Features: What We Build — November/December 2005

Where Cash Meets Culture

The marriage of a Seattle bank and the city's art museum in one building tests the creativity of a large project team

By Sheila Bacon

The museum expansion's exterior features include stainless-steel "brise-soliel" panels, that will allow varying amounts of light inside. Photo by Matt Todd/Matt Todd Photography

The old saying, "opposites attract," is proving itself true at the new WaMu Center/Seattle Art Museum expansion project in downtown Seattle.

Here, currency and creativity collide in a structure that marries two completely different tenants-one of the nation's largest financial services companies and Seattle's most popular museum of fine art.

While the coupling of Washington Mutual's new headquarters and the Seattle Art Museum's expansion in one $370-million building has involved elaborate contractual arrangements and complex space configurations, most importantly, it is shedding light on how developers, designers, contractors and tenants collaborate.

The completed project will result in two towers-one 42 stories, the other 16-and a six-story underground parking garage, all of which will operate independently. But there is enough overlap of building systems and program elements to make the design, construction and operational protocols at the site are some of the most complex the project team has ever seen.

'A Fabulous Opportunity'

Seeking to consolidate its 5,000 Seattle-area employees in one headquarters building, Washington Mutual leaders set their sights on a half-block piece of land abutting the existing 150,000-sq-ft Seattle Art Museum in the heart of Seattle's downtown. The land-most recently home to a largely vacant former department store-was owned by the museum and earmarked for future expansion space.

The site also was Washington Mutual's top choice for a new home. It is located across from its current headquarters building and central to a dozen other downtown buildings where employees are housed. It also fit the bank's vision to remain in downtown Seattle, where it established itself as a home-town lender that helped get the city back on its feet after Seattle's Great Fire of 1889, which destroyed 25 blocks.

The bank and developer Pine Street Group LLC (in association with Seneca Real Estate Group) made the museum an interesting offer. The bank would build a 16-story tower to house the museum's expansion, but because the museum would not need the space all at once, it would initially occupy just the first four floors. Arrangements would be made for the museum to take over more space in two-floor increments over the next 20 years as its needs and funding allowed.

Washington Mutual would occupy the future art space until the museum needed it but retain the top four floors of the 16-story tower in perpetuity. The bank would house the bulk of its downtown employees in a new 42-story tower it would build immediately adjacent to the museum's expansion.

The 42-story WaMu Center tower is joined at the hip with a 16-story addition, where the museum will take over space in two-floor increments over the next 20 years. Photo by Matt Todd/Matt Todd Photography

The museum's leaders were intrigued by Washington Mutual's offer, which would bring the museum's total space to 450,000 sq ft. An earlier study had indicated the museum would need an additional 300,000 sq ft of exhibit space over the next 20 years, but until now, no real plan had been put in place to fulfill that goal. "It was a fabulous opportunity for us," says Jan Hurley, the museum's expansion project manager. "We would not have been able to expand this soon without them."

The effort had begun to provide class A office space for the bank and first-class program space for the museum under the umbrella of one project.

Planning for Both Spaces

At first glance, the WaMu Center/Seattle Art Museum expansion project looks like little more than two sizable towers joined at the hip, each with its own distinct exterior identity. What is precedent-setting are the architectural and structural acrobatics required to create space that will ultimately be occupied by two users with drastically different needs.

Of the 58 floors in the entire project, most of the team's creative efforts zeroed in on the middle eight floors in the 16-story tower-the floors that will be occupied first by the bank and later by the museum.

All members of the project team had to scrutinize the design from the inside out, checking to be sure that both tenants could use the space efficiently over the 20-year transition period and beyond.

"We were basically building for office use but designing for the museum of the future," says Jack Avery, director of preconstruction services for Sellen Construction Co., Seattle, the general contractor.

The design-build mechanical system is being installed on a floor-by-floor basis so it can be replaced incrementally when the museum moves in. Since SAM's mechanical needs for tightly controlled temperature, humidity and air flow far exceed those of the bank, much of the original system will be removed and a new one installed.

However, considerable structural preplanning for future mechanical systems required close collaboration between Seattle structural engineer Magnusson Klemencic Associates and Seattle design-build mechanical contractor McKinstry.

Because the building is a highrise, it's not possible to have galleries with natural top-lighting-ideal for art space-so portions of the stainless-steel panels that form the exterior walls are movable like shutters, creating a light-control perimeter around the new galleries. When open, they will provide a view of Puget Sound and Highway 99's Alaskan Way Viaduct. Credit: Image courtesy of Allied Works

"We built in as much as we could for day one but designed some extra penetrations in some of the beams to allow for future addition of ductwork," says Jay Taylor, MKA principal.

Additionally, some robust mechanical systems have been added but won't be activated until the museum takes over the space. Electrical systems to accommodate more extensive lighting for future art displays have been similarly designed.

Dual-Use Structural Design

Engineers were faced with designing for two different case loads. Typical gallery floors must be able to support loads between 150 and 200 lb per sq ft, while office floor plates generally support only 50 lb per sq ft, Taylor says.

An easy solution would have been to install deeper beams to support the museum's future loads, but that would shorten the minimum floor-to-floor heights the bank wanted to maintain, Taylor says. To accommodate both uses, designers developed strengthening schemes in some areas that allow 6- to 8-in.-deep sections of steel for later welding onto the bottom of the existing girders, strengthening the floors and allowing for heavier loads.

