Detecting a silent bridge-killer

and may have used it on bridges, I just couldn’t find an immediate example,” he said.

DOT has been responsible for maintaining the bridge since 1985, when it was taken over from a joint New York-Vermont bridge commission. As part of the agreement, Vermont assumed maintenance of another bridge at Rouses Point.

 Carrier said the state took concrete samples from the Champlain Bridge piers, although he was not able to say when the samples were taken. The reports were not provided by DOT in time for this report.

 When first asked for bridge inspection records by a Times Union reporter last month, DOT initially released only inspection results for the bridge superstructure, and not the piers. The underwater inspection records were released last week only after a second request by the newspaper.

Delatte said the kind of waterline pier deterioration found on the Champlain Bridge usually is caused by repeated cycles of freezing and thawing. Water gets into cracks, freezes and expands, making cracks larger, and causing the concrete to crumble. The condition, called “scaling,” is essentially the concrete “turning into gravel,” he said.
This section of Lake Champlain is relatively shallow, and freezes over solid nearly every winter. “We know that freeze/thaw is a factor in pier deterioration, and we are looking at that in our investigation.” said Carrier. The state does not keep records on ice conditions around the bridge, he said.

 The rotted piers were found a year before the next inspection was due when workers noticed their condition during a period of low water this summer. The next scheduled diving inspection wasn’t due until 2010, but repairs were being done to the superstructure of the bridge.
Divers were sent in and gave DOT the shocking results that at least two of the five piers were unsafe. A DOT time line does not specify dates for the actions.

Sometimes, concrete can be salvaged through removal of weakened portions and application of a polymer sealant that seeps into any remaining fissures and cracks. “But as time goes on, and there is more and more unsound concrete, and less good material, to attempt to glue it back together isn’t possible,” he said. “It can be difficult to predict when deterioration will take off.”

Delatte said, “One of the first things I noticed in reviewing the state reports was that they called for fixing and repairing the cracks in the concrete.” The repair recommendations were in the 2005 report, which found that the concrete rot had grown from 6 inches to 10 inches from 2000 to 2005.

If piers could have been strengthened with polymer, however, the piers then also could have been sheathed at the waterline to prevent more water and ice damage, he added.
DOT could not be reached to respond to Delatte’s observations. “How could the bridge get that bad that fast? DOT misjudged the life of the bridge,” said state Sen. Betty Little, a Queensbury Republican who represents the Lake Champlain region. “This bridge closure has had enormous impact,” she said. Many people are driving hundreds of extra miles a week to detour around the lake at Whitehall, Washington County, or have to rely on state-subsidized ferry service elsewhere on the lake at Ticonderoga and Essex.

 Last week, DOT closed off boat traffic under the bridge, said Little. That would have the effect of dividing the lake in two, preventing boat traffic north of Crown Point from reaching the Champlain Canal in Whitehall.

Connecting to the Hudson River at Fort Edward, the canal is an important source of tourism for recreational vessels traveling back and forth. The canal usually closes for the season in the fall and reopens in late spring after the ice thaws. “Hopefully, we will have done something to the bridge by then,” said Little.