The legacy and future of an American icon: The precast, prestressed concrete double tee

This paper traces the origin and development of the double tee, emphasizing the influence it has had on the precast, prestressed concrete industry. It reviews the advantages and diverse applications of double tees, primarily in North America. The major features of the double tee are discussed, especially in relation to parking structures. The paper summarizes the results of selected studies conducted at several universities. It discusses the northeast extreme tee (NEXT), the 16 ft (4.8 m) wide Mega-Tee, and the bulb double tee. Examples of future possibilities of double tees using high-strength concrete, self-consolidating concrete, and large-diameter prestressing strands are explored. It is concluded that the future of the double tee, with all its enhancements and ongoing research, is promising.