The Golden Gate Bridge

SFO International Terminal

San Francisco International Airport
San Francisco International Airport at Dusk

Maintaining continued airport operations after a major earthquake is vital to the Bay Area, its people, and its economy. That's why the Airport Commission established the highest seismic performance goal of "continued operation with minimal damage" for the New International Terminal's structural system.

As a result, a $2.4 billion expansion of its facilities was completed in 2001, including the new five-story International Terminal with a total of 2.5 million square feet in built area. The structural engineers that worked together on this were: Skidmore, Owings & Merrill/San Francisco, OLMM, and Faye Bernstein & Associates.

San Francisco International AirportThe International Terminal building accommodates airline ticketing, airline offices, federal inspection services (INS, customs and USDA), baggage sortation systems, leased office space, airline VIP rooms, food service, and approximately 140,000 square feet of retail/concession space. The building also contains two new boarding areas with a total of 26 new boarding gates.

The Structural Engineers faced many challenges. The SFIA site lies very close to active faults capable of generating major earthquakes. The San Andreas fault is approximately two miles to the West, and the Hayward fault is approximately 16 miles to the east.

The Structural Engineers faced the additional challenge that the majority of SFIA's footprint sits on reclaimed land. The site is underlain by up to 40 to 50 feet of deep, young bay mud, a highly compressible marine clay. The bedrock depth is also quite variable across the site, thus adding considerable variability to the subsurface conditions and variation in the piling depths across the site.

The prime architectural feature of the new terminal is a soaring, 80-foot high arched roof that spans the 700-foot long departure hall. The roof structural concept and the integrated structural system solution effectively integrated all site demands with seismic performance goals in the design of the new terminal.

The new International Terminal's main roof structure is shaped like an airplane wing and was developed with the need to keep the main roadways completely operational during construction. The structural concept of the main roof structure which followed was designed using a Hung Span construction technique.

San Francisco International AirportThe International Terminal is among the largest base-isolated structures in the world. It is supported on 267 Friction Pendulum isolators which are placed between the building and the building's foundation. The bearing is very stiff and strong in the vertical direction, but flexible in the horizontal direction. The building is designed to remain functional under almost any size earthquake.

An immense undertaking, the building required close coordination of a multitude of complex systems, such as security, baggage, telecommunications, computer networking, lighting, disabled access, signage, airline scheduling information systems, traffic, people movers, and pedestrian circulation.

Once completed, the new International Terminal began accommodating up to 26 aircraft and baggage for 12 international flights arriving simultaneously. U.S. Customs and Immigration can process five thousand passengers per hour.