Plymouth Street Office Campus, Mountain View, CA

Broadreach Capital Partners retained Cornerstone Earth Group, Inc. to provide environmental and geotechnical engineering services for a 6-story office building totaling 245,000 SF and a 4-level parking garage. The Project is designed to achieve a LEED Platinum rating. Broadreach was established in 2002 and is a real estate investment firm that focuses on western U.S. commercial and hotel properties. The design team also consisted of WRNS Studio, Architect, and Nova Partners, Construction Manager, to meet the construction needs of Broadreach and their tenant Google.

1625 Plymouth Street is a source of contamination that dates back to prior owners and occupants of the 1960s and 1970s. To make this site suitable for commercial development, Broadreach and Cornerstone worked proactively with the San Francisco Regional Water Quality Control Board (Water Board) and the responsible parties to accelerate the cleanup of the property. These efforts resulted in the completion of a successful in-situ chemical reduction program in 2013, eventually resulting in the Water Board’s approval of site development. In addition to this successful ground water remediation effort, Broadreach directed Cornerstone to design a vapor barrier system underneath the building’s slab to effectively eliminate vapor intrusion concerns (the movement of chemical vapors from contaminated ground water or soil into a nearby building), resulting in the safest possible indoor air quality for future occupants.

Cornerstone’s Value-Added Benefits:

  • Performed load testing on test piles to reduce the number and length of piles.
  • Selected augercast pressure grouted displacement piles (APGD) piles to lower noise and vibration during installation (as compared to driven pile types); to minimize the generation of soil spoils; and to virtually eliminate the potential for downward migration of contaminated ground water.
  • Coordinated with the Water Board and Responsible Parties in Site development activities.