FORT FRANCES—If you are planning a summer vacation over the next several years that takes you east of Fort Frances, you’d better be prepared for construction delays.
Ray Krisciunas, with the Ontario Ministry of Transportation, outlined plans to rehabilitate the Noden Causeway east of Fort Frances for members of the Rainy River District Municipal Association at their annual meeting Saturday in Rainy River.
Krisciunas said the causeway was rehabilitated in the 1980s but that was a very conventional facelift. What the MTO is looking at now will be very different—and will be using construction methods not tried anywhere else in Canada.
The sides of the causeway will be cut away and the top will be covered with prefabricated cement slabs. They will be glued down and will widen the decking by a metre on each side.
“It will be a steel-free deck,” noted Krisciunas. “Even the traditional rebar in the cement will be replaced with a carbon fibre.
“While this is very expensive, it is durable. The deck should last indefinitely,” he added.
A see-through guard rail will be installed so drivers will be able to see the lake, unlike now where there is solid cement.
With the top planned out, what lies beneath the structure is another story. Each pier is supported in the water by steel pilings each 16-24 inches in diameter.
“The bridge was designed to flex with ice flows,” explained Krisciunas.
Many of those pilings are corroding, however—and not from what one might think.
Bacteria in the water have been feeding on and around the pilings, and their by-products have caused what is known as Microbial Influenced Corrosion. The problem is worse near the surface where oxygen is present.
Divers discovered it is a severe problem in places.
“We have lost 70 percent of the steel to corrosion in some cases on about 80-90 percent of the bridge,” Krisciunas said.
After reviewing several options to deal with the problem, the MTO currently is testing a method it hopes will be a viable fix.
Using a method never done in Canada (to the MTO’s knowledge) called polymer encapsulation, it is testing the use of a fibreglass collar around the piling.
Studs also are shot into the piling to give it more strength. Then an epoxy is pumped in, which displaces the water and dries to form a strengthened complete structural element.
The test trials now underway will cost about $450,000. If it works, each piling will be done at a cost of $30,000.
There are 1,120 pilings for a total estimated cost of about $35 million.
Only one part of the decking will be replaced this year as the pilings in the lower east level are good enough to support the new deck panels—each of which weight eight tonnes.
The total deck rehab will cost about $30 million for a total project estimated cost of $65 million.
Krisciunas said the MTO hopes to have it all finished by 2013, “but that is contingent upon funding flowing.”
Several RRDMA members expressed concern about delays in getting lumber trucks across the causeway to the mills in Fort Frances and Barwick.
Krisciunas said only one-quarter of the deck will be under construction at any one time, and that there will be single lane traffic with lights to control it.
“There should not be any lengthy construction delays,” he remarked.
RRDMA president Emily Watson asked if it would be possible to do the work during the night when traffic is at a minimum. Krisciunas replied safety is a concern at night.
Krisciunas also noted that the prefab decking will allow rehabilitation to go about two times faster than the conventional rehab that was done in the 1980s.
But not much of the deck work will be done until the pilings are reinforced.
Once the work is done, it is estimated the Noden Causeway will be good to go for about 40 years.
(Fort Frances Times)
Fort Frances Times
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