Span Continuous Rigid Frame Bridge Construction Control Theory And Applied Research

In recent years, long-span continuous rigid-frame bridges are more and more constructed due to their comfortable performance, easy construction and favorable maintenance, which promote the bridge design theory and the bridge construction control art. However, during bridge construction, many determinate and indeterminate factors make the actual state of bridge structure difficult to match the design state. Therefore, in order to make every stage of bridge construction to have reasonable deformation and inner force, the appropriate structure analysis theories and computation methods are necessary. The control of bridge construction is that based on structural analysis theories, parameter identification and deviation analysis, alignment and structural stress during the bridge construction are determined and modified in time. At the same time, the elevation of mould plate for next step is predicted so as the final structural stress and alignment of bridge of every step to meet to design requirements. In addition, strain modification can eliminate un-stress strain in actual, evaluate the actual stress state in bridge construction process and have great guidance meanings for bridge's safe construction.As the Shawan Bridge on the fourth line of Guangzhou railway transport and the Chongqin Qiongjianghe River Bridge on Yu-Sui freeway being engineering background in this paper, long-span bridge construction control theory and method are studied. The main contents are detailed as following:(1) Systematically review the advantages and disadvantages of self-erection construction method and development. Application of modern control theory to bridge construction is introduced.(2) Structural calculation methods to long-span bridge construction control such as forward-analysis method, backward-analysis method, stress-free status method etc. are introduced. The advantages and disadvantages of these methods are compared, and some existed problems are also pointed out.(3) Artificial neural network (ANN) technique is used in bridge construction control to effectively solve problems of complexity and indeterminate for bridge construction control. Based on the platform of matlab, the ANN program for bridge construction is developed. The ANN model for construction control is trained by the samples formed by the measured data. Then, the elevation of the mould plate for the next segment is predicted by the model. Furthermore, Noise pollution in field measurements can be effectively eliminated in this ANN model.(4) The method, to eliminate un-stress strain in measured data according to constitute of measured strain data from vibrating-wire strain sensors, is proposed in this paper, which can provide the base for effective control structural stress during the construction of the bridge.(5) The ANN model and strain modification method proposed in this paper is successful to predict alignment and modify structural stress for the Shawan Bridge and Qiongjianghe River Bridge.