Soaring High for Alaska Airlines

by Balfour Beatty

From pilots and flight attendants to mechanics and service agents, it takes a variety of roles for passengers to soar through the skies and make connections across the world. Much like passengers entrust their safety to airlines every day, Alaska Airlines entrusted Howard S. Wright, a Balfour Beatty company (HSW), to deliver a leading facility that connects everyone from frontline workers to corporate leadership at their SeaTac, Washington, headquarters campus. 

The HSW team constructed the new complex, affectionately named "The Hub," in two phases. The first phase consisted of a three-and-a-half-story parking garage, a six-story, 130,000-square-foot, Class A office building and intricately detailed custom landscapes and hardscapes. The second phase included a four-and-a-half-story expansion to the recently built garage, bringing it to eight total stories and 255,000 square feet.

Because the project encompassed several phased and discreet sub-projects, it was critical for the HSW team to be a true construction partner to deliver the industry-leading and sustainable complex Alaska Airlines desired.

Our team facilitated critical collaboration early in the design process, enabling greater alignment and best-in-class value engineering. The team ultimately delivered this highly sustainable complex while returning funds from the original guaranteed maximum price (GMP) back to the client that can be applied towards construction of future phases.

Serving as a True Construction Partner

Early collaboration between the client, development manager and trade partners was fundamental to achieving a timely and seamless project delivery. Throughout preconstruction, HSW collaborated with key trade partners to mitigate unrefined design elements, provide critical value engineering and maximize efficiencies in the field, saving time and money. 

Because Seattle experiences frequent rainfall, the team embraced the importance of quickly completing the building envelope to protect it from the elements. By working closely with our trade partners during preconstruction, the team incorporated a specific USG ExoAir sheathing with an integral water/air barrier alongside a punched window system. The latter included an EPDM rubber gasket that, once installed, created an entirely waterproof assembly.

This critical detail allowed the team to establish dry working conditions in the office building nine months before substantial completion, further accelerating interior finishes, mechanical, electrical and plumbing, and all other weather-sensitive activities within the building.

"The modern, hanger-inspired façade was a major component of the design and Alaska Airlines’ vision," says HSW Project Executive Will Colby. "By expediting the project schedule and providing the necessary waterproofing, the team was able to deliver the intricate interior details on a reliable timetable and without weather concerns."

For the Phase 2 Garage Expansion, early collaboration not only prevented re-work but also allowed the team to evaluate the garage budget, schedule and design quality – and ultimately discovering a better way to build it. The complexities of constructing the Cunningham Beam garage structure of shear walls, drop beams and deck connections, all while incorporating an interior braced steel shoring wall system, required coordination beyond typical shop drawings.

To evaluate constructability of the structure before finalizing shop drawings, the team built a detailed, three-dimensional model of all structural elements. This process also allowed for early design revisions and avoided costly re-work in the field. 

But the early coordination did far more than provide the team with a refined approach to constructing the garage. It also helped the team recognize the need to collaborate with our horizontal formwork trade partner to accomplish the vertical shear wall. The added efficiency of better structural sequencing successfully accelerated the deck schedule and maximized communication efficiencies between HSW and all trade partners, resulting in substantial overall savings.

However, even the most robust collaboration cannot prevent every challenge in a project’s lifecycle, making it critical for the team to serve as a true construction partner and provide innovative solutions to prevent delays. Prior to design completion and the start of construction, the project team and an adjacent property owner were unable to reach an easement agreement for shoring wall tie-backs, which would have been the simplest method of supporting the garage structure.

Instead, the team incorporated an alternative shoring method involving an internally braced diagonal steel raker system. The rakers connected to a large subterranean footing and extended vertically through the concrete decks. While this was a more complex solution than the original plan, the project team, client and trade partners worked together to ensure this critical element of the garage’s structural integrity was delivered as quickly as possible.

Soaring into a Sustainable Future

From the outset, HSW and Alaska Airlines established a goal to utilize innovative and sustainable construction practices throughout the project. The project team helped Alaska Airlines actualize a vision for a sustainable site that reflects the airline’s guiding principles and overall focus on people, culture and environmental stewardship.

The entire project was designed under the new LEED® v4 New Construction criteria, and in September 2020, the project achieved an LEED® Silver certification.

The most impactful element is the building's ability to manage stormwater runoff. Through a bioretention planter, infiltration wells, a green roof and additional storage available in the underground chamber system, the facility manages runoff for 98% of local rainfall events. The rainwater collected is channeled into a bioretention channel through weathering steel runnels, which hydrates the landscape of native trees while also creating a wetlands habitat for birds, insects and a grove of birch trees running through the heart of the site.

The stormwater runoff collection system infiltrates approximately 16.3 million gallons of runoff annually. It treats pollution-generating stormwater for total suspended solids, heavy metals and hydrocarbons before slowly discharging to either infiltrating wells or the city storm system. This design element provides long-term financial savings by reducing stormwater discharge costs while thoughtfully addressing sustainable design principles and landscape architecture.

Another significant focus and design element of the project was promoting access to fresh air and other natural exterior activities. The exterior terraces on levels three and six provide a break area accessible to all employees. The nearly seven-acre site contains several walking paths throughout the landscaped meadows. The pedestrian plaza access and pedestrian crossings also encourage physical activity throughout the campus. The mixed species plantings mimic natural plant associations and are resilient to drought, providing more ecological diversity and helping to offset the construction's carbon footprint over time.

To deliver optimal experiences when soaring the skies, Alaska Airlines envisioned a campus where the business could connect its entire workforce and reflect its values. As an industry leader, HSW served as a true construction partner to provide a customized building experience and innovative solutions to unforeseen challenges. Alaska Airlines’ new headquarters enables its crucial human connections and serves a community in which we are proud to build.