RETRACTABLE ROOF
The University of Phoenix Stadium retractable roof consists of two translucent, fabric covered panels (185 feet by 285 feet each) that meet directly over the 50-yard line when in the closed position, and roll downhill to reside over each end-zone when in the open position. The roof operates at a maximum speed of 25 feet per minute and fully opens or closes in approximately 11 minutes.
The retractable roof is moved by 16 transporters, each riding on two steel wheels. Half the transporters are equipped with cable drums that spool cables anchored to the fixed roof above the 50-yard line. Each cable drum is powered by electric induction motors with fail-safe DC electric brakes that automatically engage when roof movement stops.
Linear bearings on the west side of the stadium allow up to 36 inches of relative movement between the roof panels and the transporters. This allows the wheels on both sides of the roof to stay engaged with the rails regardless of roof movement caused by thermal expansion, wind, and other forces.
The control system is fully redundant to ensure 100% reliability at all times. Real-time feedback and other diagnostics allow easy operation and troubleshooting.
PLAYING FIELD
The retractable field normally resides outdoors, on the south side of the facility, where conditions for maintaining its natural grass playing surface are optimal. The field structure measures 403 feet by 234 feet and includes all components required for a healthy grass playing field, including irrigation, drainage and an optimized growing surface. When the field resides outside, the stadium can be configured for a multitude of events, including conventions, monster truck pulls, and concerts.
The retractable field is equipped with 542 steel wheels that ride along 13 rails embedded in the concrete facility floor. Guide wheel assemblies located on the center guide rail keep the retractable field in alignment as it moves in and out of the stadium. The field is driven 11.5 feet per minute by 76 one-horsepower motors into the stadium through field doors on the south side of the facility in approximately one hour.
