Construction Control Technology And Procedure Application Of Short Line Assembly Methodology For Continuous Box Girder Bridge

With the application and development of construction technology and external prestressing technology in bridge construction,the construction method of segmental assembly of prestressed concrete continuous girder bridge has received increasing attention.The bridge construction is transformed from high altitude to ground factory,which breaks the whole of bridge construction into parts and enables the simultaneous construction of both the upper and lower structures,shortening the construction period.Prefabrication of prestressed concrete box girder is divided into long line method and short line method.The fabrication of long line prefabricated pedestal is consistent with the line shape of the bottom edge of the bridge without stress structure.The long line method,though developing earlier and having more mature technology is marked with higher cost and more strict demand for the construction site.Compared with the long line method,the short line method has the advantages of high accuracy,high degree of mechanization and short construction period.Since 2003 when the short line method was first used in the construction of Su tong Yangtze River Highway Bridge in China,short line method has been widely applied in bridge construction.At present,the short line matching method is developing towards industrialization,standardization and assembly.Based on the example of the south bank bridge on the South Bank of the Yangtze River Highway Bridge in Hubei province and the characteristics of the precast assembly process,the thesis makes a comprehensive analysis and research on the construction control of the section box girder for the short line assembly of the continuous beam bridge.The main contents include that:(1)The construction process of section box girder with short line matching method and the principle of segmenting section beam are introduced,and the linear control method of the precast linear segment and the curve section is emphatically compared and analyzed.(2)A geometric control point selection method and linear control principle based on short line matching method in the prefabrication stage are put forward,and the linear control coordinates are derived;Based on Visual Basic for Application language,the bridge short line prefabrication construction analysis program is compiled,and the program is applied to this project.(3)Based on sensitivity analysis of assembly stage parameters,the cause of measurement and theoretical error is analyzed,a linear adjustment method has been formed in the short line assembly stage,and the assembly stage construction analysis program has been compiled.Based on the measured data,the results of internal force and line type analysis of segmental beam during assembly and completion stage are verified.(4)Combined with engineering example,the factors of external prestress loss are studied,The finite element model is established by ANSYS,and the detail structure(steering block and middle crossbeam)is simulated and analyzed,The stress transfer path and stress characteristics of detail structure are revealed,providing guidance for construction and design.