System Identification and Optimal Design of Tuned Mass Dampers for Torsionally-Coupled Structures

• Main Authors: Lin Poal Lung, 林保隆
• Other Authors: Chi-Chang Lin
• Format: Others
• Language: zh-TW
• Published: 1995
• Online Access: http://ndltd.ncl.edu.tw/handle/05253667202761542606

碩士 === 國立中興大學 === 土木工程研究所 === 83 === The use of active and passive control devices such as Tuned Mass Damper (TMD) has become an area of considerable research interest recently. It is gaining more acceptance not only for the design of new structures but also for the retrofit of existing structures to improve structural safety. Designing an optimum TMD requires the prior knowledge of modal properties of the controlled structure. For a real building structure, the lateral and torsional motions are coupled if the centers of mass and resistance do not coincide. Therefore,it is of great importance that system identification of torsionally-coupled buildings using real response measurements be carried out in conjunction with the design of optimal TMDs. In this study, an optimum design procedure and system identification technique are developed to evaluate the modal parameters of a torsionally- coupled structure with TMD based only on partial response measurements. First, a random decrement method is employed to reduce the measured response data to extract free vibration responses at each measured location. Then, the Ibrahim time domain technique is applied to calculate the modal parameters. To obtain the complete mode shapes, an interpolation method is also developed to calculate the mode shape value for the locations without measurement. Based on the identified modal parameters, an optimum TMD is determined. Numerical example of a five-story torsionally-coupled building shows that the proposed system identification technique is able to identify structural dominant modal parameters and responses accurately even with small number of measurements. In addition, a single story torsionally-coupled building with one or two optimal TMDs is used to verify that the proposed optimum TMD can reduce the building responses significantly.