San Francisco, CA

China Basin Landing, 185 Berry Street


The client wanted to expand their three-story 300,000 sq ft office building at 185 Berry Street. The existing structure could only accommodate a one-story, 50,000 sq ft vertical addition without further retrofit. By applying base isolation technology, SGH developed an innovative solution that added two stories and 150,000 sq ft to the reinforced concrete structure. China Basin Landing is the first building in the U.S. to have a base-isolated addition on top of an existing building.

The original structure was designed in 1988 to the requirements of the 1984 San Francisco Building Code. Highlights of SGH’s design include the following:

  • Specified base isolators at the plane of the existing roof to provide a mass damping effect that reduces the seismic demand in the existing structure eliminating the need for invasive and extensive strengthening in the occupied building
  • Developed project-specific design criteria that involved using nonlinear dynamic analytical methods and benchmarking structural performance against laboratory test data, which was subjected to rigorous peer review by the City of San Francisco
  • Consulted on building enclosure waterproofing and integration of waterproofing with the structure

Project Summary



Completion Date


New Construction
Structures | Building Enclosures
McCarthy Cook & Co.
Specialized Capabilities
Building Design | Seismic Engineering | Roofing & Waterproofing

Key team members

Ronald Mayes
Ronald Mayes
Consulting Technical Director
John Sumnicht
John Sumnicht
Consulting Principal