Research On Contact Analysis And Balance Control Of Ball Hinge In Flat Rotation Construction

With the continuous development of transportation infrastructure construction in China,it has increased sharply for the number of overpass bridge.We adopt the rotating construction method to construct the overpass bridge in order to avoid the effects of construction on the normal operation of traffic effectively.Therefore,it is widely used in the actual construction.However,it is not deep enough for its theoretical research.It will hinder its further development in practice by relying on experiences.This paper adopts the ball hinge structure of rotating body in the actual project to establish a finite element simulation model of ball hinge structure to reveal the stress distribution law of ball hinge contact surface at each stage and the influence of ball hinge edge effect by comparing with the theory of contact stress.Based on the test of unbalance torque,this paper makes research on the influence of unbalance moment on the contact stress of ball hinge structure and puts forward the control index of balance control.Meanwhile,this paper makes research on the effects of various stability factors on the rotating body of the bridge under wind environment and puts forward the concrete suggestions for balance control under wind environment.The main work of this paper is as follows:(1)According to the structural and stress characteristics of ball hinge,this paper analyzes and derives the contact stress solving theory for different structures of ball hinges by combining contact theory with elastic mechanics method,including the normalized and simplified algorithm,Hertz contact theory and the normal concentrated force on the boundary of half space.Through mutual verification of ABAQUS finite element model,it is found that it can better reflect the real stress distribution on the contact surface of the concrete of the ball hinge for the calculation method of normal concentrated force on the boundary of half space body.(2)This paper reveals the stress distribution law under static state,uniform rotation and accelerated rotation by carrying out the in-depth research on the contact force distribution problem of ball hinge and combing the contact theory with numerical simulation method.This paper puts forward the reasonable speed of rotating body process by establishing and analyzing time curve of stress comparing with current code.Meanwhile,this paper adopts the method of controlling variables to make research on the effects of the parameters of the ball hinge system on the maximum stress at the contact edge.(3)Based on the measurement methods of unbalance torque and field measured data,this paper adopts the comparison method to analyze the accuracy of different methods briefly.Based on this,this paper considers the effect of the unbalance torque and makes research on the effects of the unbalance torque on the ball hinge structure in the static and rotating states by taking the eccentricity of the rotating bridge as the control quantity.Meanwhile,this paper points out that we can adopt structure eccentricity as the control index of balance control,and puts forward the reference value.(4)In the process of rotating body,this paper considers the coupling effect of rotational angular velocity,pier height,unbalance moment and other factors with wind load and analyzes the effects of various factors on the stability of ball hinge under the wind environment in order to put forward the suggestions for balance control of process of rotation body under wind environment.