should be used to calculate the contribution of the shear area to the resistance moment of the section. For an I section, the shear resistance is mainly provided by the web. In cl. 6.2.8(5) the alternative approach calculates the bending resistance by deducting ρ times the plastic modulus of the web from the full plastic modulus of the section, equivalent to using a reduced web thickness.
Similarly, a reduced yield strength (1-ρ)fy applied to the shear area should be used when considering combined bending, shear and axial force, when the design shear exceeds half the plastic shear resistance of the section. A reduced plate thickness for the relevant part of the cross section may be used as an alternative. Clause 6.2.10(3) of BS EN 1993-1-1 refers.
Contact: Richard Henderson
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