Modal Combination Method Considering Higher Mode Effects

고차모드 효과를 고려한 모드조합법

Using existing static methods, it is possible to estimate accurately the reponses of structures governed by the fundamental mode. However, these methods do not provide reliable estimates for the structure where higher mode effects are significant. Parametric study was performed to analyze the dynamic characteristics of the structure with long vibration period. Based on the investigations, a new modal combination method using modal combination coefficients, Factored Modal Combination, was developed, and static earthquake load patterns addressing higher mode effects reasonably were proposed. Existing modal combination methods, such as SRSS and CQC, lack a theoretical basis to be applied to inelastic structures. In contrast, the proposed method can be applied conveniently in inelastic range as well as in elastic range.