自锚式悬索桥吊索张拉对主缆垂度敏感性分析

闫少敏，刘爽，卞美臣^*

天津市交通科学研究院，天津  300300

摘要：为确定大跨自锚式悬索桥先斜拉、后悬索施工方案中吊索张拉方案，以鹅公岩轨道交通专用桥工程为背景，采用有限元软件ANSYS建立自锚式悬索桥成桥的计算模型，依据Ernst公式调整材料等效弹性模量，研究在单吊点、双吊点、三吊点荷载作用下主缆的位移变化，在前期大部分未挂上吊索、后期少部分未挂上吊索时通过4个算例分析主缆位移变化，分析不同吊索张拉方案、结构体系转化工程中对主缆垂度敏感性。研究结果表明：单位荷载作用下，中跨与边跨节点主缆位移变化明显，主塔两侧、中跨跨中、主梁锚固端对单位荷载的作用不敏感；吊索张拉过程中张拉位置处的主缆变形对已张拉点主缆垂度敏感性弱相干，对未张拉相邻吊点主缆垂度敏感性强相干；吊索张拉前期，主缆位移呈非线性变化，后期呈线性变化。

关键词：自锚式悬索桥；吊索张拉；垂度敏感性；主缆线型；桥梁施工；主缆垂度

Sensitivity analysis of self-anchored suspension bridge sling tensioning to changes in main cable sag

YAN Shaomin, LIU Shuang, BIAN Meichen^*

Tianjin Transportation Science Research Institute, Tianjin 300300, China

Abstract: To determine the cable tensioning scheme for the suspension bridge with a large main span and self-anchored cables, which uses the hybrid construction method of suspended cables first and cable-stayed cables later, based on the Egongyan Railway-Transit Bridge project, an ANSYS model is established to calculate the bridge from completion to the dismantling of the cable to a cable-free configuration. The Ernst formula is used to adjust the material equivalent elastic modulus. The study analyzes the displacement changes of the main cable under the action of single, double, and triple-point loads, with the majority of the cables not yet hung in the early stage and a small portion left unhung in the later stage through four scenarios. It examines the sensitivity of the main cable sag to different cable tensioning schemes and structural system transformation in engineering. The research shows significant changes in main cable displacement at mid-span and edge-span nodes under unit loads, with insensitivity at the main tower sides, mid-span, and main girder anchor ends. During the cable tensioning process, the deformation of the main cable at the tensioning point shows weak sensitivity to already tensioned points but strong sensitivity to adjacent untensioned points. In the early tensioning stage, the main cable displacement is nonlinear, shifting to linear in the later stage.

Keywords: self-anchored suspension bridge; suspender stretching; sag sensitivity; main cable routing; bridge construction; main cable sag