Project Details:

Following the 1906 magnitude 7.7–7.9 earthquake the people of the San Francisco Bay Area learned that the bigger threat to life and property can be the fires that follow large earthquakes.  Seismic anchors installed around the perimeter of existing water tanks insure that the tanks are securely fastened to the ground during seismic events.  If not for seismic anchors the tanks are susceptible to “elephant footing”, a condition by which the wave action within the tank literally lifts the tank off of its foundation and slams it back down on the ground.  The elephant footing action can destroy the integrity of the tank thus causing it to leak.

LSI was contracted by Piazza Construction, Inc. to install twenty 20-ft seismic anchors spaced equally around the perimeter of the Rafael Highlands Water Tank.  The design called for a 16-ft bonded length at a 36Kip design load.


Elephant Footing

  Example of elephant footing. 

  Picture sourced from APWA

Project Summary:

Seismic Retrofit, Marin Municipal Water District

LSI installed 20 high strength seismic anchors around the perimeter of the Rafael Highlands Water Tank for prime contractor Piazza Construction, Inc.  LSI’s equipment was well suited for the tight access and strict anchor location tolerances outlined by Marin Municipal Water District.

Project Stats:

  • Tight Access
  • Post Tensioned
  • Strict Anchor Location Tolerances
  • Northern California

Project References:

  • Marin Municipal Water District
  • Prime Contractor, Piazza Construction, Inc.
  • James Chinchiolo, CEO,Subcontractor, Landslide Solutions, Inc.,