Study On Seismic Behavior Analysis Of A Continuous CFST Arch Bridge

With the development of new materials, as a new type of bridge the concrete-filled steel tubular (CFST) arch bridge has been used widely in China from the early 1990's.The anti-seismic analysis of CFST remains necessary to be studied in depth. This dissertation is based on the researches of domestic and international experts on CFST and the seismic theories of concrete-filled steel tubular arch bridges. The major research content as follows:1,This dissertation is based on a 5-span continuous half-through CFST (concrete filled steel tube) arch bridge. Spatial finite element analysis model is established by the software-MIDAS to analyze the characteristics of this mode and calculate dynamic parameters such as self-vibration frequencies and modes. Meanwhile the influence of self-vibration characteristic is analyzed when primary structural parameters are changed. This dissertation mainly discusses four factors here and these factors are suspender modality, wale disposal, and structures of carrying over force and stiffness's changes. The computational results of the paper may be applied to seismic design of the continuous half-through CFST arch bridge.2,This dissertation analyze the influence of seismic parameter of bridges with time-history method and the major research content as follows: (1) The longitudinal,transverse and longitudinal + transverse seismic responses in the plane of the bridge deck calculated by the transient analysis method, and analysis of the characteristics and the regularity of the force in different seismic response.Weak anti-seismic position, namely, reinforcement measures of arch foot is put forword.(2) Analysis of seismic responses of the bridge in different speed travelling wave(sV=500m/s and V=1000m/s).(3) Comparing with consistence excitation and finding out the affect regulations of travelling waves. (4)Analysis of the longitudinal+transverse seismic responses in the plane of the bridge deck when the number of wale disposal is changed, and analysis of reinforcement measures of wale disposal.(5) Under the effect of seismic wave, the influence on structural seismic performance casued by local damage effects of the boom is analyzed, and reasonable reinforcement measures are put forward.The conclusions of this dissertation can be the reference of seismic and reinforcing designs and have some meaningful guidance for this continuous arch bridge.