Study On Aseismic Behavior Of Combined Bridge Of Continuous Ridig Frame And Concrete-Filled Steel Tubular Arch

With the debelopment of the national economy, long-span bridges have made great progresses, including the combination structure of long-span continous rigid frame and concrete filled steel tubular arch. China is an earthquake prone country. It is essential to analyse the seismic response of the bridge as a lifeline project, especially of the large-span bridge.In this thesis, taking Yichang Yangtze River Bridge as a reference, the development overview and the features of three types of bridges are introduced. The types of bridge include continous rigid frame, concrete-filled steel tubular arch bridge and their combination. This thesis also describes the earthquake damage to the bridges in brief and the seismic analysis methods in detail.Generally, the methods of seismic response analysis include response spectrum analysis method and dynamic time-history analysis method. In this thesis, bridge vibration characteristics are analyzed by using 3-D space finite element model and subspace iteration method. This thesis also calculated the elasitc seismic responses by putting the standard seismic response spectrum along the longitudinal, traverse and multi-dimension directions by means of CQC combination method. Futher, by choosing the EL-Centro seismic waves, and using Newmark Integration Method, the elastic seismic response analysis to the bridge is performed under the uniform excitation and the traveling-wave excitation respectively based on dynamic time-history analysis method.This thesis takes two analysis methods. The earthquake effects of the girder, the main pier, the arch ribs and the suspenders of the bridge under various loadcases are figured out. As far as this bridge is concerned, vertical component of seismic wave account for a large proportion using seismic response spectrum analysis method and dynamic time-history analysis method under the uniform excitation. There are greater internal forces in the partial sections of the latter. If considering vertical component of the seimic wave uing the dynamic time-history analysis under the traveling wave excitation, traveling-wave effect can not be ignored because it is different in the different parts of the bridge under earthquake effects.