Modeling reinforced-concrete beam-column joints subjected to cyclic loading

A model is developed to represent the response of reinforced-concrete beam-column joints under reversed-cyclic loading. The proposed model provides a simple representation of the primary inelastic mechanisms that determine joint behavior: Failure of the joint core under shear loading and anchorage failure of beam and column longitudinal reinforcement embedded in the joint. The model is implemented as a four-node 12-degree-of-freedom element that is appropriate for use with typical hysteretic beam-column line elements in two-dimensional nonlinear analysis of reinforced concrete structures. Constitutive relationships are developed to define the load-deformation response of the joint model on the basis of material, geometric, and design parameters. Comparison of simulated and observed response for a series of joint subassemblages with different design details indicates that the proposed model is appropriate for use in simulating response under earthquake loading.