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Helix formwork
Project // United Kingdom

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Construx conceived a new type adjustable circular climbing formwork

The Helix formwork is a perfect fit for large concrete tanks with diameters between 20m and 50m and a minimum height of 20m. The system is based on a revolutionary new idea. After assembly, the formwork does not need to be dismantled and moved with a crane. The entire setup drives upwards as in a helix, using the cured concrete wall as a support.

Only the climbing shoes and the rails need to be moved with a crane. The shutters sit on the scaffolds which roll on specially twisted profiles. Moving panels and scaffolds is done with a winch, in 1 single action which takes only about 10 minutes.

This process guarantees a daily pouring of a phase.

Technical specifications:

  • Drink water reservoir
  • Caisson with knife at 45°
  • Tank sinks by its own weight and excavation on the inside
  • Height 28m
  • Internal diameter 30m
  • Wall thickness 1500mm
  • 5 internal panels 3000mm x 2400mm
  • 5 external panels 3000mm x 2500mm
  • 73mm staggered connection between the panels
  • 88 pouring stages of approx. 12,5m
  • Lead approx. 3%: rise 2,9m per circle