斜弯独塔混合梁斜拉桥参数敏感性分析

为研究斜弯独塔混合梁斜拉桥在成桥状态下受结构设计参数的影响程度，对结构设计、施工监控和关键控制量制定等提供参考，以张家口纬二桥为工程背景，建立有限元模型。基于结构参数敏感性分析的摄动原理，引入敏感度分析指标，选取塔梁固结处弯矩值、桥顶纵向位移值、背索索力、主梁最大挠度为控制目标，对桥梁钢混结合段位置、桥塔局部温度荷载、斜拉索初拉力和背索竖向倾斜角度等结构参数进行敏感性研究。分析结果表明：桥梁钢-混结合段位置、斜拉索初拉力、背索竖向倾斜角度对斜弯独塔混合梁斜拉桥主梁挠度和桥塔线形影响较大。其中，混凝土梁和钢梁的跨度比变化15.73%,塔顶纵向位移、主梁最大挠度将分别变化30.3%和29.4%;桥塔局部温度荷载主要影响此类桥塔的纵向变形，对桥塔受力敏感度较低；背索竖向倾斜角度对斜弯独塔混合梁斜拉桥影响最为显著，背索竖向倾斜角度变化7%,塔顶纵向位移较初始位置最大变化也达到205.8%。

Parameter Sensitivity Analysis of the Inclined Curved Single Tower Hybrid Girder Cable-stayed Bridge

In order to study the degree of influence of the structural design parameters of the inclined-bent single-tower mixed-beam cable-stayed bridge in the completed state of the bridge, a finite element model was established with the Zhangjiakou Wei''er Bridge as the engineering background. Based on the perturbation principle of structural parameter sensitivity analysis, a sensitivity analysis index was introduced. The sensitivity of structural parameters such as the position of the bridge steel-concrete joint section, the local temperature load of the bridge tower, the initial tension of the stay cable and the vertical inclination angle of the back cable were studied with the bending moment at the consolidation of the tower and girder, the longitudinal displacement of the bridge top, the back cable force, and the maximum deflection of main beam selected as the control targets. The analysis results show that the position of the bridge steel-concrete joint section, the initial tension of the stayed cable, and the vertical inclination angle of the back cable have a greater influence on the deflection of the main girder and the line shape of the pylon of the oblique curved single-tower hybrid cable-stayed bridge. When the span ratio of the concrete beam and the steel beam changes by 15.73%, the longitudinal displacement of the tower top and the mid-span deflection of the main beam will increase by 5.14% and 29.4% respectively from the initial position. The local temperature load of the pylon mainly affects the longitudinal deformation of this type of pylon, and it is less sensitive to the force of the pylon. Among them, the vertical inclination angle of the back cable has the most significant impact on the diagonally curved single-tower mixed-beam cable-stayed bridge. When the vertical inclination angle of the back cable changes by 7%, the maximum change in the longitudinal displacement of the tower top from the initial position also reaches 205.8%.