Finite Element Modeling Of Reinforced Concrete Columns Strengthened Externally With CFRP Sheets

Abstract

Rehabilitation of old buildings is more economical than rebuilding them. That`s why the behavior of strengthening techniques should be understood to make the best decision for rehabilitation in order to save time and cost. The behavior of reinforced concrete column strengthened externally with carbon fiber reinforced Polymers (CFRP) is highly affected by the way in which these composites are applied to the column. This study presents a simple finite element model (FE) able to estimate the load-carrying capacity and ductility of reinforced concrete (RC) square columns strengthened with externally bonded fiber reinforced polymer (FRP) plates / sheets. The finite element model of reinforced concrete columns was developed for columns externally strengthened with carbon fiber reinforced polymers (CFRP) using the commercial Finite Element Modeling software ANSYS, in order to investigate the behavior of these columns. The column which size was 250×250×500 mm is modeled and analyzed using a non-linear finite element method. Two parameters of wrap thickness and fiber orientation were considered. The finite element analysis results were in good agreement with experimental data presented by other researchers. The analysis results demonstrated significant enhancement in the compressive strength and ductility of the FRP-wrapped rectangular RC columns compared to unstrengthened RC columns. It was observed that the behavior of the columns was greatly affected by the analysis parameters. The gain in axial compressive strength was observed to be the highest in the columns wrapped with the hoop orientation; but the highest axial strain and ductility were observed in the columns wrapped with the fiber orientation of ±45° with respect to the horizontal.