Explanation: The shear strain induced influences bending stresses in flanges and causes sections to warp. This consequently modifies the bending stresses determined by simple bending theory and results in higher stresses near junction of web to flange elements with stress dropping as distance from beam web increases. The resultant stress distribution across flange is therefore non uniform and this phenomenon is known as shear lag.

Explanation: As per IS 800:2007, shear lag effects in flanges may be disregarded for outstand elements if bo ≤ L0 / 20, where bo = width of flange outstand, L0 = length between points of zero moment in the span.

Explanation: As per IS 800:2007, shear lag effects in flanges may be disregarded for internal elements if bi ≤ L0 / 10, where bi = width of internal element, L0 = length between points of zero moment in the span.

Explanation: Shear lag effect depends upon width-to-span ratio, beam end restraints, and type of load.

Explanation: The resultant stress distribution across flanges is non-uniform and is called shear lag. Point load causes more shear lag than uniform load.

Explanation: The moment capacity of plastic or compact section for V > 0.6Vd is given by Mdv = Md – β(Md – Mfd), where Md = plastic design moment of whole section disregarding high shear force effect but considering web buckling effect, Mfd = plastic design strength of area of cross section excluding shear area, considering partial safety factor γm0, β is constant.

Explanation: The value of β in equation of moment capacity of plastic section for V > 0.6Vd is given by β = (2[Vd/V] -1)2, where Vd = design shear strength as governed by web yielding or web buckling, V = factored applied shear force.

Explanation: The check for moment capacity of plastic section for V > 0.6Vd is given by Mdv ≤ 1.2Zefy/γm0, where Ze = elastic section modulus of whole section, fy = yield stress of material, γm0 = partial safety factor.