When a PATH bridge is installed Saturday under the Gardiner Expressway—connecting Air Canada Centre with South Core office towers One York Street and soon RBC Waterpark Place—it'll be the first time the city’s old downtown core is officially linked to its burgeoning new one.

Bisnow met bridge designer John White at the Portlands staging site. “We’re opening the door to the waterfront,” says the WZMH Architects principal. The glass walkway is being installed in three sections; the first, connecting to Air Canada Centre, was put in place in June (below). The second, a 40-foot span connecting ACC to One York and running under the Gardiner Expressway—the symbolic link between old core and new—goes in this weekend. (Instead of seeing Guardians of the Galaxy for the third time, grab some popcorn and a hard hat and have a look.)

The third section of the PATH bridge, which will tie together One York and RBC Waterpark Place III over Harbour Street, goes in mid-September, right before Waterpark begins taking occupancy. Oxford Properties Group VP John Peets says a PATH connection to Union Station was a must-have for RBC to move into the 1M SF, LEED Gold building. “That was the key to unlocking the value of the site,” John (below) told us on a recent tour of the project.

The section of PATH bridge that runs under the Gardiner can be moved to allow for repairs to the roadway, which floats only 10 inches above. “It slides sideways,” says architect John White. This was key to getting buy-in from the city, which John says was the biggest challenge. The city typically doesn't favour bridges because they’re “visual barriers that break up urban corridors,” he says. But WZMH did its best to make this utilitarian structure eye-pleasing, with an abundance of glass to reflect the waterfront setting.

The opening for the PATH bridge in the Waterpark Place III podium. Monumental bridge projects are nothing new for WZMH; The firm designed the mixed-use Nation Towers in Abu Dhabi, two buildings connected by a bridge that’s 202 metres in the air and houses the world’s highest interconnecting presidential suite on the 49th floor. Toronto’s new PATH connection will funnel people into South Core, where most development has been residential (though One York and Waterpark Place III are changing that). “This is creating a true mixed-use urban environment,” says John.