Cowboys Stadium

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Cowboys Stadium

Retractable Roof Structure

HKS, Inc.
Historic Retractable Roof and Operable Endzone Wall
Jerry Jones, owner of the NFL’s Dallas Cowboys, wanted to give fans a stadium unlike any other (and to show that everything in Texas is indeed bigger). The plan for his championship team included a stadium boasting the world’s largest HDTV video scoreboard, a retractable roof designed to pay homage to Texas Stadium, and two operable end zone window walls that are the biggest walls of their kind in the world. Loyalty has always been important for Cowboys fans, and so the team’s new home was designed so that the retractable roof, when open, creates a rectangular exposure that looks just like the permanent opening at the Cowboys’ previous home, Texas Stadium. Uni-Systems was presented with the challenge to design a mechanization system on two rounded arches, the steepest incline the company has worked with yet. Engineers designed a custom rack-and-pinion drive system to ensure the roof’s operation as it climbs the tall arches. An added benefit is the power generated as the system slowly allows the roof to roll downhill when opening. To help that process, Uni-Systems also designed rotating pins that the two massive arches connect to. The rotation compensates for the natural flexibility and bending the steel structures endure as movement occurs. Only a very slight rotation of these arch pins allows the peaks of the arches to move several inches. To add to the stadium’s open atmosphere, two operable window walls were installed at each end zone. These world-record-sized walls offer a stunning panoramic view of the area surrounding the stadium. The entire system is designed to give Cowboys fans and stadium guests an open-air stadium, but when the intense heat of north Texas becomes overpowering, the environment can be closed and controlled. Not only do fans remain comfortable, they remain safe. The roof and walls are protected against strong winds through a series of locks and tie-downs designed to keep moving components closed even when the wind may be blowing.

Retractable Roof

The Cowboys Stadium retractable roof comprises two 300-foot by 220-foot panels. When fully open, the exposed section of the roof is 256 feet by 410 feet.

The panels each travel 215 feet along the arches that run the length of the stadium. Each panel is driven by (64) 7.5 Hp motors within 32 tractors. The total power for each roof panel is 480 Hp which provides a towing capacity of 800,000 pounds (higher than 4 of the world’s most powerful diesel locomotives).

The custom rack and pinion system gives the roof the power necessary to climb the 23.9 degree slope it has to climb at its steepest point on the arch. When the roof is opening, however, the drive system is also able to utilize the natural weight of the roof to generate power. Because the tractors are actually used to slow the roof instead of driving it forward when opening, the motors have been equipped with regenerative drives that turn the motors into generators, drawing power back into the stadium’s power grid.

Operable End Zone Walls

Cowboys Stadium features two operable end zone window walls. Each is 256 feet wide and 120 feet tall and comprises 7 individual panels (each panel is 38 feet wide and 120 feet tall).

Each panel is clad with glass and shows minimal steel to maximize transparency, letting natural light illuminate the stadium’s interior.
Five of the panels are operable and can create a complete opening 180 feet wide in 6 minutes. Each panel is driven by (2) 24 inch diameter steel wheels, each powered by a 3 Hp motor. Each panel also has two guide rollers at the top that run on an upper track hung from the stadium’s steel structure. The top guide rollers allow for 20 inches of relative vertical movement between the steel structure and the concrete below.

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