Study On The Influence Of Thickness Of Arch Ring On The Bearing Capacity Calculation Of Arch Bridge Under The Condition Of The Combined Effect Of The Spandrel Structure

The good mechanical behavior and the huge potential bearing capacity of the arch bridge, make itself has an irreplaceable position in the history of the development of bridge. The choice of the arch axis and the combined effect of the spandrel structure are the two major factors affecting the bearing capacity of arch bridge, however, the current design of the deck arch bridge usually haven’t taking the combined effect of the spandrel structure into consideration, which is calculated according to the naked arch, especially for deck arch bridge which has beam type spandrel structure. With the bridge becoming longer span and lighter weight, the combined effect of the spandrel structure has becoming more important. Because the large-span deck arch bridge usually employing the beam type spandrel structure, so with the lighter tendency of arch ring and the greater stiffness of the bridge deck system, the combined effect of the spandrel structure which has a greater stiffness has becoming more important that it cannot be neglected. Therefore, take the combined effect of the spandrel structure into consideration and take full use of it, then choose the optimal thickness of the arch ring reasonably, to make the arch bridge becoming more safety, longer span and more economical will become the trend of the development of the arch bridge.This paper based on an actual project, using the theoretical analysis and the finite element method, firstly analysis the good mechanical behavior of the arch bridge, two major factors affecting the bearing capacity of arch bridge and the calculation method of the internal force of arch bridge, then establish the single arch model and real bridge model, take comparative analysis of the influence of the combined effect of the spandrel structure and its influencing factors and the influence of the changing thickness on the internal forces and on the bearing capacity calculation of the arch ring. The main works are as follows:① Make a study of the mechanics behaviors of the arch bridge. Mainly analyze two factors affecting the bearing capacity of arch bridge: arch axis, combined effect of the spandrel structure, to respectively analyze their influence on the bearing capacity of arch bridge.② Introduces the design method of arch bridge. By referring to the literature, introduces the method of determination of the arch axis, the method of calculating the internal force of arch bridge and the treatment of the combined effect of the spandrel structure.③ Establish a single arch model to analyze the combined effect of the spandrel structure and its influencing factors. Using the finite element software MIDAS to establish the model of naked arch and the model which including vertical wall, crossbeam, waybeam which on the arch ring to considerate the combined effect of the spandrel structure; by changing the section properties of the vertical wall and the span between the vertical wall, to analyze the influencing factors of the combined effect of the spandrel structure.④ Establish a real bridge model to analyze the influence of the changing thickness on the internal forces and on the bearing capacity calculation of the arch ring, and to determine the optimal thickness value of the arch ring. Based on the actual projects "Jiange County Jianmen New District Qingjiang River Landscape Bridge", using the finite element software MIDAS to establish the real bridge model, firstly to analyze the distinction between the multi-span arch bridge and the single arch; then by the calculation results of changing thickness of arch ring to analyze the influence of the changing thickness on the internal forces and on the bearing capacity calculation of the arch ring; lastly, in accordance with the specification, calculate the bearing capacity of arch of each thickness of the arch ring and to determine the optimal thickness value of the arch ring.