The last of the Macdonald Bridge deck segments are on track to be replaced by the end of 2016.

"We're still on track for finishing the overall project in fall 2017, just over a year from now," lead engineer Jon Eppell said at an update on the Big Lift progress Tuesday evening.

The only deck segments left to replace are those closest to the Halifax side. Because those are over the military dockyard, the segments can no longer be lifted from a barge in the harbour, Eppell said.

Instead, they'll be raised to bridge level on the Dartmouth side, and then driven across the bridge before being fitted into position.

It's a tricky operation, which Eppell calls the "ballet portion of the program."

The Macdonald Bridge re-decking project has had several delays this year. (Halifax Harbour Bridges/Dale Wilson Photography)

'Rocking and rolling' despite delays

The project fell behind schedule in the spring, after delays caused by poor weather.

"Pretty rough weather in April. It was frustrating, but we got past it," said John Callaghan, project manager with contractor American Bridge Canada Company.

"I'd say once we got past Easter, we were rocking and rolling, and we haven't stopped since."

This is the second time a suspension bridge span in Canada has been replaced overnight while keeping the bridge open to traffic by day. The first project was the Lions Gate Bridge in Vancouver.

A bridge segment is positioned for the Big Lift project on the Macdonald bridge. (Submitted by Halifax Harbour Bridges)

Sidewalk back by end of year

In September, 80 per cent of the bridge will be paved with asphalt surface. The sidewalk and bike lanes are expected to be open by the end of 2016.

Starting in January, the bridge will close overnight Monday to Friday. It will only need to be closed on a few weekends.

There is still more maintenance to be done after the deck replacement is complete, but Halifax Harbour Bridges is aiming to complete the entire project by the fall of 2017.