Project Details:

Highway 1 at Pescadero Creek Road in San Mateo County California, presented a multitude of challenges to CalTrans Geotechnical Design West Senior Engineering Geologist, Grant Wilcox:  A large 140 linear foot portion of bluff supporting Highway 1 was simply sliding out to sea, the highway needed to be stabilized immediately, CalTrans environmental department required that the repair stay within the departments current right of way and the coastal commission required little or no impact to the shoreline.

Landslides Solutions, Inc. collaborated with all CalTrans departments and emergency limited bid prime contractor, Half Moon Bay Grading and Paving, in developing a subterranean repair system that met the design criteria outlined by the agency.  Together with CalTrans supplied geotechnical soils data Landslide Solutions, Inc. designed a repair requiring minor excavation just outside of the edge of pavement, 50-ft long Self Drilling SuperNails™ soil nails, 40-ft Self Drilling SuperMicropiles™ and 1,400 SF of shotcrete.  The excavated soil was then placed back over the repair then hydro seeded with a native seed mix.  All cementitious material was contained within the excavation pit and properly disposed of offsite.

CalTrans reported a cost savings of over 2 million dollars when compared to the capitol improvement project planned for the site.   At no additional cost Landslide Solutions, Inc installed inclinometer casing to verify performance.  To date readings indicate that the site is stable and the slide has been mitigated.  In addition to a standard 1 year material and workmanship warranty CalTrans holds a five year project performance warranty from Landslide Solutions, Inc. at this site.

Project Summary:

Hwy 1 at Pescadero Creek Road, CalTrans District 4

CalTrans had experienced sliding at Hwy 1 and Pescadero Creek Road since the early 1970’s.  Temporary repair projects and regular pavement patching kept the highway in service until the highway surface dropped a dramatic 2-ft over the course of a weekend in February 2010.  This movement prompted a director’s order authorizing an emergency project to make permanent repairs.  CalTrans then selected Landslide Solutions, Inc. to complete the geotechnical design and repair at this site.


Project Stats:

  • Subterranean repair
  • No visual impact
  • CalTrans District 4
  • Northern California
  • Stayed out of the Tidal Zone
  • Completed in 5 weeks
  • Saved over 2 million

Project References:

  • CalTrans, Geotechnical Design West, Division of Engineering Services
  • Prime Contractor, Half Moon Bay Grading & Paving Inc.
  • James Chinchiolo, CEO, Project Manager, Landslide Solutions, Inc., james@landslidesolutions.com
  • Cameron Lobato, P.E., Chief Engineer,  Landslide Solutions, Inc., cameron@landslidesolutions.com

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