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SOLVING CORROSION PROBLEMS
Although bridge roadway surfaces (decks)
About $6.3 billion is needed to restore
Most States have indicated that, if present
SLIGHTLY CONTAMINATED BRIDGE DECKS
A number of bridges in the Federal-aid system
Tear Sheet. Upon removal, the report cove: date should be noted hereon.
later. The potential benefit/cost ratio of repairing and protecting an existing bridge deck needing only minor repair versus completely replacing the deck at a later date is 2.75 to 1.
Lack of funds is the primary reason that States have not installed protective systems on existing bridges.
State officials GAO contacted indicated that 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. (See ch. 3.)
GAO recommends that the Secretary of Transportation identify those bridge decks which can be economically restored, estimate the cost of restoring them, and develop a plan for repairing these decks as soon as possible.
HEAVILY CONTAMINATED BRIDGE DECKS
Many of the existing unprotected bridge decks in 32 States contain chloride levels above the corrosion threshold which will cause the bridge deck to deteriorate, and eventually to require replacement, unless a means is found to halt the deterioration. Numerous techniques are being investigated which may protect these bridge decks from further deterioration. However, the Federal Highway Administration has not yet developed proven, cost-effective techniques for stopping the deterioration.
Cost-effective solutions are needed quickly to avoid using billions of dollars for complete replacement of the bridge decks. (See ch. 4.)
GAO recommends that the Secretary of Trans-
LONG-TERM EVALUATION PROCEDURES NEEDED
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.
. For example, the Federal Highway Administration lacks a formal system to monitor and evaluate the long-term performance of protective systems which were approved for nationwide use on the basis of laboratory and short-term field performance data. (See ch. 5.)
To improve the technology evaluation process, GAO recommends that the Secretary of Transportation establish a formal long-term data collection and evaluation system for bridge deck protective systems.
The Department of Transportation agreed that
--Will modify its data retrieval program to
better identify bridge deck conditions which
--Plans to propose a new federally coordi
nated research and development project in fiscal year 1980 to search for a less expensive rehabilitation procedure which does not involve the removal of large quantities of concrete.
--Will institute in fiscal year 1979 a pro
gram to provide a long-term data collection system for protective systems. (See app. II.)
The Federal Highway Administration provided other more detailed comments that GAO included in the body of the report where appropriate.