The Static And Dynamic Analysis Of Long-Span Cfst Railway Arck Bridge And The Optimum Design Of Arch Rib

Emergence of CFST (concrete filled steel tubular) structures solves the two significant problems-the application of high intensity materials and the construction method, thereby promoting the development and application of CFST arch bridges. In this thesis a Basket-Like CFST arch bridge is introduced as a background project, to establish a spatial finite element model by the FEM software-Midas/Civil and analyze the static and dynamic characteristics of the large-span CFST arch bridge. And on this basis, it also discusses effect of the corresponding design parameters of the long-span CFST arch rib structure on the internal force and stress of rib structures, choosing relatively reasonable design parameters of the total.This thesis contains the following major elements:1. The application and development of the CFST arch bridges at home and abroad are summarized, and the dynamic characteristics and structural optimization of the status quo of the CFST arch bridge are analyzed in this article as well.2. By utilizing the FEM software Midas/Civil to establish a spatial finite element model, and to analyze the effect of rib structures of long-span CFST arch bridges under all distributional loads in different states. And apart from this, the exact proportion of every distributional load in combined effects and the most adverse combined effect of the total in bridge state are confirmed.3. Based on the FEM model, the free vibration characteristics and frequencies and model shapes are calculated for this bridge.4. In this thesis the effect of inclined angle of the arch rib structure, inner diameter of the steel tube, thickness of the pipe wall and elastic modulus of the concrete as the design parameters are discussed. Additionally, the sensitivity of cross-section internal forces and stress of the concrete and tube under the changement of every design parameter is analysed and calculated by establishing different spatial finite element models. On this basis, the relatively reasonable parameters of the rib structure are choosed, and the effect of rib structural stress after optimization is compared with before.