UC San Diego

This paper presents 3D numerical simulations of GRS bridge abutments under different conditions of bridge surcharge stress, with the goal of better understanding 3D deformation behavior and evaluating the internal stability for 3D loading conditions. Backfill soil was modeled using a nonlinear elastoplastic model with the Duncan–Chang hyperbolic stress–strain relationship and the Mohr–Coulomb failure criterion. A corresponding 2D model representative of that typically used in the routine analysis and design of GRS bridge abutments was also developed for comparison. Results show that the facing displacements, bridge seat settlements, and maximum reinforcement tensile forces obtained from the 2D simulations are close to those of the longitudinal centerline section in the 3D simulations. These findings suggest that 2D simulations can reasonably predict the deformations and reinforcement tensile forces in the abutment despite the simplified plane strain assumption. Parametric analyses further reveal that facing displacements increase with abutment width but stabilize for larger widths, while abutment width has a negligible influence on bridge seat settlements. Increasing abutment height results in greater facing displacements, bridge seat settlements, and reinforcement tensile forces due to increased stress levels within the abutment structure.