Finite element-based design simplification for geosynthetic reinforced soil integrated bridge abutments

This study presents an interface-sensitive finite element framework for the design and stability assessment of Geosynthetic Reinforced Soil (GRS) bridge abutments under serviceable conditions. The approach incorporates a stress-dependent constitutive model to realistically capture the behaviour of reinforced soil composites and their interaction with reinforcement interfaces. A field validated numerical model was formulated simulating the instrumented results of Virginia GRS IBS, to further evaluate a range of design scenarios in accordance with Federal Highway Administration (FHWA) and Indian Standard (IS) guidelines. Critical geometric and reinforcement parameters – including bearing width, setback distance, foundation width, and reinforcement length – are optimised for varying abutment heights, soil friction angles, and allowable bearing pressures. Empirical correlations are proposed for estimating reinforcement tensile strength as a function of vertical spacing across different reinforcement configurations. Additionally, secondary design elements such as clear space distance, toe-side width, and foundation thickness are rationally derived to ensure long-term performance. The stability of proposed configurations is confirmed through numerical analyses using FEM. The developed design charts offer a reliable and efficient means to design GRS abutments across varied geotechnical conditions while minimising the need for detailed iterative analyses.