Fiber reinforced polymer jacketing of reinforced concrete columns is a rapidly growing strengthening technique. Experiment-based models and data are available and have proved beneficial in the design of concrete structures; however they are expensive for two reasons: firstly, specialized equipment is needed to execute the experiment, and secondly, there are a vast number of variables that cannot always be investigated to the fullest. With the advent of high speed, sophisticated and affordable computers, numerical analysis has become increasingly important. Extensive research has been conducted on FRP-confined concrete in circular sections. By contrast, the behavior of FRP confined concrete in rectangular sections, in which the concrete is non-uniformly confined and the effectiveness of confinement is much reduced, is not yet well understood. In this study the performance of axially-loaded, small scale, circular and rectangular and FRP confined concrete columns was investigated through finite element analysis. Results achieved from finite element analysis were compared with the results of two papers existing in the literature. Also a concrete column confined with CFRP sheets and lateral steel was modeled. In general good agreement with experimental results was found. Some studies suggest that rectangular sections with sharp corners offer no confinement. To closely study the effect of corner radius on the performance of these sections, a number of rectangular sections were modeled, the results were carefully investigated and finally an equation was proposed to predict the strength of rectangular sections considering the effect of corner radius.  

Keywords: confinement, FRP composites, concrete column, rectangular section, corner radius, Drucker-Prager, modeling, finite element.