斜拉桥跨中竖向位移的温度灵敏度系数研究

STUDYON TEMPERATURE SENSITIVITY COEFFICIENTS OF MID-SPAN VERTICAL DISPLACEMENT OF CABLE-STAYED BRIDGES

环境温度变化下桥梁跨中竖向位移的变化规律是结构健康监测关注的重要问题。前期研究表明,拉索温度和主梁平均温度是引起斜拉桥主跨跨中竖向位移变化的关键温度变量。该文通过平面几何分析和级数展开得到了对称双塔斜拉桥主跨跨中竖向位移关于拉索温度、主梁平均温度的灵敏度系数的实用计算公式。该公式反映温度变形的物理机理,揭示温度灵敏度系数与材料特性(线膨胀系数)和结构尺寸参数(主跨长度L0、边中跨比γ0和塔高跨比ξ)之间的关系,为斜拉桥温度变形的研究提供了新思路。

The variation in the mid-span vertical displacement of bridges with ambient temperature changes is a great concern for structural health monitoring. The previous study has shown that the cable temperature and the average girder temperature dominate the girder’s mid-span vertical displacement of a cable-stayed bridge. By using plane geometric analysis and a series expansion, this paper presents a simplified calculation formulas of the temperature sensitivity coefficients of the mid-span vertical displacement of symmetric twin-tower cable-stayed bridges with respect to the cable temperature and the average girder temperature. The formulas reflect the root causes of thermal deformation and reveal the quantitative relationships between the temperature sensitivity coefficients and the material property(linear expansion coefficients) and structural geometries(main span length L0, side-to-center span ratio γ0, and tower-height-to-span ratio ξ). This study provides a novel solution to the temperature-induced deformation of cable-stayed bridges.