How Calgary plans to retrofit its 1960s-era Crowchild bridge to meet 21st century demands

The CrowchildTrail bridge was built in the mid-1960s, when about 300,000 people lived in Calgary.

Today, the city's population is pushing 1.3 million citizens not to mention visitors and commuters from burgeoning bedroom communities on all sides most of whom rely on their cars for getting around.

It doesn't take a traffic engineer to realize the situation isn't sustainable. Anyrush-hour traveller would tell you as much, in between cursing thenotoriously short and confusing merge lanes.

And so, the city has undertaken a multi-year$87-million project to retrofit this half-century-old piece of infrastructureto meet the needs of Calgarians for the next 50 years, and likely beyond.

The list of planned upgrades for the bridge (and sections of CrowchildTrail just to the north and south) is as long and complicated as its on and off ramps.

But one key component is widening the bridge deck.

The plan is to add an average of four metres on each side, and as much as 6.5 metres at some points, in order to accommodate an additional northbound lane and southbound lane.

But how do you go about expanding a 50-year-old structure without disturbing the environmentally sensitive riverbed below or closing any lanes during Calgarians' regular work hours?

With a lot of careful planning, and evening and weekend work.

"It's unique in that sense," saidJeff Baird, the project's senior transportation engineer.

"Nothing to this scale, anyway, has been done in the city."

Bridge beneath a bridge

As much work as you'll see on the bridge deckitself, there's even more going on below.

Temporary platforms are being built so that workers can access the underbelly of CrowchildTrail and eventually construct the supports that will hold up the new lanes.

These platforms will be no small structures, themselves.

Baird describes it as building "a bridge underneath the existing bridge"

Once in place, workerswill go about building the actual supports, which Baird said will involve a combination of cantilevers, concrete upgrades and reinforcing steel.

"Essentially it's beefing up and widening the existing columns that support the bridgeover the river," he said.

While all the expansion work is going on, crews will also be doing regular life-cycle maintenance not only to the bridge over the Bow River but also those that pass above Memorial Drive and Bow Trail.

New on ramps and merge lanes are also part of the project, as well as related work like new sound walls and a connection to the planned Crosstown Bus Rapid Transit (BRT) line farther to the north.

The final plan for the Crowchildprojectcame after years decades, actually of proposals to redesign the busy route just west of downtown that had become agrowing bottleneck for traffic.

Calling it too costly and disruptive, city council rejected a 2012 plan that would have seen homes demolished in order to reroute a section of Crowchild.

As far back as 1978, the city was drawing up complex plans to fix the traffic problems that were becoming evident with the busy north-south thoroughfare.

A proposal from that era called for the first phase of a major redesign to be completed by 1983, but it never happened, apparently for a lack of money.

Today, the current project is only considered a "short-term" upgrade for Crowchild Trail.

The city also has medium- and long-term plans for the route, which will likely include acquiring private property for future construction work.

There is no funding, as of yet, for these plans which together are estimated to cost around $1.55 billion and they're not realistically on the horizon until 2027.

Retrofitting old infrastructure is an issue Calgary will continue to grapple with as it grows.

And while the growing pains on the Crowchildbridge will come as a frustration for the next couple of years as drivers contend with temporarily narrower lanes and reduced speed limits Baird believes the work will be well worth it, in the end.

"It's an impressive feat and a very impressive design and a project that's full of challenges," he said.

"But it's definitelya good one and something that we're looking forward to get complete."

Calgary: The Road Ahead is CBC Calgary's special focus on our city as it passes through the crucible of the downturn: the challenges we face, and the possible solutions as we explore what kind of Calgary we want to create. Have an idea? Email us at calgarytheroadahead@cbc.ca