Study On The Isolated-Rubber Bearing's Tensile-shear Mechanics And Tensile-Resistant Bearing

The compression–shear behavior of rubber bearings is investigated by theoretical analysis and confirmed by extensive experimental work.Nevertheless,whether theoretical analysis predicts the tension–shear behavior of isolators is unclear.In the above studies,the mechanics of bearings in tension–shear states were considered similar to that in pure states.Thus the tensile stiffness of bearings was obtained by modifying the pure tension stiffness.Alternatively,the characteristics of bearings in tension–shear states were considered similar to those in compression–shear states,and the tensile stiffness of the bearings was obtained using the compression-shear theory.In fact,according to the results of tension–shear performance bearing experiments,as well as other shaking table tests,the behavior of the bearing in tension–shear states is not similar to that in pure tension states from the results of shaking table tests and not the mirror image of those in the compression–shear states.Furthermore,the tensile strength of rubber bearings is very small and easy to be subjected to tensile failure in high-rise buildings.In view of the above problems,the main contents of this paper are as follows:1.The tensile shear analysis model of the laminated rubber bearing was established based on the Haringx theory,then the theoretical formulas for calculating the vertical tensile stiffness of the bearing under shear deformation are deduced,and the tensile properties of the bearing are analyzed theoretically.2.The 3D solid finite element model of rubber isolator is established and the tensile-shear properties are analyzed.Then the simulation results are compared with the theoretical formulas deduced in this paper to verify the correctness of the formula for calculating the tension-shear stiffness of the bearing.3.The tensile-shear performance and the influence of different tensile deformation on the bearing mechanics is analyzed by tension test,and the experimental results are compared with the theoretical analysis formula and the finite element model to verify the correctness of the theoretical formula and the finite element model.4.A kind of tensile-resistent isolation bearing is proposed in this paper.The seismic response of a high-rise isolated structure is analyzed and some tensile-resistent isolation bearings are arranged according to the tension condition of isolation layer in order to verify the effectiveness of the proposed tensile isolation bearings.Through the above research,the following conclusions are obtained:1.Under shear deformation,the tensile stiffness of the bearing is less than pure tensile stiffness and decreases with the increase in shear deformation.2.Due to the change in rotation of rubber layers is different in a different force stage,the tension-shear performance of the bearing can not be simply considered as the image of the compression-shear performance and compression shear theory can not be directly used to analyze the tension-shear properties of rubber bearing.3.The elastic tensile strain of rubber bearing is about 5 to 10%,and obvious differences in compression and shear characteristics were not observed after the bearing experiences large tensile shear deformation.4.Compared with that subjected to pure tension,the bearing under the action of tension and shear can produce larger vertical displacement,which improves the tensile damaging performance of bearing.5.A tensile-resistent isolation bearing proposed in this paper can effectively improve the tensile ability of rubber bearing and reduce the vertical tensile deformation of the bearing,controlling adverse effects caused by flat pendulum effect Pendulum effect on Isolated structure,also,it can solve the insufficient tensile capacity of rubber bearings and ensure good isolation effect at same time.