具有初始缺陷的薄壁高墩稳定性研究

Research on the Stability of Thin-walled High Pier with Initial Imperfections

针对有初始缺陷的薄壁高墩大跨径连续刚构桥在施工阶段的稳定性问题展开研究,以沪蓉西高速公路宜恩段野三河大桥为工程背景,采用一致缺陷模态法,以桥墩的一阶屈曲模态为基础,计算分析单肢薄壁高墩分别在具有单向和双向初始几何缺陷时的稳定承载能力,得出初始几何缺陷对高墩稳定性的影响规律,发现纵桥向的初始几何缺陷较横桥向对稳定承载力的影响更大;当引入双向初始几何缺陷时,单肢薄壁高墩的稳定承载力较仅含单向初始几何缺陷时迅速下降。在对含初始几何缺陷薄壁高墩稳定承载力计算结果进行总结的基础上,对山区高墩垂直度控制给出参考建议,研究了局部材料缺陷对高墩稳定性的影响效应,找出局部材料缺陷出现的最不利位置。研究成果可为具有初始缺陷的桥墩稳定性研究提供参考。

Taking Yesanhe Bridge in the Yi-En part of the Hu-Rong Highway as an example,this paper aims at studying the stability of a long-span continuous rigid frame bridge with thin-walled high piers and initial imperfections in its construction stage.On the basis of the first-order buckling mode and by means of the coherence imperfection mode method,the stable bearing capacity of a single-leg thin-walled high pier with in-plane and out-plane initial geometric imperfections is calculated and analyzed.The relationship between stability of high pier and initial geometric imperfections is obtained.some suggestions about the uprightness of a high pier are given.Meanwhile,the paper studies the influence of partial material imperfection on the stability of a high pier and tries to find out the most dangerous place where the partial material imperfection appears.The research results of this paper can have great value to the nonlinear stability analysis of a pier with initial imperfections and to the construction control of this kind of bridges.