East Palo Alto Academy

Project Summary

The Sequoia Union High School District chose a site in East Palo Alto to expand their charter high school program.  The East Palo Alto Academy was started in 2010 with the first phase and continued in 2013 with a second phase.  The project site is on the bay side of Highway 101.  The soil conditions consist of soft to medium clay over loose to medium dense silty sand and loose, poorly graded sand.  Cornerstone Earth Group identified severe liquefaction potential and likely ground rupture at the site with estimated liquefaction settlements approaching 3 to 5 inches.

Farrell collaborated with the project team early in the preliminary design development phase to advise them of possible ground densification methods to solve the geologic hazards.  Farrell competed with Hayward Baker and won the bid for ground densification columns using the Impact pier (IRAP) method.  Farrell installed IRAPs in offset rows at on center spacing of 8 feet and 7 feet.  Two areas required additional IRAP to improve the silty sand soil to a density that controlled liquefaction related settlement to less than 1 inch.  The project was a success.  In 2013, Farrell worked on the second phase of the academy construction using the same method of IRAP and changed the layout spacing to get higher densification.  DSA and CGS came out to a site demonstration to see the work in action.