Solving Corrosion Problems of Bridge Surfaces Could Save Billions

Gao ID: PSAD-79-10 January 19, 1979

Although bridge roadway surfaces (decks) were expected to provide relatively maintenance-free service for about 40 years, the Federal Highway Administration has found that some unprotected bridge decks require major repair within 5 to 10 years, and often must be replaced after 15 years of service. The major cause of this early deterioration is corrosion of the reinforcing steel bars in the bridge deck, brought about by chloride chemicals which are used to melt snow. About $6.3 billion is needed to restore the Nation's Federal-aid system bridge decks. Most States have indicated that, if present conditions are not improved, their currently reparable bridge decks will continue to deteriorate, and eventually require complete replacement at a much higher cost.

A review of the problem indicates that a number of bridges in the Federal-aid system do not have a protective system on their decks. They contain either no areas or only small areas where chloride levels are high enough to cause bridge deck deterioration. If these bridge decks were protected with one of the systems now used for new bridge construction, significant savings could be realized by avoiding more expensive repairs later. Lack of funds is the primary reason that States have not installed protective systems on existing bridges. Funds available for bridge repair are generally budgeted for bridges so deteriorated that replacement of the deck is the only option. As a result, those bridge decks with little or no deterioration will continue to deteriorate, and eventually require repairs or replacements that are much more costly than the cost of the protective systems. Weaknesses also exist in the Federal Highway Administration's evaluation process to assess the performance of the technologies in extending the service life of the bridge decks.


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