Research On Key Technology Of Super-large Tonnage T Rigid Frame Bridge Rotation

Along with our country’s traffic network increasingly perfect,in the future bridge construction field is bound to meet more existing railway and roads need to span,the turnround construction method is a good solution to this problem.The development trend of rotary bridge will tend to be larger tonnage,which puts forward higher technical requirements for the construction of rotary bridge.Especially for large-tonnage T-shaped rigid frame Bridges,the construction technology is difficult,the construction process is complex,and the accuracy of bridge rotation is higher,which is still a difficult problem in the field of rotary construction.（1）Optimize the key design parameters of large-tonnage T-frame rotary bridge ball hinge.The design points and different force theory of ball hinge are expounded.On this basis,ABAQUS was used to build the ball hinge simulation model,and the numerical simulation was carried out to explore the influence of different design factors on the force of the ball hinge structure.The design of ball joints is optimized,and it is proposed that the height of ball joints is the key design factor affecting the force of ball joints.（2）The stress state of the upper structure and the lower structure of the large tonnage T-frame rotary bridge is analyzed and studied.The construction process of T-structure bridge superstructure is briefly described.ABAQUS finite element software was used to establish simulation models of the upper and lower structures.The stress response of the upper structure and the lower structure under different rotation speeds and acceleration was analyzed.0.02 rad/min was selected as the rotation speed and 1.00×10^-3rad/min² as the rotation acceleration.（3）Analysis and research on unbalance test of large-tonnage T-frame rotating bridge.The weighing test methods and counterweight schemes under different theories are described,and the appropriate weighing and counterweight schemes are selected according to the characteristics of specific projects.The unbalance torque,static friction coefficient,eccentricity and other parameters are obtained.According to the requirements of relevant specifications and practical engineering experience,it is suggested that the bridge can be directly carried out rotating construction without counterweight.（4）Research on key technologies for monitoring and control of large-tonnage T-structure rotary bridge.Midas finite element model was built to monitor and analyze the linear shape,stress,rotation speed,rotation acceleration,beam end deflection and box beam root stress in the process of bridge rotation in real time.The error was controlled within the specified range to ensure the effective control of the whole process of bridge rotation construction.