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针对混凝土桥梁服役过程中荷载和环境作用,研究了耦合效应的数值分析方法。通过对荷载作用下钢筋锈蚀过程的分析,将钢筋应变分解为弹性应变和锈蚀应变,定义锈蚀应变与瞬时弹性应变的比值为钢筋的锈蚀系数,引入锈蚀钢筋的名义弹性模量,得出锈蚀钢筋的时变本构关系;基于虚功原理,推导了荷载-环境耦合作用下,钢筋混凝土单元的有限元列式,并给出了采用时程分析法的计算流程;采用Fortran语言编制非线性有限元程序对这一问题进行数值求解,并通过3片梁的模型试验验证上述方法的有效性。结果表明,钢筋混凝土桥梁荷载和环境耦合分析中,不仅需考虑钢筋锈蚀引起单元刚度矩阵的改变,同时应考虑附加节点荷载,本文提出的数值方法可用于混凝土桥梁长期力学性能的预测。
Aiming at the load and environmental effect during the service of concrete bridge, the numerical analysis method of coupling effect is studied. Based on the analysis of corrosion process of steel bar under load, the strain of steel bar is decomposed into elastic strain and corrosion strain. The ratio of corrosion strain to instantaneous elastic strain is defined as the corrosion coefficient of steel bar. The nominal modulus of elasticity is introduced, Based on the principle of virtual work, the finite element formulation of reinforced concrete elements under load-environment coupling is deduced and the calculation flow of time-history analysis is given. The nonlinear finite element method The element program solves this problem numerically and validates the validity of the above method by the model test of three beams. The results show that not only the change of element stiffness matrix caused by corrosion of steel bars, but also the additional joint loads should be considered in the coupled analysis of load and environment of reinforced concrete bridges. The numerical method proposed in this paper can be used to predict the long-term mechanical properties of concrete bridges.