As part of the seismic retrofit of the Dumbarton Bridge, the CA Geological Survey, in conjunction with CalTrans, has developed a strong ground motion monitoring program. This program includes the construction of multi-staged accelerometers in bore holes ranging from ten feet deep to 250 feet deep. Geosphere provided engineering geology consultation for the installation and construction of these accelerometers. Our services included logging of 250 foot deep rotary wash borings in soft, liquefiable, alluvial soils and weathered bedrock. This work was performed in accordance with CalTrans' standard rock and soil classification requirements.
The Geotechnical challenges involved in the project were as follows:
- Soft Soils
- Liquefiable Soils
Geotechnical Services included the following:
Client / Owner: Shimmick Construction
Construction Cost: n/a