Forthside Sewer - Stirling

The main contractors for this project were Johnston Construction Limited, who awarded Carillion Piling the diaphragm wall shaft work for the sewer.

This shaft was constructed to give an internal diameter of 20m. The shaft was 25m deep and was formed using a 1m thick diaphragm wall 35m deep.

Provision was made within the diaphragm wall panel reinforcement to allow for the exit of a tunnel boring machine 16.5m below ground level.

Construction of this shaft took three weeks. 10 diaphragm wall panels each containing 260m2 of concrete were constructed. Diaphragm wall panels were fitted with water bars to ensure water tightness.

Client: East of Scotland Water
Diaphragm wall rig used: Rope suspended grab