ABSTRACT
The cable dehumidification system on the Chesapeake Bay (William Preston Lane) Bridges in Maryland, USA, is the first such installation in North America. Historically, the main cables of the suspension bridges were not fully sealed from moisture. By applying waterproof wrapping to the cables and injecting dehumidified air, the cables are dried of retained water, and the relative humidity is reduced to a level that will reduce future corrosion and extend the service life of these structures.
This paper presents theory and practice of cable dehumidification, including principles of cable drying, the calculation of effective air flow within the cable, based on the cables’ construction and condition, and the leakage rate of the wrapping system. Maintaining adequate air flow for timely cable dry-out and humidity control is achieved by effective sealing, optimal placement of injection and exhaust points, calibrated instrumentation, and effective mechanical, monitoring and control systems.
