New materials to help maintain the International Bridge can lower some upkeep costs, ensure work is done faster and potentially last longer than traditional methods used for the 54-year-old crossing.

A new coating system will be piloted on two spans of the south end of the crossing between the Twin Saults this year.
Instead of removing all paint, bridge staff will pressure wash the spans and use one coat of the coating system instead of a coat of primer, zinc and top coat. Work should be done 60% faster, said Peter Petainen, general manager of Sault Ste. Marie Bridge Authority.

Bridge engineer Karl Hansen inspected several bridges in southern Ontario that use the coating system. He found a rail bridge in Woodstock that showed no rust 23 years after that paint was applied. The durability deferred major paint projects “for a very significant period of time,” said Petainen. Hansen also visited a paint manufacturing facility in Montreal.

He estimates the coating system is used on about 4,000 bridges in North America.

“It was new to us,” said Petainen. “We went from pessimistic to cautiously optimistic.”

Ontario Ministry of Transportation approved the coating system for use on top of existing paint.

If bridge staff like what they see in the fall and spring after its application, the coating system will be used on the Canadian arch and curb rails in 2017. Workers will check rust is not seeping out where steel joints join.

SSMBA planned to paint the Canadian arch this year. Budgeted cost was $3.2 million CDN, said Petainen. But the three bids ranged in price from about $6.5 million to more than $11 million. The price quoted only covered work on the arch's top half.

Contractors told SSMBA “a number of things” drove bids up, said Petainen. They included containment costs – the upper half of the arch still has lead paint - and the need to clear customs to get to the work site. The price for similar work on the Mackinac Bridge, 90 kilometres south of the Sault, was 50% less.

Planned replacement of 15 sliding plate bearings and two rocker arms, to be done this fall, is pushed back to the spring because of “the lengthy lead time to manufacture the parts,” SSMBA says. Estimated cost is $600,000 US.

The sliding plate bearings and rocker arms allow for lateral movement of the bridge arches due to thermal expansion and contraction.
The delay in painting and replacing parts will have “zero impact” on bridge safety, said Petainen.

“We're being proactive with regard to both of these projects,” he told The Sault Star. Both will be done before their recommended replacement.

SSMBA used a new flood coat sealant on the approximately 850-foot Canadian arch concrete deck in July. The product seals into the concrete and seals all cracks – seen and unseen, said Petainen.

Bridge staff want to seal cracks to prevent water from entering the concrete and rusting the rebar. Rusting would cause swelling, causing the deck to pop apart.

The flood coat sealant is expected to last a minimum of five years. It will also improve traction for motorists, especially in the winter, when used with a granular overlay, said Petainen. The epoxy sealant used before was only applied where staff saw visible cracks.