Behavior of Axially Loaded CFRP Confined Large-Scale Capsule-Shaped RC Short Columns with Higher Cross-Sectional Aspect Ratio

Abstract

This paper aimed to experimentally and analytically investigate the behavior of reinforced concrete (RC) short capsule-shaped columns confined with carbon fiber-reinforced polymer (CFRP) sheets. The efficiency of FRP-confined strengthening system depends mainly on different encountered parameters such as the FRP confinement ratio, shape and size of cross-section, and cross sectional aspect ratio of non-circular columns. The effects of varying the aspect ratio (h/b=2, 2.5, 3 and 4), FRP confinement ratio (number of FRP layers), and FRP-wrapping configuration (full and partial system) are examined in this study. The experiment results showed that the efficiency of FRP confined system was proven to be lower with higher aspect ratio than that with the lower aspect ratio. Confinement by CFRP sheets enhances the performance of capsule-shaped RC columns subjected to axial compressive loads, and it is an efficient technique to improve the strength and ductility of capsule shaped RC columns regardless the cross sectional aspect ratio and the type of confinement. Analytical model was proposed by the authors to predict the axial load carrying capacity of short capsule-shaped reinforced concrete columns. The proposed model is compared with the existing model, showing good agreement with the experimental results and it is improved performance and gives reasonable predictions of load carrying capacity of FRP-confined columns.