STRESS ANALYSIS FOR EXTERNALLY CONFINED CONCRETE COLUMNS WITH FRP

External confinement of concrete short columns has proved to be an effective means in enhancing both strength and ductility. Stress-strain models for confined columns found in the literature are developed bised on a limited number of experimental data and hence lack a generality to practical applications.- Over 100 test results are used to examine the credibility of various models developed by other researchers. It is found that only the axial. strength of confined columns can be reasonably predicted using the ACI 440. A finite element model using ABAQUS for both circular and non-circular confined columns is developed ln order to give better understanding of the structural mechanics of confined short columns. Accordingly, simple but efficient bilinear closed form stress-strain model for confined columns is developed. The model is checked against experimental results and ABAQUS outputs and it is found to reasonably predict both strength and strain capacities. The stressstrain curve predicted from ABAQUS at column centerline is the closest curve to that obtained from experiments. The peak stress and strain at column comer from ABAQUS are greater than those at both centerline and mid-side. Comparatively, stresses and strains obtained from ABAQUS at mid-side of the column are lesser than those achieved at column centerline.