Tunnel Update: Ashbridges Bay Treatment Plant Outfall

By TBM Staff June 15, 2022

The Robbins TBM bored primarily in shale. (Photo: Robbins.)

The $300 million Ashbridges Bay Treatment Plant Outfall project for the City of Toronto, being built by Southland | Astaldi Joint Venture, is currently 75 percent complete.

The job comprises a 16-m diameter shaft, 85 m deep, 3.5 km of 8-m diameter TBM excavated tunnel with 7-m ID precast concrete segmental lining; and 50 of 1-m diameter risers from tunnel (marine work). The ground is primarily Georgian Bay shale.

Shaft and tunnel excavation are complete and the TBM has been demobilized. The offshore risers are also complete with the connections of the risers to the tunnel upcoming.

NTP was issued in January 2019. The estimated completion date is July 2024.

Consultant & Designer: Hatch with Jacob & Baird. Major Subcontractors: Johnson Bros. Corp (offshore work including riser installation).

Personnel: Contractor: Southland | Astaldi JV; Project Director (Kent Vest); Project Manager (Joe Savage); Deputy Project Manager (Francisco Urrutia); General Superintendent (Curtis Bahten); Underground Superintendent (Jeff Reagan).