sawing. The walls were divided into 16 pieces and measured to be no longer than 2.4 meters (7.9 feet) and weigh no more than 2.7 tons. The sections were rigged while the final cut was being made, then the piece was removed from the work area. The process was repeated until all 16 sections had been cut free. This took six days to complete.

Once all of the concrete pool wall sections were removed from the work area, the cutting team began to mark out the floor of the pool for cutting and core drilled holes measuring 132 millimeters (5.2 inches) in diameter to attach lifting straps. An operator then used the floor saw to cut the pool floor into 14 sections, again ensuring that each section was no heavier than 2.6 tons. As with the pool wall sections, each cut floor section was rigged by crane before making the final cut and removing the piece from the work area. The cutting of the pool floor concrete took 10 days.

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 entire cutting work, slurry was collected via wet vacs and stored in sealed containers. When filled, these containers were lowered by crane and then emptied by environmental contractors who disposed of the slurry according to current legislation. Control of the slurry and waste water was critical, as A1 Kiwi Cutters had to make sure that no waste leaked into the occupied hotel rooms on the floor below.

Due to the strict time frame applied to the whole project, time was of the essence. The hotel stood to lose a large amount of revenue if the new facilities were not available for the Rugby World Cup. In order to complete the job, A1 Kiwi Cutters had up to five operators on site most days. Mark Simons, director of A1 Kiwi Cutters & Drillers Ltd, oversaw the day-to-day management and organization of the team. Simons operated the wall saw while operators took care of the core drilling, floor sawing and slurry control. The pool was successfully removed in 16 days.

The main safety concern was the risk of pool sections falling before being removed. This concern was overcome by the core drilling of lifting holes and rigging the section to the crane prior to each final cut. Another safety concern was the weather. The work was completed during the summer months and operators were exposed to the sun for long periods of time while working on the rooftop. The contractor made sure that all operators used sunscreen, stopped regularly for breaks and kept hydrated. All operators wore standard personal protective equipment like steel toe capped boots, hi-visibility vests, hard hats, gloves, ear and eye protection. A wall saw was used to cut through the pool walls that were 250 millimeters (9.8 inches) thick.

A Hilti DS TS20-E Wall Saw was used to perform the vertical cuts to the interior walls of the pool, while the cuts to the floor of the pool were made by a 35-horsepower Core Cut floor saw from Diamond Products. Hilti also supplied a DD200 core drill to create the picking holes for the crane rigging, while Husqvarna K1250 and K960 cut and break saws were also used for some parts of the cutting work. Slurry and waste material were collected using a WVD2002 twin motor wet vacuum from Numatic.

To cut and remove the rooftop swimming pool at the SkyCity Hotel, A1 Kiwi Cutters & Drillers Ltd used the wall saw to cut over 65 meters (213 feet) of cuts and a floor saw to perform over 100 meters (328 feet) of cutting. For rigging of the concrete pieces, the contractor core drilled over 140 holes before attaching to the crane and removing over 80 tons of concrete. The CSDA member completed the job within the expectations of Hyline Construction and within budget

Following the successful completion of the pool removal project, the contractor has been further contracted by both Hyline Construction and Hawkins Construction to work on other parts of the overall project.

“The pool removal work done at SkyCity Hotel gave us an opportunity to show what we can do with our market-leading equipment and a dedicated team,” said Penny. “Hilti tells us that our high-freqency wall saw is the only one in New Zealand. Our director, Mark Simons, felt it was important to be involved, so he operated the saw and assisted with the work. We think this says a lot about our company,” she added. The development work at SkyCity Hotel completed in June 2011 thanks to this CSDA member making a big splash.

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.