Nicholson Construction has been appointed to install diaphragm walls and barrettes for a peanut shaft as part of an upgrade of Silicon Valley Clean Water’s facility in Redwood City, California, US being undertaken by main contracting joint venture JF Shea Parsons.
The peanut shaft – formed from two shafts with a shared wall – will be used to retrieve a tunnel boring machine driving a tunnel as part of the upgrade and for the receiving lift pump station (RLS).
The 11.2m diameter retrieval shaft will extend to 35.3m, while the RLS shaft will have a diameter of 21.3m and extend to 43m below ground. Steel reinforced barrettes will be constructed within the RLS shaft to a depth of 49m to resist uplift pressures.
“We’re excited to help upgrade and improve water infrastructure in Silicon Valley,” said Nicholson Construction project manager Yuri Chernyavski. “We’ll be applying the knowledge and experience we’ve gained from working with Northeast Ohio Regional Sewer District and Louisville Metropolitan Sewer District on similar projects.”
Construction of the peanut shaft is expected to take a year to complete.