Eddy current damping in roller seismic isolators: A non-contact energy dissipation mechanism alternative

Seismic isolation systems are widely used in structural engineering to mitigate earthquake-induced damage by decoupling structure displacement from ground motion. Building on this principle, this study investigates the effectiveness of a novel eddy current damping (ECD) mechanism integrated into a roller seismic isolation bearing (RSIB) system to enhance seismic performance. The proposed non-contact energy dissipation device contro s seismic-induced displacements while minimizing wear-related issues in traditional friction-based damping systems. A scaled RSIB model coupled with the ECD device was tested under free vibration and seismic excitation. Besides, a numerical model was developed to simulate the response to both far- and near-fault earthquakes and evaluate RSIB performance. The results indicate that increasing braking force reduces isolator displacements but leads to higher absolute accelerations. Displacement reductions of up to 72% were achieved, ensuring that movements remained within the physical limits. However, higher braking forces also increased peak acceleration. The equivalent damping ratioimproved by up to 61.58%, confirming the ability of the ECD to enhance energy dissipation. The numerical model accurately reproduced the experimental results, and the key dynamic parameters of the RSIB and ECD systems were identified. The findings demonstrate that eddy current damping can be effectively integrated into roller seismic isolation systems to enhance energy dissipation and displacement control in RSIB systems. However, the optimal braking force must be carefully selected based on the expected seismic demands to achieve a trade-off between displacement control and acceleration performance. Future research should focus on full-scale implementation and an ECD device optimized for target-breaking force.