A Comparative Analysis of International Standards on Curved Surface Isolators for Buildings

This study presents a comprehensive comparative analysis of a hospital located in Costa Rica, examining the performance of sliding pendulum isolators under different international seismic design standards. The standards considered in this research include the U.S. code ASCE/SEI 7-22 and various European standards, namely EN 15129, EN 1337, and EN 1998-1. The case study employs the Equivalent Linear Analysis method, as prescribed by Eurocode 8, alongside the Equivalent Lateral Force procedure from ASCE/SEI 7-22. The seismic action is defined using the acceleration response spectrum from the Costa Rican Seismic Code (CSCR-10, 2010). However, certain limitations must be acknowledged when applying the equivalent linear analysis approach. One key restriction is that the isolation system must be modeled with equivalent viscoelastic behavior, which is feasible for sliding pendulum isolators. Despite being a simplified method, this approach proves valuable in the initial selection and optimization of an isolation system, particularly for practitioners. It is recommended that this method be applied as a preliminary step before performing more advanced nonlinear analyses. After determining the optimized parameters for the friction pendulum system, the detailed design of the isolators will be conducted following the provisions of the selected international standards. This process includes verifying compliance with key performance requirements such as self-recentering capability, type testing procedures, deformation verification, and partial load verification on the concrete pedestal, where the isolators are assumed to be installed. These requirements ensure that the isolation system meets the necessary structural performance criteria, providing reliable seismic protection while adhering to international engineering best practices.