| With the widely using of concrete filled steel tube structures, the analysistheory of this kind of structures is developped fast in recently years. China holdsa leading position in the construction and application of concrete-filled steel tubearch bridges in the world, but research works concerning concrete-filled steeltube arch bridges are still needed. In addition, there is no code that can be used toconduct seismic resistance design of concrete filled steel tube arch bridges inChina. Since China is a country with many earthquakes, the seismic resistance ofbridges is very important with regard to its vital role in life line projects. However,China falls behind other countries in the field of large-span concrete-filled steeltube arch bridges. Therefore, to research the seismic resistance of concrete filledsteel tube arch bridges and provide corresponding theory is very significant topractice. The model of concrete-filled steel tube arch bridges and geometrynonlinearity are studied. Based on an example of a large-span concrete filled steeltube arch bridge, its dynamic property and seismic response analysis areresearched. The main works of the thesis are as follows,1. The development of concrete filled steel tube arch bridges is introduced.The structure forms and mechanical characteristic of concrete filled steel tubearch bridges are analyzed. In addition, the research work of concrete filled steeltube arch bridges seismic responses and seismic resistance of bridges aresummarized.2. Based on the structure characteristics of large-span concrete filled steeltube arch bridges, the linear and nonlinear vibration equations of bridges areestablished and their solutions are given as well. Also, the selection and inputmethods of earthquake accelerograms for time-history analysis are studied. Theconstitutive model of concrete filled steel tube composition materials is furtheranalyzed. In addition, the damping problems of concrete filled steel tube archbridges are discussed, and the analysis methods of arch bridge geometrynonlinearity are provided.3. Based on a260-meter span concrete filled steel tube arch bridge, athree-dimensional finite element model is established with the aid of SAP2000toanalyze natural vibration characteristics of concrete filled steel tube arch bridges.In addition, the natural vibration characteristics of concrete filled steel tube archbridges with different support conditions are analyzed.4. Amplitude modulated El Centro earthquake is used as single input,transverse orthogonal input and vertical orthogonal input to analyze seismicresponses of structures in three different directions. Also, impacts of nonlinearityand traveling wave effects on seismic responses of concrete filled steel tube archbridges are analyzed. As references, results obtaine in this thesis can be used in seismic resistancedesign of concrete filled steel tube arch bridges. |
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