大跨混凝土斜拉桥拉索施工期的可靠度分析

从结构可靠度理论出发，采用极值分布方法直接推导建立了斜拉索的强度概率模型，通过现场试验得到了钢绞线式斜拉索的索力均匀性指标，分析了影响施工期索力的主要设计变量的概率特征，在此基础上提出施工期斜拉索的可靠指标计算方法；进而分析施工阶段拉索可靠水平的变化规律，从而基于结构可靠度理论提出施工期斜拉索的安全性评价方法，并结合大跨混凝土斜拉桥实际工程背景验证了这一方法的有效性。计算结果表明：施工期斜拉索的可靠指标小于运营期；研究成果对于评价混凝土斜拉桥施工期的结构整体性能和安全程度具有参考价值。

Reliability Analysis of Stay Cables for Long-span Concrete Cable-stayed Bridges During Construction

Based on the theory of structure reliability, an extreme-value-distribution method was proposed for establishing the probabilistic model for stay cable strength directly. The uniformity indexes of the steel wire strand force of stay cable were studied through experiment in the field. The probabilistic characteristic of main design variables influencing cable force was also analyzed. Then, index reliability calculation method of stay cable during construction was put forward which was used to analyze variation rules of cable reliability level during construction. Based on the method, safety evaluation method of stay cable during construction was put forward. A longspan concrete cable-stayed bridge was selected to show the efficiency and accuracy of the proposed algorithm. The results show that reliability index of stay cable during construction is usually lower than that during running. The study result can provide reference for structural whole performance and safety degree of concrete cable-stayed bridges during construction.