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为了研究桩土相互作用下大跨度钢拱桥的地震反应特点以及塑性铰的形成部位和发展过程,利用ANSYS有限元程序对比研究了在多组地震输入条件下,考虑基础固结和桩土相互作用下的动力特性及在罕遇地震下的地震反应,并探讨了层状场地土对桩基以及上部结构的影响.结果表明:与基础固结模型相比,考虑桩土相互作用体现了土的特性对结构的影响,较好地反映了结构的动力特性,结构的自振周期延长,且对高阶振型周期影响显著;同时结构各部位的内力响应呈下降趋势,位移响应被放大,但受边界假定的影响,其总体反应趋势未发生改变,其中在主梁1/4处、梁拱结合处以及柱底处均出现塑性铰,且柱底处率先屈服,各塑性铰区的变形仍控制在较小的范围内,桩身则未出现塑性铰.
In order to study the seismic response characteristics of long-span steel arch bridge under the interaction of pile-soil and the formation position and development process of plastic hinge, the finite element program of ANSYS is used to study the effect of foundation consolidation and pile-soil interaction And the seismic response under rare earthquakes are discussed.The effects of layered soil on the pile foundation and the superstructure are also discussed.The results show that compared with the basic consolidation model, The influence of the characteristics on the structure better reflects the dynamic characteristics of the structure. The natural period of the structure is prolonged, and the effect on the period of the high-order modes is significant. Meanwhile, the internal force response of each part of the structure shows a downward trend and the displacement response is enlarged. Assuming the influence, the overall response trend has not changed. Among them, the plastic hinges appear at the junction of beam and arch and at the bottom of the column at 1/4 of the main girder, and the yield at the bottom of the column yields first. The deformation of each plastic hinge zone is still controlled In the smaller range, the plastic hinge does not appear in the pile.