Dynamic Analysis of Light Equipment in Structures: Response to Stochastic Input

A mode‐superposition method for the evaluation of the dynamic response of light equipment in structures subjected to stochastic excitations is developed. Previously obtained results for modal properties of the combined equipment‐structure system in terms of the modal properties of the two subsystems are used. Both power spectral density and response spectrum descriptions of the input are considered. Results include the effects of tuning, equipment‐structure interaction, and correlation between modal responses. Floor spectra including interaction, as well as the conventional floor spectra, are easily obtained in terms of the input response spectrum. For an example structure, excellent agreement is obtained in a comparison with time‐history results for an ensemble of 20 generated earthquake ground motions.