基于主缆内部输气的大跨度悬索桥除湿系统总体设计

Overall Design of Dehumidification System for Long-Span Suspension Bridge Based on Dry Air Conveying Inside Main Cable

针对传统的主缆被动防腐及目前采用的主缆外部压入干空气除湿防腐存在的问题,提出了从主缆内部输送干空气除湿新方案。该方案通过埋置在主缆内部的送气管道实现输气,干空气在主缆内流动过程中带走主缆中的水分,并从排气夹排出,达到除湿防腐的目的。基于龙潭长江大桥主跨1560 m大跨度悬索桥,进行了基于主缆内部管道供气的主缆除湿系统总体设计:设计特殊的送气口局部细节,干空气可从主缆外输送到缆内管道中;设计由螺旋弹簧和波纹管组成的复合式送气管道,满足了管道在主缆内径向受压、纵向适应主缆伸长和曲率变化的要求;确定主缆沿程进气点、送气监测气夹、排气夹、监测传感器的布置方案,设计了除湿系统的网络传输方案及运行管理系统。

The corrosion protection of main cables of suspension bridge is usually performed in a passive manner.Injecting dry air into the main cable to reduce the relative humidity inside it has been the common dehumidification practice in recent years.To improve the efficiency of main cable dehumidification,the concept of delivering the air flow inside the main cables is proposed.The air flow is driven to run through main cable via the pipework to collect the trapped water,as a result,the moisture-laden air is released through the exhaust sleeves to achieve the purpose of dehumidification and corrosion protection.A dehumidification system based on air flow conveying inside the main cables is designed for the Longtan Changjiang River Bridge,which is a suspension bridge with a main span of 1560 m.The dehumidification system features its special details of injection sleeves,by which the dry air can be driven inside the main cable.The air flow pipework consists of the spiral springs and corrugated pipes,adaptable to radial compression condition of pipes in the main cable,the elongation and variation of curvature radius of the main cable.The layout of the injection sleeves,monitoring equipment,exhaust sleeves and sensors is set forth.The data transmission network and operation management system of the dehumidification system are designed.