3-D Seismic Response Analysis Of Bridge Pier-pile-Soil System

In this paper, use of large-scale finite element software ANSYS / LS-DYNA and parallel computing method, the cable-stayed bridge considering the pile - soil - dynamic interaction of the bridge seismic response analysis.(1) The development of pile-soil-bridge dynamic interaction and calculating methods, as well as in the world are summarized briefly in the paper. Furthermore, emphases of this research work are presented. The introduction of ANSYS/LS-DYNA program is existed, and which is take used of in songyuan bridge is also introduced.(2) based on the model with the rigid foundation, using Ansys/ls-dyna program, a dynamic analysis model is established and the dynamic characteristics are analyzed for the Songyuan River Highway Cable-stayed Bridge. In addition, the seismic responses of cable-stayed bridge under three dimensional orthogonal components acting individually or jointly are performed by uniform excitation method of time history response analysis. The results show that the cable-stayed bridge will occur large seismic response and coupled movement under transverse and longitudinal seismic excitation, verify the importance of 3-D model.(3) on the basis of lumped masses model developed by Penzien, a improved 3-D model is proposed and improved model are introduced, the 3-D pile-soil-bridge dynamic interaction analysis model is constructed. Using above improved model, free vibration and seismic response analysis time domain analysis are conducted for the Songyuan River Highway Cable-stayed Bridge with two different foundation type, rigid and pile foundation. The results show that the seismic responses of cable-stayed bridge with consideration of pile-soil-bridge dynamic interaction increase significantly, the seismic resistance demand was reduced by using the model with the rigid foundation for cable-stayed bridge which has deep pile foundation.(4) nonlinear behaviors in cable-stayed bridges with consideration of pile-soil-bridge dynamic interaction and nonlinear simulation methods are analyzed, and nonlinear finite element analysis model is established. Then a design idea is proposed that the design earthquake level should be improved one grade when analyzing the seismic response of deck by using the model with the rigid foundation, as well as an important theoretical base to compile the related design code.(5) Using seismic waves equivalent analysis of vertical seismic waves under the seismic response, and the soil - three-dimensional analysis of bridges were compared, we can see the following conclusions: the X displacement of the top tower decrease 24.22% , the absolute peak acceleration by Small 6.67%, the main beam of X-relative displacement to decrease 8.23 percent, the absolute peak acceleration decreased 12.72 percent, a difference of less results, we can see that seismic waves equivalent input is to be implemented.