【作者】 李立峰；

【导师】 易伟建； 邵旭东；

【作者基本信息】 湖南大学 ， 结构工程， 2005， 博士

【摘要】 本文在总结中外学者研究成果和外国设计规范的基础上,结合我国大跨度正交异性钢箱梁的工程实践,系统地研究了正交异性钢箱梁结构的局部稳定问题,主要做了以下工作: (1)研究了正交异性钢箱梁在桥梁工程结构中的发展历史、应用现状、以及存在的关键技术问题,阐述了密索体系斜拉桥和自锚式悬索桥的发展使钢箱梁的局部稳定问题更加突出的原因; (2)研究了四边简支板的屈曲临界应力的理论解和各国规范对板局部稳定的规定;然后推导了加劲板的屈曲临界应力的理论解,分析了各种国内、外规范对加劲板的计算方法、并对它们的理论背景和适用范围进行了对比研究;研究了开口、闭口加劲板的弹性屈曲特性,并对一些主要影响其屈曲应力的参数进行了分析;提出了加劲肋的合理构造,推导了纵向加劲肋、横隔板的所需刚度的计算公式; (3)首次提出并建立了考虑钢桥面板第二体系应力约束时的钢桥面板的稳定优化分析模型。针对目前钢桥面铺装容易受损、开裂的现状,基于格子梁法推导了分析钢桥面板第二体系应力的刚度计算公式,以计入结构重量和焊缝体积的结构造价为目标函数,以桥面板的局部刚度(限制第二体系应力的大小、防止钢桥面板的破坏)和稳定容许应力为约束条件,采用可行方向法进行优化迭代,编制了计算程序;得到一些十分有意义的结论,可用于指导钢箱梁的设计; (4)提出了全面考虑材料、几何双重非线性以及计入初始几何缺陷、残余应力的加劲板稳定承载力的计算方法。分析理论可直接用于指导承压加劲板的设计。 (5)应用梁柱理论,推导了加劲肋的M-φ-N之间的计算公式,并采用递推的方法推导了考虑初始缺陷、残余应力的加劲板承载能力简化计算方法,编制了计算程序,并与通用程序计算进行了对比,两者吻合较好。在此基础上,进行一批共6块加劲板的稳定承载力的模型试验,得到了板件破坏时的极限荷载大小,同时对试验结果与理论计算结果进行了比较,吻合较好。 (6)在此基础上,以三汊矶大桥为工程背景,介绍两个不同结构布置的1:5典型节段钢箱梁模型试验,其中模型1的腹板采用开口加劲肋,承载力分析结果表明模型由于腹板的局部失稳而破坏;模型2的腹板采用U形闭口加劲肋,模型由于材料屈服而破坏,采用非线性有限元法得到了结构的荷载—位移曲线,详细的理论分析验证了试验结果。试验结果对钢箱梁的设计有很大的参考意义。更多还原

【Abstract】 In this dissertation, the local stability of orthotropic steel box girder is systematically studied on the basis of researcher achievements and design specifications home and abroad, and combined with the construction practice of long span bridges with orthotropic steel box girder. The main contents of this dissertation are described as follows:1. the history, the state of the art in bridge engineering and technical problems of orthotropic steel box girder are investigated. Thus the developments of self-anchored suspensions and modern cable stayed bridges make the local stability more obviously.2. The theorical solution of critical buckling stress of plate simply supported along its four edges is analyzed, and some specifications of different countries on local stability of plate, as well as the theorical solution of critical buckling stress of the stiffened plate and calculation method of some overseas specifications for stiffened plate. Besides, the theorical background and the applicable area of these codes is analyzed. The elastic buckling characteristic of open stiffening plate and close stiffening plate are carried out, and some main structural parameters, which influence the buckling stress, are studied. The reasonable arrangements of longitudinal stiffener are discussed; calculations formulas of the required rigidity for longitudinal stiffener and transverse stiffener are also deduced.3. A model for optimization design of stiffened plate, inhibited by the the second stress of orthotropic deck system, is provided. Calculations formula of the flexural rigidity of grillage, calculating the second stress of orthotropic deck, is deduced. The structural cost is taken as the object function, the rigidity and allowed stress of deck plate are taken as the constraints, and optimization methods is FDM. A program is provided. Some significative conclusions, different from current design custom, are reached and can be used for design of steel box girder.4. The dissertation puts forward a method calculating ultimate strength of the stiffened plate with consideration of material and geometrical nonlinear、 initial geometrical imperfections、 residual stress. The theory can be used for the design of stiffened plate.5. Based on beam-column theory, the calculation form for the relationship of the stiffening plate’s M-φ-N is deduced. And a simplified calculation means whichtake initial geometrical imperfections and residual stress into consideration, using step-by-step numerical method, is developed for studying the ultimate strength of the stiffened plate under axial compression. And a computer program is developed. According to comparison, this computer program is line with the software ANSYS.Based on this method, a model test of a series of stiffened plates with different structural arrangements is conducted; the ultimate load is achieved, the test result is nearly equal to the theorical analysis.6. Finally, the one-to-five model test of steel box girder based on SanChaJi self-anchored suspension in ChangSha City is introduced. The test includes two models with different structural arrangements. One is open stiffened plate for web which is destroyed because of local bucking, the other is U-rib stiffened plates which is destroyed because of material yielding. The test results are proved by means of theorical analysis. The experiment results can be referenced by design of steel box girder.更多还原