Analysis On Dynamic Characteristics And Sesimic Response Of Special-Shape Concrete Filled Steel Tube Arch Bridge

With the extensive application of Concrete filled steel tube(CFST) arch bridge and the escalating of bridge esthetics, Special-shape CFST arch bridge wich is compose of constructions stuff and artistic has emerged. This type of bridge derive from traditional CFST arch bridge wich is combinated or dissimilated. because of distinct shape,singulary landscape and harmonizing environment, she is favored by the designers. While the capability of the bridge is exerted abundantly, there are some problem about force imposed on the construction. Especially, dynamic is striking. Model dynamic behavior such as seismic response, wind induced vibration, coupled dynamic vehicle loads should be studied thoroughly.In the thesis, firstly, the situation of development about CFST arch bridge has been related, the generation of special-shape CFST arch bridge has been discussed, the solution method on natural vibration characteristics of structure has been expounded. The method of computationc alon bridge anti-seismic theory has been summarized and the idea of seismic design has been introduced. Then, based on practical project——Shimian Dadu He Bridge, certain problem relating to dynmaic response behavior of Special-shape CFST arch bridge are studied.(1) The principle of establishing model about dynamical analysis for bridge has been summarized, the main beam of the bridge has been scattered by different means and the space finite element model has been established respectively by MIDAS. The rationality of the traditionary fishbone mode by wich Xinyue arch bridge is scattered has been tested. And based on analytic result of mode shape, the dynmaic characteristics of the bridge has been expounded comprehensively, meanwhile, immanent essence of the structure has been analysed.(2) By the use of current advanced anti-seismic concept, linear and nonlinear seismic response of the arch bridge has been analysed respectively under different seismic force (E1,E2 seismic force). Under E1 seismic fore, one-dimensional and one-dimensional response linear response has been analysed by response spectrum analysis and time-history analysis, the calculations results of different analysis method have been checked and compared, base on that, the anti-seismic capability of the arch bridge has been evaluated, finally, it has been proved that time-history analysis should been adopted to make a seismic response analysis of the complex structure similar to special-shape arch bridge. Under E2 seismic force, the nonlinear seismic response of the arch bridge has been analysed, Calculation results indicate that structure is kept working within its elastic range wich show clearly that Special-shape CFST arch bridge also have obvious merits, suchas light deadweight, better seismic behavior,However, in order to reflect real seismic response more exactly, nonlinear seismic response analysis of the bridge is also necessary.