【作者】 张利华；

【导师】 刘沐宇；

【作者基本信息】 武汉理工大学 ， 桥梁与隧道工程， 2007， 博士

【摘要】 预应力混凝土连续刚构桥跨越能力强，施工技术成熟，工程造价低，外形美观，行车舒适，是大跨径桥梁的主选桥型。近年来，我国已修建了大量的连续刚构桥，80％以上的该种桥梁都出现了不同程度的病害，主梁跨中下挠与箱梁开裂尤为突出，严重危害结构安全，成为制约连续刚构桥进一步发展的关键技术难题。国内外对此进行的理论与实践研究表明，从材料性能和结构优化角度寻求最佳的组合匹配是解决跨中下挠与箱梁开裂问题的主要途径。高强轻集料混凝土（High Strength Light Weight Aggregate Concrete）具有轻质、高强、抗震性能好等优点，国外已将其成功应用于连续刚构桥中，如挪威Stolma和Raftsundet桥；国内，高强轻集料混凝土连续刚构桥的研究处于起步阶段，工程应用尚属空白。因此，本文从材料和结构优化设计出发，提出了高强轻集料混凝土与普通混凝土最佳组合匹配的连续刚构桥结构，系统研究了其结构特性，有效解决了连续刚构桥跨中下挠与箱梁开裂问题；研究成果为高强轻集料混凝土应用于连续刚构桥提供了理论依据和技术支撑，对提高桥梁的使用寿命、降低维护费用、确保桥梁运营安全具有重要的理论和实际意义。本文的主要研究成果为：1、简要介绍了连续刚构桥的发展现状，系统阐述了该桥型的结构体系特点，明确指出了连续刚构桥普遍存在的跨中下挠与箱梁开裂问题，提出了高强轻集料混凝土与普通混凝土最佳组合匹配的连续刚构桥结构。2、结构与材料的合理匹配关系研究。从应力水平、结构位移和内力三个指标，系统研究了不同长度范围、不同密度等级的高强轻集料混凝土连续刚构桥结构性能。研究结果表明：对于所研究的连续刚构桥，上部结构高强轻集料混凝土与普通混凝土的长度比例(L_LC60／L)取0.7左右较为合适；低密度等级的高强轻集料混凝土可更大幅度降低连续刚构桥跨中挠度、减小墩顶截面上下缘应力差值和墩顶区段负弯矩值。3、桥梁长期变形分析。基于高强轻集料混凝土密度小和弹性模量低的双重材料特性，系统分析了恒载、二期恒载及跨中集中荷载等不同工况下高强轻集料混凝土连续刚构桥的长期变形性能。研究结果表明：高强轻集料混凝土能够有效减小连续刚构桥主跨跨中后期下挠；随时间推移，高强轻集料混凝土连续刚构桥跨中挠度减小幅度增大。4、箱梁抗剪、抗裂性能研究。从剪力、剪应力和主应力三个方面，系统研究了高强轻集料混凝土连续刚构桥腹板的抗剪和抗裂性能。研究结果表明：高强轻集料混凝土降低了连续刚构桥的剪力与剪应力值，增大了腹板主压应力储备，改善了连续刚构桥腹板的抗裂性能，连续刚构桥上部结构的可设计性增强。5、桥梁动力特性分析。采用子空间迭代法，量化计算分析了高强轻集料混凝土连续刚构桥的自振频率、累积振型贡献率和振型特点等。研究结果表明：高强轻集料混凝土在连续刚构桥中的应用，降低了其基频与自振频率。本文的研究成果为连续刚构桥向大跨、重载、轻质方向发展开辟了新途径；对于拓展高强轻集料混凝土的应用领域，推动大跨径连续刚构桥的技术进步，促进桥梁工程与材料科学的学科交叉，具有重要的理论和实际意义。更多还原

【Abstract】 Prestressed concrete continuous rigid-frame bridge is a main chosen of largespan bridges, which has such advantages as strong span ability, mature constructiontechnology, low cost of project, good appearance and comfort driving ect,.In recentyears, lots of continuous rigid-frame bridges has been built in our country, and thereare different extent diseases occurred with more than 80 percent of them, amongwhich excessive midspan lag and cracks in box girder are outstanding, which bringgreat harm to structural safety, and they become key technology problems to restrictfurther development of the continuous rigid-frame bridge. Theory and practice athome and abroad indicate that, it is a main approach to seek a perfect composedmatching from material characteristic and structure optimization, to solve excessivemid-span lag and cracks in box girder problems.There are so many advantages like light weight, high strength and good seismicresistance with High Strength Light Weight Aggregate Concrete(HSLC in short), whichmade it successfully applied on continuous rigid-frame bridge in foreign countries, suchas Stolma bridge and Raftsundet bridge in Norway. Research on HSLC continuousrigid-frame bridge is in starting stage, and it is blank in engineering application yet inChina. So, starting from material and structure optimization, a kind of continuousrigid-frame bridge with optimal matching combination of HSLC and normal concrete isput forwarded, and its structural characteristic is studied in this thesis, which solvedexcessive midspan lag and cracks in box girder in continuous rigid-frame bridgeeffectively in this thesis. The research results provide theoretical basis and technology forHSLC to be used on continuous rigid-frame bridge. It has important theoretic andpractical meaning to improve service life, to reduce the maintenance cost, and toguarantee the security of the bridge.Main research results are as follows:1.Development and present status of continuous rigid-frame bridge is introducedbriefly, and structural characteristic of it is expounded. Universal problems asexcessive midspan lag and cracks with continuous rigid-frame bridge are point outdefinitely. After that, a kind of continuous rigid-frame bridge with optimal matchingcombination of HSLC and normal concrete is put forwarded.2.Research on optimal matching relation of structure and material. From threeindices:stress level, structure deflection and internal force, structural characteristics of continuous rigid-frame bridge with different length, different density are studied. Theresearch results indicates:the best ratio of HSLC to normal concrete on continuousrigid-frame bridge is about 0.7. Low density HSLC reduced mid-span deflection,attenuated stress difference and negative moment more at section on top of frusta.3.Long-term deflection analysis of the bridge. Based on double characteristics ofHSLC, which are small density and low modulus, long-term deformability of HSLCcontinuous rigid-frame bridge are analyzed each under dead load, second period deadload and mid-span concentrate load. The research results indicate: HSLC minishedupper deflection in mid-span of continuous rigid-frame bridge; There is obviousinfluence on decreasing degree of the upper deflection with the time of load lasting.The longer the load lasts, the more decreasing degree of the upper deflection will be.4.Research on shear resistence and anti-cracking performance of box-girder.From aspects of shear force, shear stress and principle stress, shear resistence andanti-cracking performance of box-girder on HSLC continuous rigid-frame bridge wasstudied. The research results indicate:HSLC reduced shear force, shear stress of thebridge, increased principle stress reserving on the web, and improved anti-crackingperformance of the web on continuous rigid-frame bridge.Designable ability ofcontinuous rigid-frame bridge superstructure is improved.5.Dynamic characteristic analysis of the bridge. Subspace iteration method wasadopted to calculate natural frequencies, accumulative total contributing ratio ofmode shapes and vibration characteristics of HSLC continuous rigid-frame bridge.The research results indicate: HSLC depressed basic frequency and naturalfrequencies, which made dynamic response of the structure decreased.The research results in this thesis built a new approach for continuousrigid-frame bridge developing to large span, heavy load and light weight. It hasimportant theoretic and practical meaning to extend application field of HSLC,promoting the technology progress of large span continuous rigid-frame bridge, andstrengthening bridge and material subjects intercrossing.更多还原