Abstract
The Verrazano-Narrows bridge is a 13,700-foot-long suspension bridge between Brooklyn and Staten Island. A major maintenance project planned for the lower level of the bridge included structural steel replacement and replacement of a 20-year-old coating system on the structural deck system and stiffening truss elements. The initial design approach was to remove the coating (SSPC-SP 10, Near-White Metal Blast Cleaning) in more corrosion prone locations and perform spot cleaning of the less corrosion prone locations. To bring the initial design estimates within the allocated funding, SSPC-SP 18, Thorough Spot and Sweep Blast Cleaning for Industrial Coating Maintenance was specified for all surfaces in lieu of the combination of full removal and spot cleaning.
SSPC-SP 18 is a new procedure which saves money by only removing weak coatings and allowing well adherent, serviceable coating(s) to remain. Studies have shown that the procedure can reduce the cost of maintenance coating without any performance compromise.1,2,3,4,5,6,7 The Verrazano-Narrows project ultimately used the new procedure successfully on approximately three million square feet of coated steel. This paper describes the SSPC SP-18 procedure and it’s use on this project.
