Monday, 5 October, 2015

The new 15 ml Signal Hill Reservoir was commissioned by Amatola Water for additional water storing capacity in the Mthatha Region close to Umtata. The project forms part of the bigger Presidential Infrastructure Spend Programme from government in the Eastern Cape – one of the poorest areas in South Africa.

GIBB, one of SA’s leading multi-disciplinary engineering consulting firms designed the Signal Hill Reservoir as a post-tensioned reservoir with no solid connection between the reservoir floor and walls. Walls are cast onto bearing pads to allow for any expansion and contraction. The method of construction is casting the full reservoir in four quadrants with three cast lifts per quadrant. Post tensioning will be done once the reservoir is complete and the required concrete strength has been obtained.

TVR / Mamlambo opted to use Tifa-Flex to cast the circular walls of the reservoir. Tifa-Flex is Form-Scaff’s recently launched state-of-the-art circular wall formwork system.

The system offers a high quality WISA-Form plywood face that can be set to the exact radius by adjusting the turnbuckles between the trapezoidal soldiers. A lazer-cut radius gauge is provided to the site and is used to set the required internal and external radii.

The system makes use of standard Tifa components such as Push-pull props, clamps etc. The 60kN/m² Tifa-Flex system uses a 20mm Dywidag Tie System to ensure accurate concrete wall thicknesses through-out.

The 4,5m high concrete pours were made up of standard 3,0m and a 1,5m high Tifa-Flex panels with only 3 ties in the vertical position. When compared to a Tifa-Lite Flex option, this results in 60% less ties which relates to massive time and cost savings, both in the ties itself, but also in the sealing off of the tie holes afterwards.

Form-Scaff looks forward to provide Tifa-Flex as the system of choice on many circular formwork projects in the future.

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