Seismic Response Analysis Of Arch Stiffening Continuous Rigid Frame Bridge Under Non-Uniform Exctation And Shock Absorption

Arch stiffening continuous rigid frame bridge is a new type of bridge structure, which is a kind of full consolidation of arch, beam and pier. In recent years, it has been gradually applied in the high speed railway with the advantages of large rigidity, beautiful appearance and strong ability to span. To investigate the dynamic response characteristics and seismic performance of arch stiffening continuous rigid frame under non-uniform seismic excitation, we use the finite element software to establish a 93m+200m+93m three-dimensional finite element model of continuous rigid frame bridge with stiffening arch. We also research the dynamic characteristics of the bridge. The response spectrum analysis, the elastic-plastic analysis and dynamic time history analysis are carried out on the bridge, and the seismic behavior of the main pier is checked. By using the relative motion method and the large mass method, the non-uniform ground motion and the traveling wave effect are analyzed. The effect of viscous dampers on the seismic response of structures is also studied. The main conclusions of this paper are as follows:1. When the response spectrum is used to analyze the uniform excitation, there are significant differences between the internal force response of the pier bottom consolidation model and the pier bottom spring restraint model. So, in the practical work, the influence of the foundation stiffness (model boundary condition) on the dynamic response of the structure should be considered.2. Through the elastic-plastic analysis of the main pier, the seismic performance of the main pier is obtained. The main pier meets the requirements of seismic performance I and Ⅱ,but does not meet Ⅲ. Therefore it is necessary to adjust the section of the main piers to meet the seismic performance requirements.3. When the apparent wave velocity is in the range of 500m/s-3000m/s, the internal force of the structure is influenced significantly by the traveling wave effect. The larger the apparent wave velocity is, the smaller the influence of traveling wave effect on the internal force of the structure. When the apparent wave velocity approaches infinity, the internal force of the structure is close to that under the uniform excitation.4. Compared with the uniform excitation, the multiple point excitation of the traveling wave effect is considered to increase the displacement of the two main piers with different degrees, which is disadvantageous to the seismic and high speed driving of the main pier. Since the larger longitudinal stiffness of the bridge corresponds to the smaller total displacement of the pier, the traveling wave effect cannot be considered when the longitudinal stiffness of this kind of bridge is solved.5. Carrying out the parameter sensitivity analysis of the viscous damper, we get the recommended parameter of the viscous damping. The seismic response of the bridge is dominated by the viscous damper.