Self-Bearing Shotcrete in Lieu of Self-Consolidating Concrete for Tunnel Rehabilitation

Synopsis:

Pennsylvania Department of Transportation’s almost 100 year old Liberty Tunnels underwent significant rehabilitation measures, including the replacement of aging ventilation arch walls.  The arch walls act as tunnel shaped jet structures for fresh air supply.  The original design foresaw the use of self-consolidating concrete and formwork for the replacement.  The authors developed an alternative concept and subsequest design for a shotcrete arch wall solution in lieu of the solf-consolidating concrete foreseen by the contract design.  The alternate shotcrete concept provided the contractor with a schedule and cost saving solution under the given tight, two week long construction window allowed during a complete shutdown of the tunnel.

2014 North American Tunneling Conference Proceedings
June 22-25, 2014, Los Angeles, California (Nitschke, A. G., Gall, V., Pyakurel, S., Mazzoni, D. & Becker, J.)