【作者】 徐琼；

【导师】 向木生；

【作者基本信息】 武汉理工大学 ， 结构工程， 2009， 硕士

【摘要】 随着交通事业的发展,桥梁作为交通枢纽,发挥着越来越重要的作用,已经成为经济发展的纽带。但是从七十年代兴建的许多拱桥,由于年久失修,在外界物理及化学因素作用下,混凝土结构会发生老化、裂化现象,从而降低桥梁的强度、刚度和稳定性,影响结构的正常使用,严重时甚至会发生垮塌事故。因此,如何通过对桥梁进行安全性评估和维修加固,是一项十分紧迫的任务。本文在详细分析桥梁结构和力学相关理论的基础上,结合实际情况,对桥梁技术状态、评估方法和加固方法进行了研究和探讨。详细调查了大量现存的旧桥梁,这些桥梁在长期的各种复杂环境的侵蚀作用下,桥梁的结构和技术状况与设计状态相比,其运营状态产生了较大的改变。有的甚至严重危害到桥梁的安全运营,选取病害比较严重的15座桥梁,进行技术状态评估。在评估的基础上进一步以南河大桥为工程背景,对拱桥的常见病害形式、病害原因、状态评估及加固技术等进行了分析和研究。通过分析研究表明,大跨度拱桥由于拱轴线与恒载压力线偏离引起的附加内力较大,可能导致主拱圈或截面的应力过大,在今后的大跨度拱桥设计计算中应当计入偏离弯矩对拱桥内力的影响。在利用特菲尔专家评估法对桥梁结构进行评估的基础上,选取南河大桥为主要研究对象,进行了实桥的静载和动载试验,分析了桥梁结构在荷载作用下的工作性能和使用能力,通过对实桥状况进行分析和试验研究,引入断裂力学理论,分析了桥梁的病害原因,并采用GQJS软件对南河大桥进行有限元建模,对其进行加固前和加固后的力学分析研究以及三个方案加固后力学状况的研究分析,在对各个方案模型理论技术状况和实桥试验技术状况进行研究的基础上,结合实桥结构和力学特征以及所处复杂自然环境,在进行理论计算分析和试验研究的基础上,进行了旧桥状态评估和加固技术研究,提出了最优加固方案,对其他同类桥梁结构的加固和改造具有一定的实用价值。分析了桥梁的病害原因及其结构裂缝的成因,在此基础上提出了针对桥梁病害的三个加固方案。更多还原

【Abstract】 With the development of transportation,bridge,as a junction,play a more and more important role and has already become the vital nexus of economical development.Especially in the 70s when we built many arch bridges,these old bridges,under the effects of external physics and chemical factors,concrete construction may occur aging and cracking phenomenon,which will reduce bridge’s strength,rigidity and stability.All these will influence normal use of structure and will lead Collapse if seriously.For these reasons,it is an urgent task to do safety profile and maintenauce about bridges.In this paper,based on detail analysis on bridge construture and correlation theory of mechanics,combining the actual bridge,we study the assessment and reinforcement of bridges.Within detail investigation of many existent bridges,under dynamic environment,technical conditions which are different from that of design conditions and also their using conditions are so different that lead to safety hazards. Select 15 more serious disease bridges to do technology evaluation.On the base of evaluation,Against the background of Nanhe Bridge,analyze the Disease、its reasions、bridges’ conditionsand reinforcement technology.Results show that with an additional larger internal force caused by departure of arch axis and the line of dead load,could lead to large stress of main ring or cross-section.So in the future long-span arch bridge design we should include the effects of bias flexural momentAgainst the background of Nanhe Bridge,have the tests of static load and dynamic load for a real bridge,and then identify the role of a bridge structure under the load and the performance capability,offer useful conclusions,in order to provide a basis for bridg maintenance’s decision-making.On the basis of the use of the existing research results,make reasonable analysis of all the structures of Nanhe Bridge,determine a model approximates to the facts.Detect and investigate the original structural materials,and then determine the elastic modulus reduction factor of concrete and initial internal force caused by shrinkage and creep.Use GQJS software to establish Nanhe finite element analysis model,compare internal forces before and after reinforcement,provide three reinforcing plan in connection with bridge defects,choose the best one through comparing and selecting process,and then offer a certain practical reference for other bridges.更多还原