Hospital resilience in earthquake-prone regions: a novel evaluation of base isolation systems for structural and functional performance in West Lombok

Abstract

Earthquakes pose a significant threat to hospital infrastructure, where uninterrupted functionality is critical for emergency response and post-disaster recovery. While base isolation systems have been widely recognized for reducing structural damage, their effectiveness in enhancing functional resilience remains insufficiently quantified. This study evaluates the seismic performance of three base isolation systems, Lead Rubber Bearings (LRB), High-Damping Rubber Bearings (HDRB), and Friction Pendulum Systems (FPS), applied to a representative hospital building in West Lombok using nonlinear finite-element analysis based on SNI 1726:2019 response-spectrum loading. Structural performance is assessed through key parameters, including base shear, natural period, inter-story drift, and lateral displacement. The results indicate that FPS provides the most significant performance improvement, reducing base shear by 35.6%, lateral displacement by 27.0%, and inter-story drift by 37.5%, while increasing the fundamental period by up to 692%. To address the limitations of conventional structural evaluation, this study introduces a quantitative Resilience Index (R) defined as the normalized reduction ratios of structural response parameters relative to the fixed-base condition. FPS achieves the highest resilience scores (R = 0.356 for base shear, 0.270 for displacement, and 0.375 for drift), outperforming HDRB and LRB systems. These improvements indicate enhanced structural robustness, which correlates with reduced expected downtime and improved immediate occupancy performance. The integration of structural and functional performance metrics represents a shift from conventional design approaches toward resilience-driven engineering decision-making. The findings demonstrate that base isolation systems, particularly FPS, significantly improve both structural safety and post-earthquake operational continuity of hospital facilities. Furthermore, the proposed resilience-based evaluation framework provides a scalable approach to integrating structural performance and functional recovery metrics into the seismic risk assessment of critical infrastructure, supporting resilience-based seismic design strategies for healthcare infrastructure in developing seismic regions.