The redecking of the Angus L. Macdonald Bridge, a.k.a. The Big Lift project, usually elicits one of two reactions — and sometimes both — from people.
Reaction 1: an incredible feat of engineering.
Reaction 2: an incredible nuisance if commuting.
Not much mystery to the latter. If you’re trying to drive across, you’ve got to slow down for several big bumps on the span. There’s no access after 7 p.m. or before 5:30 a.m. weekdays and none on weekends. Pedestrians and cyclists must rely on shuttle buses at all times.
So when the Halifax Harbour Bridges folks hosted an update session on the project for media types last week, I posed a few what-seemed-to-me pertinent questions.
When will those bumps be gone? When will overnight and weekend closures end? When will people who walk or cycle have access again?
The answers came as we walked, from Dartmouth, across the Macdonald after the bridge had closed to traffic that night. We had to keep clear of the busy work crews, under the direction of general contractor American Bridge Canada, moving heavy equipment, replacing cables and welding seams on new decking. In a little over 10 hours’ time, they’d have to be packed up and off the bridge in time for its 5:30 a.m. reopening.
First, the bumps.
The short answer is they’ll be gone — and the new bridge deck completely paved — by next July.
The longer explanation is interesting, too. Those bumps — except for the one that covers the point where old deck meets new deck — are located where the bridge’s new expansion joints will eventually be.
Expansion joints allow the bridge to move in response to variations in temperature, load and weather. There are four of them — at the two towers and at the points the suspended span starts on both sides of the harbour.
But the new ones can’t be installed until after the new decking is in place and paved.
That won’t be done until next May, weather permitting.
Jon Eppell, chief engineer for Halifax Harbour Bridges, poses with the Angus L. Macdonald Bridge as a backdrop in May. (TIM KROCHAK / Local Xpress)
As motorists using the bridge know, the Dartmouth side span (between the Dartmouth side tower and approach) and main span have been redecked. Those sections should be paved by year’s end, says Jon Eppell, HHB’s chief bridge engineer and Big Lift project lead.
Crews are now prepping the lifting gantry — the 60-tonne yellow structure that lifts and lowers the old and new decking as it’s being switched out — to replace the span on the Halifax side of the bridge.
The main challenge is that the work will now no longer occur over water.
That means the barge, used as a landing spot for old decking being lowered and launch pad for new decking being lifted, is no longer practical.
The plan on the Halifax side is to instead truck the old and new sections — cut to 10-metre lengths instead of 20 as before — over the bridge from Dartmouth. As part of the process, the lifting gantry will be rotating the sections in mid-air.
That work won’t start until early October, says Eppell, but should be completed by year’s end. That section, however, won’t be paved until spring.
Once that's done, the expansion joints can be installed next May and June. With the new deck paved and the bumps gone, by July motorists should enjoy a smooth drive.
How about closures?
By January, the bridge should start opening most weekends again. There’ll still be occasional weekend closures until the Halifax side span is paved, Eppell says.
Weeknight closures will continue until the project is completed in the fall of 2017.
Here’s a bit more good news. Pedestrians and cyclists should regain access to the bridge early in the new year, except for when the bridge is closed. Shuttles will be available at those times.
Now let’s talk about the engineering. You probably haven’t noticed, but the big lift has begun.
Using hydraulic jacks, work crews have been lifting the bridge span since June.
The jacks, located at each set of suspender cables on new deck sections, have been used to lift the deck, in tiny increments, overnight several times a week during the past two months.
The centre of the Macdonald — where the span will be lifted the most — is already a metre taller. By year’s end, when the big lift is scheduled to be done, the midpoint of the bridge should be about 2.1 metres higher.
For John Callaghan, the American Bridge Canada Co. (ABCC) project manager from New Jersey, the Big Lift — replacing the decking on a working bridge in a working harbour — has been an interesting project.
Callaghan loves challenging engineering jobs. Prior to this project, he and his team built the world’s tallest ferris wheel — the High Roller in Las Vegas — across from Caesar's Palace near the Nevada city’s famed strip, Las Vegas Boulevard South. The giant structure, which opened in early 2014, stands 168 metres (550 feet) high, making it the tallest observation wheel in the world.
If possible, Callaghan told me, he’d like his crews — from Ironworkers Local 752 — to be able to safely replace four 10-metre sections of decking on the Halifax side span in a single weekend. That’s never been done anywhere, he said.
How does he like Halifax? Beautiful place, nice people, he said, but the weather’s sometimes a challenge. Sounds about right.