But this scenario works only when the floors below can be removed to create double-height space. To beef up areas that would stay at a single-floor height, structural engineers worked closely with the architect to pinpoint where additional columns could be added without interrupting the gallery floor plans.

Essentially, the design process required the museum to predict what its space and floor- plan requirements would be 20 years down the road-not an easy task. "It was tough anticipating what the museum's future needs would be and then designing for that," Hurley says.

Designing dual-use space also meant determining how much natural light would come into the building. While office tenants typically want as much sunlight as possible, the museum will need fewer windows and little outside lighting, which enhances the viewing of art.

To accommodate both office and museum uses, designers developed schemes that allow 6- to 8-in.-deep sections of steel for later welding onto the bottom of the existing girders, strengthening the floors and allowing for heavier loads.

Allied Works, Portland, Ore., the museum expansion core-and-shell architect, resolved the conflict by designing a new panel system for part of the museum tower's west side. Designers specified stainless-steel "brise-soleil" panels, created by Benson Industries Inc., a curtain-wall contractor in Portland. The panels can be manipulated manually to bring in varying degrees of light, giving both the bank and the museum a high degree of flexibility.

"Because the building is a highrise, it's not possible to have galleries with natural top-lighting-ideal for art space-so portions of the stainless-steel panels that form the exterior walls are movable like shutters, creating a light-control perimeter around the new galleries," says Brad Cloepfil, principal of Allied Works. "The shutters allow curators and exhibit designers to fine tune the amount of daylight coming into the art spaces-from a low glow up to a direct view of the Olympic [Mountains] on the horizon."

Elsewhere, the bank's conventional floor-to-ceiling glazing units eventually will be replaced with opaque stainless steel panels to create an interior art wall. These panels are set off with architectural reveals to add more detail on the facade when the building converts to museum use.

Creating Separate Identities

The museum interior designed by associate architects LMN, Seattle, includes expanded gallery space, a larger restaurant and store, a new main entrance and a U-shaped public space that greatly expands upon the museum's former open areas. The new space will seamlessly connect with the existing 150,000-sq-ft museum, built in 1991 and designed by Venturi, Scott Brown and Associates, Philadelphia.

NBBJ, Seattle, and Allied Works focused specifically on the exteriors. Although the two towers are joined, each has its own identity, beginning with the stainless steel panels on the museum facade, which "express its forward-looking role in the community," Cloepfil says.

The design for the WaMu Center tower was inspired by the Embarcadero Center in San Francisco and Rockefeller Center in New York City. Bank employees will start occupying it in early 2006. Image courtesy of Allied Works

Expansive use of glass allows views into the public spaces in the lower floors as well as the galleries above. A setback running the full height of the building marks the museum's new main entrance.

"The massing of the facade also provides specific view angles up and down Seattle's streets, connecting visitors to the energy of the urban environment and [giving them] a good sense of orientation as they move from floor to floor," Cloepfil says.

Bi-Coastal Influence

WaMu Center's design was influenced by the Embarcadero Center in San Francisco and Rockefeller Center in New York City. It incorporates three rectangles offset to capture views and convey a solid-yet-progressive look. WaMu Center's lower levels are clad with a glazed terra cotta similar to the facades of downtown Seattle's historic Smith Tower and the former Frederick and Nelson department store building, says David Yuan, project manager for NBBJ.

Unlike natural stone, the glazed terra cotta retains its light color when it gets wet, a characteristic Yuan and the owner thought was important. "Even in Seattle's dull, gray winter days that extend from November through April, this material captures as much light as possible," Yuan says. The tower's solid foundation gives way to floor-to-ceiling glass on the east and west-facing rectangles while the center core retains the terra cotta facade.

Inside WaMu Center, the layout of the space reflects the bank's collaborative culture. Departments are divided into "neighborhoods" joined by interconnected stairways and surrounded by open spaces, smaller meeting areas and cafés. The interior layout, designed by Seattle architecture firm Callison, shakes up the traditional approach of upper management personnel occupying large perimeter offices.

"Here, the best views are for everybody," says Kent Wiegel, the bank's senior vice president of corporate properties. "They're not taken up by the executives."

A Big Team

As the general contractor for both towers as well as the parking garage, Sellen Construc-tion has had to work closely with two owners, four architects, three design-build teams and dozens of subcontractors. On board a full 18 months before demolition and site work started in January 2004, Sellen's crews were intensely involved in planning and preconstruction for the design-build mechanical, fire protection and curtain-wall systems.
Building for two different owners on a joint project presented cost allocation issues. Crews had to be diligent with documentation to ensure proper bookkeeping. "Every time we did an estimate or a cost study, we had to ask: 'Who is this for?'" says Avery, Sellen's director of preconstruction services. "Every subcontractor had to know where those lines were as well."

Keeping noise and vibration to a minimum during site work was crucial, says Bob McCleskey, Sellen's president. Shoring for the towers required more than 1,000 penetrations into the foundation of the immediately adjacent and then fully operational art museum.

The museum closed to the public in January and will reopen when the expansion is complete in spring 2007. Bank employees will start occupying WaMu Center in the first quarter of 2006.

"We have lots of things that have been donated but never shown," said Jan Hurley, SAM project director for the expansion. "We're very excited to get these things out on the floor."