基于几何非线性的自锚式斜拉-悬索协作体系桥成桥索力计算

目的研究确定自锚式斜拉-悬索协作体系桥成桥状态时构件的空间位置和缆索的成桥索力．方法根据无应力索长和索力的概念推导了无应力索长的索力不变原理，提出了自锚式斜拉-悬索协作体系桥成桥索力的计算方法．结果运用该方法对大连跨海大桥的设计方案进行了计算分析，利用该方法计算得到的成桥状态下斜拉索和吊索的索力均匀，主缆线形平顺．除主塔附近的加劲梁由于索距较大造成弯矩较其他区域偏大外，其他区域弯矩分布均匀合理，加劲梁的最大弯矩为14716kN·m．主塔弯矩较小且塔顶水平变位接近于零．结论计算结果表明利用该方法能够按照要求得到该类桥梁的合理成桥索力，并且通过非线性迭代计算得到的缆索无应力长度可以直接应用于施工阶段分析．

Research on Reasonable Initial Cable Force of Self-Anchored Cable-Stayed Suspension Bridge Based on Geometrical Nonlinearity Analysis

How to determine the spatial position of structural components and their internal force is the key issue in structural analysis for self-anchored cable-stayed suspension bridge. Based on the concept of the initial force and unstrained length of cable, unstrained length of cable principle of how to keep the internal force of the cable remains unchanged is deduced. According to this principle, the calculating method for the reasonable initial cable force of the self-anchored cable-stayed suspension bridge is proposed on the basis of some available methods. Dalian Gulf Bridge is taken for calculation with this method as an example. Accord- ing to the calculation results under this method, the cable forces of stayed cables and hangers are more uniform and the alignment of the main cable is smooth in the finished bridge state. Also the moment of stiffe- ning gird is more uniform and reasonable. The maximum moment of stiffening gird is 14 716 kN. m. The moment of tower is relatively small and the horizontal displacement of tower top is close to zero. The results show that the method presented in this paper can be used in determining and analyzing the reasonable initial cable force of the self-anchored cable-stayed bridge as required. The results of unstrained length of cable can be directly used in analyzing construction phases of self-anchored cable-stayed bridge.