Publication Abstract

Proceedings of the 43rd Annual Conference on Deep Foundations, 2018, Anaheim, CA, USA, (DFI)

Rock Socketed Drilled Shafts in Electrical Substations
Steve Davidow, P.E., S.E., Senior Vice President, Brock Wallis and Vice President

The following text will present the concept of rock socketed drilled shafts used to support electrical substation structures, and discuss the cost and schedule risks that traditional design responses to unforeseen shallow rock can pose to a project. Design considerations will be detailed, including rock characterization, shear strength of drilled shafts, and modeling lateral resistance of the shaft and surrounding rock. The specific case of drilled shafts installed for heavily loaded structures at the Moxie Freedom Substation will provide an example of how close collaboration between the engineer and contractor to refine designs based on site-specific feedback can provide tangible benefits to the project. In this example, value engineered designs resulted in an approximate 40% reduction in shaft/concrete volume and a 60% reduction in total rock socket depth.

 article #3092; publication #1045 (AM-2018)