三塔自锚式悬索桥中塔纵向抗弯刚度研究

Research on Longitudinal Bending Stiffness of Middle Tower Stiffness of Three-tower Self-anchored Suspension Bridge

为研究三塔自锚式悬索桥的索塔纵向刚度对结构整体受力的影响,首先,阐述了悬索桥的计算理论和增大悬索桥纵向刚度的方法,并对其中的增大中塔纵向抗弯刚度进行分析,通过建立全桥的分析模型,对某三塔自锚式悬索桥结构关键设计参数中的中边塔纵向抗弯刚度比分7种工况进行对比分析,得到了该桥中塔刚度对桥梁结构受力的影响规律,并给出了该桥中边塔刚度比的合理取值范围。结果表明:中塔纵向抗弯刚度的增加可以显著提高三塔自锚式悬索桥加劲梁的竖向刚度,而对两侧边塔的刚度影响不大;在活载作用下,中塔纵向抗弯刚度的增加使中塔的内部发生内力重分布;得出该桥的中边塔刚度比在1～1.5范围内较为合理,并给出了该桥中边塔刚度比的合理取值范围,为类似的工程建设提供参考。

In order to research the influence of the longitudinal stiffness of the tower on the overall stress of the structure of the three-tower self-anchored suspension bridge, firstly, the calculation theory of the suspension bridge and the method of increasing the longitudinal stiffness of the suspension bridge are elaborated, and the method of increasing the longitudinal bending stiffness of the middle tower is analyzed systematically. Then, the analysis model of the whole bridge is established. In this paper, the longitudinal bending stiffness ratio of the mid-side tower in the key design parameters of a three-tower self-anchored suspension bridge is compared and analyzed under seven working conditions. The influence law of the mid-tower stiffness on the stress of the bridge structure is obtained, and the reasonable range of the stiffness ratio of the mid-side tower in the bridge is given. The results show that the increase of the longitudinal bending stiffness of the middle tower can significantly improve the vertical stiffness of the stiffening girder of the three-tower self-anchored suspension bridge, but has little effect on the stiffness of the side towers. Under live load, the increase of the longitudinal bending stiffness of the middle tower causes redistribution of internal forces within the middle tower. It is concluded that the stiffness ratio of the middle side tower of the bridge is reasonable in the range of 1-1.5,and the reasonable range of the stiffness ratio of the side tower in the bridge is given, which can provide reference for similar engineering construction.