大跨度斜拉桥拉索安全性分析方法研究

A study on the safety assessment method for stay cables of long-span cable-stayed bridges

斜拉桥的斜拉索在运营期间的安全是斜拉桥结构安全的最重要条件之一,对斜拉索安全性的分析显得至关重要。考虑构成平行钢丝束斜拉索的高强钢丝本构行为的不均匀性和钢丝之间的相互影响,将Matteo的钢丝延脆性模型和MonteCarlo仿真方法相结合,建立斜拉索的强度模型,并从可靠度观点出发分析了斜拉索在桥梁运营条件下安全系数的变异和演化特性,并提出断丝率随服务期演化的线性经验公式来描述拉索的退化问题。在此基础上提出了大跨度斜拉桥拉索安全性分析的工程方法,并以招宝山大桥最长索为例,详细阐述了分析过程,该方法为斜拉桥拉索的安全评估与剩余寿命估算提供了依据。

Stayed cables are primary members for cable-stayed bridges. The safety assessment of stayed cables is a key issue to the safety of the structures. Some recently developed models for strength assessment of stayed cables are presented and illustrated. These models are based on the Matteo＇s ductile-brittle wire model and the Monte Carlo simulation. A linear equation is proposed for simulating the deterioration of the cables, and a safety assessment method for stay cables of long-span cable-stayed bridges is proposed. Application to the Zhao Bao Shan cable-stayed bridge in China is made by taking into account the tensile test results and the empirical data obtained from the design and cable force inspection of the stayed cables. The analysis of the longest cable is illustrated, and the results indicate that the proposed method could be used to assess the safety and residual life of stayed cables in cable-stayed bridges.