Mercedes-Benz Stadium

Uni-Systems Engineering designed and oversaw installation of the retractable roof mechanization. The roof is made of eight triangular structural steel petals, clad in ETFE pillows, and choreographed to resemble a camera shutter when opening and closing. In the closed position, the petals cantilever over a 125,000 square foot opening, and seal against each other with their tips interlocked at the center of the roof opening. When open, the petals rest on the fixed roof deck, out of sight from below.

Throughout operation, the control system independently monitors and adjusts each petal’s speed to accommodate differing travel path lengths and to allow all panels to simultaneously reach their ends of travel.

The eight retractable roof petals are supported by eight pairs of tracks that form a rough oval around the roof opening. The eight inner tracks support the petals’ traction drive wheels, and the eight outer tracks balance the uplift forces generated by the cantilevered petal tips. Each petal is powered by twelve 7.5 horsepower motors with gear reducers and fail-safe brakes. When not operating, two rail clamps on each petal engage with the rail and act as parking brakes to prevent unwanted movement.

The fully-automated retractable roof is monitored and controlled via a personal computer located in the stadium control room.