基于结构力学中的矩阵位移法，提出了一种利用节点位移参数来反推拱肋区段刚度的计算方法。算例验证该方法在只利用部分节点位移参数时依然具有较高的精度。然后考虑不同的加载模式和损伤模式，采用该方法对借助非线性有限元分析技术和试验手段获得的既有钢筋混凝土拱肋加载过程中的节点位移值进行了分析，证实了既有拱肋的区段刚度具有较大幅度的波动变化特性。基于拱肋区段的变化规律，研究了既有拱肋破坏过程中节点竖向刚度值的变化趋势。结果表明，既有拱肋的节点竖向刚度变化规律与区段刚度较为一致。在此研究基础上，提出了一种适用于既有钢筋混凝土拱肋的承载能力评估方法。实例分析表明，该评估方法具有较高的精度。%Based on displacement method in matrix from structural mechanics, a method is proposed to calculate the stiffness of arch rib with nodal displacements. Example proves that the method is accurate with partial nodal displacements. Then based on this method, the nodal displacements derived from non- linear finite element analysis techniques and experimental measures are analyzed with different loading mode and damage mode for existing reinforced concrete arch rib. It is found that the section stiffness holds the characteristic of fluctuation with large range. The trends of nodal vertical stiffness are also studied with the law on section stiffness changes of arch rib. It shows that the law on nodal vertical stiff- ness changes is similar as the law on section stiffness changes within the whole loading process. Finally, a method is proposed to evaluate the bearing capacity of existing reinforced concrete arch rib. Example proves that this method is accurate too.
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