A Response Spectrum Approach for Analysis of Nonclassically Damped Structures

Keywords: Nonclassically Damped Systems, Building Structures, Response Spectra, and Seismic Response Analysis.

Abstract: A response spectrum approach for analysis of nonclassically damped structural systems is presented. Similar to the response spectrum procedure for 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 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 an approximate classically damped procedure. The accuracy of the present approach is quite reasonable.