Application of Risk-Based Design Methodology to Tuned Mass Damper

Abstract

Abstract Suppressing earthquake damage in chemical plants has great benefits not only to a business continuity of a company but also to surrounding areas and social activities. For example, chemical plants have a lot of slender structures such as distillation columns and chimneys, which may be damaged by large earthquakes. Tuned mass dampers (TMDs) are one of the effective approaches to suppress seismic response of slender structures. The TMD consists of a mass, a spring and a damper, and it is generally installed at the top of a target structure. The damping effect depends on the mass, natural frequency, damping ratio of the TMD. In general, its natural frequency and damping ratio can be determined by the optimum tuning theory and a TMD having large mass has good performance of vibration control. However, the cost of TMD depends on the mass. In addition, since the optimum tuning theory assumes that the target structure is a simple single degree of freedom system, application of the optimum tuning theory to the TMD for a slender structure is not easy. Therefore, this study proposes a risk-based design methodology for TMDs. The proposed method considers a seismic hazard of a site where a target structure located and a damage state of the target structure. Then the mean annual frequency of exceeding the damage state can be calculated as function of the mass of the TMD.