Study On Three Dimensional Vibration Isolation Device And Its Application In Museum Structure

In recent years,subway transportation system has been developed rapidly in China.On the one hand,subway bears the burden of transportation tasks;On the other hand,due to that subway in a city generally passes through downtown area,vibration induced by it to buildings including residential buildings,offices,museums and historic buildings around gradually become a problem.At present,seismic isolation technology has been more mature and proved an effective measure to reduce seismic response.However,seismic isolation design used now mainly based on horizontal earthquake,ignoring the vertical vibration caused by rail traffic.Therefore,three dimensional isolation technology which could reduce horizontal seismic response and vertical vibration has been the focus in engineering field.In this paper,on the basis of analyzing the domestic and foreign relevant research,for the purpose of isolating horizontal seismic action and reducing the vibration induced by subway,constructed a three dimensional isolation device using rubber bearing and disc springs.Through theoretical research,numerical simulation and application research,feasibility,practicability and effectiveness of the device are analyzed.The main achievements and contents including:(1)Based on the basic principle of structural dynamics,the vertical vibration isolation principle of vibration isolation device is analyzed.The stiffness of rubber bearing and disc springs are decoupled through reasonable and appropriate measures to ensure the effectiveness,safety and stability of the three dimensional vibration isolation device.Meanwhile,the design method is put forward.(2)FEM model of rubber bearing and disc springs are established respectively by using ABAQUS.Load are applied in accordance with the corresponding norms to obtain load-displacement curves.After calculated,horizontal and vertical stiffness of three dimensional isolation device which can provide essential parameters for application in engineering are obtained.(3)Based on a museum structure in Sichuan,both original and isolated 3D model are established by using finite element analysis software SAP2000.Seven earthquake records are selected as the input ground motion and four indicators including structural period,base shear force,lateral displacement and peak horizontal acceleration are analyzed.The results show that the three dimensional vibration isolation device has good performance in horizontal seismic isolation.(4)Vertical acceleration time histories of outdoor floor of the museum when subway passes by are collected through field vibration test.Three of them are chosen as the input excitation to analyze vertical acceleration response of each floor of two models.Z vibration level of each floor slab are obtained by using Matlab.The results show that the vertical acceleration response and Z vibration level of each floor are significantly reduced.(5)By using the three dimensional vibration isolation device in a museum model in Sichuan province,not only the structural response under earthquake but also the vertical acceleration response of each floor when subway passes by are reduced,achieving fairly good seismic and vibration isolating effectiveness.