A nonlinear finite element (NLFE) simulation using DIANA software  was performed in order to estimate the temperature which produced the first transverse crack at the bar surface and the corresponding tensile stress. It was also used to predict the extent and direction of the thermally induced cracking due to thermal incompatibility between the concrete and GFRP bars when the temperature increases. The NLFE results were verified by comparing the output of the proposed 2D NLFE model with experimental results. The results confirmed the influence of temperature variations on the state of stress within the GFRP reinforced concrete slabs, and the necessity for a recommended minimum concrete cover to avoid the formation of through cracks. The NLFE model generally shows good agreement with the experimental results for a concrete cover of 1.5 x bar diameter db.