钢管混凝土拱桥稳定极限承载力的线弹性迭代方法

摘要

利用单一组合材料线弹性梁单元建立钢管混凝土拱桥稳定极限承载力计算的有限元分析模型,并以压弯稳定承载力相关方程为基础,通过全面试验法和回归分析方法建立具有广泛适用性的钢管混凝土构件压弯稳定分析的齐次广义屈服函数.结合弹性模量缩减法,研究用于钢管混凝土拱桥稳定极限承载力计算的线弹性迭代方法.通过与试验结果及不同数值方法计算结果的对比分析表明:建立的齐次广义屈服函数能够克服传统广义屈服函数容易受荷载初始值影响的缺陷;通过弹性模量缩减法调整弹性模量实现结构内力重分布,利用线弹性迭代方法计算结构的极限承载力,克服了增量非线性有限元法的局限性,能够取得更高的计算精度和效率;钢管混凝土拱桥规范建议的稳定系数表达式具有良好的稳定性与适用性.%The finite element model for calculating the ultimate stability bearing capacity of the concretefilled steel tube (CFST) arch bridge was established using linear elastic beam element characterized by single composite material property.Based on the correlation equations of stability bearing capacity for CFST members under compression and bending,a widely applicable Homogeneous Generalized Yield Function (HGYF) was derived by means of comprehensive test method and regression analysis method.Then a linear elastic iteration method was proposed for determining the ultimate stability bearing capacity of the CFST arch bridge by means of elastic modulus reduction method.Comparisons between the results of the proposed method and those from experiments and different numerical methods show that the proposed HGYF can overcome the drawbacks of the traditional generalized yield function whose results vary with initial load.The elastic modulus can be adjusted by means of elastic modulus reduction method to realize the redistribution of structural internal force.The ultimate bearing capacity of the structure can be calculated by means of linear elastic iteration method.The limitations of incremental nonlinear finite element method are overcome,and higher calculation precision and efficiency can be obtained.The stability coefficient expression suggested in the code of CFST arch bridge has good stability and applicability.