Architects seek composite solutions to add both strength and beauty to buildings that will stand the test of time.
When “A Gathering Place for Tulsa” opens in the Oklahoma city later this year, the nearly 100-acre park along the Arkansas River will feature sports courts, bike and skate parks, nature trails, large lawns for concerts and more. At the heart of the park will be the three-level ONEOK Boathouse, including boat storage on the lower level, educational programming space on the second floor and a restaurant and outdoor patio on the top. The ONEOK Boathouse will not only be functional, but also attention-grabbing thanks to an 8,000-square-foot composite canopy that will cover the patio.
“The boathouse was designed to be the focal point for the park, and the white, modernistic, composite roof will become a very iconic image for the park,” says Jeff Stava, executive director and trustee of Tulsa’s Gathering Place LLC. “There is no other building roof like it.”
Composite materials are increasingly finding their way into architectural projects – ranging from new construction to building restorations and traditional ornamental elements – because of their design flexibility, durability, corrosion-resistance and strength.
The patio roof for the ONEOK boathouse comprises 130 sail-shaped, curved panels, which are being fabricated by Kreysler & Associates in American Canyon, Calif. When the company saw the design from Mack Scogin Merrill Elam Architects (MSME) more than two years ago, it thought it was a perfect project for GFRP, says Josh Zabel, vice president of business development at Kreysler. The company, which has been fabricating composites for the construction market since 1982, submitted a proposal. However, it didn’t originally win the bid.
Initially, the project team opted to make the roof from polytetrafluoroethylene (PTFE) panels. “They went down that route, but found out it was going to cost just as much or possibly more. And they also discovered they would have to change the design to make it out of [PTFE],” says Zabel. “So, they came back around, dredged up our original proposal, and that’s how we got on board.”
Kreysler & Associates is using hand lay-up to fabricate the panels, all of which are different sizes and shapes. Each panel includes a top and bottom skin, made from polyester resin and fiberglass, and a balsa core. The molds are created on a 65-foot-long, 5-axis CNC machine. “One of the tricks we’re using is rather than creating separate molds for the top and the bottom, we’re making a mold for the bottom, fabricating the bottom panel, then using that panel as a mold for the top,” says Zabel. That reduces mold-making time – and just as importantly, cost – in half.