Numerical and theoretical analysis of FRP reinforced geopolymer concrete beams

The current paper aimed to numerically and theatrically evaluate the flexural performance of polymer bars reinforced geopolymer concrete (FRP-GPC) beams based on applying numerical and theoretical investigations. The numerical study incorporates developing nonlinear finite element models, using ABAQUS software, validated with the data available in the literature. The developed model was then utilised to implement parametric studies for the parameters governing the structural behaviour of FRP-GPC beams, including compressive strength, FRP reinforcement type, shear reinforcement ratio, and shear span-to-depth (a/h) ratio. The results indicated to a reasonable agreement between the FE results and experiments collected from the literature concerning failure mode, failure load, and the load-deflection response. The statistical calculations showed that the mean, standard deviation, and the coefficient of variation between the measured and the FE failure loads are 1.03, 5.4%, and 5.3%, respectively. The FE results indicated that the compressive strength plays a considerable role in the load capacity for the specimens made without any web reinforcement, unlike those supported with web reinforcements. Moreover, the absence of web reinforcement and low a/h ratios resulted in a shear behaviour, which is more likely to be controlled by compressive strength rather than other parameters. The FE results also indicated that the web reinforcement ratio of 0.7% was sufficient to avoid the occurrence of shear failure, and therefore, the increase of the shear reinforcement beyond this level seems to have no considerable impact on the load capacity. Besides, the theoretical study included assessing the Canadian (CSA S806–12) and American (ACI-440–1R-15) codes to evaluate their performance in predicting the loading capacity of FRP-GPC beams investigated in the current study. The findings indicated that both codes provided conservative predictions when they are applied on FRP GPC beams, giving a mean value of 0.66 for the calculated-to-the FE results. Therefore, developing the existing design standards of ACI-440–1R-15 and Canadian CSA S806–12 is strongly recommended to improve the accuracy of applying these codes on FRP GPC beams.