Now that crews from Kiewit Infrastructure West have started pouring concrete bridge deck pieces, the ability to watch the nation’s largest transit bridge void of personal vehicles take shape offers a bit more intrigue in Portland, Ore.
The new Portland-Milwaukie Light Rail Bridge—don’t fret, it will get a new name sometime in 2014 after a commission spends countless hours picking out one that could prove almost as boring as its current moniker—will eventually boats 1,720 ft in length in a four-pier cable-stayed bridge design.
With two towers, each 180 ft high, and five total spans, the bridge and its 78 concrete bridge deck segments, each 16 ft long and 75 ft wide and weighing 200 tons, will carry only light rail, TriMet buses and pedestrians and cyclists. The pedestrian/cyclist corridor features two 14-ft-wide paths.
Crews are pouring each segment on site, using the balance cantilever construction method, completing a segment on each side of the bridge before moving farther in. During the concrete curing process, crews will attach post-tensioning tendons and then repeat the process until the entire span completes sometime in spring 2014.
When opened in 2015, the new bridge will serve as the first new span over the bridge-heavy Willamette River in 35 years, also making the final connection for the $1.49 billion Portland-Milwaukie light rail route. Three bus lines currently using the Ross Island Bridge will likely move to the new bridge and TriMet officials hope to eventually add a Portland Streetcar extension to the bridge.
To watch the process unfold, TriMet has set up two bridge cameras. Access them here.
Tim Newcomb is Engineering News-Record’s Pacific Northwest contributor. He has also written for TIME, Popular Mechanics, Popular Science and more. You can follow him on Twitter at @tdnewcomb or visit his website here.