In the sprawling landscape of American airports, Portland International has quietly cultivated something rare: an architectural identity that resonates deeply with its community. The latest $2 billion expansion, nearing completion in 2025, may be its most eloquent statement yet.

Since 1956, when the main terminal first opened with humble brown terrazzo floors, PDX has undergone constant reinvention. But no relationship has shaped this evolution more than its 60-year partnership with ZGF Architects, which began in 1965 when the Port of Portland commissioned the firm to reimagine the 1958 terminal.

The current expansion represents the airport's most ambitious transformation, doubling its capacity while creating a structure that feels distinctly of its place. Entering the new main terminal, one encounters what ZGF partner Gene Sandoval describes as "your first walk in an Oregon forest" – a 9-acre mass timber roof that undulates above travelers' heads like a canopy of trees.

This isn't mere aesthetic posturing. The roof's 34,000 timber elements were sourced within 300 miles of Portland, supporting local economies while reducing carbon footprint. Its construction required genuine innovation: the entire structure was built on the ground adjacent to the existing terminal, then "unzipped" into 18 massive "cassettes" and installed during narrow nighttime windows when flights were suspended.

The engineering challenges were formidable. KPFF Consulting Engineers developed unprecedented moment connections for the wood-steel hybrids and mounted seismic isolators at column tops rather than bases, allowing the roof to move up to 22 inches during earthquakes. This solution required 160 building code appeals but ensures the terminal remains operational after a major seismic event – critical for a region anticipating a Cascadian subduction zone earthquake.

Beneath this technical virtuosity lies a deeper narrative about regional identity. The terminal's layout draws inspiration from Portland's human-scaled city blocks and walkable neighborhoods. Local firms like Timberlab (formerly Swinerton Mass Timber) and century-old Freres Lumber developed new capabilities to manufacture components never before attempted. Even Eugene-based Zip-O-Laminators stretched its expertise to create 80-foot glulam beams with dramatic 15-foot arches.

Perhaps nothing reflects PDX's distinctive relationship with its public better than the saga of its carpet. When the Port announced in 2013 that the teal geometric carpet designed by SRG Partnership in 1987 would be replaced, the response was unprecedented. The pattern – based on the air traffic controller's view of intersecting runways – had become a genuine cultural touchstone. Portlanders took "foot selfies" on the carpet to announce their return home. The pattern appeared on merchandise from socks to sneakers, inspiring its own hashtag with over 20,000 posts.

In a remarkable concession to public sentiment, the new terminal incorporates sections of the original pattern in designated areas – a strange but moving acknowledgment of how infrastructure can transcend function to become symbol.

The expansion emphasizes sustainability throughout, using 50% less energy per square foot while doubling in size. The interior features 70 large trees and 5,000 plants, creating an environment designed to reduce traveler stress.

As airports increasingly become generic non-places, Portland has created something increasingly rare: public infrastructure with a distinctive sense of place, crafted through genuine dialogue between architects, engineers, and the community they serve. In its timber lattice and even its carpet, PDX offers a model for how airports might once again become sources of civic pride rather than mere waypoints of transit.