Honorable Mention: Transportation Category
Interstate Route 480 Bridge Repair
Submitted by Vector Corrosion Technologies
Nebraska Department of Roads
Vector Corrosion Technologies
Winnipeg, Manitoba, Canada
In the summer of 2002, the Owner undertook the 3rd phase of a large rehabilitation project on a 1.5 mile elevated section of Interstate Route 480 in downtown Omaha. Constructed in the early 1970s, the viaduct had experienced significant chloride induced corrosion and deterioration to the concrete deck and substructure. The overall project included the rehabilitation of sixty-six hammer-head piers, application of a chloride resistive sealer, and complete deck replacement.
With the replacement of the deck, the long-term performance of the repaired substructure was a concern. In order to extend the service life of the concrete repairs and extend the life of the substructure, Owner elected to perform electrochemical chloride extraction, install embedded galvanic anodes in the patch repairs and apply a chloride resistive sealer to the substructure.
Twenty-three of the hammer-head piers were treated with electrochemical chloride extraction, a technique that removes chloride ions from concrete and restores the rebar to a passive condition. Fifty-five of the piers had embedded galvanic anodes installed within the patch repairs, to extend the life of the patch repairs. Finally a chloride resistive sealer was applied to all sixty-six piers to prevent future chloride contamination.
The application of advanced rehabilitation technologies including chloride extraction and embedded galvanic anodes played a vital role in restoring this structure, and assuring that the substructure will serve as well as the new deck. These technologies allowed the Owner to tailor the level of protection to suit the varying needs of the structure, addressing future corrosion concerns as well as current problems.