IS 800Cl. 9.3

Combined axial + bending (beam-column)

Member subject to combined axial force and bending must satisfy the interaction equation including second-order effects (P-δ amplifier on the bending term).

Formulas

Interaction (combined)

P/P_d + (C_my × M_y)/(M_dy × (1 - P/P_dy)) + (C_mz × M_z)/(M_dz × (1 - P/P_dz)) ≤ 1.0

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Editorial paraphrase for fast lookup — the official IS 800 text is authoritative. For exact wording, refer to the published code.