Equation 5.39

{[\frac{M_{Ed, z}}{M_{Rd, z}}]}^{a} {[\frac{M_{Ed, y}}{M_{Rd, y}}]}^{a} \leq 1

M_Ed,z/y	Design moment around the corresponding axis, including nominal second-order moments
M_Rd,z/y	Bending resistance around the corresponding axis
a	= 2 for circular and elliptical cross-sections, according to Image 02 for rectangular cross-sections

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