Environmental Suitability of Weathering Steel Structures in Florida – Materials Selection, Phase 2
For the purpose of establishing guidelines for selection of weathering steel material for bridges in Florida, data were collected to help establish appropriate guidelines. There were 30 monitoring stations set up for direct (weight loss) measurements and weather data. Data indicated that the corrosion rates in Florida are generally low for weathering steel. The use of weathering steel material for bridges in Florida in the context of adjusted guidelines is very favorable. Consideration should be given to increasing the allowable deposition rate of chloride to approximately 13 mg·m–2·d–1 corresponding to 4 miles from the shoreline. An alternative direct assessment at the site considered is recommended for determining the advisability for uncoated weathering steel in this manner: (1) Expose several plate specimens and collect monthly for a minimum of 4 months. (2) Directly compare the time series weight losses to known corrosion studies. ISO methods permit this alternative. Additionally, estimates of chloride and sulfur compound depositions can be obtained from the same exposed panels by analyses of panel wash water prior to oxide removal, if desired. The advantage of direct assessment is that no environmental factor will likely be neglected, such as pH, ammonia, fertilizer, ozone, exposure/sheltering, or unanticipated factors (positive or negative).
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