Evaluation of Seismic Acceleration Amplification Factors for Building Nonstructural Components Based on Coupled Analysis of Structure‐Nonstructural 2‐DOF System

ABSTRACT In this study, seismic demand on nonstructural components (NSCs) was analyzed using a combined structural‐nonstructural 2‐degree‐of‐freedom (2‐DOF) model. This model was specifically employed to incorporate coupling effects, which arise from the dynamic interaction between supporting structures and NSCs. The effect of structure‐NSC coupling on peak component acceleration ( PCA ) was investigated, with a focus on key dynamic properties such as the structure‐NSC mass ratio, period ratio, and component ductility. The analysis results showed that PCA varies significantly with the severity of coupling effects, and that these effects are most sensitive to the mass ratio between supporting structures and NSCs. Furthermore, the coupling effects on PCA were found to be affected by the ductility level and damping ratio of the components. However, as the mass ratio increases, the differences caused by damping diminish, causing the component amplification ( C AR ) to converge to a single value. Based on a comparative evaluation of C AR using ASCE 7‐22 provisions, a more rational C AR factor was proposed for moderate to heavy‐weight NSCs.