wouldn’t work technically. In the end, they went with a rack-andpinion retractable roof drive system, the first in North America for this kind of roof, that would efficiently generate the tow force needed to pull the panels up the steep slope. A total of 128 motors power a pinion that eases the panels down 328 feet of toothed steel rack that’s attached to the arch trusses. Pulling the dead weight of the panels back up the slope is the real challenge. “The efficiency of this system is demonstrated in the modest power requirements to move the panels’ 3.5 million-pound weight back up the slope. Each of the 128 motors produces 7.5 horsepower, making the 960 horsepower required to close the roof roughly Special Advertising Supplement to Texas Construction 21 Images courtesy of Uni-Systems