Highway 103 overpass in Halifax to be demolished this weekend

Christmas shoppers in Halifax beware. Detours will be in place this weekend in an area that sees some of the highest volumes of traffic in Atlantic Canada.

The old Highway 103 overpass over Highway 102 will be torn down over a 48-hour period beginning Friday night, one of the final stages of a project that's seen a new interchange built at the site.

"We'll be bringing in a couple of machines and they'll start to break it apart and we'll dismantle it from there,' said Department of Transportation project engineer Colin Weaver, who noted the 56-year-old overpass is about 40 metres wide and nearly 600 tonnes.

Beginning at 10 p.m. on Friday night motorists traveling northbound on Highway 102 will be required to detour on to Dunbrack Street. Motorists travelling southbound will be required to detour at Exit 1A to Highway 103 westbound.

Paul Palmeter/CBC

Signs will be in place to note the detours in both directions. Highway 102 will reopen by 10 p.m. on Sunday. The full Highway 102/103 interchange project is expected to be complete in late December.

"It'll be a big difference if you're heading inbound on Monday morning, or even outbound for that matter, the new structure is quite a bit taller than the old one," said Weaver.

The existing interchange was built in 1963 and it's been well used. It experiences average annual daily traffic of about 30,000 vehicles on Highway 103 and 55,000 vehicles per day on Highway 102.

Submitted by Nova Scotia Department of Transportation and Infrastructure Renewal

In October, the new overpass was opened up to traffic as part of the upgrades to the interchange took shape.

A new ramp leading to Dunbrack Street has now been built and will soon be opened. The ramp travels under a tunnel that had to be constructed.

Paul Palmeter/CBC

Original estimates for the work came in at $20 million, but there were complications that drove the final total up by approximately $10 million. The province is paying for two thirds, and the federal government the remainder.

One of the issues was environmental. A large hill had to be built by work crews next to the new overpass to dispose of more than 100,000 cubic metres of rock.

"This area of Halifax has sulfide-bearing rock which can generate acid when exposed to water and air," said Weaver. "So we've had to encapsulate all that material in a permeable membrane."

Weaver said the construction will continue for a few more weeks, and the area should be completely cleaned up early in 2020.