P-M interaction curve for reinforced concrete columns exposed to elevated temperature

The strength and deformational capacity of slender reinforced concrete (RC) columns greatly rely on their slenderness ratios, while an additional secondary moment (i.e., the P-δ effect) can be induced especially when the RC column members are exposed to fire. To evaluate the fire-resisting performances of RC columns, this study proposed an axial force-flexural moment (i.e., P-M) interaction curve model, which can reflect the fire-induced slenderness effects and the nonlinearity of building materials considering the level of stress and the magnitude of temperature. The P-M interaction model proposed in this study was verified in detail by comparing with the fire test results of RC column specimens reported in literature. The verification results showed that the proposed model can properly evaluate the fire-resisting performances of RC column members.