Stadium mechanization designer Uni-Systems utilizes ACS800 drives with Direct Torque Control to move stadium roof; full torque at zero speed critical to operation As professional sports venues become bigger and more complex in design and scale, architects and engineers are looking for bold new ideas. Retractable roofs have become a popular feature in those structures because they provide the ability to control the stadium's interior environment more effectively. Only a select number of companies have the knowledge and expertise to mechanize and control these immense structures, which, themselves, become architectural feats. Uni-Systems, based in Minneapolis, Minnesota, is just such an expert.
Whether it's a retractable roof, a retractable pitcher's mound, movable walls or seating, Uni-Systems has established itself as the industry's premier provider. The company's impressive resume includes work on Minute Maid Park and Reliant Stadium, Houston, Texas; Miller Park, Milwaukee, Wisconsin; RFK Stadium, Washington, D.C.; and most recently, the Arizona Cardinals' Stadium, Glendale, Arizona. With its curved roof track, the Arizona Cardinals' project presented interesting challenges in designing the retractable roof mechanism.
Uni-Systems partnered with ABB and selected the ABB ACS800 drive to provide optimum control of the roof's torque-distribution system.
Building an Architectural Oasis in the Desert; Take the Grass Outside
When the National Football League's Arizona Cardinals made the decision to construct a new arena several years ago, the desert climate was a major consideration in the design plan. The heat can take its toll on fans and players, alike, and can be detrimental to the playing surface, as well - especially if it's natural grass. On the other hand, in cooler months, the world-famous climate is perfect for hosting outdoor activities. The exterior design of the stadium resembles the basic form of the barrel cactus and was created by renowned architect Peter Eisenman, along with HOK Sport. The retractable roof can be closed so the facility can be air conditioned in the hot months, and then opened in the cooler months.
The roof's panels consist of a PTFE (polytetrafluoroethylene) coated woven fiberglass fabric, and are much lighter than a traditional, clad roof. The stadium design includes not only a retractable roof, but also a retractable playing surface. The innovative, roll-out field will save an estimated $50 million in operating costs, as it is more economical to move the field outside, rather than having the entire roof retract to allow the necessary sunshine to reach the grass.
The retractable, natural-grass playing surface is contained in a 16.9-million pound tray that is 234 ft. wide by 400 ft. long - the first of its kind in North America.
All in all, the design of the stadium is so unique that, to date, it's been featured in a multiple series on "The Discovery Channel."
