This paper presents a numerical investigation of the performance of geosynthetic reinforced soil integrated bridge system (GRS-IBS). The numerical simulations were conducted using two-dimensional (2D) PLAXIS 2016 FE program. The hardening soil model proposed by Schanz et al. (1999) was used to simulate the behavior of the backfill material; the interface between the backfill materials and the reinforcement was simulated using the Mohr-Coulomb frictional model, and the reinforcement and facing block were simulated using the linear elastic model. A FE parametric study was conducted to evaluate the effect of internal friction angle, , width of reinforcement soil footing (RSF), BRSF, secondary reinforcement (bearing bed reinforcement), and setback distance, ab, on the performance of the GRS-IBS in terms of lateral facing displacement, maximum strain along the reinforcement, and maximum strain envelope. The FE results indicates that the internal friction angle and both the setback distance and width of strip footing have siginficant and medium impact, respectively, on the performance of the GRS-IBS in terms of strain distribution along the reinforcemnt. However, it was found that width of RSF and the length of reinforcement have no impact on the performance of GRS-IBS in terms of strain distribution and lateral facing deformation. Finally, based on the parametric study, the potential failure envelope of the GRS-IBS abutment was found to be a combination of punching shear failure envelope (top) and Rankine failure envelope (bottom), in which the failure envelope is developed under the inner edge of the footing and extending vertically downward to intersect with the Rankine active failure envelope.