Cyclic shear displacement model for reinforced concrete columns

Lateral response of reinforced concrete (RC) columns can be modeled and simulated considering three displacement components: flexural displacement, displacement due to slippage of longitudinal bars at column ends, and shear displacement. The incorporation of shear displacement in a computational model is essential for accurate calculation of lateral load–displacement relationship. The contribution of shear displacement can be significant for RC columns with low displacement capacity or ductility. An easy-to-apply shear displacement model is proposed in this study, and implemented in the open source software, OpenSees. The proposed model is based on a pre-defined envelope or monotonic model and does not require updating of modeling parameters during each cycle. The model is validated using experimental data. New rules are developed for the cyclic model to capture the effects of cracking and change in stiffness and strength during the loading and unloading cycles. Comparison of the calculated and measured shear displacements indicates that the cyclic shear response can be captured by the proposed model.