A RESPONSE SPECTRUM APPROACH FOR SEISMIC ANALYSIS OF NONCLASSICALLY DAMPED STRUCTURES

A response spectrum approach for the analysis of nonclassically damped structural systems is presented. In this approach, which is similar to the response spectrum procedure for the analysis of classically damped systems, the only required information regarding the ground motion input is its response spectrum. The procedure takes into account the effect of cross-correlation between modes with closely spaced frequencies, and it is simple for practical application. The proposed method is used to approximate the maximum response of several nonclassically damped structural systems. Emphasis is placed on nonclassically damped primary-secondary systems in which the effect of nonclassical damping is known to be significant. Numerical results indicate that the maximum structural responses predicted by the proposed response spectrum approach are generally closer to the exact solutions than those obtained using the approximate classically damped procedure. © 1990.