【作者】 钟惠萍；

【导师】 张建仁； 张克波；

【作者基本信息】 长沙理工大学 ， 桥梁与隧道工程， 2004， 硕士

【摘要】 目前,随着我国危、旧桥的逐年增加,一个日益严重的问题摆在了广大桥梁工作者的面前:如何通过科学合理的检测方法和试验手段评估现有桥梁的技术状况,确定可靠性评估方法,从而为危、旧桥的改造提供科学依据。 采用系统的试验研究,建立同一时期、同一地区、同类型桥梁结构的技术状况资料库,将为旧桥尤其是缺失资料的桥梁在可靠性评估基础上实施维修、加固及拆除工作提供技术保障。本文首先根据国、内外文献和我校多年检测旧桥经验,对既有钢筋混凝土桥梁存在的问题进行了分析和总结,详细介绍了桥梁现状检查的方法,为缺失资料钢筋混凝土桥梁的钢筋分布状况检查提供了选择检测位置和检测手段的方法。然后以湖南省常宁北门桥拆除的两片拱肋为足尺模型,进行了试验室破坏性试验:通过目测、局部破损检测和无损检测相结合的方法对拱肋的混凝土缺损状况、裂缝状况、钢筋锈蚀程度等进行了测定;分析了既有钢筋混凝土拱肋的常见病害及其产生原因以及耐久性的影响因素;试验结果验证了构件耐久性能的降低会对其承载能力产生较大影响;并由此引入构件耐久性最弱截面的概念。最后根据构件现状的检查结果,提出了采用层次分析法确定拱肋耐久性最弱截面的方法,在此基础上,利用模糊神经网络对既有钢筋混凝土构件的可靠性进行了评估。 本文为既有钢筋混凝土桥梁进一步的耐久性研究提供了试验资料,并在可靠性评估方法方面进行了理论上的探讨。更多还原

【Abstract】 Recently, With the increase of dangerous and old bridge in our country, there is a serious problem which many bridge researchers face with: how to estimate technology state of existing bridge structure and make reliability evaluation methods by scientific detective and test ways to provide scientific basis for rehabilitation of dangerous and old bridge.To give a technological support for good maintenance, strengthening and removal of old bridge, especially the old bridge in short of data, it is very important to make a technology data bank of the same period, the same zone and the same type bridge structure through systematic test study. In this thesis,firstly,the problems and the detective method of existing reinforced concrete bridge are summarized in detail, according to international research and our experience. A method how to choose the detective location and inspect the state of rebars of old bridge in short of data is proposed. Secondly, a destructive test of two ribs is carried out, which are removed from the north gate of Chang-ning bridge in Hunan province:the defecive state, concrete crack and rebar corrosive level are tesed by combined method composed of observation, local failure and nondestructive testing; the common damages and the causes of damages of existing bridge are analysed; influence factors of the durability are discussed; it is verified that the degradation of durability makes a notable impact on bearing capability; the concept of the weakest section of durability is presented. Lastly, the weakest section of durability is given by analytic hierarchy process.Further more ,the reliability of the existing reinforced concrete member is estimated by neuro-fuzzy network.In this paper , the next durability research is provided with experimental data and the mothed for reliability evaluation is discussed theoretically.更多还原