STP841: Zinc-Plus-Paint System for Corrosion Protection of a Steel Bridge

    Lwin, MM
    Specifications and Estimate Engineer, Washington State Department of Transportation, Olympia, WA

    Pages: 10    Published: Jan 1984


    Abstract

    Steel bridges are commonly protected from corrosion by the use of weathering steel (unpainted), paints, or zinc. The use of zinc and paints in combination has not received much attention in bridge construction. This paper describes the factors influencing the selection of a zinc-plus-paint system for corrosion protection of the structural low-alloy steel lift spans of the Hood Canal Floating Bridge. This bridge is situated in a marine environment and is designed to have a service life of 75 years.

    A zinc-plus-paint system consisting of 1.07 kg/m2 (3.5 oz/ft2) of zinc and two coats of paint each 0.005 mm (2 mils) thick is predicted to provide corrosion protection in a marine atmosphere for more than 70 years. The initial cost for this system is higher than for a three-coat paint system, but the long-term advantages and cost savings are substantial.

    Keywords:

    corrosion protection, glavanizing, paint, steel bridge, zinc


    Paper ID: STP29526S

    Committee/Subcommittee: D01.25

    DOI: 10.1520/STP29526S


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