Abstract: In order to study the influence of auxiliary pier position on the internal force of composite girder cable-stayed bridge, a composite girder cable-stayed bridge with a span of 1380m in Hubei province was taken as the object. 9 kinds of auxiliary pier position schemes were designed and finite element models were established respectively. 7 key indexes were selected, including the stress amplitude of the lower edge of the steel main girder, the stress amplitude of the upper edge of the concrete slab, the vertical deformation amplitude of the main girder, the stress amplitude of the stay cable, the bending moment amplitude of the main tower root, the bending moment amplitude of the lower beam of the main tower, and the bending moment amplitude of the tower column in the main tower. The internal forces of the 9 scheme models were compared and analyzed, and the reasonable location range of the auxiliary pier was obtained according to a single index. Using the comprehensive evaluation method of variation coefficient and standard score method, based on the principle of regression, the reasonable location of auxiliary pier for comprehensive evaluation of all indicators was determined. The results show that: for the stress amplitude of the composite girder, vertical deformation amplitude of composite girder, stress amplitude of stay cable and bending moment amplitude of main tower, the reasonable location range of the auxiliary pier is 0.230L~0.320L, 0.300L~0.320L, 0.275L~0.320L and 0.360L ~0.410L. Considering all indicators comprehensively, the optimal reasonable location of the auxiliary pier of the composite girder cable-stayed bridge is 0.285L away from the side pier (L is the side span).

Key words: bridge engineering; composite girder cable-stayed bridge; auxiliary pier; comprehensive evaluation method; optimum reasonable location

摘要： 为了研究辅助墩位置对组合梁斜拉桥成桥内力的影响，以湖北某跨度1 380 m的组合梁斜拉桥为对象，设计了9种辅助墩位置方案，分别建立有限元模型；选择钢主梁下缘应力幅、混凝土板上缘应力幅、主梁竖向变形幅、斜拉索应力幅、主塔塔根弯矩幅、主塔下横梁弯矩幅、主塔中塔柱弯矩幅等7个关键指标，对比分析了9个方案模型的内力，得到了针对单一指标的辅助墩合理位置区间；采用变异系数法结合标准分数法的综合评价方法，基于回归原理，确定了综合评价所有指标时的辅助墩最佳合理位置。结果表明：对于组合梁应力幅、组合梁竖向变形幅、斜拉索应力幅及主塔弯矩幅，辅助墩合理位置区间分别为距离边墩（0.230～0.320）L、（0.300～0.320）L、（0.275～0.320）L及（0.360～0.410）L处；综合考虑所有指标，组合梁斜拉桥的辅助墩最佳合理位置为距离边墩0.285L处（L为边跨跨径）。

关键词: 桥梁工程；组合梁斜拉桥；辅助墩；综合评价法；最佳合理位置