Shear strength model for RC beam–column joints under seismic loading

This paper presents a new shear strength model for reinforced concrete (RC) beam–column joints subjected to cyclic lateral loading. In the proposed model, the reinforced concrete in the joint panel is idealized as a homogenous material in a plane stress state. The contribution of the joint shear reinforcement (including both the transverse steel reinforcement and the intermediate longitudinal steel reinforcement of the column) is taken into account through the nominal tensile strength of the idealized material. The effect of tensile straining in the transverse direction on the compressive strength of the idealized material is accounted for using the Kupfer–Gerstle biaxial tension–compression failure envelope. Comparisons with the results of 106 existing tests of both exterior and interior beam–column joints, with and without transverse steel reinforcement, demonstrate the accuracy of the proposed model. These comparisons also illustrate the superior accuracy of the proposed model over existing models. A subsequent trend analysis using the test database confirms that all key parameters influencing the shear strength of beam–column joints have been appropriately considered in the proposed model. The proposed model is believed to be suitable for design use due to its simple form, wide applicability and accuracy.