With over 1 million pounds of extraction force, the rotator was able to remove the temporary casing while maintaining as much as 40’ of concrete above the bottom of the casing.
The soils overlying the bedrock unit consisted of loose fine sands and silty clays. The bedrock unit was comprised of a interlayered zones of siltstones and sandstones. The weathering of this material ranged intermittently from intensely weathered to decomposed to fresh with a maximum unconfined compressive strength of approximately 9,000 psi. RQD values ranged from 0-100%. Full length temporary casing was ultimately required to successfully complete large diameter drilled shafts in this material.
The shaft integrity was tested using Gamma-Gamma Logging and detected no anomalies within the rock sockets.
An Osterberg load cell confirmed the capacity of the rock sockets. The results of this load test demonstrated that the shafts performed well within industry standards in this type of bedrock. (Katzenbach 2004)
This job was managed by
our Northern California Division
located in Hayward, California.
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