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2016SpringShotcreteEMag

Shotcrete Corner Fig. 2: Preparing to shotcrete the wall. The heavily congested reinforcing bar required for seismic reinforcement made application challenging. Photo courtesy Kryton International Inc. (1 m) thick raft slab and all below-grade walls. The Kryton Waterproofing System was used to supplement an externally applied sheet membrane, as the sheet membrane could not be trusted as the only waterproofing solution for this high-risk project. Comprehensive training on the application of the Waterstop System was provided by Kryton’s Technical Team, and multiple site support visits were made. Because construction was completed in early 2014, the substation has been working as a key part of an ambitious portfolio of hydroelectric and transmission projects completed by BC Hydro to meet the projected growing energy needs of the province. Brian MacNeil is the North American Regional Manager for Kryton International Inc. He has worked more than 25 years in the construction industry, with the last 15 focused on mitigating the risk associated with concrete waterproofing and protection. He has worked on both cast-in-place and shotcrete waterproofing projects across Canada and the United States, from tunnels and wine caves to large foundations and water containment projects. Sea walls and marine applications are no problem. As the walls were to incorporate the drain mat system around their outer perimeter, close attention to joint details and placing of the four walls would be critical. The system needed to be completely sealed, which was especially challenging where the shotcrete wall met the cast-in-place walls (refer to Fig. 2). The wall placed by shotcreting involved a number of challenges. To begin with, the wall was much larger than normal at 120 x 30 ft (36 x 9 m), needing four stories of scaffolding for the shotcrete placement. Additionally, as the structure was reinforced to seismic standards (leaving it essentially bomb-proof), the heavily congested reinforcing bar made for more difficult placement to ensure complete compaction without voids. Commonly used sheet membranes are often problematic where cast-in-place meets shotcrete. As a sheet membrane had originally been specified for the project, the team began to search for a more compatible waterproofing solution that would provide assurance that the building would remain watertight. After much research and consultation, the construction team selected Kryton’s Krystol Internal Membrane (KIM) concrete waterproofing admixture to waterproof the belowgrade areas, and the Krystol Waterstop System to fully seal the joints against water penetration. These areas would include the 3.28 ft Shotcrete • Spring 2016 39


2016SpringShotcreteEMag
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