Work in progress: Constructing the curvy “cassettes”

Published July 08, 2021

Construction crews and a crane work on segments of the roof at a job site near the airport

(Photo credit: Courtesy of Swinerton)

 

Pssst! Want to see something cool? We’re sharing regular “work in progress” snapshots to show you what we’re up to. Up next: The building blocks for the curvy wooden roof.

PDX always seems to do things a little differently than most other airports. That’s especially true when it comes to building the new main terminal, which is equally impressive for its architectural vision as its many construction challenges.

The curvy roof and the lattice wooden ceiling are two defining elements in the new renderings. Perhaps unsurprisingly, these striking designs have required teams to come up with some pretty ingenious solutions. 

First, you have to get the curves just right. But no one has ever made curved wooden pieces quite this big. So Hoffman-Skanska decided to build a full-scale mockup, as project manager Katrina Day showed us earlier this year

After determining how best to fabricate the curvy beams into the desired shapes, the next step was to figure out how best to put it all together. And installing a new roof over an existing airport leaves absolutely no wiggle room for errors. That’s why the builders have taken a rather novel approach to pre-fabricating the entire 9-acre roof — building it a block at a time, then eventually moving each block into place over the terminal. 

 

A crane helps slide a curvy beam into a segment of the new roof

 

If you step out on the job site right now, you’ll hear teams refer to these blocks as “cassettes.” These are obviously not old-school VHS rentals, though they both have at least one thing in common: They slide into place to give you the full picture.

Currently, crews are taking the glulam (aka those giant curvy wooden pieces, custom built in Eugene by Zip-O) and assembling the individual blocks on airport grounds but off the runway (and yes, visible when you fly out). Throughout 2021, crews will continue working on enough of these giant cassettes to have a full roof. Come 2022, the finished pieces will fit together to form one of the largest sustainable timber projects in recent history, with much of the wood directly traced to healthy forests in close partnership with the Yakama, Coquille and Skokomish tribes as well as other landowners practicing responsible forest management.

Some friends of ours took a field trip and snapped these images of both the glulam fabrication and cassette assembly processes. This gives you a rare glimpse into the ongoing production.

 

The curvy beams are fabricated separately in Eugene

Construction workers stand on lifts as they work on completing one segment of the new roof

(Photo credit: Courtesy of Swinerton)

As one roof cassette is completed, you see light filtering through a skylight

An aerial view shows the job site from above, where crews will work throughout 2021 on completing each segment of the new roof

(Photo credit: Courtesy of Hoffman Skanska Joint Venture)