腐蚀斜拉索承载力退化模型研究

Research on Degradation Model of Bearing Capacity of Corroded Stay Cables

文章以国内某大跨径斜拉桥为背景,根据并列模型理论,提出腐蚀斜拉索承载力的退化模型,并利用此退化模型,分别分析了腐蚀分布均值和变异系数对拉索承载力的影响,以及该桥拉索可靠度随腐蚀程度和服役年龄的变化。研究表明:随着拉索内钢丝数的增加,拉索强度均值减小并趋于固定值,同时拉索强度的变异系数渐近于0,拉索的强度趋于确定量;腐蚀均值是影响斜拉索承载力的主要参数,而腐蚀变异系数对斜拉索承载力的影响较小,建议在腐蚀斜拉索承载力分析中,重点考虑腐蚀均值的影响,腐蚀变异系数的影响可作为次要因素处理;最长拉索Z17与最短拉索Z1在设计使用年限内均能满足承载力可靠度要求,并将分别在服役37年与36年后不再满足承载力可靠度要求。

Taking a long-span cable-stayed bridge as the background, the capacity degradation model of corrosion cable is put forward based on parallel model theory to analyze the influence of corrosion distribution mean and coefficient of variation on bearing capacity. In addition, the bridge reliability with the change of corrosion degree and age of the service is analyzed. The experimental results indicate that with the increase of wire number in cable ,the strength mean of cable tends to be constant and the variation coefficient of cable strength approaches zero.The corrosion mean is the main parameters influencing the bearing capacity of the cable, and coefficient variation of corrosion of cable bearing force has little influence. Research proposals especially considering the effect of corrosion mean and the influence of the coefficient variation of corrosion can be treated as the secondary factor on corrosion cable bearing force analysis; The longest stay cable Z1 and the shortest stay cable Z17 can meet the requirements of bearing capacity reliability in the design service life, and will not meet the reliability requirements of bearing capacity after 37 years and 36 years respectively.