摘要
主梁是斜拉桥的重要基本承载构件之一，主梁的强度、刚度和稳定性直接影响到全桥的刚度和稳定性。本文运用平面杆系有限元法，考虑拉索垂度对结构的非线性影响，计算斜拉桥的初始索力，并通过计算来确定恒载作用下的主梁的内力和变形以及索塔内力，应用能量法来调整斜拉索恒载张力，使主梁和索塔的内力都达到较优的状态；同时对主梁进行了运营阶段的强度和稳定性的计算，计算成桥状态下的索力和主梁在各种荷载作用下的内力和变形。对斜拉索锚固区，配置U型预应力钢束来平衡斜拉索的强大的水平分力，其预留孔道采用最新的PT-PLUS塑料波纹管，以减小钢束的摩阻损失。
但该计算仅仅是斜拉桥设计的一部分，通过本设计为将来设计大跨度桥梁打下一定的基础。

关键词  主梁   斜拉桥  有限元  垂度  非线性  初始索力  锚固区  塑料波纹管  摩阻损失
Abstract
Girder is an important elementary load supportive part of cable stayed bridge.The intensity and rigidity and stability of girder influence the rigidity and stability of the whole bridge directly.In this paper I  use plane bar system limited elements method ,taking into account the nonlinear influence of cable deformation ,to calculate the original force of each cable,to calculate the force and deflection of both girder and girder ,using energy method to regulate the force of cables under dead load ,and to analyse the rigidity and stability of cable stayed bridge girder in service phase,including the force of each cable and the force and flexibility of girder under several different loads.I use PT-PLUS plastic corrugated pipes to reduce frictional loss.
This is only one part of computation in the design of cable stayed bridge,yet this design pave the way for my future work and study.

Keywords　 cable stayed bridge  nonlinear  deformation  dead load  service phase  plastic corrugated pipes  frictional loss