This study examines the seismic vulnerability of non-structural components in high-rise buildings by proposing a normalized floor response spectrum (FRS) suitable for practical application. A Bayesian-mode-based method (BMBM) is used to develop the FRS, incorporating both modal amplification effects and the probabilistic variability observed across different building heights and story levels. The resulting spectrum is methodically compared with existing code-based and empirical methods to assess its consistency, conservatism, and relevance to engineering practices. The findings demonstrate that the proposed FRS provides a realistic yet reliable upper-bound estimate of floor accelerations, particularly in the upper stories where modal interactions are significant. This research offers a robust and practical framework for enhancing the seismic design of nonstructural components in vertical structures.

Seismic demand on nonstructural components (NSCs) is highly dependent on the coupled behavior of a combined supporting structure- NSC system. Because of the inherent complexities of the problem, many of the affecting factors are inevitably neglected or simplified based on engineering judgments in current seismic design codes. However, a systematic analysis of the key affecting factors should establish reasonable seismic design provisions for NSCs. In this study, an idealized 2-DOF model simulating the coupled structure-NSC system was constructed to analyze the parameters that affect the response of NSCs comprehensively. The analyses were conducted to evaluate the effects of structure-NSC mass ratio, structure, and NSC nonlinearities on the peak component acceleration. Also, the appropriateness of component ductility factor (R p) given by current codes was discussed based on the required ductility capacity of NSCs. It was observed that the responses of NSCs on the coupled system were significantly affected by the mass ratio, resulting in lower accelerations than the floor spectrum-based response, which neglected the interaction effects. Also, the component amplification factor (a p) in current provisions tended to underestimate the dynamic amplification of NSCs with a mass ratio of less than 15%. The nonlinearity of NSCs decreased the component responses. In some cases, the code-specified R p caused nonlinear deformation far beyond the ductility capacity of NSCs, and a practically unacceptable level of ductility was required for short-period NSCs to achieve the assigned amount of response reduction.

Interest and requirement of seismic qualification for nonstructural components are increasing in South Korea after observing nonstructural component failures by Kyungju earthquake on 12, October, 2016. However, amplification of input motion by hight of building are not considered in most of seismic qualification or design for nonstructural components in South Korea. In this study, seismic loads are compared which is applied to seismic qualification or design for structural or nonstructural component. As a result, amplification effect by vertical location in a building for nonstructural component should be considered for efficient seismic qualifications. Also, further studies are needed how to apply those amplification effects to required response spectra.