First in the World 50 deg Inclined Slipformed Linings to Penstock Tunnels.

Subject to a maximum static head of 6.2 meters, two inclined penstocks are arranged at an inclination of 50o to the horizontal. The upper include penstock is 206m long and the lower 347.5m; both excavated to 8.7m diameter and reinforced concrete lined to 8.5m across. CSM slipform equipment was introduced for the lining operation. With some improvements at the project site the slipforming of over 635m tangential section of both penstocks lasted 113 days a major breakthrough in the International construction techniques for inclined shafts.

The slipform equipment comprised of a steel rig consisting of a central mast with anchorage's at both ends. The form is pulled up by hydraulic jacks along the mast. Platforms are attached around the mast to facilitate Reba fixing, concreting and finishing works. The system allows for continuous concrete placing throughout the length of the shaft. Concrete, Rebar and personnel were transported from the top of the tunnel by CSM's variable speed (0-90 meters a minute) 8.5 ton capacity hydraulic transport system. The transport system was key to the success of slipforming speed obtained, given the harsh tunnel environment.

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Fixing rebar to tunnel wall

Twin rope 8 ton 0-80 meters/min winch

Concrete finishing to tunnel surface

Dismantling equipment