Research On Key Technology Of Reasonable Control For Large Span Cable-stayed Bridge

With the rapid development of track traffic, the number of large span cable-stayed bridges for the track use is increasing day by day. Reasonable alignment control for this kind of bridge plays a significant role in guarantee the comfort, durability and the safety of bridge during operating period. Concrete shrinkage and creep belongs to long-term effects and train-track-bridge coupling interaction belongs to short-term effects. They are both the main factors which influence the alignment control for large span railway cable-stayed bridge and are not well mastered. In addition, there are not a uniform and clear theory and specifications in bridge alignment control area. Therefore, this paper studies the alignment control theory for large span railway cable-stayed bridge considering concrete shrinkage and creep and train-track-bridge coupling interaction effects. This paper provides the basis for alignment control of the same kind of bridges and it also has positive point in promoting the generating of specification. The main research respects and results are as follows:? After elaborating models of concrete shrinkage and creep and their calclulative methods, reasonable prediction model and calculation method for concrete shrinkage and creep are selected combined with measured environmental humidity, environmental temperature and selected materials. The adopted model is analyzed and verified through FEA calculation and measured data.The result shows that the choosed model is reasonable.?After elaborating the models, interactions and equation of motions of train-track-bridge coupling, the dynamic characteristics of large span cable-stayed bridge are analyzed combined with the measured dynamic load test data. The ratio of maximum dynamic displacement and maximum statistic displacement is obtained. Then, the quantitive relationship between train-track-bridge coupling interaction and camber is got based on this specific value.?The effect of concrete shrinkage and creep and train-track-bridge are considered into method of Kalman filter alignment control theory through state-transition matrix and prestressing camber expression. Then, Kalman filter alignment control theory considering concrete shrinkage and creep and train-track-bridge is obtained. The predictive values are calculated by MATLAB mathmetical software. Comparison and analysis of calculated values, measured values and prestrssing values show that the Kalman filter alignment control theory considering concrete shrinkage and creep and train-track-bridge coupling interaction can be suitable applied into alignment control for railway bridge.?The analysis for alignment control of the largest span in Asia and second largest span railway bridge in the world Chongqing railway transportation line 6-Caijia Jialing River Bridge is accomplished. The selected model, method and theory are verified reasonable. Therefore, Analysis and verify of Kalman filter alignment control theory considering concrete shrinkage and creep and train-track-bridge coupling effect for large span cable-stayed railway bridge is come true.