Acceleration Response of a Geosynthetic Reinforced Soil Bridge Abutment under Dynamic Loading

This paper presents results from dynamic testing of a half-scale geosynthetic reinforced soil (GRS) bridge abutment using a shaking table, with the goal of understanding the acceleration response of the backfill soil, bridge seat, and bridge beam under dynamic loading. The GRS bridge abutment model was constructed using modular facing blocks, well-graded angular sand backfill, and uniaxial geogrid reinforcement in both the longitudinal and transverse directions. A series of input motions was applied to the GRS bridge abutment system in the direction longitudinal to the bridge beam. The horizontal accelerations increase with elevation in the reinforced soil zone and retained soil zone. The average peak acceleration of the reinforced soil zone is slightly greater than the calculated value from the current design guidelines, indicating that the guidelines may not be sufficiently conservative. The acceleration response spectrum for the bridge beam indicates a slight attenuation compared with that of the bridge seat, likely due to the isolation effect of an elastomeric bearing pad between the bridge beam and bridge seat.