Abstract: In order to better predict the deterioration life of the outer sheath of the sling in service, the damage condition of the outer sheath of some slings in service was investigated through data collection and literature retrieval, and the deterioration and damage mechanism of the outer sheath of slings were analyzed. The internal and external factors which caused the deterioration of the outer sheath of the sling were studied, such as raw materials, production temperature, coil and construction installation, service environment (acid rain, ultraviolet ray, etc.) and the alternating stress in operation process. A logarithmic probabilistic mapping method was innovatively proposed to predict the life of the outer sheath of the sling in service. Based on the actually measured data of a certain Yangtze River Bridge in southwest China in 2004, 2006, 2009, the logarithmic probabilistic drawing method was used to deduce the deterioration life of the outer sheath of the sling in service. The results show that the calculation results of the proposed method are in good agreement with the actual detection, which can provide references for design, construction and maintenance of sling as well as the decision-making of cable replacement.

Key words: bridge engineering, in service, pull sling, outer sheath, damage mechanism, life, prediction method

摘要： 为了更好地预测在役拉吊索外护套的劣化寿命，调研了部分在役拉吊索外护套的破损状况，分析了拉吊索外护套劣化、损伤机理，研究了引起拉吊索外护套劣化的内、外因素，包括： 外护套的原材料、生产温度、盘卷及施工安装、服役环境(酸雨、紫外线等)及运营过程交变应力作用等；创新性地提出了一个预测在役拉吊索外护套寿命的对数-概率作图法；以西南某长江大 桥2004、2006、2009年的实际检测数据为基础，运用对数-概率作图法推演在役拉吊索外护套劣化寿命。结果表明：方法的计算结果与实际检测吻合度较好，可为拉吊索的设计、施工、维护以 及换索决策提供参考。

关键词: 桥梁工程, 在役, 拉吊索, 外护套, 损伤机理, 寿命, 预测方法