【作者】 吴光宇；

【导师】 徐兴； 项贻强；

【作者基本信息】 浙江大学 ， 桥梁与隧道工程， 2006， 博士

【摘要】 目前大跨度预应力混凝土桥梁的应用日趋广泛。但按三维空间非线性分析理论研究大跨度预应力混凝土桥梁的极限承载力却鲜有涉及，这严重制约着该类桥梁的安全评估。 本文对大跨度预应力混凝土桥梁的非线性行为分析理论及其极限承载力计算进行了系统研究和探索，得出了若干有价值的研究成果和创新点，主要有： (1)提出了建立在三维实体退化虚拟层合单元理论基础上同时考虑结构双重非线性的大跨度桥梁结构极限承载力分析方法，并以此编制非线性有限元分析程序。该程序既可用于大跨度钢桥的极限承载力分析，也可用于大跨度混凝土桥梁的极限承载力分析。 (2)通过对多个典型材料和边界条件下的结构破坏试验和经典算例的模拟分析，研究了本文所提出的极限承载力分析方法及其程序的适用性和可靠性。 (3)对大跨度预应力混凝土桥梁极限承载力计算中的关键问题进行了探索研究，包括预应力效应的准确模拟；成桥内力的正确考虑；桥梁开裂荷载的合理计算；考虑初始内力，有限元法迭代格式的处理；提高计算效率，合理建立有限元模型的建议等。 (4)应用本文程序，对苏通长江公路大桥辅桥连续刚构桥进行了多工况的极限承载力分析，并讨论了预应力筋不同的预应力度对极限承载力的影响。根据分析获得的破坏荷载、破坏特征、荷载位移曲线以及桥梁安全系数等，对该桥设计进行了评价并获得一些有价值的结论。更多还原

【Abstract】 Large-span P.C. bridges are widely used nowadays, but the ultimate bearing capacity of them is seldom calculated with three-dimension spatial nonlinearity analysis theory, which seriously restricts the safety evaluation of bridges of this type.The nonlinearity behavior analysis theory and ultimate bearing capacity calculating method for Large-span P.C. bridges are researched systematically in this paper, and some valuable results and innovations are brought forward, includes:(1) A large-span bridge structural ultimate bearing capacity analysis method considering dual nonlinearity based on degenerated three-dimension solid virtual laminated element theory is put forward, and based on which an nonlinearity finite element analysis program is programmed. And this program can be applied to the ultimate bearing capacity analysis of both large-span steel bridges and large-span concrete bridges.(2) The dependency and applicability of the analysis method and program are verified by several classic mechanical numerical examples and various model failure tests with different materials and support conditions.(3) Several detail treatments for some key problems in the ultimate bearing capacity calculation of large-span P.C. bridges are investigated, such as the accurate simulation of pre-stress effect, the proper consideration for the established internal force, the reasonable calculation of cracking load, the FEM iterative format considering initial stress, constructing analysis model rationally to promote calculating efficiency, etc.(4) In multiple load case, the ultimate bearing capacity of the secondary navigable span of Sutong Yangtse River Highway Bridge (which is a continuous rigid frame bridge) is analyzed with the above program, and the influence of various level of pre-stressing is also discussed. According to the calculated ultimate loads, failure characters, load- deformation curve, and safety coefficients, etc, the bridge is evaluated and some valuable conclusions are attained.更多还原