Experimental Parametric Study and Phenomenological Modeling of a Deformable Rolling Seismic Isolator

This paper presents an extensive experimental study of a low-cost, high-performance seismic isolator comprising a deformable sphere rolling on concrete surfaces. Polyurethane spheres, with and without steel core, rolling on flat or spherical concrete plates, are investigated. Lateral cyclic tests under large displacements demonstrated a rolling friction coefficient between 3.7% and 7.1%. When tested in a shake table under 1170 ground motions, the isolators substantially reduced the acceleration transmitted to the superstructure (to less than 0.15 g) while maintaining reasonable peak and negligible residual displacements. A phenomenological model was calibrated on the lateral cyclic tests and predicted the shake table tests with reasonable accuracy.

Automated summary

This paper presents a study on a low-cost, high-performance seismic isolator which consists of a deformable sphere rolling on concrete surfaces. The study investigates polyurethane spheres with and without a steel core, rolling on flat or spherical concrete plates. The lateral cyclic tests showed a rolling friction coefficient between 3.7% and 7.1%. When tested in a shake table under 1170 ground motions, the isolators effectively reduced the transmitted acceleration to the superstructure to less than 0.15 g while maintaining reasonable peak and negligible residual displacements. A phenomenological model calibrated on the lateral cyclic tests accurately predicted the shake table tests.