Research On The Behavior Of Steel Damping Pot Rubber Bearing Under Horizontal Force

As an important part of lifeline engineering,the destruction of the bridge will directly affect the rescue work after the earthquake,which makes the secondary disaster more serious.The continuous girder bridge has the advantages of large structural rigidity,small deformation of bridge deck,good dynamic performance,smooth deformation curve,and favorable characteristics of high speed driving.So it is widely used in small and medium span bridges in China.The support system of the continuous girder bridge is usually arranged only on a middle pier with a fixed bearing,and the rest of the piers are arranged with sliding bearings.This kind of bearing arrangement will cause the fixed pier to bear the main longitudinal seismic force during the earthquake,and can’t make full use of the seismic capacity of the pier group.In order to solve this problem,this paper presents a new type of seismic isolation bearing for steel damping pot rubber bearing,and the mechanical behavior of the bearing under horizontal force is studied in detail.Firstly,the paper introduces the construction and working principle of steel damping pot rubber bearing.Next,this paper studies the mechanical properties of I-shape steel dampers under large deformation.Firstly,the paper deduces the calculation formula of the stiffness before yield and yield force of the I-shape steel dampers.Then,considering the size of the actual pot rubber bearing,the paper determines the range of the section height and the length of the damper.In this paper,the simplified formula for calculating the post yield stiffness and limit force of I-shape steel dampers is obtained by fitting method.On this basis,the paper studies the hysteresis curve and restoring force model of I-shape steel damper.After obtaining the main mechanical parameters of the force-displacement relationship of the I-shape steel dampers,the paper studies the mechanical behavior of the steel damping pot rubber bearing in the unidirectional and low-cycle reciprocating loads,and the paper deduces the force-displacement segmentation function of the new bearing.Finally,the correctness of the segmentation function is verified by finite element method.On this basis,the paper proposes the model of restoring force of new bearing.Finally,the paper proposes a method of bearing optimization based on simulated annealing algorithm,and introduces the calculation flow of the method in detail The objective function of the algorithm is defined as the sum of reduction rate of the bending moment of the fixed pier,the reduction rate of the total bending moment of the pier and the reduction rate of the relative displacement of the bridge.In order to meet different optimization goals,the paper introduces three weight coefficients to characterize the proportion of the three reduction rates.Finally,the parameters of a four-span continuous girder bridge are optimized by using the new bearing parameters method.The results show that the new bearing can reduce the bending moment of the fixed bridge and the relative displacement of the bridge.Compared with the initial new bearing,the seismic performance of the bridge structure is improved by using the optimized parameters,and the feasibility of the new optimization method of the bearing parameters is verified.Through the analysis,it is concluded that the optimization method of bearing parameters based on simulated annealing algorithm has the advantages of versatility,ease of operation and high computational efficiency,and can solve the problem of parameter optimization of steel damping pot rubber bearing.