Wednesday, December 17, 2014

Tilikum Crossing - Bridge of the People

This summer Pratt & Larson had the honor of working on a project with TriMet, Portland's transit authority. 
Tilikum Crossing - Bridge of the People Image courtesy of TriMet

The latest bridge to cross the Willamette River in Portland since the Fremont Bridge in 1973, the Tilikum Crossing was designed specifically for pedestrians, cyclists, buses, light rail and the street car. In fact even it's name means "people" in the Chinook Wawa language used by the traders in the Pacific Northwest in the 19th century. Check out this cool time lapse video of the building of the bridge.

The Sonic Dish
Artists rendition of the Sonic Dish
TriMet allocates 1.5 percent of a projects budget toward art installations along the transit line. One of the art installations for this project is the Sonic Dish, designed by artists Douglas Hollis and the late Anna Valentina Murch. Here's a great 1 minute clip about them.

The idea behind the Sonic Dish is to link the bridge to it's surroundings by amplifying ambient sounds under the bridge as pedestrians and cyclists pass the bridge's curved abutments. The environment plays an active role in the artwork, in the same way that the changing lights illuminating the bridge at night are controlled by changes in the river. The image above explains how the dish will magnify the sounds and focus them at a point 5 to 10 feet from the wall. Of course, its also meant to be a visual experience as explained by Mary Priester, manager of TriMet's public arts programs."The dish is there to be experienced as it is; more art than science, as much visual as aural"

Here's the Sonic Dish's underlying concrete structure. Pratt & Larson supplied the tile that would be attached to this surface. We made 1400 square feet of  white 2" circle tiles and mesh mounted them in our factory just a few blocks away from the bridge. That's 63,000 tiles!! We also mounted 436sf of smaller metal circles in sheets to make installation easier. As you can see our team had a great time visiting the site:

The tall guy overseeing the installation here is our CEO Timothy Roberts.
And our Production Manager, Anthony Asch. Obviously the hard hats were a hit with this crowd.
Here you can see the two different kinds of tile as they are being installed. 
Curved surfaces are very challenging to install flat tile on. These guys did a great job!
This shot shows the finished grouted installation. 63,000 white circles!!
The east side Sonic Dish, completed.
The bridge doesn't open until September 2015 but the Springwater trail is open again and passes right under the bridge by the Sonic Dish.  Check it out and let us know what you hear!

Tilikum Crossing Fact sheet
1/5/15 - Update - They took the fencing down so now you can go and try it out for yourself!


  1. Those tiles in that design look super cool. I love seeing tile pictorial mosaics under the freeway overpasses. I wonder what type of adhesive they'd have to use to keep the tiles on, throughout a year's worth of weather.