For two way action, i.e. punching shear, the calculated shear stress, τv should satisfy the following relation \({\tau _v} \le {k_s}{\tau _c}\), where τc according to working stress method is expressed as:
1
\(0.1\sqrt {{f_{ck}}}\)
2
\(0.16\sqrt {{f_{ck}}}\)
3
\(0.25\sqrt {{f_{ck}}}\)
4
\(0.4\sqrt {{f_{ck}}} \)