The Research Of Controlling The Vertical Seismic Response Of The Structure

Earthquake is one kind of the paroxysmal natural disasters. In order to mitigate the disaster as light as possible, the structural control technique has been put forward. So far, the most practical control systems may be classified into three approaches, namely, base-isolation, energy-absorbing dampers and active control, and the base-isolation technique is used widely. It has been adopted by the new code for seismic design of buildings of our country so that we can make good use of the advantage of the new technique. However, all of these control systems only weaken or isolate the horizontal earthquake responses, as to the vertical earthquake responses, all these methods may not work well. As we all know, the ground motion consists of several components, and in some cases the vertical ones can't be ignored. Therefore, on the basis of horizontal base-isolation and TMD (Tuned Mass Damper), this paper involves the vertical earthquake responses of three systems: the vertical TMD systems, the vertical base-isolation systems and the combination of vertical base-isolation and TMD systems. Some basic conclusions drawn are as follows:(1) For vertical TMD system, mass ratio, frequency ratio and damp ratio are three important parameters. In some conditions, TMD design attached to the main structure can decrease the vertical response; the fundamental period of the main structures should be apart from the vertical seismic predominant period,otherwise, it maybe increase the main structures'response; when the vertical TMD system is designed reasonably, we can get better results.(2) For vertical base-isolation system, it is effective when the vertical stiffness of the base isolater is smaller, the period of the base-isolation system is longer,and apart from the vertical earthquake's predominant period. Accordingly, the base-isolated layer should be designed reasonably and the period of the base-isolated system should be apart from the vertical seismic predominant period. (3) For the combination of vertical base-isolation and TMD system, the results show that both the acceleration response of the main structure and the displacement response of the base-isolator can be reduced when it is well designed.