The Combined Sewage Storage Tunnel (CSST) project is part of the Ottawa River Action Plan and will greatly reduce the frequency of sewage overflows during storms from entering the Ottawa River. The project consists of the design and construction of two TBM tunnels running east-west and north-south along 6.2 km in total, and multiple shafts and support buildings.
CSST Overview map
Contractor Dragados Tomlinson Joint Venture (DTJV) was awarded the $232 million CAD contract in 2016 and the CSST will be in operation in 2020. The 3.7 m diameter TBM successfully completed the north-south drive in summer 2018 at Site 6 and was subsequently disassembled and moved to Site 5.
TBM at Site 6 with the Parliament of Canada in the background.
The TBM was then assembled at Site 5 and commenced the east-west drive in late 2018.
TBM Assembly
TBM Assembly
The TBM has successfully crossed the Rideau river this year and is currently driving under Cumberland Street in a south direction. Dr. Sauer & Partners provided the TBM segmental lining design, the rock mass grouting design for the crossing of the Rideau bedrock valley and continues to provide engineering support services to the DTJV during construction.
For more project information, please visit the project website.