Tiny cracks that have formed on some of the concrete piers of the Chesapeake Bay Bridge have not affected the structural integrity of the 42-year-old span, the head of the Maryland Transportation Authority said yesterday.
The cracks, detected in 1980, have appeared on 17 concrete footings beneath the surface of the bay. Experts have blamed the 1/16th-to-1/4-inch cracks on the effects of the bay's salty waters on the cement used in the concrete.
Last fall, the authority awarded a $600,000 contract to McLean Contracting Co. to examine the cracks on two of the piers, then reinforce their footings with a concrete jacket several feet thick that is less susceptible to the effects of salt water.
The repairs began this spring and are expected to be finished in a month, said Stephen L. Reich, the authority's executive secretary. Traffic is not expected to be delayed.
Similar repairs will be made to the other 15 piers within a year at a cost of about $5 million, he said.
"This is a preventive maintenance action," Mr. Reich said. "We're just trying to stay ahead of it."
An October 1991 study conducted by a Baltimore-based concrete specialist found the cracks posed no danger to the bridge. "In view of the fact that it has taken approximately 40 years of exposure to produce the present condition, the concrete may serve adequately for another 40 years," Dr. Michael Z. Ozol concluded.
John A. Moeller, the authority's engineering director, said the cracks have not appeared to worsen over the 14 years, but "Left unchecked for 10 or 20 more years . . . they would have hurt the integrity of the piers." One of the two piers under repair is about one-half mile west of the Eastern Shore, the other one-half mile east of Sandy Point.