The Research On Reasonable Completed Cable Force And Construction Control Of Cable-Stayed Arch Bridge

In recent years, with the progress of society, the rapid development of national economy and people’s pursuit for spans and aesthetics of bridges,more and more unique and novel bridges appeared. Cable-stayed arch bridge was a new type of hybrid bridge which arose at the beginning of this century, but the research of them is inadequate neither in the domestic nor abroad, on the other hand, it has particular advantages compared with other bridges, so a deep and systemic study is necessary about the structural features、reasonable completed cable force and construction control. This paper focuses on one cable-stayed arch bridge under construction, then analyze its static characteristics, afterwards a comprehensive algorithm is proposed which considering weight values based on mechanical characteristics, and to determine the reasonable completed cable force of the bridge as the objective, an adaptive control method is taken for the bridge construction. The main research contents are as follows:(1) According to the research background of engineering, the stiffness and internal force are analyzed among the cable-stayed bridge, arch bridge and cooperative system bridge under the same spans, and the results show that the mechanical characteristics of cooperative system bridge are more inclined to arch bridge, but it also exists the beam-column effect like cable-stayed bridge. The axial compressive stress in main girder of cooperative system bridge reserves more than arch bridge and less pressed steel beams will be needed; compared the cooperative system bridge with arch bridge, the spans could be much longer obviously. Furthermore, the beam-column effect will be lower in the cooperative system bridge compared with cable-stayed bridge, also the force in cable tower is smaller.(2) Under live load, the research focuses on effect of mechanical properties of the structure based on stiffness parameters changes of main girders, arch rids, suspenders and cables. It is clearly seen that with increasing stiffness of arch ribs and suspenders can reduce the bending moment of main girder and tower root, the displacement of main girder and tower top also decreases.(3) Reasonable completed cable force of traditional correlation analysis theories and methods are elucidated of cable-stayed arch bridge, combined with mechanical characteristics of the cooperative system bridge, a comprehensive algorithm is put forward which considering weight values based on conventional methods. Finally, an example is provided to illustrate the validity and feasibility of this method.(4) Due to the research of the dependence of completion state of bridge on parameters of cable-stayed arch bridge is insufficient, this paper mainly focuses on analysis about internal force and linear because of parameters changes of main girder weight, cable tension, suspender tension, environmental temperature in completion state of bridge, and conclusion is that environmental temperature affects internal force and displacement of this structure most conspicuous, cable tension and main girder weight error affect less than environmental temperature, and suspender tension error has the minimum impact on it. And parameters are identified by using the least-squares method of Xiangfeng River Bridge.(5) With the above method to determine reasonable completed state of the bridge as the target, a construction control finite element model is established combining the bridge features, and according to the model to analyze the efforts, a reasonable and effective construction monitoring scheme is confirmed eventually. So taking adaptive control method for the Xiangfeng River Bridge construction can achieve the good control effect.