HYSON-CELLS

Overview

---

Concrete cast in Hyson Cells has particular application as a channel liner. The Hyson Cells is used as formwork and remains embedded in the cast concrete as a reasonably waterproof joint.

No conventional formwork is needed to cast even complex profiles such as are encountered at confluences and for culverts.

The Hyson Cells liner is a flexible concrete liner that is more forgiving of a certain amount of movement of the underlying material than is a conventional concrete liner. Any movement is distributed over a number of blocks which then "lock up". Hyson Cells is "chain mail" armour. With a conventional concrete panel it only takes one panel to move for a significant unevenness at a joint to be caused. The vortexes of high velocity flow create suction that can tear out the rubber jointing and then tear out the panel itself. A chain reaction then develops into a major failure.

The Hyson Cells system is therefore especially suitable for construction on underlying clay. See the Photo tour for aspecial sectiondevoted to this.

Flotation of an empty canal with a rising water table does not occur. The flexibility of the lining allows slight local deformations which open the joints sufficiently to relieve back pressures. Empty canals and drains can be observed to weep. The same mechanism release trapped water or air which can result from overtopping in flood conditions. The engineer may of course still prefer to provide sub-drains as is done with conventional canals.

Despite the above, the canals do not leak. When the internal pressure pushes the blocks against the supporting earth the plastic in the joint is then pinched by the undulations in the blocks and the water-tightness of the joint is improved. It has been found in practice that the seepage of a Hyson Cells canal compares with that experienced with a conventional concrete canal with jointing.

A very real benefit of the Hyson Cells system is that it has less exacting requirements for preparation of the site. This makes it a method of choice when budgets are limited and for rehabilitation after floods when the contractor is working in the !!?#!

See our general discussion onconstruction costs.