Study Of Active Control And Passive Control On Frame Structure

Many seismic reduction and isolation methods have been used to enhance the resistance of structure under earthquake force. According to whether external energy is needed, all these methods are classified in two types: passive control method and active control method. Passive control method does not need external energy, it depends on the relative displacement and motion between control device and structure to create control force or consume energy. Based on the external force and the response signal of structure which are measured by sensor, active control method uses some algorithm to get the value of control force which is applied by control equipment on the structure to reduce the response of the structure, external energy is needed. Semi-active control method is primarily active control method, but little amount of energy is needed. Based on the information of dynamic response and load, the parameter (stiffness, damp) of control device is changed to reduce the dynamic response.This paper analyses and researches two of these seismic reduction and isolation methods: passive control by setting lead rubber bearing and semi-active control by using LQR algorithm. A set of MATLAB simulation programs are used to compute the transient response of a three-floor frame structure under earthquake force, the natural period, frequency, peak value of displacement and acceleration and seismic energy response of the structure with and without seismic reduction and isolation methods are compared.The results indicate that the natural period of structure with lead rubber bearings can be extended to avoid the principal period of ground and the earthquake energy is efficiently consumed by the deformation of lead rubber bearings; the seismic response of the frame structure is reduced after control force is applied on it whose value is gained by using LQR algorithm. Further more, the conclusions about the effect of original stiffness and yielding displacement of lead rubber bearing and the effect of the semi-active right matrix are presented.