Study On Vibration Control For Long-span Bridge Of Rigid Frame-continuous Girders

The bridge as the transport hub and the lifeline project and the main lines of communication important component, is national and the social development important basis facility.As Bridge of rigid frame-continuous girders reduced the* side main pillar high requirment with multi-span continuous rigid-framed bridge, therefore this kind of bridge is suitable for the different terrain, the geological condition and the navigation request. Bridge of rigid frame-continuous girders is the combination of continuous beam and continuous rigid frame,it has given consideration to both's merit to develop the good and discarded the respective shortcomings and gathered the advantages of two structures,besides,it has also many characteristics,such as powerful strong seismic capacity, good integrality, reasonable structure stress,beautiful line shape,so it has many superiorities in the acclimatization, mechanical behavior of structure and application functions aspects,and so on. it has also obtained the fast development, and have the tendency. of speeding up the development in near several years.As a result of its randomness and burst characteristics,the earthquake often causes the disastrous consequence,and brings the huge life and the property damage, is a natural disaster which possesses great destructive power and forecasted with difficulty in advance.How to guarantee that the structure security in earthquake is important question throughout in the bridge development for our country, because the country is one of multi-earthquake countries in world.The traditional earthquake resistance methods by resisting the earthquake function through superstructure own resistance, often can make the structure not only uneconomical but also insecurely due to the uncertainty of earthquake .In recent years, the bridge earthquake resistance technology which is based on the structure vibration control theory already received various countries' scholar widely to take seriously, As a result of the structure complexity for Bridge of rigid frame-continuous girders, its vibration control method's research is also at the start stage.so this paper carried on the control to the bridge earthquake vibration with the active variable damper device,studied its control effect and the project feasibility for the reference of the project applicationThis paper which was taked an actual Bridge of rigid frame-continuous girders as the background, based on structure vibration control theory, applied the active variable damper in the vibration control for Rigid Frame-Continuous Girders under earthquake action.the control system is simulated during respectively inputting three earthquake waves—EL-Centro wave,Taft wave,Tianjin wave,and studied by the optimal bounding criterion semi-active control algorithms (Hrovat) with MATLAB.the earthquake response of Bridge of rigid frame-continuous girders are given out respectively without control devices and semi-active control.,the corresponding computed result is analyzed and discussed,the research of vibration absorbing effect of earthquake respond of Bridge of rigid frame-continuous girders is conducted,with uniform earthquake excitation which is imposed longitudinally, obtained the vibration control rule of active variable damper device to Bridge of rigid frame-continuous girders.1,At first,this paper introduces finite element method on spatial beam element and illustrates the base theory for establishing structure finite element model, earthquake wave selection and amplitude modulation rule and solving method of dynamic differential equation,then a model for spatial dynamic analysis of Bridge of rigid frame-continuous girders is presented in order to provide the analysis basis for seismic calculation and vibration reduction analysis.in addition, summarize the structure vibration control elementary theory and the method.2,Control-strategy analysis of active variable damper device.Based on classical linear optimal control algorithm (LQR), the control policy absorption of shock effect of semi-active control algorithm and passive strategy are analysed.The results calculated indicate that, that active variable damper as a semi-active control device on bridge can effectively control response of longitudinal vibration response; An excellent control effectiveness has been achieved for the control structure. The reasonable control algorithm (Hrovat)may have the good control effect.3,The research of Longitudinal free vibrations and semi-active control effect for Bridge of rigid frame-continuous girders. applied the active variable damper in the vibration control for Rigid Frame-Continuous Girders under earthquake action.the control system is simulated during respectively inputting three earthquake waves—EL-Centro wave,Taft wave,Tianjin wave,and studied by the optimal bounding criterion semi-active control algorithms (Hrovat) with MATLAB.The results of earthquake responses of pre and post control are comparatively analyzed. The findings indicated that the control for Bridge of rigid frame-continuous girders is feasible, an excellent control effectiveness has been achieved for the control structure.4,The situation which is realized to the control algorithm is studied about active variable damper in control,and control force between active control and semi-active are compared and analyzed.The results show that the device very good has realized the optimal algorithm(Hrovat); Two kind of control forces exist the very wide difference, the control using active variable damper device for Bridge of rigid frame-continuous girders can only as far as possible the close controlling force, but cannot realize the controlling force completely.