The Vibration Reduction of Building Using Multi-Stories Isolated Systems

• Main Authors: Yang, Jia-Ru, 楊佳儒
• Other Authors: Huang, Li-Jeng
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/23238509834649392417

碩士 === 國立高雄應用科技大學 === 土木工程與防災科技研究所 === 97 === Recently the aseismic performance of buildings and theories and techniques of earthquake isolation are continuously developed. The thesis is proposed to investigate the dynamic responses of buildings using various isolation approaches, including base isolation, mid-story isolation, multi-stories isolation, etc., under various external loadings. Lumped mass model is employed for simulating the dynamic model of buildings without and with isolation designs wherein horizontal displacement of each story is chosen to be the degree of freedom. Lead Rubber Bearing (LRB) is adopted to be the isolator. Various types of eternal loads are considered, such as free vibration, unit step excitation, harmonic forcing and ground motions. A simplified theoretical model is first employed to depict the fundamental behavior of isolator embedded at base and top-story. It is found that as the mass of top-story isolator is very smaller its behavior is similar to a tuned mass damper (TMD). Then dynamic equations of 8 Cases of different layouts of non-isolated and isolated are derived, respectively, and then transformed into state-space descriptions and then Runge-Kutta method is used to calculate the time-domain dynamic responses. Numerical experiments show that the all-stories isolation and base-mid-story isolation systems are better than classical base isolation and mid-story single isolation systems in the inter-story displacements and inter-story accelerations of the floors. Parametric study leads to the fact that adjustment of the mass, damping and stiffness parameters of isolators would cause significant influence of dynamic response of the systems. Mass effect is relatively small, damping constants are the most effectively in reducing the displacements, while frequency ratio ωb = 2 ras/s is the best choice among the current cases.