ArchitectureChicago PLUS: The Construction of Chicago's New Riverwalk in Photos

This weekend, the City of Chicago opened the first two blocks of its new $100 million Riverwalk. We'll be writing more that - and exploring it in pictures - soon, but first up, here's a photo essay on the ambitious multi-year construction.

Click the images to see them larger - recommended.

click images for larger view (recommended)(seriously)

In the beginning was the leftovers from the Wacker Drive reconstruction project. At the beginning of the new century, $200 million was spent rebuilding the double-check highway that huges the river from Michigan Avenue to Randolph. While the upper sidewalk levels were given a handsome makeover, there was no money to fix up the lower level, which remained an austere urban amenity.

In the summer, the city found restaurants willing to open temporary outposts.

Some were more elaborate than others . . .

Still, the riverwalk remained sparsely populated. At night, especially, it seemed an abandoned, vaguely threatening place where the brave and hardy could contemplate existence.

In March of 2013, Chicago Mayor Rahm Emanuel announced a deal which would see the U.S. Department of Transportation loan the City of Chicago $100 million to rebuilt the Riverwalk.Construction began in September of that year, and continued through two successive Chicago winters.

According to an excellent account on the Walsh Construction website of the challenges faced in rebuilding the Riverwalk, the first step was to completely demolish all the existing sidewalks.

March, 2014:

Just behind those arches are cars speeding down the mini-expressway that is the lower level of Wacker Drive.

A continuous steel sheet pile retaining wall was constructed across from the existing dock wall.

2014, May:
A new edge was constructed 25 feet into the 200-foot-wide river, with steel piles pounded into the river at 10-foot intervals. Large pumps removed the water, and tons of crushed stone brought in to replace it.

A fleet of 12 barges filled the river to support the project. In July, a 50-foot barge and its ten-ton boom lift sank to the river bottom, requiring divers to go down and secure cables so the crane could be lifted back to the surface.

One of the key features of the new Riverwalk is that, for the first time, there are connections beneath both the State and Dearborn street bridges. Previously, each block was isolated, and you had to walk back to Upper Wacker to get to the next one.

Each underbridge passage was built atop four, six-foot diameter caissons sunk to a depth of 75 feet. Great care was taken not to pierce the tunnel for the State Street subway, although some undocumented phone equipment necessitated a one-week delay while a caisson was drilled at a different location a few feet away.

2014, August:

See Also: Pour le Concrete: Chicago's New Riverwalk Emerges

Flood.

Because constructing the connecting walkways required opening the bridges under which they passed, each one had a one-week deadline for completion, requiring crews to work 24 hours a day.