Research On Construction Monitoring Technology Of Separated Overpass Of Weiqing Expressway K13+920 Separation Overpass

With the rapid development of infrastructure construction in China,the demand for bridge construction is increasing day by day,and the quality,beauty and driving comfort of bridge are also put forward higher requirements.The prestressed concrete continuous girder bridge plays an important role in the field of bridge construction because of its good integrity,large structural stiffness,small deformation,beautiful linear shape and many other advantages.The application of cantilever construction method greatly improves the environmental adaptability of the bridge and makes it get considerable development.However,in the construction process of continuous beam bridge,it is still vulnerable to many uncertain factors,which will lead to the deviation of bridge deformation and force,and affect the safety and durability of bridge structure.Therefore,it is necessary to monitor the construction of the continuous beam with suspended prestressed concrete,and the monitoring method should be optimized and perfected continuously.Based on the actual project of Weiqing Expressway K13+920 separation overpass,this paper systematically studies and introduces the construction monitoring.Midas Civil finite element analysis software was used to establish the main beam simulation calculation model,the model calculation results of several key construction nodes were deeply studied,and important construction parameters were selected for parameter sensitivity analysis,to grasp the deformation and stress characteristics of the structure as a whole,which laid a theoretical foundation for the implementation of construction monitoring.In the linear control of bridge,the theoretical mold elevation was established according to the calculation analysis of precamp and the preloading test of hanging basket,and the dynamic correction of mold elevation was carried out by the forward analysis method,which verified the feasibility of this method in the dynamic control of continuous beam bridge.Based on the calculation results of the model,the deflection control in the construction process and the correction results of the mold elevation,the deformation characteristics of the main beam are analyzed,and the Kalman filter model,BP neural network model and Kalman-BP neural network combination model are introduced to predict and analyze the deflection of the key beam segment,and the prediction effects of the three models are compared.The accuracy and superiority of Kalman-BP neural network combined model in deflection prediction compared with single prediction model are proved,and the applicability and feasibility of the combined prediction model for continuous beam bridge deflection prediction are verified.This paper summarizes and analyzes the construction monitoring results of K13+920 separation overpass,and verifies the feasibility of the construction monitoring method in this paper.