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Global sway imperfection of a frame

Initial sway imperfection and the equivalent horizontal forces for a multi-column frame. Reference: EN 1993-1-1 5.3.2.

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Global sway imperfection of a frame: worked example sheet in Equation Pad with typeset equations and results.

Example only. This sheet shows one way to set out the check. It is not endorsed by the bodies that publish the design codes and does not reproduce them. Check every clause, value and assumption against your own copy of the current edition of Eurocode 3 and its national annex before you use it, and have the result checked by a competent person. See the disclaimer.

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# Frame
h_f := 6.0 m
m_c := 4
N_Ed := 2000 kN
phi_0 := 1/200

# Imperfection
alpha_h := min(max(2/sqrt(h_f/(1 m)), 2/3), 1) =
alpha_m := sqrt(0.5*(1 + 1/m_c)) =
phi := phi_0*alpha_h*alpha_m =
H_eq := phi*N_Ed = kN
# H_eq is applied at the floor level with the total vertical load N_Ed; it may be omitted when H_Ed >= 0.15 V_Ed.

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