A single-lane detour on an abandoned railway bridge will be ready soon for the closure early next year – followed by a rebuild – of the Pine Point Bridge over the Hay River.
"The detour preparation work should be finished by about mid-November," said Ann Kulmatycki, manager of the structures section (bridges) with the Department of Infrastructure. "Then the contractor is going to demobilize and they're going to come back after the first week of January. And at that point we'll close off the highway bridge and detour traffic onto the single-lane railway bridge."
Work on the detour began in late September.
The timber-deck detour will have traffic lights on either side to regulate the flow of vehicles.
"And occasionally there will be flagpersons there when something a little bit different is happening in the area," said Kulmatycki.
The usual traffic on Highway 5 will be able to use the detour on the railway bridge, which was left over from the days when trains ran to the Pine Point Mine.
"Normal, legally-loaded, legally-sized vehicles can go over the bridge, but there will be a restriction to maximum load size of 4.5 metres wide," said Kulmatycki.
She noted the Department of Infrastructure posted an advisory in midsummer about the width restriction, which might affect the movement of such things as buildings.
"We gave at least six months advance notice, plus contacted carriers to let them know this was happening so they could plan for their wide moves," she said.
Kulmatycki said the Pine Point Bridge will be closed from January to about Nov. 15, 2019, to allow time to construct a new bridge.
It is fortuitous for the GNWT that the railway bridge exists next to the highway bridge.
"We would have had to construct a detour bridge alternate. So we would have had to kind of redirect the traffic down," said Kulmatycki of what would have likely happened without the railway bridge. "Or maybe just do a winter construction like when they did the Hay River West Channel Bridge in town, and then detour traffic down across the ice."
An ice crossing might have meant a longer time period to complete the project.
Kulmatycki noted the old railway bridge has been determined to be "absolutely" safe for all legal highway traffic.
"We have had an engineering assessment done on the old railway bridge and found that it would be suitable as a detour," she said.
The railway to Pine Point operated from 1964 to 1988 to transport lead and zinc concentrate.
A recent project on the Buffalo River Bridge on Highway 5 did not require a detour.
"The Buffalo River Bridge was rehabilitated one lane at a time," explained Kulmatycki. "In this case, we're replacing the whole superstructure. So we're tearing down the truss. It's totally getting removed."
Only the foundations of the 550-foot-long (167-metre-long) Pine Point Bridge will be reused.
At the height of construction next year, there will be about 20 workers at the site.
Kulmatycki noted the new bridge will have a design life of 75 years.
"It should last even longer than that with proper maintenance," she said.
The main contractor on the $12.8-million project is Eiffage Innovation Canada Inc., which also had the contract for the Buffalo River Bridge.
When completed, the new Pine Point Bridge will look very different than the existing bridge.
"It's going to look like the West Channel Bridge that's in Hay River," said Kulmatycki. "So you'll have the railway truss on one side and the open deck bridge on the other side."
The railway bridge is going to remain after the project is completed.