From its earliest days, Portland’s airport—PDX International—has grounded its visitors in dynamic experiences of the local. As the first jets began to land in 1959, PDX’s homey architecture began with a new terminal opening like a front porch to a wide, ground-level view of the volcano you just flew by, or soon would.

In the ‘70s, the automobile approach—Airport Way—featured a corridor of chevron-shaped plantings of cedars spaced closer and closer as you approached the terminal. To those flying over, the design offered a landscape version of a runway, and to those speeding by in cars, it viscerally signaled drivers to slow down in a drive-by illusion of the Doppler Effect. As the trees grew over 30 feet high, the design won the American Society of Landscape Architects prestigious 25-Year Award.

When PDX’s passenger counts rose exponentially, roads widened, and parking garages grew, the Port traded in those kinds of external landscape experiences for the internal: the drop-off area’s arched glass canopy, the garage’s hanging gardens, and the Oregon Market, what was widely lauded as the first locavore airport shopping experience. Then, of course, there was the carpet: a kind of sci-fi postmodern pattern of Mondrian-esque lines and squares that didn’t so much evoke the local as create it, exemplified by the DIY t-shirts, mugs, and tattoos–and the fury over its removal.

Though many architecture firms have contributed parts to PDX, the overall experience has been shaped almost entirely by ZGF. (The 1987 carpet, FIY, was by SRG Partnership). The latest, the $2-billion new main terminal scheduled to open August 14, is a grand effort to completely reimagine what “the local” can be in the form of a nine-acre space processing as many as 250,000 people a day. In an intricate collaboration between KPFF and PAE engineers, and Hoffman Construction–partnered with global construction giant Skanska—ZGF arguably has succeeded while also arguably building the most innovative work of architecture Oregon has ever produced.

Hyperbole? In the cloudy malaise of the city’s low self-esteem these last few years, it’s hard not to want to break out the brass band for any blast of sunshine. But if you define the term “architecture” widely, encompassing sustainability, seismic resiliency, and construction logistics, the new terminal sets many important precedents. The design even purposefully sourced its materials and fabrication to maximize regional economic impact.

But before we nerd out on those features, many measurable but invisible to the eye, let’s enjoy what you can see: the light, the space, and the craftsmanship.

A terminal like a “walk in an Oregon forest”

The new main terminal offers a powerful combination of landscapes, artificial and real, packaged in a single 400-by-1,000-foot volume—about twice the size of Memorial Coliseum. What grabs the eye first is the roof. Stretched over thirty-four 55-foot-high columns that branch outward like muscular oaks, it rolls, rises, and falls over arched glulam beams (laminated and glued timber beams of extreme strength) skinned in a basket weave of 34,000 lengths of 3-by-6-inch timbers. Surrounding three sides are curtain walls of glass through which you can see, just steps away, the airplanes taxiing and long luggage trains rolling by. The effect is like standing in a grove of trees watching beasts wander in surrounding savannah.

“We wanted it to be like your first walk in an Oregon forest,” says ZGF’s design partner Gene Sandoval. “A big idea,” adds project architect Nat Slayton, “was to create this direct connection to the airfield right through the middle of the building.”

Sunlight is welcomed in by 46 skylights, some circular, some oval, some filtered by screens of wood that rise in scallop shapes or open like the breaks in a tree canopy. Seventy-one living trees rise from wells in the floor. Hanging plants rain vines downward. There is so much natural light, even on cloudy days, that the design team was able to reduce the number of artificial lights by 50 percent below city codes.

The architects apply the faddish term “biophilia” to all the wood and foliage. The goal at every turn is a sense of calm. A grove of smaller trees, for instance, rises next to gently curving combinations of bench/counters for what Port officials call “recomposure”—the frenetic collecting belts, shoes, phones, etc. after the stresses of getting through security check. Even the rooms where TSA agents will search and question passengers are shaped to reduce blood pressure: cylindrical curvilinear chambers, their exposed-fir walls reminiscent of a Scandinavian sauna. 

Many new airport main terminal designs prize pure spatial drama. In true Portlandia tradition, ZGF scaled things to people, breaking the space into lounging areas loosely based on the size of Portland’s 100-by-200-foot downtown Park Blocks. Shops and restaurants align along a corridor modeled on the width of Northwest 23^rd Avenue. Two sets of Oregon oak bleachers face each other to create a central gathering space while also rising to a mezzanine that, besides offering views of the expansive urban theater below like a rooftop bar overlooking a town square, features vast expanses of the beloved carpet.

Sandoval says his team was inspired by airports in Singapore and Amsterdam where the most beloved spaces aren’t in private airport lounges or restaurants but are fully public. “People flying on economy tickets always get the lowest level of service,” Sandoval notes, adding that the 2,000-plus people who work at the airport will also enjoy the space. “Here everybody is treated equally. This is going to be the civic room for Portland.”

