Grey System Theory And Its Applications In Construction Flexibility Deformation Monitoring Of Concrete Bridge

Self-erection system is applied to construction of most of modern large span concrete bridges. In the process of construction,cantilever beam is changing continuously because of the gravity of concrete,the stretching force,the load and temperature variation etc. In order to ensure that two cantilevers constructing opposite can normally close up and that the bridge linearity can accord with design,flexibility deformation has to be monitored. The aim of flexibility monitoring is to forecast possible flexibility of constructing girder according to the principle generalized from constructed girder so that measures can be taken. On account of the complexity of flexibility deformation and its influence factors,it can't be exactly measured,so it is thought as a grey quantum. In theory,it is feasible that using grey system theory to forecast flexibility. On the basis of this theory,taking 270 meters span continuous rigid frame bridge of HuMen Bridge as an example,this paper analyzes the flexibility deformation in the process of construction. At the same time,the other two models,namely regression analysis and time series analysis model,are used to compare calculation result.The whole paper is divided into four chapters. Chapter one introduces the aim,significance,classification of deformation monitoring and the development state of deformation analysis and forecasting study. Chapter two discourses the basic theory,calculation model and main advantages and disadvantages of regression analysis and time series analysis. Chapter three discusses grey system theory in detail,including the basic theory,grey incidence analysis,model in common use and forecasting method. Chapter four analyzes the results of flexibility deformation of 270 meters span continuous rigid frame bridge of HuMen Bridge,calculated with regression,time series and grey system model.Grey system theory applied to construct control in modern large span concrete bridge is in the stage of study. GM(1,h) model,considering the temperature variation influence on long cantilever girder,is proposed to solve the fitting and predication problem of flexbility deformation for the first time. After the applications,it shows higher precision and wider application prospect in small quantity data condition. The model would be popularized for cable-stayed bridge and continuous beam bridge.