Equivalent Member Length

Equivalent member length

l_{ef} = \frac{L}{a_{1} \cdot (1 - a_{2} \cdot \frac{a_{z}}{L} \cdot \sqrt{\frac{E_{0.05} \cdot I_{Z}}{G_{0.05} \cdot I_{T}}})}

l_ef	Equivalent member length
L	Beam length, spacing between lateral supports
a₁,a₂	Lateral buckling factors
a_z	Distance of load application from shear center
E_0.05	5 % quantile of modulus of elasticity
G_0.05	5 % quantile of shear modulus
I_z	Second moment of area about weak axis
I_T	Torsional constant

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