Retractable roof stadium
A retractable roof is a roof system designed to roll back the roof on tracks so that the interior of the facility is open to the outdoors. Retractable roofs are sometimes referred to as operable roofs or retractable skylights. The term operable skylight, while quite similar, refers to a skylight that opens on a hinge, rather than on a track.
Retractable roofs are used in residences, restaurants and bars, swim centres, and other facilities wishing to provide an open-air experience at the push of a button.
The United States Patent and Trademark Office (USPTO) shows that David S. Miller, founder of Rollamatic Retractable Roofs, filed a patent in August 1963 for a movable and remotely controllable roof section for houses and other types of buildings. As Rollamatic was founded five years earlier, the first installation of a motorized retractable roof must be between 1958 and 1963.
While any shape is possible, common shapes are flat, ridge, hip-ridge, barrel and dome. A residence might incorporate one or more 3' by 5' retractables; a bar or restaurant a retractable roof measuring 20' by 30'; and a meeting hall a 50' by 100' bi-parting-over-stationary.
Stadium retractable roofs are generally used in locales where inclement weather, extreme heat, or extreme cold are prevalent during the respective sports seasons, in order to allow for playing of traditionally outdoor sports in more favorable conditions, as well as the comfort of spectators watching games played in such weather. Unlike their predecessors, the domes built primarily during the 1960s, 1970s, and early 1980s, retractable roofs also allow for playing of the same traditionally outdoor sports in outdoor conditions when the weather is more favorable.
Another purpose of retractable roofs is to allow for growth of natural grass playing fields in environments where extreme hot and/or cold temperatures would otherwise make installation and maintenance of such a field cost prohibitive. Installations throughout the world employ a variety of different configurations and styles.
The first retractable roof sports venue was the now-demolished Civic Arena in Pittsburgh, Pennsylvania, United States. Constructed in 1961 for the Pittsburgh Civic Light Opera, the arena was home to minor-league and NCAA D-1 basketball and ice hockey teams before becoming the home of the NHL's Pittsburgh Penguins in 1967, as well as hosting over a dozen regular season NBA games in the 1960s and 1970s. The arena's dome-shaped roof covered 170,000 square feet (16,000 m2) and was made up of eight equal segments constructed from close to 3,000 tons of steel, in which six segments could retract underneath the remaining two, supported by a 260-foot (79 m) long exterior cantilevered arm.
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