Study And Practice On Monitoring Technology Of Cantilever Construction For The Songhuajiang Continuous Box Girder Bridge

Cantilever construction method used in long-span continuous prestressed concrete girder bridge to be going through a complicated process, this process will be determined by many certain and uncertain factors, and a bridge leading to the actual structure of the state is expected to depart from it, which appears by unreasonable structure stress and construction linear, so that the closure of bridge and the design does not to be required. Therefore, Construction Monitoring of the bridge is very important. It is necessary to adopt a reasonable analysis theory and calculation method to determine the stress and deformation at every stage of the bridge construction process. Construction Monitoring of the bridge is based on analysis the construction process of stress and linear control, the construction of the error analyzed to identify, the problem be corrected in a timely adjust and at the same time the structure of the followed stage be able to correctly predict. The ultimate goal of the finished bridge state is to meet the design requirements.Based on the construction of Songhuajiang Bridge, the finite element model of the bridge is established by the MIDAS software to analyze the bridge construction in various stages of deformation and force, according to the analysis of the results to calculate the flip-height. In accordance with the practical construction monitoring situation of Songhuajiang Bridge, the reasonable observation schemes are proposed, the flow of construction monitoring is designed, and the effective control system is built. Deflection, temperature and stress are observed, material mechanical property, physical dimension of box beam and prestressing are measured. Then analyze the difference between the theoretical calculation and original data collected. Gradually adjusted the theoretical model so that match the theoretical calculation to the original data collected. By using modern predictive control theory, through parameter adjustment, forward and backward analysis, to forecast the control information and propose reasonable plan, so as to instruct the construction. Finally, monitoring results of the project of Songhuajiang Bridge are introduced in this article, the real deflection; displacement and stress of segments are accordance with comparing. Then, the Songhuajiang Bridge on the geographical location of the cold areas Bridge structure temperature field and temperature effects are monitor and tested. The results showed that the ultimate control of this bridge have reached an anticipative goal in smooth linear and reasonable structure stress.