超大跨度V塔斜拉桥的经济与力学特性

Study of Economic and Mechanical Properties of Super-long Span Cable-stayed Bridge with V-shaped Pylon

摘要:

分别建立了超大跨度V塔斜拉桥和常规直立索塔斜拉桥的有限元分析模型，通过对比研究，给出了V塔斜拉桥的一些经济、力学特性。推导了材料节省量公式，和常规直立索塔体系斜拉桥相比，当V塔斜拉桥的塔柱倾角为对应跨最外侧拉索倾角之半时，节省量最优，但此时塔柱材料用量仅节省6%，拉索用量节省1%，总节省量并不大。V塔斜拉桥能够降低塔高，减小拉索悬挂长度，增大拉索倾角，使得结构整体刚度增加，稳定性系数得以提高，算例中塔根弯矩比常规体系小26%左右。另外，V塔体系能更好地抵抗横向风荷载的作用，满足斜拉桥向更大跨度方向发展的需求。

关键词:V型索塔，经济特性，静力特性，稳定性系数，自振频率

Abstract:

Two finite element models are established in this paper for super-long span cable-stayed bridges with V-shaped pylon or with conventionally erected pylon. Then, some economic and mechanical properties are given by comparative study method. Constructive materials can be saved from the bridge with V-shaped pylon, compared with the bridge with erected pylon. From the derived formula of material saving of pylon and cables, it gets the optimum when the inclination of V-shaped pylon is half of the inclination of farthest cable, and the pylon materials save 6% while cable materials save 1%. But the advantages of V-shaped pylon cable-stayed bridge are reducing the height of tower and the length of hoisting cable and decreasing the moment of tower root by about 26%. At the same time, the inclination of cables in this structural system is larger, the overall stiffness is increased, so the stability factor is improved. In addition, its state manifests better than conventional bridge under horizontal wind load. At last, it is adapt to the development of cable-stayed bridge towards longer span.

Key words:V-shaped pylon; economic properties; static properties; stability factor; natural frequency.