Performance of concrete beams reinforced with GFRP bars under monotonic loading

The use of GFRP bars in concrete structures has emerged as an alternative to conventional RC due to the corrosion of steel in aggressive environments. Although many studies were reported on concrete beams reinforced with GFRP bars, still the full potentiality of GFRP reinforced concrete is yet to be known. This study reports experimental, analytical and numerical investigations carried out on concrete beams reinforced with TMT and GFRP bars under monotonic loading. Experimental studies were carried out on concrete beams of size 100 x 200 x 1500 mm reinforced with TMT (10 mm and 12 mm dia.) and GFRP bars (10 mm and 13 mm dia.). The deflection of GFRP reinforced concrete beams corresponding to service load is found to be 2.75 times the deflection of TMT reinforced concrete beams. Widely used analytical/empirical models were compiled to predict the load deflection behaviour of beams. The analytical models were primarily based on effective moment of inertia to account for beams stiffness after cracking. Nonlinear finite element (FE) analysis has been carried out on concrete beams reinforced with TMT and GFRP bars. FE models were developed by employing the appropriate constitutive relationship of concrete, TMT and GFRP bars. The integrity of all the elements has been ensured by applying the appropriate constraint conditions. Average load-deflection plots obtained from experiments were compared with computed load-deflection of analytical and numerical studies. From the load-deflection behaviour, it is observed that (i) numerical prediction is stiffer and (ii) the analytical models incorporated with tension stiffening aspects predicted the deflections close to experimental observations.