Displacement-Based Compatibility Strut-and-Tie Method and Application to Monotonic and Cyclic Loading

The compatibility strut-and-tie method (C-STM) is an efficient minimalist nonlinear modeling approach for shear-critical reinforced concrete members. This paper presents two key improvements to the C-STM to better model overall behavior through failure. First, modified softened diagonal concrete struts are incorporated directly into the analysis, thereby eliminating any need for post-processing analysis, to enable accurate modeling of the failure load. Second, modeling modifications are made so that the analysis may be conducted in displacement control, thereby permitting cyclic loading and post-peak (failure) load-displacement behavior to be predicted. The modifications are implemented in SAP2000 and verified with experimental results for both monotonic and cyclic loading cases. It is observed that the C-STM predicts the overall force-deformation behavior of the structure quite well. Additionally, the C-STM also predicts the internal strain-dependent behavior of the structure and gives insights into the cause of failure of the structure. (C) 2016 American Society of Civil Engineers.