Double Helix Staircase

ChemoCentryx, now part of South San Francisco’s biotechnology tour de force, Amgen, is a biopharmaceutical group headquartered in the San Francisco Bay Area. Amgen’s new team treats autoimmune diseases, inflammatory disorders, and cancers. As part of their buildout, the client wanted a functional architectural element to highlight their craft and connect their main lobby with office/lab spaces a floor below. The answer to that challenge is a unique steel stair showcasing a double helix.

Salas O’Brien provided structural engineering design and consulting services for this one-of-a-kind project. The heart of the project is the staircase connecting the 5th and 6th floors. The structural supports are both sculptural and kinetic, maintaining the spiral shape. In addition, threaded rod hangers enable the structure to remain the focus while creating the illusion that the stair is floating.

Finalist in AISC’s 2022 IDEAS2 Awards
Featured in Modern Steel Construction Magazine



Project Completion



75,000 square feet

Project Partner

DGA Architects, Truebeck Construction