Study And Practice On The Control Technology Of Cantilever Construction Of 50m+3×70m+50m Of South Central River Continuous Girder Bridge

Each segment of the cantilever construction of pre-stressed continuous beam bridge has to go through template elevation adjustments, pouring concrete, pre-stressed steel and other processes. If there was problem emerge in any of the segment, it would adversely affect the safety, stability, bridge linear and the force state of the structure. So it is important to implement control to its linear and stress during cantilever construction.The paper combine South Central River Bridge 50 m+3×70 m+50m pre-stressed continuous beam project and use MIDAS software to build finite element model in order to obtain stress and deformation at various stages of bridge construction by simulation calculation analysis of the entire construction process. Use ANSYS software to establish dimensional solid element to analyze the local stress of 0# block and to obtain the detail stress state on the basis of MIDAS analysis so as to verify the rationality of structure design. Calculate the pre-cast high values of each segment of the construction process as the theoretical value of template elevation through analyzing the results of model. Develop construction monitoring program of South Central River Bridge. And bury JMZX-212 surface-intelligent digital wire strain gauges and elevation measuring point in accordance with the program to observe deflection, temperature and stress of structure in each construction phase. Then analyze the data collected with theoretical date comparatively to adjust the parameter and conduct structure regression analysis and notice control information while using modern bridge prediction and control theory in order to propose amendments to the program to guide the construction. Analyze beam deflection and bridge linear and the influence and relationships between calculated and measured values of roof section stress, fourth cross-sectional stress and the key section stress of ultimate closure and tensile stage.The monitoring result shows that the boom phase stress and linear meet the design requirements and the ultimate bridge has smooth appearance linear and reasonable force.