Research On Construction Monitoring Of Long-span Continuous Rigid Frame Bridge With High Piers Based On Grey Prediction Theory

In the southwest region,the mountains are steep and steep and the ravines are longitudinal,and the high piers and large spans of continuous rigid bridges can adapt well to the mountainous terrain,and in recent years,they have gradually occupied an important position in the transportation construction of the southwest region.High pier large span continuous rigid structure bridges are more sensitive to the influence of environmental factors in the construction process due to the flexible structure of the large scale of the piers and main girders.In order to ensure the safety of construction and the smooth completion of the whole bridge,it is necessary to rely on construction monitoring,at present,the domestic bridge construction monitoring technology has been relatively mature,but the control theory is still relatively lacking.Based on this,this paper takes the Xixi River Bridge in Wuxi County,Chongqing as the research object,and studies the bridge construction monitoring based on the gray theory,and the main work and corresponding research results achieved are as follows:Ⅰ.Introduces construction monitoring theory and grey theory.The methods and main contents of bridge construction monitoring are introduced,the concept and modeling process of grey theory are introduced in detail,the characteristics of a variety of typical grey prediction models are compared,and the prediction model suitable for this paper is selected according to its characteristics-the metabolism GM(1,1)model.Ⅱ.Establish a finite element model based on engineering.The finite element software Midas/Civil is used to establish a simulation analysis model of Xixi He Bridge,and the simulation analysis of the whole process of construction is carried out by using the formal calculation method,and the theoretical values of deflection and stress of each construction stage of the main girder are obtained.Ⅲ.Analyze the parameter sensitivity of a gray predictive model.Among the many influencing factors,the initial defects of the piers,the temperature load and the wind load will have a great influence on the construction of the high pier and the large span continuous rigid bridge,and the sensitivity of the grey prediction model to the initial defects of the pier,the temperature load and the wind load are analyzed.Ⅳ.This paper proposes an optimization method for grey prediction model.Aiming at the problem that the large dispersion of the original data will cause the error of the gray model prediction result to be large,a method of raw data preprocessing is proposed to optimize the prediction model,and two gray models of the original model and the optimization model are established to predict the deflection and stress of the main beam.Ⅴ.Compare the accuracy of the two predictive models.The residual,posterior and similarity test methods are applied,and the prediction results of the two models are compared with the measured data of the construction site.