Research On Seismic Response Of Continuous Rigid Frame Bridge With Corrugated Steel Webs Considering Soil-Pile Interaction

Continuous rigid frame bridge with corrugated steel webs is a new structure in recent years. Compared with the bridge with common concrete webs, this type of structure attracts wide attention as it has a great deal of advantages in the structure, mechanical performance and economic benefit, etc. The research of this kind of bridge in China has mainly focused on static performance, but rarely on dynamic performance. Based on the continuous rigid frame bridge with corrugated steel webs in Xiaoshagou, various analysis models of pile-soil interaction are established. The dynamic characteristics and seismic response of continuous rigid frame bridge with corrugated steel webs are researched in this thesis, as well as the contrast to the bridge with common concrete webs in same circumstances. The main work and results are listed as follows:(1) Four different pile-soil interaction analysis models (direct embedded model, equivalent embedded model, six-spring model and M model) are established for the dynamic characteristics of comparative study. The results show the natural frequency in the same order modes decrease in the order of direct embedded model, equivalent embedded model, six-spring model and M model which suggests the pile-soil interaction reduce the stiffness of bridge structure and prolong the natural vibration period.(2) A comparative research is made about the seismic response of four different pile-soil interaction analysis models under the El seismic action by multi-mode response spectrum method. The results show the displacement response increase in the order of direct embedded model, equivalent embedded model, six-spring model and M model; The difference of internal force response between direct embedded model and M model states that after considering pile-soil interaction, the seismic response of the substructure decreases while the results of the whole structure will not always be safe which demonstrates the necessity of consideration of pile-soil interaction; The result of equivalent embedded model is slightly greater than M model while the difference is small; the difference of result between six-spring model and M model is within 5%, and six-spring model is less slightly.(3) 3D embedded model, H embedded model and 5D embedded model are built to explore the effect of embedded depth H to the dynamic characteristics and response of equivalent embedded model. The results show that with the increase of embedded depth H, the stiffness of equivalent embedded model decreases, and the natural vibration period and seismic response increase.(4) A comparative research on the dynamic characteristics of continuous rigid frame bridge with corrugated steel webs and the structure with common concrete webs is made which shows the fact that the low order natural frequency difference is very small, while high order frequency has large difference and the natural frequency of continuous rigid frame with corrugated steel webs is smaller generally.(5) Dynamic time history analysis method is used for the comparison between two continuous rigid frame bridges on the seismic response under the E2 seismic action. The results show continuous rigid frame bridge with corrugated steel webs has better seismic performance whose seismic response under the action of the same earthquake is smaller than the bridge with common concrete webs.