Issue link: http://digital.canadawide.com/i/109465
renderings courtesy Graziani + Corazza Architects Inc. double-height ceilings. It has a few tenants taking space in the upper levels (Bed Bath & Beyond netted a 60,000-square-foot space and Marshall���s took 42,000 square feet ��� both unusually large spaces for downtown), and a lower level filled with smaller tenants and a food court, as well as a connection to College Park, parking, the subway and the underground P.A.T.H. system. At ground level are banks and some restaurants with outdoor patios wrapping along the Gerrard Street side. The Yonge Street sidewalks here have been widened from 12 to 18 feet as part of the local BIA���s ongoing improvement initiative that is standardizing light fixtures and working to make the street eminently more pedestrian friendly. Rising from the retail podium is a glass and steel tower ��� a thin blade flanked on its east and west sides with two curvilinear forms that help to step the building back. In total, it will contain 985 individual units and house some 1,500 owners, including penthouses valued from $3.5 to $7.8 million and a top floor for $18.4 million. The curvilinear form of the tower further defined as it manifests in the curved form of the roof���s structure. The project is actually comprised of three separate condominium corporations (the retail podium, residential floors six to 58 and floors 59 to 78) all opening at different times mostly to ensure ongoing financial viability of a project that will take longer to build than a typical condo, but also to avoid congestion during move-in periods. Structural consultant Yolles, a CH2M Hill Company had to work with the distinct challenges that arise when building to such a height. ���The lateral design against wind and seismic effects becomes a challenge,��� says Agha Hasan, senior principal of the firm. ���Wind forces acting on towers increase exponentially as the height increases. Moreover, the effect of wind forces for a tower of this proportion cannot be assessed by code-specified methods, and experimental study using windtunnel technology becomes mandatory.��� Hasan notes another specific challenge to a building of Aura���s magnitude. ���The gravity load from the floor slabs induces differential shortening between columns, and between columns and core walls. These elements have to be super-elevated, which means the floors must be formed at levels higher than the theoretical levels to ensure a reasonably flat floor at the time of substantial completion,��� he says. The transfer slab at the fifth floor, under the tower footprint, is a unique feature. ���Because of the retail occupancy at the lower levels, most of the tower���s vertical structure could not be continued below Level 5. Consequently, a 2,500-millimetre-thick post-tensioned slab was introduced at Level 5 to transfer the load from the 73 storeys above,��� says Hasan. ���Mega columns sized from 1.5 metres to five metres were provided to support the transfer slab at that level, and to satisfy seismic requirements relating to relative storey stiffness.��� Now that the podium is operational, Canderel wanted to lift the inconvenience of the ongoing work overhead, so rather 13-01-11 10:10 AM Aura at College Park CAD Overflow.indd 1 p58-63Aura.indd 61 february 2013��� ��� /61 13-01-03 10:58 AM 13-01-22 3:38 PM