A double tee or double-T beam is a load-bearing structure that resembles two T-beams connected to each other side by side. The strong bond of the flange and the two webs creates a structure that is capable of withstanding high loads while having a long span. The typical sizes of double tees are up to 15 feet (4.6 m) for flange width, up to 5 feet (1.5 m) for web depth, and up to 80 feet (24 m) or more for span length. Double tees are pre-manufactured from prestressed concrete which allows construction time to be shortened.
Double-tee roof structure of an indoor swimming pool
Precast parking structure showing an interior column which supports two girders, left and right. Double-tee beams hang onto the girders.
The first NEXT Beam bridge, in York, Maine, which uses four double tees to form a bridge span
A double-tee retaining wall
A multistorey car park or parking garage, also called a multistorey, parking building, parking structure, parkade, parking ramp, parking deck, or indoor parking, is a building designed for car, motorcycle, and bicycle parking in which parking takes place on more than one floor or level. The first known multistorey facility was built in London in 1901, and the first underground parking was built in Barcelona in 1904. The term multistorey is almost never used in the US, because almost all parking structures have multiple parking levels. Parking structures may be heated if they are enclosed.
Entrance to the parking garage of the Aquarium of the Pacific
A multistorey car park in Hradec Králové
Parking garage in Sweden
Basement parking
