Responses of geosynthetic-reinforced soil (GRS) abutments under bridge slab loading: Numerical investigation

This study evaluated the responses of geosynthetic-reinforced soil (GRS) abutments subjected to bridge slab loading under working stress conditions using two-dimensional finite difference numerical software. A parametric study was conducted to investigate the effects of different combinations of reinforcement spacing Sv and reinforcement stiffness J, beam seat width b, and setback distance ab on the responses of the GRS abutments in terms of additional vertical stresses under the beam seat centerline Δσv induced by the bridge slab load, additional lateral earth pressures behind the abutment facing Δσh-facing and under the beam seat centerline Δσh-cetner induced by the bridge slab load, and maximum tension in the reinforcement Tmax. Numerical analyses evaluated trapezoidal and uniform reinforcement layouts and showed that both reinforcement layouts generated similar responses of the GRS abutments. Under the same ratio of J/Sv, different combinations of Sv and J generated similar distributions of Δσv, Δσh-facing and Δσh-center. The maximum of Tmax with depth decreased almost proportionally with the decrease of Sv. Larger b and ab caused lower Δσv, Δσh-facing, Δσh-center, and smaller Tmax in the upper reinforcement layers. The truncated 2 to 1 distribution method, which considers the effects of abutment facing on the Δσv distribution, could reasonably predict the Tmax in the reinforcement.