Seattle Convention Center Summit Addition

Exterior twilight view of the Seattle Convention Center Addition illuminated from within, featuring the Pine Street overpass and streaming headlights and taillights of vehicle traffic along Interstate 5

Team

Architect

LMN Architects, Gustafson Guthrie Nichol

Contractor

Clark-Lewis, A Joint Venture

Stats

PROJECT TYPE

Convention Center

COMPLETION

2023

PROJECT SIZE

1.5 million ft² / 4 blocks

MKA ROLE

Structural and Civil Engineer

Seattle, WA
Seattle Convention Center Summit Addition

Expanding a convention center originally designed by MKA in 1988, the "Summit" building features five stories and exhibition and flex halls, a ballroom, meeting spaces, below-grade parking and loading dock, and two public streets that cross over the building structure. In addition to the site design for four city blocks and Summit, MKA provided designs for two co-developments atop the loading dock—a 30-story Performance-Based Seismic Design residential tower with 409 units, and a 17-story office tower. MKA’s civil team led the site design for four city blocks encompassing over 3,400 ft of street frontage improvements, of which 725 ft involved the complete reconstruction of right-of-way over the building structure. MKA integrated a rainwater harvesting system and stormwater detention tank sized to manage urban runoff across the development. The design relocated 700 ft of electrical and telecommunications duct banks and provided service feeds for a relocated substation. MKA coordinated with multiple transportation agencies and developed temporary designs to maintain uninterrupted operations of an adjacent transit tunnel, surface streets, and interstate ramp during all construction phases.

Super Trusses Take the Stacked Program to the Extreme

Presented with the opportunity to design an addition to the Seattle Convention Center, MKA incorporated a structural solution that located key program elements within the structural depth—and achieved this twice within the program stack.

Strategically spaced trusses spanning over the exhibit hall housed three parking levels and created an efficient parking layout with 90-degree parking and a two-way drive aisle between each truss, as well as cross-aisles around the ends of the trusses.

Higher up in the building, two meeting-room levels were located within trusses spanning 180 feet over the flex hall and supporting the ballroom above. These stiff, strong trusses not only supported three levels of public assembly space but also delivered the strict vibration criteria required for a ballroom.

Stacked-program convention centers present significant structural challenges and an incredible design opportunity to unlock project value: interstitial program spaces. MKA’s successful design solution created a more efficient structure with reduced building height—a double win from a cost perspective.