Base Isolation

Forell Elsesser pioneered the use of seismic base isolation in the early 1980s.  Over the past 30 years we have gathered immense experience in the performance, behavior, and details of isolation systems, and a high level of expertise from hands-on project design and development.  

We have provided base isolation feasibility studies, upgrade concepts, and complete designs for more than 30 buildings including the first base-isolated existing building retrofit in the world (Salt Lake City and County Building), the tallest building (Oakland City Hall, at the time of construction), the largest existing building (San Francisco City Hall; at the time of construction), and the first seismically isolated aqueduct in the U.S. (Mokelumne Aqueduct #3, Sacramento River Delta, California).

Seismic isolation is the “separation” of the building from the ground, severing the rigid structure-to-ground contact with a mechanical device usually located between the structure and the foundation.  The isolator is designed to relieve most of the destructive earthquake movement, thus protecting the building.

Our base isolation portfolio includes:

  • Autozone Headquarters, Memphis, TN
  • Caltrans Traffic Operations/CHP Communication Center, San Diego, CA
  • Coronado Bay Bridge, Seismic Retrofit, San Diego, CA
  • Centre Block and Peace Tower, Ontario, Canada
  • East Bay Municipal Utility District (EBMUD), Mokelumne Aqueduct, Seismic Upgrade
  • Martin Luther King, Jr. Berkeley Civic Center, Seismic Upgrade
  • Oakland City Hall, Seismic Rehabilitation
  • Old St. Louis Courthouse
  • Oregon Supreme Court, Salem, OR
  • Oregon State Capitol, Salem, OR
  • Ottawa Centre Block, Ottawa, ON
  • Pasadena City Hall, Seismic Retrofit
  • Salt Lake City & County Building, Seismic Rehabilitation
  • San Francisco Asian Art Museum
  • San Francisco City Hall, Seismic Retrofit
  • San Francisco 911 Emergency Communications Center
  • San Francisco New Main Library
  • UCSF Parnassus, Ray & Dagmar Dolby Regeneration Medicine
  • Utah State Capitol, Seismic Retrofit