ABSTRACT
Enclosed spaces created by box sections in long (and short) span steel deck bridges are often perceived as high risk spaces for corrosion requiring design mitigation. This risk is often poorly defined and leads to onerous requirements for mitigation and corrosion protection. Anecdotal evidence and prior research suggests the real corrosion risk in such spaces is much less than anticipated.
Accepted practice around the world for long span structures of this type is to use de-humidification systems to control the environment to less than a critical relative humidity. It is assumed these systems offer a life cycle cost benefit compared to painted steelwork which is assumed to require relatively frequent maintenance.
This paper presents results, over eighteen to twenty-four months, the environment within this type of enclosed space (one structure with a de-humidification system and two without) by means of monitoring temperature, relative humidity and surface wetness. Where possible this data was correlated with external weather data to understand how the internal environment reacts to the external conditions.
