Nonstationary Seismic Response of Light Equipment

by Mahendra P. Singh, (M.ASCE), Assoc. Prof.; Dept. of Engrg. Sci. and Mechanics, Virginia Polytechnic Inst. and State Univ., Blacksburg, Va.; formerly, Sr. Engrg. Analyst, Sargent & Lundy, Chicago, Ill.,
Yi-Kwei Wen, (M.ASCE), Assoc. Prof.; Univ. of Illinois, Urbana, Ill.,

Serial Information: Journal of the Engineering Mechanics Division, 1977, Vol. 103, Issue 6, Pg. 1035-1048

Document Type: Journal Paper


A method is developed to obtain floor spectra curves that include the effect of nonstationarity of seismic motions. Such spectra are usually required for design or qualification of light secondary systems such as piping and equipment. The response of a simple structure-equipment system is examined for excitations modeled by Gaussian shot-noise and filtered shot-noise. The Markov vector approach is used to obtain the time-dependent second moments of the response in closed form. The nonstationarity due to time-varying intensity of the excitation and also due to the zero-starting condition is considered. The effects of various seismic intensity modulation functions and structural parameters on the response are evaluated. Useful results of practical importance are obtained in terms of response ratios of nonstationary-to-stationary responses, and their application in the generation of floor spectra curves for a structure is illustrated.

Subject Headings: Seismic tests | Seismic effects | Equipment and machinery | Floors | Curvature | Light (artificial) | Excitation (physics) | Ground motion

Services: Buy this book/Buy this article


Return to search