Discussion of 'Modeling Reinforced-Concrete Beam-Column Joints Subjected to Cyclic Loading' by Laura N. Lowes and Arash Altoontash

摘要

An innovative reinforced concrete (R/C) beam-column joint model is presented in this paper. The model is capable of simulating inelastic connection behavior resulting from reinforcement bond slip (anchorage failure of beam and column longitudinal reinforcement) and joint shear deformation (failure of the joint core), which is demonstrated in the paper by comparing simulated (model) versus observed (laboratory test) responses of four R/C beam-column connection subassemblies. Based on this, the concluding remarks in the paper indicate that the connection model can well represent the fundamental response characteristics for R/C beam-column joints subjected to "moderate" shear demands. However, given some of the paper's introductory comments regarding poor performance of joints with little transverse reinforcement (or with only moderate amounts of transverse reinforcement), one may be tempted to employ the model in a variety of situations (ranging from low to high joint shear demands and from very little to considerable joint transverse reinforcement). For this wide range of practical cases, then, it is interesting to note how applicable is the proposed constitutive model for the joint shear panel component of the beam-column connection element. In particular, the authors used the modified compression field theory (MCFT) of Vecchio and Collins (1986) to define the envelope of the joint shear stress versus joint shear strain history (as a function of material properties, joint geometry, and joint reinforcement layout), with some experimental data to guide the treatment of response under cyclic loading.