Method of Seismic Response Reduction for Crossover Piping Using Inertial Mass Element

Abstract

Piping systems crossing between isolated and non-isolated structures are designed to have relatively long length not to restrict the displacement of the isolated structure during earthquakes. Therefore, the natural frequencies of these piping systems are not high enough to avoid the resonances due to earthquake movements. In such cases, supports are required not to restrain the displacement of isolation, and to suppress the resonances of the piping systems. Because of this requirement, rigid supports cannot be applied to crossover piping systems. In this paper, the method of seismic response reduction for crossover piping using inertial mass element is proposed. Inertial mass element generates the force which is proportional to the relative acceleration acting on the element. In this paper, it is shown that the participation factors of the target vibration modes are minimized by optimizing the parameter of the inertial mass element. Additionally, by earthquake response analysis, it is confirmed that the resonances of piping systems are suppressed without restraining the response displacement of the isolated structures.