Sea-Tac (SEA) North Satellite Modernization Project

Team

Architect

Fentress Architects, w/URS Corporation

Contractor

Hensel Phelps

Stats

PROJECT TYPE

Aviation

COMPLETION

2021

PROJECT SIZE

467,684 ft²

MKA ROLE

Structural Engineer

SeaTac, WA
Sea-Tac (SEA) North Satellite Modernization Project

This four-story expansion and seismic rehabilitation of an operational airport concourse adds eight gates, updates 12 gates, introduces an upper-level mezzanine, expands the dining and retail offerings, and adds an Alaska Airlines boardroom. The project includes a new long-span roof structure spanning 260 ft, traversing entirely over the existing North Satellite, and a complete seismic retrofit of the existing concourse.

Image of Sea-Tac International Airport (SEA) North Satellite Modernization Project (NSAT Renovation)

Innovative and Flexible “Seismic Hug”

When the magnitude 6.8 Nisqually earthquake rattled the Seattle area in 2001, Seattle-Tacoma International Airport assessed the seismic integrity of its buildings and decided to upgrade its 1960s-era North Satellite Terminal (NSAT), adding gates and concessions, replacing the mechanical system, and incorporating innovative seismic improvements.

MKA facilitated this project by surrounding NSAT with a perimeter moment-frame lateral system—fondly referred to as a “seismic hug” and often compared to a weightlifter’s belt—that seismically reinforced the structure without needing to strengthen the existing columns and beams, saving construction-related time and costs. The design also provided an open floor plan for future flexibility. In addition, a clear-span, curvilinear “river roof” runs longitudinally through the concourse, allowing natural light to pour into the heart of NSAT and its busy retail shops, food court, and passenger circulation areas.

MKA’s innovative structural solutions completely transformed NSAT while saving tens of millions of dollars, maintaining airport operations during construction, and reducing the airport’s carbon footprint by extending the facility’s life for decades to come.