Tsections

Tsections, or T-shaped cross-sections, are structural shapes formed by a horizontal flange attached to a vertical stem (web). When viewed in cross-section, the shape resembles the letter T. T-sections are common in structural and mechanical design where a balance of bending strength, bending stiffness, and weight is desired.

Geometry and properties

A typical T-section is defined by a flange of width bf and thickness tf, and a stem (web) of width bw and height hw. The overall height is H = tf + hw. The cross-sectional area is A = bf tf + bw hw. The centroid location from the top can be found by a composite-area calculation: ȳ = [bf tf (tf/2) + bw hw (tf + hw/2)] / A. The second moments of area about the centroid are obtained by summing the contributions of the flange and stem and applying the parallel-axis theorem: Ix = Ifx + Af df^2 + Iwx + Awx^2, and Iy = I_yf + I_yw (with appropriate distance terms df and dw). In practice, standard dimensions have tables of Ix, Iy, and section moduli (Sx = Ix/ȳ, Sy = Iy/x̄) for quick reference, or they are computed with design software.

Manufacturing and materials

T-sections are produced by hot rolling, cold forming, or welding, and are commonly made from steel or aluminum, though other metals and composites are also used. They exist in various variants, including top-flange T-sections (flange on top) and inverted or asymmetrical forms.

Applications and considerations

T-sections are favored when a strong flange is required for bending about the major axis and a narrow stem fits the design constraints of a frame or connection. They provide good bending resistance with relatively low weight but may exhibit inferior stiffness about the minor axis and can be susceptible to lateral-torsional buckling if not properly braced. Selection depends on load paths, manufacturing availability, and cost.