【作者】 翁健成；

【导师】 唐怀平；

【作者基本信息】 西南交通大学 ， 工程力学， 2013， 硕士

【摘要】 桥梁在其建造及服务期间不可避免地要受到环境及有害物质的侵蚀,诸如超重车、地震、结构疲劳、材料老化、构件缺陷以及人为破坏等,会造成桥梁不同程度的损伤,降低桥梁的实际承载力。桥梁因存在结构缺陷和损伤而垮塌的事件时有发生,对桥梁进行有效的长期健康监测、定期安全评价和针对性的维护加固,保障桥梁安全使用已成为桥梁管理运营部门最为关注的问题。本文以交通部颁布的20m至40mT梁和箱梁的通用图为基础,首先建立先简支后连续梁桥有限元模型,数值计算连续梁的模态参数,且系统计算分析不同截面、不同跨径和不同跨数对连续梁自振特性的影响。其次对基于曲率模态理论桥梁结构损伤识别方法进行研究,研究结果表明：1、曲率模态法、曲率模态微分法、曲率模态绝对差法均能对结构损伤进行识别,且低阶模态出现误导小峰的概率较小,损伤识别效果较好,其中曲率模态绝对差识别效果又优于另两类方法,而曲率模态微分法则不需要桥梁原始数据即可对结构进行损伤识别。2、以曲率模态理论为基础的三类识别方法的识别效果与桥梁振型选取有关,当损伤位置位于振型节点附近时,则无法识别。3、在单处损伤识别中,曲率模态绝对差曲线在损伤位置处会有突变,突变程度与损伤程度有关,损伤程度越大,突变越明显。对于存在多处损伤的结构,相同损伤程度且不同位置的曲率模态绝对差增量不同,相互独立,曲率模态绝对差能够判定损伤程度大小。4、基于频率的损伤识别方法依赖桥梁的原始数据。频率的变化中可以评定结构是否存在损伤,但无法判断损伤位置和损伤程度。更多还原

【Abstract】 The bridges are corroded by the environment and harmful substances during the construction and service inevitably, such as overload, earthquake, the structure fatigue, material aging, defect and man-made sabotage, causing the damage of different degree and reducing the actual bearing capacity of the bridges. The bridges often collapse due to the presence of structural defects and damages. The effective long-term health monitoring, regular safety evaluation and the reinforcement for the bridges to ensure the safety of the bridges have become the most concerned problems for the departments of bridge management. In this paper, the simply-supported continuous bridge model was set up based on20m to40m general diagram produced by the ministry of communications, the modal parameters of the continuous beam was obtained by numerical calculation and studying the impact of different section, different span and different span number on natural vibration characteristics of the bridge. And the damage identification of the bridges was studied based on curvature mode theory, the results show:1、Modal curvature method, the curvature modal differential method and absolute deviation of curvature modal method are all able to identify the damage of the bridge, the probability of small misleading peal appears in the low order modes is small. The effect of damage identification is good. The curvature modal absolute difference recognition effect is better than the other two kinds of methods. Curvature modal differential method does not need the raw data of the bridge to identify the damage of the structure.2、The three kinds of identification methods based on curvature mode theory are all relating to the selection of bridge vibration mode. When the location of damages is near the nodes of mode shape, the three kinds of methods could not identify the damages.3、In the single damage identification, absolute deviation of curvature curve will have a mutation at the damage location. Degree of mutations associated with damage degree, damage degree, the more obvious mutation. The structure with several damages, under the same damage degree condition, absolute deviation of curvature modal of the increment of different positions is different and independent. Absolute deviation of curvature modal method could identify the damage degree.4、The damage identification method based on the changes of frequencies depends on the raw data of the bridge. We could identify the damages of the structure by the changes of frequencies, but we can not decide the damage location and degree of the damage.更多还原