Weathering steel is widely used in bridge construction for its atmospheric corrosion resistance; however, harsh environments—such as Canadian winter de-icing salts—can compromise its protective patina, leading to accelerated degradation. Corrosion rates often vary across different areas of a structure, yet the controlling factors are not fully understood. To investigate these variations, the National Research Council of Canada (NRC), in collaboration with the Ministry of Transportation of Ontario (MTO), instrumented a weathering-steel highway bridge in Ontario. Fiber-reinforced plastic (FRP) plates carrying steel samples and a suite of sensors—including thickness loss, temperature, relative humidity, time of wetness, and galvanic corrosion sensors—were installed at eight strategic locations, from piers exposed to traffic to abutments farthest from exposure. The system enables continuous, real-time monitoring over a one-year period. Preliminary results indicate that both the orientation and location of bridge components significantly influence corrosion behavior. These findings provide new insights into the spatial variability of weathering steel degradation and offer valuable information for more accurate life prediction and maintenance planning of steel bridge infrastructure in harsh environments.
