Analysis Of Seismic Response Of Bridge Considering Soil-structure Dynamic Interaction And Local Site Condition

Bridges are major projects related to people’s livelihood, They are likely to suffer earthquake damage resulting in disastrous consequences in the period of construction and use, therefore, the study of the dynamic response of the bridge structure under seismic action is important. For the problems of bridge seismic response analysis in this period, author conducted a comprehensive analysis of the seismic response of long-span bridges considering the effects of the soil- structure dynamic interaction effect, local site conditions, the near-field finite field and artificial boundary, multi- support excitation and other factors. The work surrounding soil- structure dynamic interaction, artificial boundary of finite fields a, local site condition and multi-support excitation and other factors affecting the seismic response analysis carried out as follows:First, through theoretical analysis and formula derivation, author elaborated bridge seismic response analysis methodology of handling artificial boundaries of finite field and considering soil- structure interaction and multi-support excitation. Then used finite element software ANSYS to simulate near-field finite fields, studied law of valley terrain surface reaction and law of the response of earthquake site surface and pier foundation consideration interacting between site with pier foundation under seismic waves. Then obtained acceleration of characteristic points’ seismic response on site surface and pier foundation in both cases, then use the acceleration as multi-support excitation’s input data. Finally, using the finite element software Midas Civil established a continuous beam bridge finite element model under four conditions of uniform excitation, uniform excitation considering soil-structure dynamic interaction, multi-support excitation in local site and considering soil- structure dynamic interaction and multi-support excitation in local site to analysis the seismic response. Author obtained time curves of bridge seismic response of the control parameters and the influence of seismic response of bridge in different conditions, Presented an integrated approach system of bridge response analysis under earthquake considering soil-structure dynamic interaction, site conditions and multi-support excitation and other factors on the seismic response of the bridge comprehensively. The numerical results show that the seismic response analysis conducted bridges must consider ground motion characteristics changing in space and time, dynamic response of local site finite field on seismic waves and the soil- structure dynamic interaction, must use projects as the background of earthquake response analysis and a reasonable integrated approach system with the core of multi-support excitation and other reasonable methods to analysis bridge seismic response.