Achieving heavy loads and long spans with double tees.
Double tees are precast structural members with efficient sections typically used as framing to achieve long spans. Consisting of two beam elements and a flat deck, double tees are used for a variety of building types. From highly loaded structures with assembly or storage loads to lightly loaded roofs with over 100 ft spans. The prestressing steel incorporated during manufacturing of the double tee results in increased durability and longevity over the lifetime of the structure.
Double tee options for your structural needs.
Double tee flanges can be designed as the structure's primary diaphragm with varying thicknesses to transfer loads to the lateral system of the structure. In most cases, double tees can accommodate heavier loads on the double tee deck like CMU. For flexibility of framing, the widths of double-tees are variable: from a 12-ft-wide module to 6-ft-wide. Even narrower sections can be achieved with additional engineering support. Depending on the structure demands, double tees can have depths ranging from 10” for building types requiring shallower floor systems to 42” to accommodate higher loads or longer spans, eliminating the need for additional structural elements.
Double tees can have a variety of finishes depending on the detailing and final state of the project. From a raked finish to allow for composite action to be achieved with field topping to a broom for a finished driving surface.
For preliminary double tee section selection, reference PCI load tables.
Ideal Project Types for Double Tees
Parking Structures
Natatoriums
Gymnasium Roofs
Bridges
Industrial
Manufacturing Facilities
Structural benefits of precast double tees.
- Less material usage
- Great for achieving long spans
- Ability to achieve varying cross-sections
Double tees are inherently durable and fire-resistant.
Double tee decks are fire resistant, reaching multi-hour fire ratings as needed with the ability for plant or field-topped finishing. Openings can be added to the double tee stems to account for MEP components. In addition, the design of the precast flanges offers enough redundancy to allow for flexibility when it comes to openings for MEP that need to run vertically through the structure.
Double Tee Resources
Design Guide Series Video: Design & Engineering with Double Tees
In this video, Phil Thomas, Wells Corporate Engineering Trainer, covers information on designing with precast double tees.
The Possibilities in Podium Design
Explore the benefits of precast podiums in construction projects, and how double tee components can create clear-span podium designs.
Double Tee Roofs and Floors
Learn how double tees can go beyond parking structures with various uses in floors, roofs, pools and more and the benefits of long spans in construction.