Project Description

Location:   Gilliam and Morrow Counties, Oregon
Installed Capacity: 845 MW
Construction Cost: $500,000,000+
Year Commissioned:   2012

The Shepherds Flat Wind Farm is located near the City of Arlington within Gilliam and Morrow Counties, Oregon. As one of the largest wind farms constructed in a single phase in the world at the time of this posting, the project consisted of construction and installation of 338 GE 2.5 MW wind turbine generators with a total nameplate capacity of 845 MW.

RRC provided geotechnical engineering, structural engineering, and construction materials testing for the project. From a geotechnical engineering perspective, the subsurface soils and bedrock conditions were challenging across the site and ranged from collapse-prone soils to basalt bedrock exposed at relatively shallow depths. The design also required implementation of Deep Dynamic Compaction (DDC) to alleviate the subgrade soil collapse potential, as well as providing a plan for the execution of the DDC. Due to the large scale of the project, it was particularly important for RRC to optimize and provide the most economical foundation designs. RRC provided the design and sizing of the concrete, reinforcing, embedment rings, and anchor bolts for the wind turbine foundations to adequately resist the loadings provided by the turbine supplier.