CQC and SRSS methods for non‐classically damped structures

Two mode combination methods are presented for structures with non‐classical (non‐proportional) damping. They are of the same level of complexity as the well‐known SRSS and CQC methods. They require only a single, real‐valued participation factor for each mode, a single correlation coefficient, and standard relative displacement response spectra. A base‐isolation study shows that the standard SRSS and CQC methods for classically damped structures give under‐conservative response predictions, and that the proposed methods give accurate predictions.