The Narragansett Bay Commission Board of Commissioners has awarded the Combined Sewer Overflow (CSO) Phase III A/Pawtucket Tunnel project to the CBNA team consisting of Bouygues/Barletta/AECOM and for which GZ a team member. The CSO Phase III is the final phase of an extensive program to prevent CSO discharges into Narragansett Bay. Included in the project will be an 11,600ft long 30ft diameter TBM tunnel that will be bored through hard rock. The tunnel will be designed to store 58.5 million gallons of CSO and is expected to be completed in 2025 and operational in 2026.

Gall Zeidler Consultants is responsible for the temporary and permanent works design of all SEM tunnels/adits and the permanent works design for the large diameter shafts.  Gall Zeidler Consultants is also providing Independent Design Verification (IDV) services for the TBM segmental lining.

For the full TunnelTalk article, please visit the site here.

To learn more about the project and GZ’s involvement visit the project page here.

Layout of Pawtucket Tunnel (Image Courtesy Narragansett Bay Commission (NBC))