The craftsmanship of this building is extraordinary for its scale. An eye-level example can be found in the stairway profile rising to the mezzanine lounge: an intricately angled joinery of steel and oak more commonly found in a custom high-design home than a public building. Overhead, the workmanship got a technological helping hand: ZGF designed a finish carpenter’s nightmare of the roof’s basket weave of 2-by-6s into seven repeating sizes that could be computer-cut and bar-code labeled for easy, patterned assembly. 

The same care can be found in the form and articulation of the steel columns. First, that the steel is visible and touchable at all is notable: Normally, fire code demands structural steel to be covered by protective material such as sheetrock or coated in intumescent paint. But by filling the hollow columns with concrete, ZGF successfully appealed the requirements.

Thus, ZGF’s team articulated the columns—and Vancouver, Wash. fabricator Thompson Metal Fab cut and smoothly welded them–into origami folds with sharp reveals that both abstract the form of a tree and illustrate the engineering for the loads they are carrying with the elegant minimalism of a Donald Judd sculpture.

A $2 billion good fit and an earthquake-safe zone

On Aug. 3, the Port invited Portlanders to a “dress rehearsal” for the new terminal. Thousands came. As lines of pretend passengers snaked through the garage’s various checkpoints, the scene was like a cross between a bad day queuing at the dreary old LaGuardia Airport crossed with the giddiness of Sunday Parkways.

A faint scent of weed wafted. Therapy llamas posed for pictures. A tutu-clad fairy wandered about. But as the crowd popped, one by one, through the tiny door in the plywood construction wall and into the new terminal, the first sound heard was a steady, breathy cadence of “Wow.” Necks craned. The bleachers quickly filled. iPhones waved in “pano” mode.

At $2 billion, PDX’s new main terminal is a dazzling mega-project by any Portland building measure. (The money, BTW dear taxpayers, comes from fees, not government.) But it’s actually on the lower, quieter end of the latest generation of new airports such as the dazzling $11.5-billion redo of Beijing Daxing by Zaha Hadid & Associates, the $8.5-billion expansion to come of Chicago’s O’Hare by Studio Gang, and the Jewel Changi Airport in Singapore by Moshe Safdie, with its “Vortex,” at 135 feet, the world’s tallest indoor waterfall.

By comparison, PDX has the quintessentially Portland fit of a comfortable shoe. But beneath and behind all the breathtaking beauty and good vibes are a mind-bending array of engineering, construction, sustainability, and logistical innovations.

Doubling the old terminal in size and capacity, this single volume will serve all functions: ticketing, shopping, and airport security, all with a projected 90 percent reduction in fossil fuel use through such features as a radiant-floor system tied to a ground-source heat pump drawing from a sandstone aquifer 500 feet below. Curtain walls of the scale that surround the terminal generally lose huge amounts of energy through their metal mullions, so ZGF designed them into an exoskeleton, allowing tight seals between the vast expanses of glass.  

When the inevitable 9.0+ Cascadian subduction zone earthquake comes, the new terminal will be, along with Pioneer Courthouse, one of the two safest places in the city to be: The main terminal will not only still stand but will be operational within days. Where Pioneer Courthouse is “base-isolated,” allowing it to slide around on huge pads within a kind of concrete bathtub, you could say PDX is “roof-isolated”: KPFF engineered cups and bearings atop the columns to let the roof slide around. With the glass curtain walls hung from perimeter beams, the roof and walls will be able to move up to 22 inches free of the slab and columns. Beyond providing resiliency, the design allowed the steel columns to be narrowed to their thin, tree-like profile.

Construction logistics were a major driver. The new facility had to be built while the old terminal remained operational. Control tower sightlines preclude cranes. Federal Aviation Administration rules forbid nighttime construction except during the four-hour, early-morning no-flight window. And any work in the security zone would add measurably to labor costs, with hundreds of workers standing in TSA queues.

The team’s response: monster prefab. ZGF and KPFF designed the roof to be built in its entirety–structure, insulation, and utilities—on the ground next to the existing terminal, then “unzipped” into 18 separate “cassettes,” each about 120 by 110 feet. The individual pieces could then be installed by giant transporters in just three nights: lift, move, and place.

To achieve the terminal’s blend of energy efficiency, seismic resiliency, and aesthetics, Sandoval notes, the team had to win 160 local building code appeals.

Overall, the architecture leapfrogs a cluster of practical problems. Like virtually every major airport, PDX grew through an agglomeration of additions; the main terminal, alone, was made up of eight separate structures of different eras sitting atop 200 columns, some built of 1950s-era wood—all in the liquefaction-prone soils that filled what once was marshlands.

According to Vince Granato, chief projects officer for the Port of Portland, attempting to upgrade the old structure would have triggered dozens of complex, individualized, and costly seismic upgrades. And such a terminal would lack the open spans prized by airlines, and the ability to accommodate the Transportation Security Administration’s (TSA) ever-changing ticketing and security protocols. The new facility, he says, “needed to be flexible enough to adjust to the changes in the passenger journey that we can’t even anticipate today.”

