Numerical study on the flexural behaviour of normal- and high-strength concrete beams reinforced with GFRP bar, using different amounts of transverse reinforcement

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This study was numerically focused on the non-linear behaviour of glass fibre reinforced polymer (GFRP) reinforced concrete beams with different amounts of transverse reinforcement. The mid-span deflection of concrete beam cannot effectively be restricted using higher amount of flexural GFRP bars, owing to their low deformability factor. So, the use of high transverse reinforcement ratio is proposed to decrease the mid-span deflection and crack widths. Following this, the effect of reinforcement is required to carefully assess to better understand the flexural behaviour of concrete beams. The main goal of this study was to numerically evaluate the mid-span deflection, stress distribution and failure mechanism of normal- and high-strength concrete beams with low and high flexural reinforcement ratios (GFRP bar) and different amounts of transverse reinforcement using finite element (FE) analysis. The results revealed a fair agreement between the developed FE models and experimental beams. Besides, the mean value of experimental-to-predicted load ratio was 0.96, with average coefficient of variation of 2.69 %. Moreover, the truss action mechanism generated the diagonal compression in the cracked concrete and tension in the transverse reinforcement, resulted in decreasing the mid-span deflection. In addition, for all specimens with and without transverse reinforcement, the highest stress intensities were observed in the bottom of concrete component at service load. However, by increasing the load from service to ultimate, the use of transverse reinforcement caused to propagate some parts of high stress intensities near to the sides of concrete component. Furthermore, the presence of the transverse reinforcement resulted in distributing the stress intensity in the normal-strength concrete beams more than that in the high-strength concrete beams either at service load or at ultimate load.