In addition to reducing heat energy loss, the structural thermal breaks prevent concrete structures on the warm sides of both the exterior and interior walls from becoming chilled, reaching dew point, or support- ing mold growth. Installed between the concrete-to-concrete thermal breaks are special Isokorb® thermal breaks that resist seismic shear forces in compli - ance with National Building Code of Canada 2010 standards for seismic resistance. “The most unusual application for structural thermal breaks was a high parapet wall at the top of the tower,” says Meredith Andersen, associ- ate engineer with Read Jones Christoffersen Engineers. The parapet changes in height from about 4 to 14 ft (1.2 to 4.3 m) as the top of the building steps down behind it. A parapet is essentially a vertical cantilever and, because of its height, can encounter significant moment, shear and seismic forces. Concrete- to-concrete thermal breaks were aligned horizontally at each “step” and vertically in the plane of the wall to prevent thermal bridging. Other energy-saving measures The high-performance building envelope allowed the designers to reduce the size of the building’s heat pump to one-fifth of that needed for a comparable code-compliant building in Vancouver. The heating/ cooling system is supplied by a high efficiency ground-source heat pump served by 15 geothermal bore holes. An 80 kW solar panel ar- ray supplements electricity and six energy recovery ventilators transfer heat from outgoing interior air to incoming fresh air, reducing the required capacity of the HVAC system. Overall energy savings allowed the designers to include elements that reduce energy loads further such as electro-chromatic glass that blocks heat gain and glare by becoming translucent when activated. “This project responds to the urgency of the climate crisis,” says Darryl Condon, managing partner at the Vancouver architecture firm HCMA. “It shows that even large, complex facilities can lead the way in reduc - Schöck Isokorb® concrete-to-concrete structural thermal break transfers bending moments and shear forces, while preventing heat energy waste, chilled interior floors, and formation of condensation and mold.
ing our industry’s carbon footprint, while still improving the public service they provide.” In the words of Danica Djurkovic, Director of Facilities Planning and Development at the City of Vancouver, “This community facility is a leading example of the City of Vancouver’s climate commitments, showing that we can make near zero-emissions buildings the new normal, while enhancing occupant comfort, and reducing energy and water consumption costs.” This model of Schöck Isokorb® thermal break is a load-bearing thermal insulation element for transfer of earthquake forces parallel to the insulation layer as well as uplift forces when used in combination with concrete-to-concrete structural thermal breaks.
Isokorb® structural insulation element isolates steel cantilever attachments, such as balcony supports, canopies and sunscreens, from supporting concrete slabs. The element transfers bending moments and shear forces.
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csengineermag.com
july 2021
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