考虑几何非线性的新型索拱桥拱轴线优化

鉴于新型索拱桥存在明显几何非线性的力学特点,针对已有拱轴线迭代优化方法收敛性不好的问题,提出在主拱圈为两铰拱的索拱桥有限元模型基础上,进行几何非线性的拱轴线迭代优化方法,以解决考虑几何非线性的超大跨径索拱桥拱轴线迭代的收敛性问题。以跨径600m索拱桥作为算例,验证方法的有效性及收敛性。算例结果表明,与仅考虑线性迭代相比,考虑非线性迭代后的主拱圈弯矩分布更合理,最大正弯矩小35%,最大负弯矩小17%,主拱圈应变能小23%;收敛性分析结果表明,该方法比主拱圈为无铰拱有限元模型方法收敛性能更好,不同的初始拱轴线均能收敛于稳定的结果。

Arch Axis Optimization of New Type Arch Bridge with Diagonal Web Cables Based on Geometric Nonlinear Mechanical Analysis

There are obvious geometric nonlinear mechanical characteristics in new type arch bridge with diagonal web cables. Meanwhile, the convergence of the existing arch axis iterative optimization method is not good. In order to solve new type arch bridge axis iteration convergence problem considering geometric nonlinear mechanical analysis, an arch axis iteration optimization method was proposed based on the iteration basis finite element model with two hinge arch model in main arch ring. A 600m span arch bridge with diagonal web cables was selected as an example to test the convergence performance and applicability of proposed method. The results showed that the bending moment of proposed method had better distribution along arch span, and it is about 35% smaller in maximum bending moment, 17% smaller in minimum bending moment and 23% smaller in bending strain energy compared to the results of linear iteration optimization method. Convergence analysis results demonstrated that proposed method had better iteration performance than the existing method. Meanwhile, different initial arch axis can converge to stable results.