In structural control, semi-active strategies are considered most promising for the hazard mitigation of buildings and civil infrastructures. They can be used to effectively suppress the dynamic responses of a structure with a small amount of external energy. During the past 20 years, a number of semi-active devices have been implemented in buildings and bridges for reduction of wind-, earthquake- or traffic-induced vibration. All semi-active control devices developed in the past require the use of external energy. Although low in energy use, this requirement necessitates the maintenance of such devices over the life span of a structure being controlled. In this study, a maintenance-free tank filled with liquid and fine particles is proposed to mitigate the dynamic responses of a structural system. The device (tank) works following the principle of a Tuned Liquid Damper. Its mass, however, can be changed as base excitations increase, based on the "soil liquefaction" mechanism in soil dynamics. Therefore, though no external energy is required in operation, the device functions as a semi-active unit. The objective of this proposed work is to demonstrate the device's effectiveness with a proof-of-concept testing program. Buildings and civil infrastructures are subjected to multi-hazards such as blasting, windstorms, and earthquakes. The uncertain nature of these man-made or natural hazards dictates the constant inspection of a semi-active device if maintenance for such a device is required. The proposed work is unprecedented in developing a maintenance-free device in structural control. It will therefore generate a surge of new research activities in structural control.
The project will be completed in one year with one graduate student. The results and findings will be disseminated in an authorative journal and national conference.