Abstract
This paper presents a series of uniaxial compressive loading tests on concrete cylinders confined by tie reinforcements in order to develop an unloading and reloading stress-strain model of confined concrete. Variables considered as parameters were the volumetric ratio of tie reinforcement ρs, the cylinder strength of concrete σc0 and the number of unloading and reloading cycles at the same strain. To predict an unloading and reloading path, the plastic strain εpl·n and the stress at the unloading strain σul·n are controlling parameters. These controlling parameters were analyzed based on the test data to propose an empirical relation. The predicted relation provides good agreement with the test data.
