Construction World September 2019

GEOTECHNICAL ENGINEERING

“F ibertex South Africa partners with municipalities and building contractors, assisting with the technical support, supply, installation and quality checks of geogrids used in various infrastructure developments, including the erection of retaining walls,” says Meera Govender, Technical Sales Engineer, Fibertex South Africa. “Construction of retaining walls often requires extensive earthworks, in order to execute the exact design heights and levels required of a particular structure. “Secugrid ® , a high-performance soil reinforcement product produced with state-of-the-art manufacturing technology – strengthens naturally unstable soil and subgrades to be able to withstand the loading conditions imposed by modern engineering demands. Secugrid is available in both biaxial form, for use in basal reinforcement applications and uniaxial form, for use in other markets. These applications include mechanically stabilised earth walls, including veneer stabilisation, the segmental retaining wall market, embankment reinforcement and pile cap platforms.” Secugrid is available from Fibertex in biaxial grades of up to 80 kN/m (ultimate tensile strength) and in uniaxial grades of up to 400 kN/m, or 1 200 kN/m with Secugrid HS ® . However, realistic design conditions demand a strength transfer in the range of less than 2%, which is the critical factor. Geogrid reinforcement decreases the dependency on base course thickness, also extending service life and reducing long- term maintenance needs. Secugrid is manufactured from extruded monolithic PET or PP strands that are drawn to orientate the polymers into high-tenacity flat bars to achieve a high modulus i.e. high strength at low elongations. This, combined with the Naue patented welding technology, provides a structurally sound and stable geogrid. Furthermore, the surfaces of bars are embossed, offering additional frictional interaction with the soil. This enables the Secugrid to pick up the load transfer quickly through both an interlocking and frictional effect, with little or no movement in the overlying soil materials. Secugrid is supplied in rolls and is easy to handle; quick and efficient to install, with minimal demand on labour resources. The product is also highly resistant to biological and chemical degradation and installation damage. Secugrid is a robust reinforcement material that can be easily and safely installed during virtually all weather conditions, without the need for heavy equipment or special construction techniques. Panels are joined and continuity is assured with simple overlaps depending on the application. Standard cutting tools can be used for on-site trimming and various geometrical shapes for steep sided slopes

can be formed when necessary. In addition to the standard Secugrid range, Fibertex South Africa also supplies Combigrid ® , a combination Secugrid/Geotextile composite product. Combigrid delivers reinforcement, filtration, separation and drainage all in one product. This product is predominantly used in conjunction with soft and low ‘California Bearing Ratio’ (CBR) soil, where reinforcing in combination with separation and filtration is needed. For example, in base and embankment reinforcement and load transfer platforms of pile caps. Other Naue Geosynthetics products available locally from Fibertex include Bentofix Geosynthetic Clay Liners (GCLs), which are composite materials, designed for use as efficient sealing barriers in various applications, including landfill projects. Fibertex South Africa supplies an extensive range of environmentally-friendly geosynthetic products from its KwaZulu-Natal, Gauteng and Western Cape facilities that encompasses nonwoven and woven geotextiles, gabions and mattresses, drainage pipes and fittings and erosion control and cellular confinement solutions. The company also supplies soil reinforcing products, including geogrids and geocells, as well as geosynthetic clay liners and geomembranes as part of composite lining systems used in modern landfills and for other environmental protection applications.  Fibertex South Africa, distributor in South Africa for the German manufactured Naue Geosynthetics range of geogrids, supplies durable PET (polyester) and PP (polypropylene) high-strength geogrid reinforcement materials for all civil engineering applications, including infrastructure projects.

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CONSTRUCTION WORLD SEPTEMBER 2019