Influence of the Inelastic Response of Reinforced Concrete Frame Buildings on the Inelastic Displacement and Acceleration Ratios of Nonstructural Elements

Damage to Nonstructural Elements (NEs) observed during recent major earthquakes indicates that the seismic design of NEs can significantly affect the overall seismic performance of buildings. NEs are subjected to floor accelerations that are usually higher than ground accelerations, resulting in an increased likelihood of inelastic deformations at their anchorages or support elements. However, the inelastic response of NEs has not been comprehensively analyzed. This research evaluates the influence of the inelastic behavior of Reinforced Concrete Frame Buildings (RCFBs) on the Inelastic Displacement Ratios (IDRs) and Inelastic Acceleration Ratios (IARs) of acceleration sensitive NEs, IDRs and IARs being important parameters to characterize the inelastic response of NEs. For this purpose, three RCFBs located in Colombia were subjected to scaled ground motions representing different levels of seismic intensity. The findings of this research are: a) as buildings enter the inelastic range, the IDRs show a reduced oscillation amplitude, and the local minima of the IDRs occur at the effective modal periods of the building rather than at the modal periods; b) existing prediction equations for IDRs provide good estimates for low seismic intensities (i.e. essentially elastic building response) and reasonable estimates for higher seismic intensities; c) the characteristic period of the IARs remains relatively insensitive to seismic intensity levels; and d) prediction equations for IARs provide accurate results regardless of seismic intensity levels, especially when the NE damping ratio is relatively low.