The Seismic Research On Pin-axle Constraint System Of Curved Girder Bridge

The seismic study of the bridge is significant because the earthquake damage of the bridge will cause huge human and economic losses.Compared with the linear bridge,the curved girder bridge are widely used and exist coupling effect of bend-twist.And the dynamic response is more complicated under the seismic excitation.At present,the design of curve girder bridge still follows the support design and support system of the straight girder bridge,there are great disadvantages.The seismic resistance of curve girder bridge support at home and abroad is relatively less,and is no theoretical basis.This paper reviews the research and development of the seismic problem of bridges,summarizes the research progress of the seismic behavior of curved girder bridge bearings.Next,taking an example of a curve girder bridge,the pin-axle constraint system is proposed for the shortage of ordinary support of curve girder bridge.Then,This paper will analyze the regular pattern of different parameters on the seismic behavior of curved girder bridge.The main contents are as follows:(1)The function principle and structural installation of the pin-axle constraint system are elaborated in detail.The system is composed of pin shaft and common support.The design point of the support is that the welding assembly of the pin-axle is inserted into the limit pin groove on the bridge cover beam,the appropriate initial gap is reserved,forms the pin-axle bearing restraint device of the curved girder bridge and is suitable for the structural characteristics of the curve girder bridge.According to the Kelvin model of the contact element method in the collision problem research theory,the numerical simulation model of the pin-axle bearing is established.There are three main influencing factors in this model: contact unit stiffness,contact unit damping coefficient,contact unit initial gap.(2)The seismic response rule of the curved girder bridge.For curve girder bridge,the choice of seismic wave and the input direction of seismic wave are essential factors,which will affect the analysis of bridge structure.It has been proved that the direction of seismic wave input of curve girder bridge is carried out in different seismic directions along the direction of the adjacent bridge and its vertical line.It also analyzed the influence of seismic collision response,displacement response and structural force response of the curve girder bridge under different parameters,such as pin-axle unit stiffness,initial gap,seismic wave input angle,upper and lower mass ratio and bridge height by means of time-process analysis.(3)Based on grey relational analysis,the two-dimensional single-factor model analysis is transformed into a three-dimensional element analysis,the correlation is calculated,and the essential influencing factors of collision effect,displacement,bending moment,shear and torque of the curve girder bridge under seismic action are obtained.Based on the BBD method in the response surface method,the three-factor five-point test on the collision force,number of collisions,relative displacement of the pier and beam and the internal force of the structure is designed to obtain the respective quadratic polynomial regression equation.The fitting polynomial is compared with the numerical simulation results to verify the accuracy of the equation.(4)After optimizing the parameters of the curve girder bridge,the curve girder bridge with the pin-axle constraint system will be compared with the curve girder bridge with the ordinary bridge bearing to verify the seismic performance of the pin-axle constraint system.It shows that the pin-axle constraint system is more suitable for curved girder bridge.