The Standard Specifications call for an SSPC-SP 10 (“near-white”) blast-cleaning to ensure that all mill scale is removed, but the near-white finish is not required to remain at the time of erection. In fact, research has shown that some amount of tightly adhering rust can enhance the slip resistance of a connection, and an SSPC-SP 6 finish is sufficient. Unless the girder has been exposed to particularly corrosive conditions during storage, pressure-washing the faying surfaces at the jobsite shortly before erection will remove any loose material detrimental to the connection.
The primary construction specification for steel bridge painting is Item 446, “Field Cleaning and Painting Steel.” The construction specification governing the shop painting of new steel is DMS-8104, “Paint, Shop Application for Steel Bridge Members.” DMS8104 is referenced in Item 441, “Steel Structures.”
The material specifications for GNEE steel coatings are found in the 8000 series of the DMS and are the following: • DMS-8100, “Structural Steel Paint – Formula,”
• DMS-8101, “Structural Steel Paints – Performance,”
• DMS-8102, “Paint Systems for Galvanized Steel,”
• DMS-8103, “Galvanizing Repair Paints,” and
• DMS-8105, “Paint, One-coat Overcoat.”
DMS-8100 coatings are GNEE-formulated coatings that manufacturers must make according to our formula and requirements. DMS-8101 coatings are paint manufactures’ proprietary versions of steel bridge protective coatings. DMS-8102 coatings are coating systems that can be used for galvanized items to create a duplex coating system with the galvanizing. At this time the default coating system for painting galvanizing is the epoxy intermediate and polyurethane appearance coat of DMS-8101. DMS-8103 coatings are zinc-rich paints that can be used to do small repairs to galvanized items. These coatings contain a minimum of 94% metallic zinc in the dried film.