The new U.S. Olympic Museum in Colorado Springs, Colo., is being built by design architects Diller Scofidio + Renfro and general contractor/construction manager GE Johnson Construction Company.
timize wind-girt supports, which increased certainty and repeatability in installation while also decreasing costs overall. Even as the structure reaches its highest elevation, preconstruction activities continue. For the specialized subcontractors developing a sequence of efficiently attaching the exterior skin to the structure, nothing is more valuable than the full-scale exterior wall section being erected onsite. McCorkle and Redfern estimate that the 20-foot by 20- foot mock-up wall section will require more than 1,000 labor hours to assemble and will likely cost in excess of $150,000 to build. Eight subcontractors must delicately interlace their work through a maze of structural framing, light-gauge framing, waterproofing, drain- age, glazing, and aluminum panels. Identifying components within wall sections that can be prefabricated off site, like the micro-framing system and laser cutting framing plates, increases quality control and supports repeatable processes during construction. Each component is individually numbered, indicating where, how, and to what it attaches, like a giant model, and each placement can be checked against the point cloud to verify accurate alignment. Thinking outside of the box hasn’t been limited to solving challenges on the outside of the building. Placing the museum’s extremely large, yet whisper-quiet, air handling unit has presented a series of sequencing challenges with a ripple effect that will likely continue to reverberate. “It’s low speed, high volume and is by far the largest air handler I’ve ever put in,” said Redfern. “The size dictates a basement placement, which meant installing it before we put in the structural steel for level one.”
Once installed, this unorthodox situation left the massive (and expen- sive) unit unprotected from the weather until the floor above it could be dried in. Complicating matters, structural engineering indicated that the concrete floor slabs across the building’s many elevations should be poured from the top down to deflect loading. Waiting until the mu- seum’s 15 elevations were poured and cured would greatly extend the exposure period for the mechanical system, presenting significant risk and an extremely difficult situation to rework if the unit was damaged. “We encouraged the owner and design team to install terrazzo on the first level floors in lieu of stained concrete so that floor placement could be moved up in the schedule, increasing protection of the AHU and equipment below,” Redfern said. Placing the air handling unit first also required fireproofing the base- ment before setting structural steel, one of several conditions that make multiple mobilizations of key trades likely throughout construction. “We have been empowered to use ingenuity to solve complex chal- lenges at every turn on a very, very cool building,” Redfern said. “GE Johnson is using anything and everything we can to build this right. Pushing boundaries, gaining outside expertise, and asking more of oneself than others will is the Olympic spirit this museum is being built to honor.”
SEAN O’KEEFE has more than 18 years of experience articulating the complexi- ties, challenges, and comradery of construction and design. He writes built environment stories for owners, architects, builders, and product manufacturers and can be reached at sean@sokpr.com.
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august 2018
csengineermag.com
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