A major roadway in California’s Bay Area presented a multitude of challenges to the state’s Department of Transportation where a large 140-linear foot portion of bluff supporting the roadway was simply sliding out to sea. While the highway needed to be stabilized immediately, the DOT’s environmental department required that the repair stay within the department’s current right of way and the coastal commission required little or no impact to the shoreline.
GeoStabilization International® collaborated with all of the DOT’s departments and the emergency limited bid prime contractor to develop a subterranean repair system that met the design criteria outlined by the agency. With the DOT’s supplied geotechnical soils data, GeoStabilization designed a repair requiring minor excavation just outside of the edge of pavement, 50-ft long Self Drilling SuperNails™, 40-ft Self Drilling SuperMicropiles™, and 1,400 SF of shotcrete. The excavated soil was then placed back over the repair before it was hydro-seeded with a native seed mix. All cementitious material was contained within the excavation pit and properly disposed of offsite. The DOT reported a cost savings of over 2 million dollars when compared to the
The DOT reported a cost savings of over 2 million dollars when compared to the capital improvement project planned for the site. At no additional cost GeoStabilization 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, the DOT enjoys a five-year project performance warranty from GeoStabilization International®.
In June, GeoStabilization received a phone call about 7:30 am that KY 221 had slipped down the hillside creating a large drop in the pavement.