San Francisco, CA
Market: Institutional
Architect: WJE (Wiss, Janney, Elstner) Associates
Hamilton-Aitkin
General Contractor: Webcor
FTF Engineering served as Structural Engineer of Record, responsible for verifying all temporary and permanent loads on the existing structure throughout a complex, phased envelope upgrade at SFO’s iconic International Terminal. The scope included confirming that the original long-span roof trusses — designed in the mid-1990s — could accommodate new solar panel dead loads without exceeding allowable stresses or compromising the building’s base isolation system performance.
Providing construction access to the ITB’s signature exposed structural steel presented significant challenges of its own. With lower levels, streets and AirTran required to remain operational below, scaffold leg loads became a critical design constraint. FTF worked closely with the scaffold engineer to assess existing slab capacity and develop support solutions — either repositioning scaffold posts to bear directly over existing steel framing, or introducing sill beams to bridge concentrated loads across to those members, bypassing the slab entirely. Scaffolds reached 90 feet high over active roadways and AirTran tracks while the terminal remained fully operational.
A new roof access stair added further complexity: it had to be sited over an existing mechanical plenum, clear window-washing equipment, span between the fixed-base rear structure and the base-isolated high roof, and cantilever past the parapet and eyebrow — all without modifications to the existing structure.
