NONLINEAR ANALYSIS OF R.C. BEAMS STRENGTHENED USING PRE-STRESSED NSM CFRP RODS

Abstract

A nonlinear finite element study has been conducted to investigate the effectiveness of strengthening RC beams with pre-stressed NSM CFRP rods in enhancing the flexural strength of the beams. Four beams have been considered. One acted as control to simulate an existing structural member. The other beams were strengthened with non-pre-stressed CFRP rod (0% pre-stressed), and pre-stressed CFRP rod (40%, or 60% pre-stressed of the CFRP rod tensile strength). The results of analysis showed that strengthening of the RC beams with non pre-stressed NSM CFRP rods improved both of the flexural capacity and deflection response. Increases in the cracking, yield and ultimate load of 17%, 20% and 48% were achieved. With a pre-stress level of 40%, an enhancement of 117%, 53% and 80% respectively over that of the control beam. For the beam strengthened with pre-stress level of 60%, more enhancements in response were achieved in term of the cracking and yield loads, but a slight reduction in ultimate loads (compared with lower level of pre-stress). Increments up to 160% and 67% in the cracking and yield load respectively. While 77% in ultimate load over that of the control beam were obtained.