| Arch bridge, with extremely high aesthetic value, acting as one of the fundamental bridge types and possessing a profound historical origin, is widely applied in engineering and is a popular bridge type in our nation's construction. As the application of CFST (Concrete Filled Steel Tube) structures to bridges has solved the problem of the application of high-strength material of arch bridge and the problem of the construction of arch bridge, two main bridge puzzles, arch bridge becomes much lighter and has stronger expressive force and the development of arch bridge is infused with fresh vitality. Therefore, CFST arch bridge has gained a booming opportunity in our country and meanwhile a large number of arch bridges have been constructed in our country. With wonderful architectural styles, through and half through arch bridges, are commonly favored in urban bridge design and construction so as to be the symbol of civic constructions. For the moment, they are still advancing on wider span and larger scale and their application region and scope are enlarged continually. Currently,.the design and construction of CFST arch bridge can only be based on the CFST specifications in the construction industry with the combination of relevant clauses in the bridge design codes which bring about certain difficulties to the practical application of this sort of bridge for the lack of special design codes and construction codes.In recent years, some subjective and objective reasons resulted in some accidents of arch bridge collapses and severe casualties and economic loss related. Such conclusion can be derived from these accidents' analyses that breaking up and collapse of through and half through bridges mostly relate with the health condition of suspenders; if timely and real time online monitoring and diagnoses are conducted, a majority of serious accidents can be avoided. Only by adopting refined FEM (Finite Element Method) to analyze the whole bridge's mechanical properties to get the stress and strain characteristics of the bridge, can the suspenders' health conditions of the through and half through arch bridges be exactly estimated. Especially the suspenders, as one of the vital load-bearing members of the arch bridge, whose internal forces are calculated by making the model of deck simple-supported beam and ignoring the effects that are brought on to the suspenders' internal forces by the factors such as deck's continuity and elastic supports, are coarsely calculated during the traditional design. Consequently, only by adopting the whole and fine finite element calculating model which is integrated by arch ribs, suspenders and the bridge deck system, can its internal forces be precisely calculated to provide references to the tied arch bridge's design and detailed mechanical materials to the health detection and diagnoses of suspenders. Conducting the analyses of arch bridges' mechanical properties takes on its important theoretical senses and practical values, and this dissertation is written and developed in this background.In this dissertation, the Yellow River main bridge in Zhengzhou section of Jingzhu freeway, a through CFST arch bridge is discretized by the FEM according to its structural characteristics with the spatial beam element simulating the horizontal tied beams, end floor beams, middle floor beams, arch ribs and the like and with the spatial link element simulating the suspenders to erect the bridge's spatial mechanical computational finite element model. Finite element common software ANSYS is applied for its spatial mechanical calculation and mechanical properties in various cases are obtained. Meanwhile, influences that the damage of the suspenders has brought on to this arch bridge's mechanical properties of the static state, dynamic characteristics and stability are discussedso as to acquire the main fruit in the dissertation below:(1) From the static calculation and analyses of the bridge under the dead load and the deflected live load of the outboard automobile load, it is obvious that... |
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