Study On Short-line Construction Control Of Ultra-wide Concrete Box Girder

In recent years,people pay more and more attention to quality engineering and green engineering.The section box beam short-distance method prefabrication and assembly technology that combines these advantages has been placed in a more prominent position.At present,China is vigorously promoting the application of short-term prefabrication and assembly technology.Prefabrication of wide-segment multi-section concrete box girder constructed by short-term prefabricated assembly method is more complex than the construction of conventional prefabricated sections of continuous box girder,and the control is more difficult.This paper takes the prefabricated construction of the north side span of Shishou Changjiang Highway Bridge as the engineering background,and studies the key technologies for the construction control of ultra-wide section box girder short-term method.The main research contents are as follows:(1)According to the characteristics of super-wide box girder short-term prefabrication and assembly construction,the construction control content and methods for this construction method are introduced,including the calculation of the prefabricated line shape of the main girder,the calculation method of the prefabricated dimensions of the box girder of the concrete segment,and the longitudinal direction of the main girder,Horizontal linear control method.(2)Conduct research on the practical application of short-line prefabrication and assembly technology in prefabrication of wide-beam concrete section box girder.Including:full-bridge theoretical simulation calculation;calculation of segmental box girder prefabricated dimensions and the actual positioning method of the beam segment;segment box girder prefabricated size specific correction method.The precise prefabrication of the super wide box girder is achieved.(3)The safety control in the construction of sliding,lifting and storage of box girders in the prefabrication of wide-span concrete box girders was studied.In the prefabrication of wide-span concrete box girder,the timing of the transversal prestressing and the control target are determined by grasping the timing of system transformation.The finite element analysis method is used to accurately analyze the lateral prestress effect of the wide prefabricated box girder according to the stress and displacement constraints.The conditions reasonably determined the specific tensioning scheme for transverse prestressing.Effectively ensure the safety of the transverse force of the concrete box girder in the process of sliding,lifting,and storing the beam.(4)It can be seen from the previous example of the project that when the wide section box beams are glued together,the tooth-to-tooth gaps between the beam sections are likely to interfere and affect the glueing of the beam sections.This paper analyzes the reasons for the interference of tooth-to-tooth splines in the glue segment of beam segment and proposes solutions.