Shaking Table Test of a Half-Scale Geosynthetic-Reinforced Soil Bridge Abutment

This paper presents an experimental study on the dynamic response of a half-scale geosynthetic-reinforced soil (GRS) bridge abutment system using a shaking table. Experimental design of the model specimen followed established similitude relationships for shaking table tests on reduced-scale models in a 1-g gravitational field, including scaling of model geometry, geosynthetic-reinforcement stiffness, backfill soil modulus, bridge load, and characteristics of the earthquake motions. The 2.7-m-high GRS bridge abutment was constructed using well-graded sand backfill, modular facing blocks, and uniaxial geogrid reinforcements with a vertical spacing of 0.15 m in both the longitudinal and transverse directions. A bridge beam was placed on the GRS bridge abutment at one end and on a concrete support wall resting on a sliding platform off the shaking table at the other end. The GRS bridge abutment system was subjected to a series of input motions in the longitudinal direction. Results indicate that the testing system performed well, and that the GRS bridge abutment experienced small deformations. For two earthquake motions, the maximum incremental residual facing displacement in model scale was 1.0 mm, and the average incremental residual bridge seat settlement in model scale was 1.4 mm, which corresponds to a vertical strain of 0.7 %.