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DECEMBER 2018 | 13 Concrete PHOTOGRAPHY COURTESY LMS GROUP PHOTOGRAPHY BY JACIA PHILLIPS/COURTESY ALTUSGROUP under construction by Westbank Corporation at Howe Street and Beach Avenue in Vancouver. The tower rises from a 7,500-square-feet triangular base to a 13,000-square-feet rectangular building. The non-symmetrical design of the cast-in-place concrete building posed considerable structural challenges that were addressed by many key experts, including Carion Construction Ltd., which began the project by creating a 14-foot thick concrete foun- dation. "Two 24-ton capacity luffing cranes were instrumental in meeting the construction schedule and to handle the weight of our forms as well as the rebar for the project," says Bill Iles. "Also, we had to excavate in two phases. During phase one excava- tion braces were braced to the future phase two and could not be removed until phase one was poured up to ground floor; then phase two could be excavated." Achieving the desired vertical alignment of the can- tilevered floors required diligent management of the deflection as there were very few typical floors. LMS Reinforcing Steel project manager Cody Lake notes that a concrete core strengthened with verti- cal post-tension rods encased in the concrete enabled the transference of loads from the wider upper floors of the tower to the core and columns. "Vertical post tensioning is very rare, and it required 11 steel bars each 67-millimetres thick to be anchored to the foun- dation and travel up the core, with most of these bars reaching the 36th level – whereupon we brought up a stressing machine to tension the bars to specified design forces," says Lake. The structure required approximately 10,000 tons of rebar. John Carson, executive director of the AltusGroup, Inc., says the concrete sector overall – and especially pre-stressed precast – is "exceptionally robust across North America, with lead times stretched and sched- ules filling up even into 2019." For those with either a presence in or who sup- ply product to the U.S., the reason for the increased activity south of the 49th parallel is simple, accord- ing to Carson. "Federal government tax reforms, corporate tax cuts, rising interest rates, and other pro-business initiatives have had a huge positive impact on the construction industry," he says. "That is not to say there aren't challenges: raw material prices are increasing, labour supply is tight, and there might be shifts in procurement of supplies in the future." With energy efficiency being foremost in the minds of developers and suppliers, AltusGroup, Inc. is currently testing a product from Kingspan called Kooltherm. Its an epoxy foam insulation for use with AltusGroup's CarbonCast insulated sandwich wall technology, says Carson, referring to the enclosure Vancouver House, Vancouver, B.C. CarbonCast wall technology at Hilton — Des Moines, Des Moines, IA, U.S. Surespan.indd 1 2018-11-12 8:56 AM

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