Similar example calculation.
Design load (P) = Safe Working Load (SWL) x Dynamic coefficient (Dynamic coefficient is taken as 1.3.)
Tensile stress, σa = Yield limit / (1.5 k) = 235 ƒ1 / (1.5 k)
Shear stress, τa = σa / √3 = 235 ƒ1 / (1.5 k x √3 )
where k = 0.85 (mild steel) and 1.0 for high tensile steel, and ƒ1 = 1.0 (mild steel), 1.08 (AH27), 1.28 (AH32), 1.35 (AH34), 1.39 (AH36), 1.43 (AH40)
Required section area for shear stress, Ars
For shear stress the area shown by the hatch on the righ section is applicable.
Ars = P / τa = 1.3 x SWL / (235 ƒ1 / (1.5 k x √3 )) = (3.38 x k x SWL) / 235 ƒ1
Actual section area for shear stress, Aas
Aas = b x t (as shown in the shaded area on the right section)
Required section for tensile stress, Art
For tensile stress, the area is shown by two shaded hatch on the lower part is applicable.
Art = P / σa = 1.3 x SWL / ( 235 ƒ1 / (1.5 k)) = (1.95 x k x SWL) / 235 ƒ1
Actual section area for tensile stress, Aat
Aat = 2 x b x t (as shown by two shaded hatch on the lower drawing)
Aas ≥ Ars (satisfies shear stress requirement )and
Aat ≥ Art (satisfies tensile stress requirement)