Shear Force
Internal force acting transverse to the member axis; governs stirrup design
Shear force is the internal force acting perpendicular to the longitudinal axis of a member, equal to the algebraic sum of all transverse forces on one side of a section, in kN. The shear force diagram (SFD) plots it along the span; shear is maximum near supports where the SFD peaks.
In RCC design (IS 456 Cl. 40) the nominal shear stress τv = Vu / (b·d) is compared with the design shear strength of concrete τc (Table 19, a function of grade and tension-steel percentage). If τv ≤ τc, only minimum shear reinforcement is needed; if τc < τv ≤ τc,max, shear stirrups are designed for the excess Vus = Vu − τc·b·d using Asv = Vus·sv / (0.87 fy d). If τv exceeds τc,max the section must be enlarged. The critical section for shear is taken at distance d from the support face for members with compressive support reaction.
- Stirrup / shear-link design in beams (IS 456 Cl. 40)
- Punching-shear check of flat slabs + footings (IS 456 Cl. 31.6)
- Steel section shear capacity (IS 800 Cl. 8.4)
- Shear-wall + deep-beam design
- Locating bent-up bars + stirrup spacing zones