Shaking Table Substructure Testing Based On Three Variable Control Method And Its Investigation On Seismic Performance Of Tuned Liquid Dampers

Tuned liquid damper(TLD) is one kind of passive vibration control device and is normally applied for the vibration control of high-rise structures. However, the seismic performance of structure with TLDs are difficult to be investigated by traditional experimental methods, such as the quasi-static testing, the pseudo-dynamic testing, as well as the conventional shaking table testing method. Shaking table substructure testing has advantages of conducting the TLD test with large scale or even full scale, which provides a reliable method for disclosing the seismic performance of structures with TLDs. The control accuracy of loading system is the key element of the shaking table substructure testing, which provides a challenge to the shaking table system, especially for old shaking tables with undesirable performance due to the traditional displacement controller. Therefore, the investigation to eliminate the time delay of displacement responses, improve the working frequency bandwidth of shaking table system and the accuracy of waveform reproduction is of great significance and practical value. For solving these problem, this paper investigates the shaking table substructure testing based on three variable control(TVC) method, and applis this mothod for discloding the seismic performance of structure with TLDs. The major contents of the present thesis are listed as follows:(1) Aims to improve the control accuracy of the existing servo-hydraulic shaking table system, this paper investigates the loading control method based on TVC theory and the corresponding tunning method of TVC controller gains. The method is then validated by numerical simulations and convensional shaking table tests. It is shown from the numerical and experimental results that the TVC method can effectively resolve the time delay of displacement responses, increase the response speed and working frequency bandwidth of the shaking table, and improve the control accuracy of acceleration responses.(2) Investigates the shaking table substructure testing based on TVC method and validates the accuracy and effectiveness of the testing method by comparing the results with traditional shaking table tests of overall structure. It is shown from the experimental results that the TVC feed-forward and feedback loop controller can improve the response speed of shaking table system and the acceleration and displacement control accuracy of shaking table substructure testing, and with proper controller gains the shaking table substructure testing based on TVC method can obtain similar experimental results with the traditional shaking table tests of overall structure.(3) Investigates the influence of liquid heights and effective mass ratio on the seismic performance of TLD by the shaking table substructure testing based on TVC method. It is shown from the experimental results that with the increase of the effective mass ratio the control effects of the TLD behaviors increases at first and then decreases, under El Centro earthquake wave excitation the TLD system obtaines the optimal control effect when liquid height is 40 mm and the effective mass ratio is 2%, and the control effect of TLD may varied for different types of earthquake wave excitations.