In this chapter, we introduce the concept of response spectrum, which in recent years has gained wide acceptance in structural dynamic practice, particularly in earthquake engineering design. Stated briefly, the response spectrum is a plot of the maximum response (maximum displacement, velocity, acceleration, or any other quantity of interest) to a specified load function for all possible single degree-of-freedom systems. The abscissa of the spectrum is the natural frequency (or period) of the system, and the ordinate the maximum response. A plot of this type is shown in Fig. 8.1, in which a one-story building is subjected to a ground displacement indicated by the function y s (t). The response spectral curve shown in Fig. 8.1(a) gives, for any single degree-of-freedom system, the maximum displacement of the mass m relative to the displacement at the support. Thus, to determine the response from an available spectral chart, for a specified excitation, we need only to know the natural frequency of the system.
KeywordsPeak Ground Acceleration Response Spectrum Ground Acceleration Amplification Factor Spectral Acceleration
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