土-结构相互作用的桥梁多尺度建模与分析

考虑土-结构相互作用(SSI)是地震激励下桥梁抗震性能评估的热难点之一.由于考虑土体影响多而建立的结构模型计算耗时极长,为了提高效率,现采用一致多尺度建模方法,将所研究部位建为实体单元,其他部位建为梁单元,单元之间采用适当的方法进行界面连接,保证宏观、精细单元间的变形协调,并对某一桥梁进行分析,验证了该方法的正确性.在此基础上,基于多尺度建模方法,建立三跨连续梁桥模型,对其进行弹塑性时程分析,对比分析考虑SSI和不考虑SSI效应的桥梁模型在地震激励下的响应结果,研究SSI效应对桥梁抗震性能的影响.结果表明:多尺度建模方法可以在保证计算精度的前提下有效地提高计算效率;考虑SSI效应能够有效地降低桥梁的抗震性能需求.因此,在设计时应加以考虑.

Multi-scale Modeling and Analysis of Soil-structure Interaction in Bridge

Soil-structure interaction (SSI) is always one of the hotspots and difficulties in the evaluation of anti-seismic performance of bridges under seismic excitation. It takes a long time to calculate the structural model due to considering the influence of soil. In order to improve the efficiency, the consistent multi-scale modeling method is adopted. The studied parts are built as solid elements and the other parts are built as beam elements. The appropriate method is used between the elements for the interface connection in order to ensure the deformation coordination between the macro and fine elements. The correctness of the method is verified by analyzing a bridge. On this basis, a three-span continuous beam bridge model is established based on the multi-scale modeling method, and its elastic-plastic time history analysis is carried out. The response results of bridge model with SSI and without SSI under seismic excitation are compared and analyzed. The influence of SSI effect on the seismic performance of bridges is studied. The results show that the multi-scale modeling method can effectively improve the calculation efficiency under the premise of ensuring the calculation accuracy. The SSI effect can effectively reduce the seismic performance requirements of bridges. Therefore, this should be taken into account in design.