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PDX Next project ushers in new era of airport operations, traveler amenities

Submitting Firm: KPFF Consulting Engineers
Location: Portland
Client/Owner: Port of Portland
Other Consultants/Key Participants: Fentress Architects, GRI, Hennebery Eddy Architects, HNTB Corp., Interface Engineering Inc., Mayer Reed Architects, Skanska USA

From the beginning, it was clear this new concourse extension would be different than previous PDX concourses. Gone were the columns framing the edges of the central corridors due to the desire for a flexible space. Gone were the skylights, necessitating the need for alternative solutions to bring natural light into the center of the building.

The PDX Next Portland International Airport Terminal Balancing and Concourse E Extension project added six new gates, passenger concessions, amenities, and airline operation spaces. It included improvements to the existing airport facilities to balance the number of passengers using the north and south sides of the airport and extended Concourse E by more than 800 feet.

At concession nodes, the girders change shape to create a large, open space with tall window walls, creating an inviting space for passengers to relax and enjoy views of the Pacific Northwest.

Early design decisions drove the structural design team to provide the unique bent 鈥渮-girder鈥� roof design that shapes the Concourse E experience. These 鈥渮-girders鈥� clear the width of the concourse with spans between 60 to 80 feet.

Coordination with the contractor during design helped the design team better understand the contractor鈥檚 fabrication and erection preferences, and enabled them to choose systems to facilitate an efficient erection. These conversations led to the 鈥渮-girder鈥� being fabricated completely in the shop, shipped to the site, and lifted into place in one piece, thereby minimizing the extent of field welding required for the girders.

Certified LEED Gold, the new concourse also is designed as an Essential Facility for seismic structural performance. The lateral system includes SidePlate moment frames and steel buckling-restrained braced frames. South sloping columns, important to the fa莽ade design along Airport Way and responding to the outward projection of the adjacent Headquarters Building, led to the building experiencing a permanent lateral force.

A pile-supported foundation and a structural slab on grade was provided in lieu of a more typical slab on grade due to the project soil conditions, liquefaction, and high groundwater levels. The structured slab is designed to span between deep pile foundations after a major seismic event when the soils are anticipated to experience liquefaction-induced settlement of up to 12 to 18 inches.

Among the challenges, the new concourse is located between an active airstrip to the north, Airport Way to the south, the existing Concourse E to the west and existing utilities below, all of which remained operational throughout construction. The building had to be constructed without impacting PDX operations.

Joanna Ambroz, PE, project engineer for the Port of Portland, noted the KPFF team had to incorporate large mechanical equipment within the structure and maintain flexibility for potential unknown future changes to hanging art exhibits within the public spaces. The Port required that the cost associated with this customized structure be minimized.

KPFF was able to minimize the cost by focusing on a repetitive design along the length of the structure. This meant that the contractor could construct multiple ribs of the structure using the exact same design to increase construction efficiency and minimize construction errors.

鈥淭hroughout construction, KPFF made frequent site visits and provided excellent timely updates to the owner based on observations,鈥� Ambroz wrote in a letter supporting KPFF and the project for an ACEC Oregon award, adding there were numerous modifications due to field conditions as well as unexpected floor sag that exceeded the designed calculations. 鈥淜PFF provided options and solutions to construction issues for owner review. Technical issues were well explained to nontechnical members of the Port team, and project direction was not provided without owner buy-in and approval.鈥�

The east end roof and east end fa莽ade extend 20 feet beyond the building to create a frame around the east end window that looks toward Mt. Hood.

Anticipating a future Concourse E expansion to the east, the roof framing is designed with a bolted splice connection to enable easy removal of the cantilever sections. The roof framing tapers from a 21-inch-deep member to a structural depth of 6 inches max at the east edge.

鈥淭he level of communication between KPFF and the owner was high throughout the design and construction process. KPFF was always looking out for the project鈥檚 best interests and did not make suggestions or recommendations to only appease the contractor,鈥� Ambroz wrote. 鈥淜PFF truly understands the Port鈥檚 commitment to low-maintenance, long-term structural investment and was very responsive with providing excellent customer support during design and throughout construction.鈥�

Together, the structural shape and architecture create a dynamic and light space that brings the Pacific Northwest into the concourse extension.