The Research Of Construction Control Technology On Long-span Prestressed Concrete Beam Bridge

Long-span PC beam bridge mainly refers to the long-span prestressed concrete continuous beam bridge, continuous rigid-frame bridge and T-type rigid-frame bridge, occuping an important position in bridge construction. Since 1953, with the successful inception of cantilever casting method, prestressed concrete beam bridge has developed rapidly. The ideal geometric linear and rational internal force of Long-span PC beam bridge is not only design-related, but also depends on the scientific construction methods. In order to ensure the safety of the bridge structure during the construction phase, acquire a smooth linear and reasonable internal force of the bridge after completion and meet the requirements of the design, it is indispensable to monitor and control the actual response of the structure(segment deflection, the main beam stress, etc.) in the bridge construction process.This thesis summarizes the construction control methods and the construction process analysis theory of the structure applied recently in bridge engineering. Based on the construction monitoring and controlling of a prestressed concrete continuous beam bridge, the methods of parameter identification and the self-adaptive control theory applied in the beam bridge construction control, linear factors of PC beam bridge, stress analysis methods, and the construction control technology of closure segment are researched. Using least square method, prestressed tube friction resistance parameters k andμare obtained through on-site testing, and then the structure model which was established by the software Midas civil\6.71 was amended. Calculation results are basically consistent with the actual state of the structure. After the analysis of various factors affecting the structure's deflection, the impact of temperature on template adjustment was dealt with using relative-elevation template adjustment method. That lay the foundation for the effective control of linear. By increasing the frequency of strain monitoring, the shrinkage, creep and other non-stress-strain of concrete are separated simply. The stress-strain of control section derived from analysis is basically consistent with the theoretical values. Finally, the method of stress analysis on the closure segment is given when the temperature changes and the impact of provisional tension on rods rigidly connected to the closure segment is analysed using general finite element software ANSYS. That provides a reasonable proposal for the closure segment construction.Monitoring results show that the content of the research is comprehensive. The research results meet the needs of long-span PC beam bridge in construction control and the research results have certain engineering application value. In particular, the methods of parameter identification and relative-elevation template adjustment are worthy reference for other similar projects.