The Construction Control Research On The Long-span Continuous Rigid Frame Bridge

With the rapid development of China's traffic, more and more long-span bridges are needed to span wide rivers and straits. The longer-span, the more difficult is in construction. As the important part of modern construction technology, construction control is playing a more and more important role of long-span bridges. In recent years, the continuous rigid frame bridge has been growing up rapidly with it's unique predominance. It almost has become the first selective bridge style when the span is long and the pier is high, so it's construction control has been an essential measure and step to ensure that the quality and safety are obtained during bridge construction, also to ensure that the final structural state is in agreement with what the designer requires. In this paper, the author expatiates some viewpoints to these problems, and brings up some improvement methods.(1) On the basis of the construction control data collection and aim at the nodus of bridge construction control—arameter identification and state prediction,the theory of Artificial Neural Network(ANN)has been applied to long-span bridge construction control in the thesis.(2) The paper expounded the current methods of simulation analysis and camber calculation and installation of construction control, emphasized the forward analysis and backward analysis and the absolute deflection method. On the basis formula of the camber, analyzing how to calculate the camber by using these kinds of methods in the continuous rigid frame bridge construction control.(3) This paper analyzed amply the application of the methods of parameter identification and state prediction to continuous rigid frame bridge construction control, and compared the least squares,Kalman's filtering method and Gray system method to Artificial Neural Network,augmengted the advantage of ANN method.(4) On the basis of the analysis of disadvantage of the BP network, an improvement neural network—Recurrent Network with bias elements—has been developed compared with BP network, the results show that it's applicability to continuous rigid frame bridge and advantage compared with BP network.(5) By means of the application of the methods that developed in this thesis to Nanmengxi bridge, proved this method's applicability and advantages,and executed construction control effectively to Nanmengxi bridge for safety of bridge's construction,ensured of smooth closing-join at mid-span,meeted need of design and keeping the ideal alignment after closing join.