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对一座两主跨跨长为2 000 m的四跨悬索桥的变形特征进行了研究。通常,四跨悬索桥的变形性状受到中间桥塔刚度的巨大影响。本文着重研究了加劲梁的弯曲和扭转刚度、垂跨比和恒载的特性。本研究的结果澄清了与三跨悬索桥相比较,四跨悬索桥加劲梁在活载作用下的较低刚度是因为主跨主缆的弹性刚度系数只有边跨的1/6造成的。然而,这个趋势是稳定的并且能得到加强中间桥塔刚度的帮助,用加强中塔弯曲系数的方法来使加劲梁的活载挠度能够减到主跨长度的1/200以下是有用的和经济的。而且,对于主跨为1 000 m的情况,设挠度比相同,2 000 m跨度的较低的中塔刚度也是足够的,主缆的三维垂度几何外形对于限制加劲梁的扭转变形是有效的,这对于中塔受扭引起的四跨悬索桥加劲梁的扭转变形是特别重要的。
The deformation characteristics of a four-span suspension bridge with a span of 2 000 m spanning two main masters are studied. In general, the deformation behavior of a four-span suspension bridge is strongly influenced by the stiffness of the intermediate bridge tower. This article focuses on the bending and torsional stiffness of stiffening girder, vertical to vertical ratio and vertical load characteristics. The results of this study clarify that the lower stiffness of the four-span suspension bridge stiffener under live load is compared with that of the three-span suspension bridge because the elastic rigidity coefficient of the main span main cable is only 1/6 of the side span. However, this trend is stable and can be aided by strengthening the stiffness of the intermediate bridge tower. It is useful and economical to reduce the live load deflection of the stiffening girder to less than 1/200 the length of the main span by strengthening the tower camber coefficient of. Moreover, for the main span of 1 000 m, assuming the same deflection ratio, a low mid-tower stiffness of 2 000 m span is sufficient. The three-dimensional vertical geometry of the main cable is effective in limiting the torsional deformation of the stiffening girder , Which is particularly important for the torsional deformation of the stiffening girder of a four-span suspension bridge caused by the mid-tower torsion.