100-foot Pool Enclosure Makes Third Time the Charm
Metro Family YMCA
It sounded like a good idea in 1980: top the Metro Family YMCA pool, in Portland, Oregon, with an air-supported cover. But by January 2003, the arch-shaped cover had collapsed three times under the weight of snow and ice. Twice before it had been replaced; now it was time for a permanent solution.
For a year and a half, the project struggled like a tired swimmer in a riptide. The YMCA, working with an area restoration contractor, had proposal after proposal rejected by the city's design review panel. Their reason: the replacement arch had to be light-transmitting. At long last, BOORA Architects, Cooper Construction, and structural engineers KPFF Engineers teamed up. The controlled daylight of Kalwall translucent panels and the clearspan, structural capabilities of Structures Unlimited, Inc. joined forces. And the untiring efforts of longtime Kalwall distributor DeaMor Associates got the project off the ground.
Structures Unlimited, Inc. pool enclosures are strong. From Canadian snowstorms to Caribbean hurricanes, each enclosure and skylight is custom-designed and engineered to meet or exceed all local snow and wind load requirements. Structures Unlimited, Inc. projects have stood up, for example, to some of Florida's most infamous hurricanes. In new construction, computer-generated shop drawings assist in ideal foundation placement and location of box beam connections.
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For the Metro Family YMCA project, a Structures Unlimited, Inc. clearspan, structural arch was the ideal solution, but the existing structure would not be able to sustain the resulting thrust loads of the 100-foot SkyroofTM. To remedy this, an arched truss system with a slip connection at one eave was proposed. The arch could be combined with a truss, creating a segmented arch, scissor-truss Skyroof, with a V-pattern and diagonal bracing to give the structure more height.
Then came a number of conversations, calculations and detail changes. No fewer than three engineering firms worked together to integrate the new Skyroof with the existing building. Portland's city engineer became involved, insisting that a Portland-approved inspector observe the welding. Since the trusses were to be preassembled under factory-controlled conditions, the only way to meet the installation deadline with Portland's blessing was to fly the city's inspector all the way to the Structures Unlimited plant in New Hampshire. Interestingly, the inspector allowed that the Structures Unlimited, Inc. welds were the best he had ever seen!
The members of Metro Family YMCA took a keen interest in the pool enclosure project: after three air-supported covers had failed, the membership wanted assurance that Structures Unlimited, Inc. would deliver a viable solution. And deliver they did, as trucks arrived at the job site on time, the trusses and translucent panels all loaded inside in the proper order for installation. By the end of the first week, the trusses and related bracing were installed and secured. After two weeks, all purlins and bracing were complete and nearly a third of the roof panels installed. Except for areas at the ends of the Skyroof left open for wall plastering, the job was finished in just three weeks.
With DeaMor Associates doing the installation, the entire Metro Family YMCA pool project went, well, swimmingly. As eager as the YMCA members were to get back into the water again, many took time to notice the new Structures Unlimited, Inc. Skyroof and mention how much they loved it. And Structures Unlimited is just as thrilled to have its first segmented arch, scissor-truss Skyroof take its place on the Portland skyline.
Metro Family YMCA
Portland, OR
Architect: BOORA Architects
General Contractor: Cooper Construction
Structural Engineers: KPFF Engineers, Berry Nordling, Inc.
Structures Unlimited, Inc. and Kalwall Specifications:
Skyroof: 64' x 100', consisting of 12 bays
Grid: 12" x 24" shoji
Light Transmission: 20%
Solar Heat Gain Coefficient: .23
Panel U-Value: .23
Exterior Panel Color: Superweathering .070 Crystal
Interior Panel Color: .45 White
For more information, contact:
Structures Unlimited, Inc., 603-645-6539 (800-225-3895 N. America)
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