Technical Research On Rotation Construction Of Largetonnage Prestressed Concrete T-Frame Bridge

In recent years,bridge rotation construction is widely used mainly because it can solve the problem of intertwined traffic while its impact on existing roads is also small.The foremost for the bridge horizontal rotation construction is the design and construction of the rotation system.The difficulties and key points in the construction of the bridge rotation system are processing accuracy of the rotation system components,the installation accuracy,the design of the spherical hinge,the construction of the rotation system,the rotation construction process and the influencing factors for the fast rotation.This paper deals with the items mentioned above by studying a 2×65m T-frame rotation construction project,from which the main conclusions are obtained as follows:First of all,it summarizes,the construction considerations,countermeasures and quality control standards of the construction of each key part of the rotation system,depending on which a complete set of rotation system technology is formed.It also puts forward the precision standard and control requirements of the key components of the rotation system through the study of the accuracy requirements of the rotation system combined with the practical situation of the project and the construction experiences of the similar bridges In this project,the spherical degree of finish of the spherical hinge is not less then ?3.The curvature of each part of the shperical surface is not more then 2mm.The steel pipe gradient is not more than 3‰.The installation elevation error of the lower spherical hinge is not more than 0.5mm.The slide flatness is not more than 0.5mm / m.The gap between the frame brace and slide is controlled in the range of(20±2)mm.Secondly,ANSYS is used herein to simulate the construction condition,and thus analyze the stress influences of different rotation linear speeds and rotation acceleration,etc.on the T-frame.The results show that the effect of uniform rotation on the structure stress is slight,the correctness of which is verified by the monitoring data.In the case of accelerated rotation,the root stress response of the main beam is the most sensitive,and its maximum normal stress is basically directly proportional to the acceleration of the angle of rotation.Finally,this paper analyzes the stability of the T-frame under the maximum cantilever state and the wind load.The results show that the anti-overturning stability,the transverse and transverse stability and the the rotation resistance of the structure under the static load of the wind meet the design and construction requirements.The research output of this study can provide reference for the rotation construction of similar bridge.