钢筋混凝土桥梁结构损伤评估研究

【作者】 王爱勤；

【导师】 宋一凡；

【作者基本信息】 长安大学 ， 桥梁与隧道工程， 2002， 硕士

【摘要】 根据既有钢筋混凝土桥梁的受力特点和损伤程度，采用两种方法：即《规范》法分析理论和分级刚度退化非线性分析理论，分别建立了既有钢筋混凝土桥梁正截面强度计算和承载能力评定的计算分析模型。指出《规范》公式中的主要参数均基于线性(弹性工作阶段)分析，对结构实际工作阶段(包括弹塑性、塑性工作阶段)由于损伤累积而引起结构性能的变化涉及较少，对常见的偏压构件的刚度计算也未作专门规定，这使得以往内力计算较为粗糙。基于此，本文着重考虑了混凝土的非线性性质，研究了不同受力构件在开裂后单元刚度变化规律及分级刚度退化计算方法，讨论了不同工作阶段钢筋混凝土结构截面应力计算和非线性分析方法，并结合某实桥进行了结构损伤诊断的数值模拟和空间结构的非线性理论分析计算。结果表明，考虑结构损伤的累积效应和材料的非线性性质，结构的内力重分布较为显著，开裂单元范围加大，适用性能与耐久性能降低。这与实桥检测结果也较为吻合。因此得出结论：在评定既有钢筋混凝土桥梁结构的承载能力时，应按分级刚度退化非线性理论跟踪模拟其损伤过程。文中给出的非线性理论分析方法对被改造桥梁的静力评价和拟定加固方案提供了可靠实用的定量分析资料，可为工程应用参考。更多还原

【Abstract】 According to the load behavior and defection degrees of existed reinforced concrete bridge, the calculating modeles for normal section strength and bearing capacity for reinforced concrete bridge are established by the elasticity analysis and nonlinear analysis of grade stiffness degeneration. In the current criteria, the principal parameters are given from linear elasticity analysis. The effects of cumulation in elasto-plastic working stage is hardly analysis. The stiffness calculation of current eccentric compression member is not specialy stipulated, with the result that the calculation of internal forces are crude. Based on the nonlinear behavior of concrete, the change feature of the element stiffness matrix and the method of grade stiffness degeneration for crack columns under various load are presented, and the methods of calculation and nonlinear analysis on the section stress of reinforced concretes under different load stage are discussed. The numeral simulation of structure defection diagnosis and nonlinear analysis of space structure to one reinforced concretes bridge is achieved. The results obtained show the effects of defection cumulation material nonlinear and internal force distribution are remarkable with increase of crack element. The theoretical analysis squares with the test results of bridge. The nonlinear method of grade stiffness degeneration is very effective to simulate defection situation and evaluate bridge load capacity, the method of nonlinear analysis from this paper provides reliable quantitative analysis way to static evaluation and reform existed bridge, and has potentially applied valuation to practical engineering.更多还原