A compelling case of Northwest regional design

Over the decades, the idea of a “Northwest Regional Style” of architecture comes and goes. It was most deeply manifested in the 1930s into the ‘50s in a series of homes, churches and occasional commercial and public buildings designed by Pietro Belluschi, John Yeon, Van Evra Bailey, John Storrs, and others steeped in a fealty to local materials, building traditions, and the natural landscape.

Pull the lens back and that age of regionalism can be seen as part of a local expression of a nationwide political, cultural, and economic movement for local cultural and economic autonomy wrought by the failures of World War I and the Great Depression. Today, most expressions of Northwest Style are just that; style: a vaguely pleasing veneer of wood and landscaping steeped in romantic illusion.

What, beyond perhaps cuisine, really can be “regional” in the world as we know it?

I’d argue, the new PDX terminal offers a compelling example—one rooted in Oregon’s traditions as a laboratory for environmental innovation.

For one, there’s the location. Many airports—among them Denver, Salt Lake City, New Orleans, and Kansas City—solved their growth problems by building anew on greenfield sites. Oregon’s half-century-old agricultural-land protection laws long ago precluded the airport leapfrogging the suburbs to the nursery and grape-rich Willamette Valley. The Port, in effect, recycled its land. “It’s all we’ve got,” says Granato, “so we’ve had to get creative.”

The Port pushed for as much wood as possible, for its lower carbon footprint and to showcase Oregon’s forest-products heritage while chasing the grail of carbon sequestration. The jury’s still out on exactly how much the growing movement of mass timber construction really is reducing architecture’s carbon footprint, but the Port and the design team set a high new bar by building entirely with so-called “good wood”—33 million board feet of it—all Douglas fir, grown, cut, milled, and manufactured within 250 miles.

The result: a whole lot of regional entrepreneurship. The ceiling’s curves, for instance, are shaped by 1,684 variously flat or arched glulam beams, some 80 feet long. Eugene’s Zip-O-Laminators had never fabricated such beams before, much less ones 9-feet-3-inches deep and bent into 15-foot-6-inch arches. For longer spans, KPFF developed never-before-achieved rigid connections between 6-foot-deep steel-and-wood girders.

The terminal’s massive amount of wood and other structural materials was largely sourced from and fabricated in the Pacific Northwest. Photos: Randy Gragg

The roof’s resulting ski-mogul bumps are shaped by a 2-inch-thick mass-timber diaphram. Freres Lumber, a 100-year-old family-owned Oregon company that invented its own mass-plywood panel, geared up to uniquely shape 1,350 panels, most 11 by 30 feet, many with parabolic curves, for the undulating roof. Another company, Sankofa Lumber, got its start taking an idea its founder, Valerie Carey, had—to recycle wood tailings from construction sites into the particle board for veneered cabinetry—by giving her the necessary scale of a contract to figure out and purchase the necessary machinery.

To go a little deeper, the Port, ZGF, and other consultants pioneered a “Wood Supply Chain Transparency Specification” requiring that every piece of glulam, layer of mass timber, and ceiling 2-by-6 be sourced, to name only a few of the requirements, from multi-age forests that are thinned, as opposed to clear-cut, while retaining the complexity and resilience of under- and over-story. No more than 350,000 board feet could come from any one forest. Thus, the Port spread the wealth to sources like Camp Adams Youth Camp, Camp Bishop Gray’s Harbor YMCA, Camp Namanu, and Willamette University Educational Forests, along with the Skokomish Tribe, Yakama Nation, and Klickitat.

As the architectural historian and Portland State University associate professor Laila Seewang recently wrote in the online journal e-flux Architecture, the new airport defines “what a ‘region’ is in a productive and meaningful way.”

“The efforts made by ZGF and the Port of Portland project team,” she adds, “make it possible to imagine this process becoming regionally streamlined in the future, and to imagine a regional architecture that embraces the sustainability and equity of its supply chain.”

Though the new main terminal is just one project, it offers a template for what the urbanist writer Jane Jacobs theorized was the key to thriving cities: import replacement. Though she is primarily known for her writings on urban planning (The Death and Life of Great American Cities), in later books such as The Economy of Cities, Jacobs probed how cities, since the emergence of Neolithic settlements, consistently grow best economically by buying and making local: creatively innovating technologies and materials they otherwise would need to import and, in turn, transforming them into exports. Urban economists such as Richard Florida and Ed Glaeser have championed contemporary versions of Jacobs’s theories with concepts of the “creative class” and the primacy of cities’ role in combating climate change. Notably, propelled by its innovations at PDX, ZGF is now competing internationally for airport commissions.

But ZGF’s Sandoval threads the synergies another, more local, way: as a stitch to mend Oregon’s widening urban/rural divide. “Maybe,” he says, “we can bring everybody together with a building made by many, from scientists to architects and engineers and people who just like working with their hands.”