San Francisco Int'l Airport (SFO) Traffic Control Tower
Location: San Francisco, California | United States Architect: HNTB Corp. & Fentress Architects; Los Angeles, CA & Denver, CO | United States Construction: Hensel Phelps Construction Co., San Jose, CA | United States Fabricator: Keith Panel Systems Co. Ltd., North Vancouver, BC | Canada Year of construction: 2015 Material: ALUCOBOND® Plus Custom SFO Silver
The resulting 221-foot-tall 5,652-square-foot shimmering-metal tower features a geometrically complex design resembling a sweeping torch that is topped with an offset control cab – the latter providing Federal Aviation Administration (FAA) air traffic controllers with an unobstructed 270-degree view of airport runways and taxiways.
The new tower – which is designed to withstand a magnitude 8.0 earthquake and remain operational – replaced the previous airport control tower built in 1981 that does not meet stricter seismic standards. The new air traffic control tower is the tallest vertical self-centering post tension concrete structure in the United States and is designed to achieve LEED Gold certification from the U.S. Green Building Council.
A total of 10,000 square feet of formable 4mm Alucobond® Plus aluminum composite material (ACM) in the custom SFO Silver color clads this spiraling torch-shaped structure. (Recyclable Alucobond – which is manufactured with both post-manufacturing and post-consumer content – contributes LEED credits to building projects.)
The west face of the airport control tower is “opened” vertically with a backlit glass façade that stretches 147 feet in the air to create a local visual landmark. Situated above a new three-story FAA office building and walkways connecting Terminals 1 and 2, the open-core design allows passengers to gaze directly up into the tower through corridor skylights to view the cascading waterfall lighting.
“The tower lighting can be changed based on the mood of the airport,” according to Mark Costanzo, P.E., project manager, SFO, who said the façade’s changing LED colored lighting transforms the tower in recognition of holidays and special events.
This iconic tower concept design was the collaborative work of SFO and Los Angeles-headquartered HNTB Corp., which served as master architect for the project. Detailed design work was completed by Denver-based Fentress Architects, which served as architect of record and worked in a design-build capacity with general contractor Hensel Phelps Construction Co., of San Jose, Calif. Walter P Moore, of San Francisco, served as structural engineer for the tower.
In developing the tower’s design – which began in 2010 – SFO and HNTB personnel reviewed Olympic torch designs through the years as well as tower precedents from around the world. The resulting design reflects the SFO brand as an iconic symbol that is both “elegant and timeless in approach,” according to Paul Kim, AIA, NCARB, project manager, HNTB.
“This idea is manifested in the sweeping torch form and is the impetus for opening of the tower shell to expose the ‘core’ with a backlit glass façade, which greets passengers arriving along the upper-level roadway and SFO’s AirTrain,” said Kim. “The intent was to provide a tectonic and elegantly detailed façade with a subtle but dynamic skin with spiraling aluminum panel joints around the conical surface. We also saw an opportunity with the tower’s location. Unlike towers at most airports, the SFO tower is located immediately adjacent to drivers and pedestrians. We wanted people to experience the tower up close as well as from afar.”
While the tower’s cladding originally was specified with 3/16-inch aluminum plate panels, Keith Panel Systems Co. Ltd., of North Vancouver, British Columbia, Canada, suggested Alucobond aluminum composite material.
“We felt that Alucobond would be better suited to handle the specific challenges presented by the tower’s geometry,” said Paul Dalzell, operations manager, Keith Panels Systems (KPS). “We knew that Alucobond had much more flexibility and could be formed into these complex shapes.”
“Alucobond was a material that could carry the shape of the building with an outward appearance that is sleek and dynamic,” said Fentress. “It gives a futuristic quality to the building. Technically, it was able to create all of the joints and worked well with the complex structural engineering designed to ensure that this building will be there after a seismic event.”