2. General Multigrid is a lightweight, expandable cellular confinement system which creates an erosion barrier and structural foundation. The system is used for: Road Stabilization. Slope Erosion Barrier. Structural Retaining walls. Multigrid is guaranteed to be durable for a minimum of 25 years in natural soils with 4<pH<9 and ambient soil temperatures of up to 60 ° C. The manufacturer complies with ISO 9001:2000. Multigrid is certified by the Public Works Department of the Israel, Poland, Russia and Lesotho.

4. Background Cellular Confinement Systems were first developed by the US Army in the 1970’s in order to construct roads, airstrips, etc. on soft soil and under wet weather conditions. It was determined that placement of thin walled, sand filled cells over a soft subgrade provided significantly greater load bearing capability than compacted soil alone. High density polyethylene (HDPE) was found to provide an optimal solution in terms of strength, durability, ease of handling and economics. Multigrid confinement system can be used with a variety of infill materials – soil, aggregates, concrete etc. - depending on the application. Restricting the movement of the fill material while allowing free passage of water through the layer, it can be used in gravel road construction, new road beds, slope protection and open channel construction.

5. Principle of Multigrid Load distribution

6. Principle of Multigrid

7. Characteristics and types Multigrid is characterized by it’s honeycomb appearance, where the individual cell dimensions may vary, dependant on soil type and application. It is manufactured from High Density Poly Ethylene ( H.D.P.E ) CELL HEIGHT : 50, 75, 100, 125, 150, 200 MM CELL DENSITY : 10, 15, 20, 25, 30, 35, 45 cells per M2 AVAILABLE COLOURS: black, tan, green

8. Applications Embankment Stream / channel protection Retaining wall Roadways

9. Erosion Control Erosion occurs when the forces exerted by water or wind dislodge and transport away soil particles. The amount of erosion depends on: –Strength of wind/water. –Dimensions of the slope (height, length and steepness). –Type of soil. The cells of Multigrid system can be filled with soil, sand, pebble, concrete etc. The infill is protected by the cell thus preventing its removal by erosion forces. Each cell functions as a small dam allowing water or wind to pass over the top without removal of the infill. If infill concrete is used, the system will protect the underlying soil from either wind or water erosion.

10. Soil and Gravel Roads Gravel and in-situ soil roads, can be easily and in-expensively constructed with Multigrid –The load bearing and load distribution characteristics of the cells allow for such roads to be constructed with minimal preparation (mostly just leveling). Considerable savings are achieved by infilling with local soil, so that costly hauling of imported infill material is eliminated. –100 mm cells filled with sand are equivalent to at least 300 mm of sandy gravel or 250 mm of crushed stone. Additionally, maintenance costs are reduced to a minimum thanks to the fact that rutting is eliminated. If so required, Multigrid can be removed from the site once the road becomes redundant and the site will be revert to its original condition. –The removed units can be easily packed and used elsewhere.

16. Multigrid in the African Context Due to the products designed ability to dramatically reduce erosion of the wearing road course, Multigrid reduces the need for the following: 1)Imported fill material. 2)Reduction in the cost of expensive earthmoving plant. 3)Imported construction water. 4)Specialist Road construction expertise. Local Community Involvement –Multigrid can be Installed and Maintained by un-skilled village communities, without the use of earthmoving equipment and plant.

20. Retaining Walls A Multigrid gravity wall is constructed by filling the cells with local, soil and/or aggregate. An additional benefit is that the outer cells can be vegetated, thus giving the wall a pleasing and environmentally compatible look. The size of the expanded Multigrid panels increases the effective thickness of the retaining wall. –This in turn enables the construction of walls of considerable height without resorting to the use of additional reinforcing elements.

23. Channel and Stream Protection. Multigrid can be used to prevent erosion of channels and stream bed. –Where strong currents are to be expected, concrete should be used to prevent erosion. –The utilization of geo-cells allows for reduced quantities of concrete, especially in the case of steep embankments, due to the fact that the concrete is contained in the cells and down pouring at the embankment will not occur.

25. Water and Sewage Reservoirs Multigrid can be used as load supporter on the bottom and sides of water/sewage reservoirs. In this manner savings in the construction can be affected. Furthermore, geomembranes of lower thickness may be used to seal the reservoir, contributing to even more savings without compromising the quality of the project.

27. Installation of Multigrid for Gravel Roads 1)Top layer of road removed and pushed into a wind-row next to road. 2)No in-situ compaction required. 3)Multigrid laid out onto road area. 4)Cells backfilled with in-situ material. 5)Compaction of wearing course.

29. Transportation and handling of Multigrid 2kms ( 10 000m2) can be transported in 1 x 20Ft Shipping Container. This reduces costs of delivery to site. Materials are packed so that they can be loaded and off-loaded by hand.

31. Multigrid in Lesotho A test strip of 0,5 km’s was installed on a severely sloped and eroded road section in Lesotho in 2008. After continuous traffic use and rain, to date, the surface has not required any further maintenance and surface erosion has been dramatically reduced. Installation carried out by hand with minimum earthmoving plant.

32. Lesotho road before and after Multigrid Before After

33. Multigrid in Tanzania A 12km installation in the Mtwara Coastal region was carried out in single grain beach sand. Oil Field trucks of 35 Tons carried equipment for 3 years without maintenance. No pre-compaction or water was required during the installation.

34. Multigrid in TANZANIA

35. Multigrid In Uganda In 2008, a 15 KM installation in the Lake Albert Region of Uganda was carried out in soils with a high clay content. Heavy truck traffic carried continuous and heavy equipment across the gravel roadway without maintenance or failure. Post Compaction was carried out after the installation.

36. Multigrid In UGANDA

37. Multigrid – one product for all your road needs Roads Embankment Storm Channels

38. Thank you

43. Contacts GRANT ALDRIDGE – Director grant@Multigridafrica.com Tel: (+27) 82 377 3715 Skype: grant.aldridge11 Fax : +27(0) 86599 1738 BROOKE BUSSELL – Director brooke@Multigridafrica.com Tel: (+23) 0737 8005 Skype: brooke.bussell1 Fax: +27(0) 86599 1738