【作者】 潘东宏；

【导师】 周建庭；

【作者基本信息】 重庆交通大学 ， 桥梁与隧道工程， 2010， 硕士

【摘要】 钢筋混凝土桥梁是应用非常广泛的一种桥梁结构形式,由于钢筋混凝土结构材料自身和使用环境的特点,混凝土桥梁结构存在着耐久性问题。国内外有关资料表明,由于混凝土结构耐久性病害而导致的经济损失是非常巨大的,并且随着环境的变化和功能要求的提高,耐久性问题会愈来愈突出。西藏地区桥梁处于高寒、缺氧、干燥、年冻结期长,日照时间长,年蒸发量大、气候多变,四季不明,昼夜温差大;部分河流存在氯离子、硫酸根离子等有害离子的恶劣环境中,桥梁的耐久性受到更为严重的威胁。关于西藏地区混凝土桥梁耐久性问题的研究有十分紧迫和现实的意义。本文主要研究混凝上桥梁的耐久性问题,进行的主要工作有:①在进行现场调研的基础上,充分利用已有资料,广泛征求西藏交通建设、养护部门及国内知名专家的意见,对西藏高寒地区桥梁混凝土耐久性的研究现状给予科学、客观的评价。②根据大量的西藏已建钢筋混凝土桥梁的运营状况,通过层次分析法剖析出现有西藏高寒地区桥梁施工、养护条件下的影响混凝土耐久性的多因素机理。如混凝土的冻融循环、混凝土碳化、应力对混凝土的损伤、硫酸盐侵蚀、混凝土裂缝、桥梁的施工、养护、运营以及多重因素影响下桥梁结构混凝土的耐久性。③从提高混凝土抗冻融循环、抗盐碱侵蚀、抗干缩湿胀变形等性能出发,通过系列加速试验,研发出适宜西藏高寒地区混凝土桥梁的复合型多功能外加剂与掺合料。④研究了结构与构造细节对于桥梁耐久性的影响,首次较为系统地从体系及构造细节、防水性能、可换性、可检性等方面提出了进行耐久性设计的原则与方法,分析了具体的设计措施,给出了较详细的例子及设计要求。⑤通过现场的养护对比试验,总结出提高西藏地区混凝土耐久性的养护方式,并给出了养护的具体细节步骤。最后,利用已取得的研究成果,以现场预制梁为依托,通过对比试验,对取得的研究成果进行进一步效果验证。试验表明:主梁混凝土的各项耐久性能指标得到较大的提高。本文研究成果对提高西藏地区混凝土桥梁耐久性、保证在役桥梁的安全,节省建设资金,加快公路建设步伐,提高公路建设质量均具有积极的现实意义。更多还原

【Abstract】 Reinforced concrete bridge is very widely applied structure form;as a result of the reinforced concrete structural materials and environmental features, the durability problems of concrete structures exist.Domestic and foreign information shows the economic loss due to perdurable diseases of concrete structures is very great ,and as the environment changes and functional requirements of the increased, durability will be an increasing prominence。In Tibet, the bridges are in the condition of cold, oxygen, drying, freeze-year long period, long sunshine hours, annual evaporation, climate variability, seasonal unknown and large temperature;there is chloride ions, sulfate ions and other harmful ions in part of the rivers, so the durability of the bridges is more serious threat in such harsh environment . The research on the durability issues of concrete bridges in Tibet has a very urgent and practical significance。This paper studies the durability issues of concrete bridges, and the main work are as follows:①On the base of site investigation, full use of existing material , soliciting Tibet transportation construction, maintenance departments and well-known experts, I have scientific and objective evaluation on bridge durability research of alpine region inTibet.②Based on the operation condition of large amounts of reinforced concrete bridges that have been built in Tibet, through analytic hierarchy process with alpine region, cure of the multi-factor mechanism of concrete durability such as construction condition, maintenance condition. The circumstance such as freezing and thawing of concrete, concrete carbonation, stress on the damage of concrete, sulfate attack, concrete cracks, bridge construction, maintenance, operation and under the influence of multiple factors,which affect the durability of concrete bridge structures.③To improve freezing and thawing, salt and corrosion, anti-shrinkage properties of swelling and deformation proceed, after a series of accelerated tests, develop composite multifunctional additive and admixture that can be used in alpine region of Tibet.④Study structure and structural details of the impact on the durability of the bridge; for the first time systematic and structural details from the system, waterproof performance, transsexual, testing set for durability and other aspects of the design principles and methods, analyze the specific design measures,and give more detailed examples and design requirements.⑤Comparing with site maintenance test, summarize the conservation methods for concrete available inTibetan, and gives details of the conservation steps.Finally, use research results achieved the basis, relying on field precast beams and comparing with the tests , verify further the effect of the research results obtained. Results show that: the concrete durability of the main beam is greatly enhanced. Research results of this passage have positive and realistic significance to improve the durability of concrete bridges in Tibet , ensure the safety of existing bridges, save construction funds , accelerate the pace of road construction, and improve the quality of road construction.更多还原