The chesapeake bay bridge-tunnel, completed in 1964, was 24 years old when wilbur smith associates, btml division, supplied engineering services as part of an in-depth, above-and-below water inspection of the substructure for the chesapeake bay bridge-tunnel district.As part of this inspection, a visual inspection of all substructureelements was conducted. A total of 60 bents were selected for a hands-on inspection. From these bents, 10 piles were selected for an in-depth evaluation. The 24-year-old substructure of the chesapeake bay bridge-tunnel was in fair condition. The splash zone and below-water portions of the piles were in good condition because of the protection provided by excessive marine growth. The above-water portions of the piles were found to be in generally fair condition. Almost all piles had hairline cracks; some piles had open cracks that allowedthe ingress of corrosive agents. The prestressing strands were in good condition wth no section loss. Corrosion generally began as thesurface of the pile crack increased beyond 1/4 in. Chloride ion presence in the concrete at the level of prestressing strand was almostnegligible. The corrosion potential readings correlated with the rating of the crack tested. Caps were found to be in good condition with only isolated signs of deterioration. The report to the chesapeake bay bridge-tunnel district made the following recommendations: cracks open less than 1/16 in. Need only be monitored; cracks open 1/16to 1/4 in. Should be sealed by epoxy injection to prevent corrosioninitiation; and piles with cracks open more than 1/4 in. Should be rehabilitated using a structural jacket or replaced. This paper appears in transportation research record no. 1268, Highway maintenance operations and research 1990.
Samenvatting