Research On Cyclic Behaviors Of Circular R.C. Columns Confined With FRP Jackets

In this paper, cyclic behaviors of circular reinforced concrete (R.C.) columnsconfined with FRP jackets are researched. The main work is as follows: 1. Eight circular R.C. columns confined with fiber-reinforced polymer (FRP) jackets and six circular R.C. columns were tested under constant axial load and cyclically increasing flexural loading. The main parameters in the experiment are axial compressive ratio and FRP ratio, and the influence of those parameters on the strength, ductility, stiffness, and energy dissipation is investigated through analysis of hysteretic skeleton curves. 2. Based on the stress-strain models of FRP, steel bar and the confined concrete under monotonic and cyclic conditions, theoretical model for the analysis of moment-curvature and load-deflection relationship was put forward. The calculating results of the theoretical model are in good agreement with the test results. 3. Based on the theoretical model, parametric analysis was performed on the behaviors of moment (M) versus curvature (φ) response. The parameters include: FRP ratio, steel strength, steel ratio, compressive strengthof concrete and axial compression ratio. 4. Based on the theoretical model, parametric analysis was performed on the behaviors of lateral load (P) versus lateral deflection (?) response. The parameters include: FRP ratio, steel strength, steel ratio, compressive strength of concrete, axial compression ratio and slenderness ratio. 5. Simplified models for the moment (M) versus curvature (φ) response, and the lateral load (P) versus lateral displacement (?) relationship were suggested. In general, the calculating results of the simplified model agree well with those of numerical results and the test ones.