Study of the performance of a 3D modular geosynthetic reinforced soil bridge abutment under overloading

Abstract

The objective of this study was to investigate the response characteristics of three-dimensional geosynthetic reinforced soil (GRS) bridge abutments subjected to overload conditions in terms of deformation, soil stresses, and reinforcement strains. To this end, a 1:2 scale model of a GRS bridge abutment was constructed and subjected to a detailed analysis when the vertical load was increased in incremental steps. The results showed that the GRS abutment performed well and did not reach the plastic state at six times the service limit state (SLS) load. The settlement at the top of the abutment increases with increasing load, and the settlement results in the central bulging of both the front and wing walls, which is inconsistent with the assumption of plane strain. Therefore, a novel three-dimensional facing displacement model that outperforms traditional calculation methods is presented. The incremental vertical soil stresses in the center of the abutment increased significantly, and the U.S. Federal Highway Administration (FHWA) method better predicted the vertical soil stresses on the GRS bridge abutments under SLS loads; however, this method underestimates the incremental vertical soil stresses under overloads. The maximum reinforcement strain occurred in the middle of the abutment, and the deformation of the reinforcement was not uniform under overload, indicating that an overload may lead to the destruction of the reinforcement under the beam seat. The results of this study can serve as a reference for the design and application of GRS bridge abutments.