The corrosion performance of the weathering steel members of the bridges inspected during this study varies considerably from one bridge to another and between different components of a given bridge. The majority of the bridges were observed to be in good condition with few corrosion problems; however, exceptions do exist. Based on a critical review of the corrosion performance of the inspected bridges, the following three factors have been identified as being most influential to the performance of weathering steel bridges: deck type, span type (e.g., stringer, arch, frame, etc.), and crossing (e.g., stream, highway, railroad, etc.). A discussion of the influences of each of the deck, span, and crossing types encountered in weathering steel bridges in West Virginia follows. Various additional factors relating to the environment of a bridge site have previously been set forth by other researchers as being influential to the performance of weathering steel. Some of these environmental factors include: proximity to industrial locations, surrounding vegetation, clearance over bodies of water, and terrain that shelters the bridge site from sunlight. A broad range of site environments were investigated in this study including bridges that were: near two different power plants, immediately adjacent to a coal field, in urban environments, located in rural areas, and densely sheltered by terrain and vegetation. While it will not be disputed that these factors may affect the corrosion characteristics, for the broad range of site environments investigated in this work, it is believed that these factors alone are not sufficient to create a situation where the performance of the weathering steel is unsatisfactory. Instead, these factors may only intensify a corrosion problem caused by some other source, as discussed below.
A deck consisting of a continuous, solid surface should be provided. Reinforced concrete decks with or without stay-in-place metal deck forms are recommended. Conversely, the use of timber decks and metal grid decks (filled with concrete or unfilled) is highly discouraged as these decks do not prevent water from reaching the girders and in many cases act to trap water on the top flange of the girders, exacerbating the situation. Construction joints in concrete decks should be grouted. These joints should be carefully inspected during biennial inspections to monitor water penetrability. In many newer bridges, a construction joint located approximately 10 ft from the abutments was observed; consideration should be given to revising design practices to eliminate this joint. The overhang width should be extended as wide as feasible to provide additional shelter to exterior girders.