Page 35

2013WinShotcreteEMag

deck-level water capability. Two pockets on either finish, a more substantial waterproofing product side of the beach-entry area were constructed to was used. hold natural rocks from the surrounding property On projects like this, South Shore Gunite to help the pool blend into the landscape. After prefers to use its Airplaco mobile batch plants. initial curing and once the pool shotcrete reached When we use Airplaco mobile batch plants, all the required strength, the boulders were installed. the worrisome aspects when using ready mix are Shotcrete was placed around the boulders to secure them in place (Fig. 4). The complexity of the pool structure created sections located from well below the frost line to right at and above the frost line. This required extensive structural design, resulting in a lot of reinforcement. The reinforcing steel consisted of two layers of No. 4 (No. 13M) reinforcing bar in the entire pool. The horizontal reinforcement spacing was 8 in. (203 mm) on center and vertical spacing was 6 in. (152 mm) on center. During shooting, a blowpipe was used extensively to keep the outer layer of reinforcing bar clean and prevent any rebound from building up on the bar surface, where it would reduce the quality of the in-place concrete. Overall, with the multiple phases, the Fig. 3: Deep excavation required for forming and, shotcrete portion of the job was completed in 5 days. subsequently, filling with free-draining stone to prevent frost The customer wanted to have the negative- heave. Also seen is the dowel reinforcing bar that was tied edge wall act like an aggressive waterfall. Producing into the pool floor in the second phase the waterfall effect required high flow rate demands that also affected water turnover. Based on the length of the perimeter overflow, the calculated flow rate required to create the water- fall effect was 740 gal./minute (350 L/s). This high flow was provided by a 10 hp pump outfitted with a variable-speed drive to allow for increased energy efficiency and control. The main feature plumbing lines were 8 in. (203 mm) polyvinyl chloride (PVC) to smoothly convey the substantial volume of water. With the high flow rates needed for the waterfall, conventional 2 in. (50 mm) pool returns produced too much turbulence for the vanishing-edge waterfall effect. Thus, additional main drain-type fittings were installed at the bottom of the pool to supply the high-flow-rate Fig. 4: Completed shotcrete with large rocks placed return water with minimal disturbance on the pool surface for the vanishing-edge waterfall. There were also multiple main drains for suction and additional drain-type fittings used as inlets. A buried precast concrete surge tank was also used to ensure that an adequate volume of water was available at all times. To blend with the natural Maine surroundings, the tiles and coping stones were custom-manufactured from an indigenous stone local to Maine. The majority of the stone was a dark gray with some white veins that fit in perfectly. We installed the coping stones on the shotcrete gutter so the inner stone allowed water to pass over it in a small slot between two rows of stone and then into the gutter. The pool was waterproofed before the final finish of black pebble was installed on the interior. In the rock pockets that would not be able to have a final Shotcrete • Winter 2013 33


2013WinShotcreteEMag
To see the actual publication please follow the link above