Force Analysis And Unbalanced Torque Prediction Of Spherical Hinge In Parallel Swivel Bridge Construction

The horizontal rotation construction technology can minimize the impact on the normal operation of traffic lines such as adjacent roads and bridges due to its construction process.The complex high-altitude and water construction is converted into flat construction,which ensures the safety and quality of construction.In recent years,the development tonnage and span of swivel bridges are increasing,but at the same time,the theoretical understanding of the swivel process lags behind the practice.In this paper,the spherical hinge of a rotating bridge is taken as the main object of analysis.Through theoretical and finite element simulation,a reasonable stress model of spherical hinge is established.The speed and acceleration limits and unbalanced loads during the rotating process are simulated and analyzed to guide the construction.Main work and study of this article are as follows:1.The simplification algorithm is analyzed separately,the semi-plane subjected to the concentrating force algorithm,the semi-space body subjected to the normal concentration force algorithm at the boundary,the half-space body subjected to the uniform pressure algorithm,the Hertz contact theory,and the vertical stress of the spherical hinge under different algorithms are compared.The ABAQUS FE simulation is carried out to verify the accuracy of different algorithms.And provide the basis for the calculation and size design.2.The stress and displacement distributions of spherical hinge and the upper and the lower caps under static loads are obtained by using FE simulation,and the accuracy of the theoretical value of the vertical contact force from the algorithm of uniform force distribution in half space is verified.3.The FE non-linear dynamic time history analysis of the spherical hinge rotation process is carried out,and the effects of different rotating speed and angular acceleration on the stress and displacement of the spherical hinge are obtained.It is found that to assure the safty,the allowable uniform rotation speed should not be more than 0.03 rad/min and the allowable angular acceleration of the rotation should not be greater than 1×10-3rad/s2.It can be as an supplement for the deficiencies of the design code.4.The advantages and disadvantages of the common unbalanced moment measuring methods are analyzed.and by comparing with the measured data,the accuracy of different measuring methods are verified,which shows that the method based on spherical hinge rotation is the most accurate;the method based on deflection of main beam only considers gravity effect in the landing process of main beam,which can also be used to evaluated the unbalanced monment if only the construction quality is guaranteed.5.The unbalanced moment measured from the construction site is applied to FE static analysis model of the swivel system and the stress and displacement distribution of the spherical hinge under the unbalanced moment are obtained.At the same time,based on the height difference limit of the edge of the spherical hinge,which is 1mm.From the real structure and the stess limit,the current spherical hinge can be considered being safe.6.Considering the unbalanced load and angular acceleration of the spherical hinge in the rotating process of the bridge structure,the FE dynamic time history analysis of the rotating system is carried out,and the effects of different unbalanced moment on the stress of the spherical hinge in the rotating process under the same acceleration and different acceleration are compared.The limit values of acceleration are obtained.