环境因素对铁路桥梁桩基础锈蚀疲劳研究-桥梁与隧道工程专业论文.docx

硕士学位论文 硕士学位论文 摘要 摘要 目前对钢筋混凝土桥梁疲劳损伤的研究证明，影响铁路钢筋混凝 土桥梁桩基础寿命的主要原因是：混凝土的碳化、钢筋的锈蚀和反复 荷载长期作用带来的钢筋疲劳损伤。本文针对钢筋混凝土桥梁中普遍 存在的环境侵蚀和疲劳问题，研究与探讨了两不利因素共同作用下铁 路桥梁桩基础的锈蚀疲劳损伤。从混凝土碳化成因和钢筋锈蚀机理出 发，依据电化学原理，在已有实验成果下，建立桩基础中钢筋锈蚀量 的时变模型。与现有的疲劳损伤理论只偏重疲劳荷载下的损伤不同， 环境因素影响下铁路桩基础疲劳有自身的特点，需将机械疲劳与材料 锈蚀结合分析考虑，即进行锈蚀疲劳分析；本文研究了铁路桥梁桩基 础的锈蚀疲劳的特点，从钢筋面积损失出发，对比选用适合本文锈蚀 后构件的计算理论，结合分段线性解的方法建立混凝土桩基础在锈蚀 疲劳不同阶段的预测模型，应用于不同跨度桥梁桩基础锈蚀疲劳的预 测。 同时，编写了程序，并通过计算～些铁路桥梁桩基础的疲劳损伤 及剩余寿命，结果表明环境劣化造成的损伤大小决定了桥梁桩基础的 疲劳寿命，针对此项破坏，提出一些有意义的防腐及加固措施。 关键词：环境，混凝土碳化，锈蚀疲劳，疲劳寿命，钢筋锈蚀 硕士学位论文 硕士学位论文 ABSTRACT ABSTRACT Currently the study of reinforced concrete bridges shows that the carbonation of concrete，the long—term corrosion of bar and the fatigue damage of the bar because of cyclic reverse loading are the main reasons that affected the life of the reinforced concrete pile foundation in railway bridges．In this paper,the environment erosion and the fatigue damage are contraposed，the corrosion fatigue damages of the pile foundation in railway bridges under the disadvantageous factors are studied and explored．From the causes of Concrete carbonation and the mechanism of bar corrosion，Based on the existing experimental results of electrochemical principles，the time—varying model about bar corrosion of pile foundation is established．Differed from the theory of fatigue damages that considering only fatigue loads，the fatigue of pile foundation in railway has its own characteristics under the influence of environmental factors，·both corroded material and mechanical fatigue need to be considered，namely,corrosion fatigue analysis have be done； The characteristics of fatigue corrosion of the pile foundation in railway bridges are studied in this paper，from the aspect of the damage area of the reinforcement，the theoretical calculation of components after corrosion are compared and choosed，the prediction model of the concrete pile foundation in various stages