Research On Deformation Analysis And Prediction Model Of Track Control Network During Operation Of Long-Span Rail-Road Cable-Stayed Bridge

The Shanghai-Suzhou-Nantong Yangtze River Bridge is the world’s first lone-span rail-road cable-stayed bridge with a span of over 1,000 meters.The bridge structure is greatly deformed by the temperature,wind,load and other environmental factors,which result in the dynamic change of the bridge.The track control network CPIII on the bridge will also change with the deformation of the bridge.In addition,CPⅢ resurvey and linear track survey need to be completed in multiple skylight periods.And CPⅢ on the bridge has changed under different skylight periods,which leads to the problem of whether CPⅢ can provide stable reference for linear track survey.At present,there is no CPⅢ operating and maintaining technology for the long-span cable-stayed bridge over 1,000 meters at home and abroad.The operating and maintaining CPⅢ surveying technology of the bridge is in the state of theoretical research and practical exploration.Therefore,this paper studies the CP Ⅲ operating and maintaining technology of the Shanghai-Suzhou-Nantong Yangtze River Bridge in the operation period,including the following main contents:(1)According to the structural deformation characteristics of long-span cable-stayed bridge.Studying suitable the measurement and data processing methods for CPIII.Researching the precision standards of CP Ⅲ measurement and data processing method.Studying the optimization effect of reinforced referencing points on CPⅢ control network.(2)This paper study the transverse,longitudinal and vertical deformation laws of CPⅢunder different temperature,wind and load conditions.analyzing the causes of CP Ⅲdeformation by combining the measured data of various automatic sensors in operation period and the basic mechanical relationship of bridge engineering structure.Study the spatial correlation deformation analysis between upper GNSS and lower CPⅢ.(3)Based on the vertical deformation law and influencing factors of CPⅢ.Through principal component analysis to extract the main factors in affecting CPIII elevation changing.A variety of elevation prediction models for three key points across the main span are established,respectively: CP Ⅲ prediction model based on temperature,CP Ⅲprediction model based on GNSS and CPⅢ prediction model based on temperature and GNSS.Finally the accuracy of each model was compared and analyzed to determine the optimal prediction model.(4)To study the change of CPIII on the main bridge caused by the expansion and contraction deformation of the girders.Based on the linear change pattern of CPIII on the bridge and the change relationship between the girder joints and CPIII.The CPIII plane prediction model of the bridge was established and the accuracy of the prediction model was verified.