Effect of nonclassical damping on instructure response spectrum

One of the popular methods to obtain the response of a secondary system attached to a primary system is the Instructure Response Spectrum (IRS) method. In many applications, the damping matrix is defined as nonclassical damping matrix and may be assumed to be of the classical form. The main objective of this study is to investigate such assumption on a real problem. A study is carried out by applying the El Centro earthquake (May 18, 1940, S00E component) as response spectra at the base of the primary system. The primary system is chosen as six-story-building. The secondary system is attached to the top primary story. Various parameters are investigated such as secondary system frequency, mass ratio, and damping ratio.