Design Memorandum



TO:                  All Design Section Staff

FROM:            Richard Stoddard
DATE:             February 27, 2006
SUBJECT:       Concrete Deck Slab Reinforcement

The following revisions are made to the use of epoxy coated reinforcement in bridge structures:

  • Epoxy coated reinforcement shall be specified for both top and bottom layer rebar of all bridge deck slabs without longitudinal post-tensioning.

  • Epoxy coated reinforcement shall be specified for only top layer rebar of bridge deck slabs with longitudinal post-tensioning.

The above recommendation is applicable to all prestressed girder, concrete box girder, and steel girder bridges with cast-in-place concrete deck slabs.

Background

Performance and longevity of concrete deck slabs have always been a major concern for bridge deck slabs. Although the mix design, placing and curing of cast-in-place concrete deck slabs have significantly been improved in recent years, the inspection of WSDOT bridge decks indicates that cracking is still apparent in bridge decks.

The condition of cracks in non-post-tensioned bridge decks worsen over the service life of the structure, with possibility of cracks extending through the deck thickness, causing corrosion in bottom layer reinforcement due to chloride penetration. Use of epoxy-coated reinforcement in bottom layer rebar will inhibit corrosion of reinforcement and deterioration of concrete.

However, the performance of longitudinal post-tensioned bridge decks is satisfactory with epoxy-coated reinforcement for top layer rebar only.

If you have any questions regarding these issues, please contact Bijan Khaleghi at 705-7181.

cc:   Mohammad Sheikhizadeh, Bridge Construction - 47354

       F. Posner, Bridge and Structures 47340