Optimization And Analysis Of The Continuous Girder Bridge Lead Rubber Bearing Mechanical Parameters And Seismic Isolation Performance

Currently, the Lead rubber bearing is applied in earthquake engineering, it is one of the widest range of seismic isolation device for reducing the damage to bridges and is greatly significant. Continuous beam bridge is one of the most common forms of the bridge structure.It is widely used in the construction of urban bridges, road bridges, railway bridges and other transportation of engineerings. In previous devastating earthquake, continuous beam bridge is damaged mostly and have distinctive characteristics. By counting the damage to bridges and researching bridge seismic statistics, be able to play an effective defense bridge seismic ground effect. LRB is a new seismic isolation device.It can effectively reduce the seismic response of the bridge structure, improve seismic performance of the bridge structure. Using LRB to designe seismic isolation of continuous girder bridge is currently the hot topic in the field of bridge seismic research.The main content of this article is finishing the base of continuous bridge common earthquake damage and the development of reducing and the seismic isolation technology, summing up the seismic isolation technology principle and common isolation bearing, summing up bridge seismic design methods. Firstly, establishing a three-span continuous girder bridge entity model based on finite element software Midas Civil, using time seismic analysis method, do not consider two kinds of conditions for the interaction with soil isolated bridge seismic response reduction similarities and differences analysis and comparison. Then select the initial group of eight LRB as the research object, its seismic isolation effects are optimized. Finally, in order to make the LRB achieve better seismic performance and the seismic isolation play the best results, we study the two important parameters,the yield ratio and yield strength of the LRB wire type mechanical model.By considering and not considering interactions with soil and vibration characteristics of the two conditions to comparising the bridge structure and the modal characteristics. It shows that, when considering the pile-soil interaction, the vibration period of the bridge structure will be extended, modal displacement reduce relativily small, and pile-soil interaction will lead the bridge structure forces change greatly, especially in the bottom two different conditions moment and shear are significantly different. Therefore, considering the impact of pile-soil interaction in the bridge seismic analysis is an important and indispensable work.For loads caused by bridge bearings based on the weight of the upper part of the bridge structure..reaction force is the major consideration, make matching the right LRB, a series of the research and analysis is carried so that the bridge seismic isolation structure can achieve the best of this issue. This paper initially selected eight groups of the bearings as the research object. The pier at the end of internal forces, internal forces bearing, bearing hysteretic energy capacity, a number of seismic isolation index pier top acceleration, acceleration and main beam observation point are the major consideration, doing optimized analysis to isolation and reducing the effect of the LRB. The results show that the side pier bearing, when LRB vertical capacity is 1.31 times of reaction force under the weight of the beam, it is about 1.09 times of reaction force under seismic load, each seismic isolation indicators achieve better results. For the middle pier bearing, when LRB vertical bearing capacity is 1.24 times of bearing reaction force under the weight of the beam, it is about 1.05 times of bearing reaction force under seismic load, each seismic isolation indicators achieve better results. And this time, the sum of all the LRB Lead yield strength is about 0.08 times of the beam weight.Finally, the paper do a series of studies for the impaction caused by the effect of reducing and isolating concussion because of the yield ratio and yield strength of LRB wire type mechanical model. Studies have shown that when the yield ratio is in the range of 7 to 10, it has the most obvious effect of reducing and isolation. The increase of bearing yield strength has obvious effect to reduce the shear deformation, we should increase the capacity of shear deformation for the side pier bearing.