The first season of play in Toronto's new concrete Skydome brought the city's baseball team, the Bluejays, the 1989 American League East pennant. The world's first multipurpose stadium has a retractable roof and will accommodate 56,000 spectators for football, about 59,000 for baseball, and up to 70,000 at concerts. The basic structure of the stadium consists of 48 concrete bents. In addition, the playing field base is a concrete slab. All structural elements are concrete except for the retractable roof and movable bleachers. The basic material of the exterior is also exposed concrete, with limited use of metal grilles and curtain walls.
The roof can be opened or closed within 20 minutes. The track beams on which trucks ride to move these three roof sections are of cast-in-place reinforced concrete. Bar setting time was cut in half by assembling rebar cages on site and hoisting them by crane. Full tension mechanical connectors at the intersection of tie beams and bent frames also helped speed the work. Using cast-in-place reinforced concrete not only saved time, but was cost-effective as well.