Earthquake Resistance Overturn Analysis Of Buildings With GFRP Rubber Isolation Bearings

With the rapid development of economy and society and the continuous improvement of people’s living standard,the rural areas of our country have set off the upsurge of house construction.However,affected by the imbalance of regional development,most of these buildings are low cost and without considering earthquake fortification.Once the earthquake disaster happens,a large number of the houses in rural areas will collapse,and there will be serious casualties.Although the traditional laminated steel-reinforced rubber isolation device is mature in technology and has good isolation effect,it is difficult to popularize and use in rural areas because of its high quality,complicated processing technology and high-cost.In recent years,with the continuous development and improvement of the concept of isolation technology,some new modular seismic isolation devices with light weight,simple processing technology,convenient construction,low-cost and good performance have been gradually developed,some of which have been used in township houses in the earthquake area.However,because these new type of modular isolation devices do not have connection plates,compared with the traditional laminated steel-reinforced rubber isolation device,the isolation structure using this kind of isolation technology is more prone to take place the whole overturning under the action of earthquake.,however,most of the current researches on the new type of modular isolation device are limited to the theoretical analysis and experimental study of its mechanical properties and isolation efficiency.Therefore,this paper takes modular glass fiber-reinforced polymer rubber bearing(GFRP rubber bearing)as the research object,and the shaking table tests are carried out on the steel frame based isolated structure model with different height-width ratio.The effects of vertical compressive stress of modular isolation device,seismic intensity and site type on the limit value of height-width ratio for the model structure are studied,and the anti-overturning performances of the model.The main contents of the study are as follows:(1)Taking the rigidity and flexibility of the stiffening material in rubber bearing as the narration point,this paper introduces the theoretical research background of laminated steel plate rubber bearing from three aspects: compression characteristic,shear characteristic and limit property respectively.Then,the theoretical research progress of compression characteristics,bending properties and warpage properties of fiber-reinforced laminated rubber bearings are summarized.(2)The horizontal shear property,compressive stress correlation and shear strain correlation of the GFRP laminated rubber bearing are studied systematically by compression-shear test method.The calculation formulas of the corresponding mechanical performance parameters are statistically regressed.According to the shear restoring force characteristics of the bearing,a GFRP laminated rubber bearing restoring force model based on modifing Bouc-Wen model is proposed.(3)Taking the modularized isolation technology to conduct the base isolation design for two kind of steel frame model structures.Using the simulated seismic shaking table test method,under the condition that the compressive stress of the rubber bearing is 2.5MPa and 3.75 MPa respectively,the responses of the absolute acceleration,inter-story displacement and overturning resistant ratio for the isolated model structure with a height-width ratio of 1:1,2:1,4:1 under the action of different earthquake intensities and seismic waves in different sites are studied.The limit values of the height-width ratio for the different height-width ratio model structures are calculated,and the overturning resistant performance for the model structure is analyzed.(4)On the basis of the shaking table test,the anti-overturning performance of the model structure used in the test is analyzed by the finite element numerical simulation method,and the reliability of the test results is verified.(5)Based on the results of the shaking table test,taking a multi-story reinforced concrete frame structure in a township as an example.Then,the isolation and non-isolation finite element models for the frame structure are established by using the OpenSEES finite element software.Through conducting dynamic time history analysis to them,the changes of the inter-story shear force,inter-story displacement and absolute acceleration for the frame structure before and after isolating are compared,and the seismic performance of the isolated structure is analyzed.