FLEXURAL BEHAVIOUR OF RC BEAMS STRENGTHENED WITH NSM CFRP AND GFRP BARS - EXPERIMENTAL AND NUMERICAL STUDY

The paper presents the results of experimental and numerical investigations of the reinforced concrete (RC) beams strengthened with the near surface mounted (NSM) carbon and glass FRP bars. Three concrete beams were tested for bending during which the deformations of beams, pattern of cracks and the strains in steel, FRP and concrete were recorded until failure under monotonically increased loading. Additional glass (empty set10mm) and carbon (empty set8mm) FRP bars improved the bearing capacity over the control RC beams by increasing it by 73% and 89%, respectively. A nonlinear analysis model based on FEM is proposed to analyse the behaviour of the strengthened beams. The model was developed using ANSIS software package and the recommended constitutive models therein for concrete, steel and FRP reinforcement. The numerical results obtained using the developed model correlated very well with the experimental results and demonstrated not only significantly increased loading capacity and stiffness, but also considerable ductility of the strengthened beams.