HYSON-CELLS

	Application and method	Estimated installed cost			Estimated installed cost
		S A Rand			US Dollars			unit
Velocities < 6 m / sec

	Hyson Cells
a	10 to 20 MPa concrete fill with Manning between 0.012 and 0.014	R35	to	R45	$6	to	$8	/ m²
b	No-fines concrete fill with vegetation	R25	to	R45	$4	to	$8	/ m²

	Cast concrete panels	R45	to	R65	$8	to	$11	/ m²
	Needs shuttering. Alternate slabs poured. Thickness can vary.
	Concrete block lining placed on non woven geotextile	R65	to	R85	$11	to	$14	/ m²
	Concrete block lining is connected with wires. Prone to rust.

	Concrete with grass blocks placed on geotextile	R65	to	R85	$11	to	$14	/ m²

	Reno mattress / gabion placed on geotextile	R125	to	R250	$21	to	$42	/ m²
	Needs selected stone. Labour intensive.

	Thick-wall geocells	R45	to	R85	$8	to	$14	/ m²
	Rigidity means limited ability to mould to contours and can allow water to flow underneath the cell mat.

Velocities 6 m / sec to 10 m / sec

	Hyson Cells	R35	to	R55	$6	to	$9	/ m²
	Fill is 20 MPa to 30 MPa concrete. Manning of 0.012 - 0.014.
	Soft-wall cells act as formwork to cast a 3D interlocking "cell slab". The formwork is sacrificial and acts as jointing. Flexible on poor founding materials such as clay.
	Releases hydrostatic pressures caused by varying water tables yet as waterproof as conventional concrete canals.

	Cast concrete panels	R110	to	R150	$18	to	$25	/ m²
	Needs jointing for this velocity. Uses shuttering. Compaction and curing important.

Velocities 10 m / sec to 20 m/sec

	Hyson Cells	R45	to	R65	$8	to	$11	/ m²
	Fill is 30 MPa to 40 MPa concrete. Manning of 0.012-0.013.
	Parabolic cross-section preferred. Advise use of 200 mm deep cut-off beams across the channel under the concrete liner up to 1 5 metres of channel length. Settlement pond to be used at end of fall. No steps.



	Reinforced concrete panels
	Usually involves stepping to break the velocity. Rubber jointing needed. Also uses cut-off beams and settlement ponds.

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