Thermomechanical behavior of geosynthetic reinforced soil integrated bridge systems: Field monitoring and numerical modeling

Abstract

Compared with traditional bridge support structures, the geosynthetic reinforced soil integrated bridge system (GRS-IBS) technology offers a more economical, environmentally friendly, and time-efficient alternative. Due to its economic efficiency and superior performance, GRS-IBS has been widely implemented worldwide. A 34.4 m-span GRS-IBS was constructed in Anhui Province, China, which represents an exceptionally rare case of such long-span applications globally. A fully automated monitoring system was installed to evaluate the abutment performance during service. Over two years of post-construction observation demonstrated satisfactory performance, with abutment deformation significantly below the thresholds specified in the current Federal Highway Administration (FHWA) GRS-IBS design guidelines. Moreover, the effective thermal insulation properties of the abutment successfully prevented soil frost heave. The abutment performance exhibited strong correlations with seasonal temperature variations, where both lateral displacement of the abutment facing and internal earth pressure displayed significant temperature responses. Based on this prototype structure, a three-dimensional numerical model was developed using the finite difference software FLAC3D to further investigate temperature effects on abutment behavior. The results indicate that the abutment facing exhibits accumulated irreversible lateral displacement due to thermal cycles, primarily in the upper-middle sections. Significant ratcheting effects were observed in the lateral earth pressure behind the backwall, and uneven vertical stress distribution beneath the beam seat was amplified by temperature changes. These findings highlight potential long-term performance risks under continuous thermal loading and provide insights for the refined design of GRS-IBS.