Tension Member

A tension member is a structural steel element that carries axial tensile force — truss bottom chords and ties, bracing, sag rods, hangers and tie rods. Tension members are efficient because the whole cross-section can reach the material strength without buckling, but the connection regions govern: bolt holes remove area, and the load does not enter all parts of the section evenly (shear lag).

Per IS 800 Cl. 6, the design tensile strength is the least of three modes: gross-section yielding (Tdg = Ag·fy/γm0, a ductile limit on the full section), net-section rupture (Tdn, on the reduced area at bolt holes, with a shear-lag factor for sections connected through only some elements, e.g. an angle by one leg), and block shear (Tdb, a block of material tearing out at the connection along combined shear and tension planes). The smallest of these controls — net-section and block-shear checks at connections, not the gross member, are the usual governing and most-missed cases.