Structural response reduction using tuned mass damper with semi-active control

A semi-active control scheme is developed for improving the performance of tuned mass dampers (TMD) without the requirement of a high power supply. The application of using a hydraulic device "functional switch" as a central feature of the control scheme is derived and experimentally verified. A practical application is numerically demonstrated by a case study of a real high-rise building originally equipped with passive TMD.;The TMD is a practical solution in the area of structural response control for high-rise buildings. It is a cost-effective technology for reduction of wind induced vibrations. The vibration level in an entire building can be greatly reduced by placing a single TMD at a single selected position in the structure. As more high-rise buildings are erected, the number of TMD applications is steadily increasing. However, the limit of performance for passive TMD, which contains only the mass, linear springs, and viscous dampers, is usually set by the size of the mass. Using an Active Mass Damper (AMD) can overcome this limit and provide more options on optimization for designers to consider. It can handle more complicated dynamic load cases, structural configurations, and functional requirements of the structure. Yet, mechanical complexity, high cost, and high power requirement are concerns on deciding which system to use. It is highly desirable that a system be capable of achieving the performance of AMDs without inducing extra complexity and power consumption. To reduce or eliminate the above limitations becomes the motivation of this study on semi-active control schemes for controlling TMD's.;In this study, the special features of active control systems are examined and the desirable and achievable features for the semi-active system to imitate are identified that could be used to improve the performance of TMDs, It is the first attempt to improve TMDs by using passive forces. The system may be called "Semi-active TMD" (SATMD). The performance of such system is both theoretically and experimentally proven to be superior to that of passive TMDs, achieves minimal power consumption and has less complexity than active TMDs.;The case study of a real building equipped with a TMD not only demonstrates the engineering merits of the semi-active control of TMD, but also perceives better understanding on the dual applications under wind and earthquake loads.