Seismic Design Seismic Isolation Nonstructural Components Floor Accelerations Nonstructural Elements Global Isolation Period

External authors:

• Juan Carlos Obando ( Universidad de Antioquia )
• Orlando Arroyo ( Universidad Industrial de Santander )
• Daniela Novoa ( EstrucMed Ingn Especializada SAS )
• Henry A. Colorado ( Universidad de Antioquia )

Abstract:

Non-Structural Components (NSCs) comprise all building elements that are not part of the load-bearing system. These elements are often subjected to floor accelerations significantly higher than ground accelerations, which can compromise building functionality and are generally the primary source of post-earthquake losses. A potential strategy to mitigate these demands is to equip NSCs with seismic isolation systems. However, few studies have attempted to generalize the seismic behavior of isolated NSCs. This study introduces the concept of the global isolation period (Tg), defined as the period of a seismic isolation device for rigid NSCs that ensures a target reduction in acceleration demands, regardless of the NSC's location within the building or the damping ratio adopted for the isolation system. To establish Tg, an extensive parametric study is conducted on the response of rigid NSCs isolated and anchored at different levels of various elastic buildings. Based on this analysis, a simple equation is proposed that relates Tg to the fundamental period of the building and the target reduction in NSC accelerations. The equation is validated using accelerations obtained from three inelastic reinforced concrete frame buildings, considering the Friction Pendulum System (FPS) as the isolation device for the NSCs. The proposed equation for Tg provides reasonable estimates that can serve as a basis for the design of seismic isolation devices for NSCs. It yields conservative results when the target acceleration reduction of the rigid NSC is close to 50%, whereas for larger reductions it tends to be less conservative.