斜拉桥斜拉索防腐保护问题分析与建议

Analysis of Stay Cable Corrosion Protection for Cable-Stayed Bridge and Suggestions

斜拉桥斜拉索的腐蚀破坏将直接影响桥梁结构的安全与使用寿命,国内、外已出现大量由于斜拉索破坏而进行换索的典型案例。目前斜拉桥斜拉索的常用防护形式为高密度聚乙烯(HDPE)护套,该类护套易发生开裂和老化而导致斜拉索锈蚀。为了研究斜拉索的防腐保护问题,对HDPE护套防护破坏的因素:索体交变应力、HDPE原材料特性、自然环境、施工作业方式和斜拉索的不均匀截面形状等进行分析,在此基础上提出采用长纤维增强护套结构以及在斜拉索护套与斜拉索之间设置粘弹性隔离层的防护建议。

The corrosion damage of stay cables of cable-stayed bridge is possible to influence the safety and service life of bridge structure directly. Many typical cases of stay cable replace- ment due to stay cable damage are reported both at home and abroad. Currently, the stay cables of cable-stayed bridges are usually protected by the high density polyethylene（HDPE）sheath, but such kind of sheath are vulnerable to cracking and aging, which in turn lead to the corrosion of stay cables. In order to study the corrosion protection problem of stay cables, the main damage factors of HDPE sheath such as cable alternating stress, the characteristics of HDPE raw materi- als, natural environment, construction ways and the non-uniform shape of cross sections of stay cables, were analyzed, and on the basis of the analysis, the protection measures of adopting long fiber reinforced sheath and installing a viscoelastic isolation layer between the sheath and stay cables were suggested.