Experimental Study On Mechanical Properties Of New Bridge Bearing

In order to solve the laminated rubber bearing durability problems caused by the aging of rubber.A new kind of bearing was presented by replacing traditional rubber with mental rubber,the key structure parameters was given,three groups new bridge bearings were designed and processed.The mechanical properties of new bridge bearing was experimented,based on the test results of bearing,the study of the theory of the constitutive relation was studied.Through the compression experiment of new bearing under different design stress,vertical force and displacement curve of new bearings were obtained.The vertical force-displacement relationship curve of new bearing has obvious nonlinear characteristics,and can be divided into two stages: soft characteristics and hard characteristics.The influence of load amplitude,loading speed,relative density,and bearing shape coefficient on the equivalent stiffness,secant stiffness,tangent stiffness,dissipation factor,cyclic energy dissipation,tangent modulus and other mechanical properties of bearing were studied.The influence of loading speed on the vertical mechanical properties of new bearing can be ignored.The equivalent stiffness and cyclic energy dissipation of new bearing increase linearly with the increase of load,but the dissipation factor decreases.The cyclic energy dissipation of new bearing decreases with the increase of nominal relative density,and the secant stiffness of the bearing increases with the increase of the shape coefficient.Referenced rotation experiment of laminated rubber bearing,the new bearing rotation experiment was designed which considering the influence of the design stress(the load when using the bearing)for bearing’s rotational stiffness,the bearing’s rotation moment-angle curve was obtained.The rotational performance of new bearing can meet the requirements of the relevant specifications for the rotational performance of the bridge bearing.The rotational stiffness of new bearing is linearly related to the design stress.Based on the MATLAB platform,the constitutive relation of the new bearing experiment was numerically fitted,and the function expression which can represent the new bearing constitutive relation was obtained.The tangent modulus of the new bearing was obtained by analyzing the stress-strain relationship.By analyzing the relationship between tangential modulus and stress,a function expression which can express tangent modulus was obtained.On this basis,a theoretical formula for vertical stiffness of the new bearing is derived,which is in good agreement with the experimental results.The calculation formula of vertical stiffness can be used to calculate the vertical stiffness of the new bearing and determine the key structural parameters of new bearing.With strong earthquake record,shaking table model test examined the reduction and isolation effect of new bearing,the displacement 、acceleration and strain of each important point was obtained.Compared resurts with the laminated rubber bearing that the structure size is similar to new bearing.The seismic response of new bearing bridge model is similar to laminated rubber bearing bridge,the new bearing has better reducing and isolating performance.The new bearing can improve the performance of the existing small and medium span bridges,and the research results have certain theoretical and practical value for the processing design and engineering application of new bearing.