Study On Mechanical Performance And Structure Of Through Flexible Tied Arch Bridge

The arch bridge is one of the oldest bridges. Because of its unique structure, the arch ring does not need to withstand intensive bending moment and tension, which makes the masonry work material (a kind of material which is cheap, accessible and of good resistance to pressure) suitable for the construction of this type of bridge. With the development of the modern bridges, the emphases in the construction of arch bridges are placed on the optimization of mechanical properties, beautification and economization. Nowadays there are many kinds of arch bridges. One of these is the tied arch bridge which employs tie bars to overcome the powerful horizontal thrust and achieve self-balance. Among the researches into this kind of bridge, few of them are on the bearing capacity of through flexible tied bars arch bridges. This thesis probes into the structure and mechanical characteristics of this kind of bridge in hopes that it could provide reference material for the design and application of this kind of bridge.To make the transmission structure more visualized, and for the convenience of the experiment, a model of through flexible tied bars arch bridges is designed and made, and this model is the object of the study. Based on this model, the study adopts the finite element simulation and experimental methods to explore the structural characteristics and mechanical characteristics of this kind of bridge from different angles, and probes into the power performance with an engineering case. Accordingly the thesis includes six parts as follows:(1) The development history and classification of arch bridges, the development history and classification of tied arch bridges, and the state of the field and findings of the research on tied arch bridges at home and abroad are introduced. In addition, the range of the present study and its contents are presented as well.(2) Introduces manufacture of the experimental model and selection of the arch axis. The influence and shape deformation of the arch rib, bridge decking and booms under local loads in the deck are discussed.(3) The mechanical characteristics of the arch rib and tie bars are expounded. Furthermore, the dynamic characteristics and the deflection relationship of arch springing under the three boundary conditions are analyzed, and some useful conclusions are gained.(4) Through the static analysis, dynamic analysis and stability analysis, the mechanical characteristics of the structure under four different wind bracings (i.e., "1" shape, "K" shape, "X" shape and " " shape) are investigated. Moreover, the advantages and disadvantages of the four different wind bracings are compared on the basis of the results of the analysis, which is helpful for the choosing of the right wind bracing for the bridge.(5) With an engineering case, the present study conducts a dynamic response analysis of the real bridge by finite element analysis and on-site environmental fluctuation test methods, and compares the results of the two methods, thus verifying the reliability of the conclusions and offering valuable data of dynamic characteristics.(6) A summary of the contents and the results of the present study is made, and the omissions existing in the study and the issues that need in-depth research are also pointed out.