NUMERICAL AND EXPERIMENTAL ADVANCEMENTS IN ROLLING ISOLATION SYSTEMS USING ELASTOMERIC SPHERES

Rolling isolation systems utilizing elastomeric spheres have the potential to offer cost-efficiency advantages compared to traditional methods such as rubber bearings or frictional pendulum systems. This paper discusses a system that uses elastomeric spheres between the foundation and the superstructure, allowing them to roll in response to seismic activity. Energy dissipation occurs through rolling resistance as the elastomeric material continuously deforms. The paper investigates the isolator behavior, including the force-displacement relationship and sphere material deformation; this is done through finite element modeling and experimental tests. The findings reveal that the creep of the ball due to the structure weight adversely affects the system performance, resulting in oblong shape distortion. Finite element models indicate that the inner part of the ball contributes more to the oblong shape, while surface material aids in energy dissipation. To mitigate oblong shape distortion without compromising energy dissipation, an inner steel core can be introduced into the sphere, preventing deformation in the inner region.