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I have a 3.6m internal diameter bolted concrete segmental tunnel enter

Thread starter Ginger
Start date Jul 27, 1999

Status: Not open for further replies.

Jul 27, 1999

Ginger

New member

I have a 3.6m internal diameter bolted concrete segmental tunnel entering a circular shaft of 12.5mID. The tunnel turns through 120 degrees on plan before exiting the shaft. To form this circular curve in the tunnel I intend to cast an in-situ concrete block arount a 3.6mID curved former in order to maintain the correct tunnel cross section. Has anyone done something similar? Is the formwork best constructed of timber or a fabricated steel tube, or GRP to form a permanent formwork? The tunnel is to carry sewage. Any thoughts gratefully received.<br>
Thanks<br>
Ginger