T-beam

A T-beam (or tee beam), used in construction, is a load-bearing structure of reinforced concrete, wood or metal, with a capital 'T'-shaped cross section. The top of the T-shaped cross section serves as a flange or compression member in resisting compressive stresses. The web (vertical section) of the beam below the compression flange serves to resist shear stress. When used for highway bridges^[1] the beam incorporates reinforcing bars in the bottom of the beam to resist the tensile stresses which occur during bending.^[2]

The T-beam has a big disadvantage compared to an I-beam (with 'Ɪ' shape) because it has no bottom flange with which to deal with tensile forces, applicable for steel section. One way to make a T-beam more efficient structurally is to use an inverted T-beam with a floor slab or bridge deck joining the tops of the beams. Done properly, the slab acts as the compression flange.