风沙冲蚀钢混组合梁斜拉桥动力响应的影响规律研究

Study on Influence of Sand Erosion on Dynamic Response of Steel-concrete Composite Girder Cable-stayed Bridge

摘要:

由于风沙冲蚀，斜拉桥钢梁涂层变薄甚至脱落会导致钢梁锈蚀。此外，混凝土塔柱也会因风沙冲蚀面积减少而强度降低。为研究钢混组合梁斜拉桥在整个寿命周期内的变形以及抗震性能，建立全桥计算分析模型，输入12条地震波，探究其抗震性能。结果表明：考虑风沙冲蚀和地震共同作用对拉索的抗震性能影响较小；地震作用下墩身易损部位为塔身底部，考虑风沙冲蚀的时变作用后，塔身底部的弯矩-曲率增大了10.39%，地震强度的变化对弯矩-曲率的影响最大；跨中挠度不仅随着风沙冲蚀的时间而增大，也随着地面峰值加速度的增大而增大。研究成果为钢混组合梁斜拉桥在风沙地区的抗震设计提供支撑。

Abstract:

Due to the wind-sand erosion， the steel beam coating of cable-stayed bridge will become thin or even fall off, which will lead to the corrosion of steel beam. In addition, the strength of concrete pylon columns will also be reduced due to the reduction of sand erosion area. In order to study the deformation and seismic performance of steel-concrete composite cable-stayed bridge in the whole life cycle, a calculation and analysis model of the whole bridge is established, and 12 seismic waves are input to explore its seismic performance. The results show that the combined effects of wind-sand erosion and earthquake have little effect on the seismic performance of the cable. The vulnerable part of the pier under earthquake is the bottom of the pylon. Considering the time-varying effect of wind-sand erosion， the bending moment - curvature at the bottom of the pylon increases by 10.39%, and the change of earthquake intensity has the greatest influence on the bending moment - curvature. The mid-span deflection increases not only with the time of wind-sand erosion, but also with the increase of ground peak acceleration. The research results provide the support for the seismic design of steel-concrete composite cable-stayed bridges in wind-sand areas.