The Analysis Of Bridge Deformation Prediction Based On Chaotic Time Series

The bridge connect road and rail,is a hub constitute accessible transport network criss-cross of our country,it is an important part of road transport network. It provides a reliable protection for the country's economic development.It brought great convenience for people's work and life. But when affected by human activities and the external environment, bridge will also have deformation,and will give harm to the safety of human life and economic development. So,it is very important make deformation monitoring of bridges and expected future trends in bridge deformation according to the measured data.As a complicated system,all sortsof the bridge parameters itself are uneertain and random. They exchange substance, energy and information with outside continuously and their activities manifest complicated nonlinear actions during the proeess of evolution. The nonlinear nature of its determine we must established non-linear model to predict. As a non-linear prediction method,the chaotic time series prediction broke through the limitations of traditional methods to build models of subjective,it based on chaos theory, To predict through Analysis the internal rules of time series,it have been successfully applied in many areas.The thesis applies chaotic time series method in bridge deformation prediction, First,determine the system's chaotic by the calculation of the maximum Lyapunov index,then phase space reconstruction to the measured time series of bridge deformation, embedded the time series Reflect the bridge deformation to the phase space by choosing appropriate delay time and embedding dimension. By contrast,the chaotic time series prediction results is better than the method of exponential smoothing, it can prove this method is feasible.Finally,predict the future bridge deformation by the weighted local method and the weighted zero-order one-rank local method. At the same time,the article also analyzes the five main factors loading on the bridge deformation,and predicted by chaotic time series prediction methods, Have an important engineering significance for the future bridge deformation.