Nonlinear Analysis of Solid and Box-section RC Beams Strengthened in Torsion with CFRP Reinforcement

This study is devoted to investigate the behavior and performance of solid and box-section R.C. beams strengthened with (CFRP-reinforcement) and subjected to pure torsion. Also, compares the effectiveness and efficiency of two strengthening techniques viz. FRP bars as NSM reinforcement and CFRP strips as external reinforcement. For this analysis, a system of computer program (ANSYS V.۹.۰) is used for this study. The ordinary reinforced concrete was modeled by ۸-noded isoparametric brick elements, while the steel reinforcing bars and NSM reinforcement were modeled as axial members (bar elements) connecting opposite nodes in the brick elements with full interaction assumption. The CFRP strips were modeled by shell elements. The interface elements were modeled by contact element to represent slip and uplift separation between the ordinary concrete beams and CFRP-reinforcement. The results showed that the torsional capacity of the strengthened beams can be increased by either decreasing the spacing of the CFRP, or increase compressive strength of concrete, or replacing of CFRP strips by NSM FRP.

کلیدواژه ها:

reinforced concrete beam ، torsional strengthening ، near surface mounted ، CFRP strips.