基于正交试验的高铁混合梁部分斜拉桥设计参数优化研究
Research on the Optimization of Design Parameters of Partially Cable-Stayed Bridges with Hybrid Girders for High-Speed Railways Based on Orthogonal Test

依托实际的工程背景并结合Midas Civil有限元软件，选取4组不同的设计参数(主塔无索区高度、塔旁无索区长度、中跨及边跨无索区长度、主梁截面刚度)进行模拟计算，再依据参数分析结果确定正交试验因素和水平，设计正交试验方案并制定试验表，最后找出各指标的主次因素并选取最合理方案。研究结果表明：中跨及边跨无索区长度为主梁中跨最大挠度f₁、最大弯矩W₁、边跨最大正弯矩W₂及次边跨最大挠度f₂的主要因素；塔旁无索区长度为主梁墩顶中跨侧W₃及边跨侧W₄弯矩的主要因素；主梁刚度比为f₁、f₂、W₃及W₄的次要因素。最终选取最优的因素水平方案为主塔无索区高度36 m、塔旁无索区长度38 m、中跨无索区长度与中跨比0.106、主梁截面刚度比1.2。本研究基于正交试验对高铁混合梁部分斜拉桥进行设计参数优化，为同类型桥梁提供参考依据。
Relying on the actual engineering background and combining with the Midas Civil finite element software, four groups of different design parameters (the height of the cable-free zone of the main tower, the length of the cable-free zone beside the tower, the length of the cable-free zone in the middle span and the side span, and the stiffness of the main girder section) are selected for simulation calculations. Then, according to the results of the parameter analysis, the factors and levels of the orthogonal test are determined, an orthogonal test scheme is designed, and a test table is formulated. Finally, the primary and secondary factors of each index are identified, and the most reasonable scheme is selected. The research results show that the length of the cable-free zone in the middle span and the side span is the main factor for the maximum deflection of the middle span of the main girder (f₁), the maximum bending moment (W₁), the maximum positive bending moment of the side span (W₂), and the maximum deflection of the secondary side span (f₂). The length of the cable-free zone beside the tower is the main factor for the bending moments on the middle span side (W₃) and the side span side (W₄) at the pier top of the main girder. The stiffness ratio of the main girder is a secondary factor of f₁\f₂\W₃\W₄. Finally, the optimal factor level scheme is selected as follows: the height of the cable-free zone of the main tower is 36 m, the length of the cable-free zone beside the tower is 38 m, the ratio of the length of the cable-free zone in the middle span to the middle span is 0.106, and the stiffness ratio of the main girder section is 1.2. This study optimizes the design parameters of the partially cable-stayed bridge with hybrid girders for high-speed railways based on the orthogonal