WHAT IS A GABION?
The term ‘gabion’ refers to a modular containment system that enables rock, stone and non-degradable inert materials to be used as a construction material.
The modules, units or ‘cages’ as they are known, are formed from wire mesh fabric panels, jointed to form square, rectangular or trapezoidal shaped units.
These units are part pre-assembled in the factory to form a flat-pack system.
These flat-pack units are supplied to the customer and formed into the final shaped module on site with the necessary lacing wire, helicals and/or ‘C’ rings as required. Each module has to be connected to adjacent modules to form a monolithic structure.
The types of mesh used must be of a non-ravelling type such as welded wire mesh or hexagonal woven wire mesh and provided with corrosion protection to suit the required exposure conditions.
The gabions are normally machine-filled in layers with the contractor picking the stone over by hand to reduce excessive voids. The exposed faces can be hand-placed to provide an appearance of a dry stone wall.
Although some structures are only machine-filled, this procedure is not normally recommended as it may give rise to a high void content which can result in deformation. For gabion structures to perform correctly, the quality of installation is of paramount importance.
Wire & Coatings.
Mild steel wire to SANS 675 is used in the manufacture of all our wire mesh products. All wire is coated to Class A with Zinc Galvanising or Zinc Alloy Galvanising (Galfan Zn 95AI5). Galfan is a eutectic Zn-Al mischmetal: a combination resulting in a more uniform crystalline microstructure
and improved mechanical characteristics. It consists of a steel wire corrosion protection with a ±95% Zinc and ±5% Aluminium Alloy. Small additions of Cerium-Lanthanum rare earths is added to improve the reliability of the coating process. These heavy duty Class A Zinc coating or Zinc Alloy (Galfan ZN 95AI5), coating are applied by hot-dip galvanising to SANS 675, SANS 10244-2 and EN10244-2 and ASTM A641. Gabions and Mattresses are also coated to meet the additional requirements of SANS 1580.
The Class A Zinc Galvanising or Zinc Alloy Galvanising (Galfan Zn 95AI5I) coated wire can be,if required, provided with a PVC (to SANS 1580 and
EN 10245-2 and ASTM A975) or PA6 Nylon coating (to EN 10245-5) which are extruded over the galvanised wire to provide added protection for use
in aggressive environments such as acidic soils or water, in salt water, in water carrying a high abrasive sediment load or wherever the risk of corrosion is present. The PVC coating comes in grey or tan and has a nominal thickness of 0,5 mm and the PA6 Nylon coating comes in black and has a nominal thickness of0,4mm.
The stability of mass gravity retaining walls relies upon the structural integrity of the units, and their filled mass, to support or contain unstable earth slopes. In order to select the optimum retaining wall solution, key considerations include: • The geotechnical parameters of the retained and foundation soils
• The presence of water and hydrostatic loads
• External loads from structures and live or seismic loads
• The simplicity and speed of construction
Great for you
Dson Industries is an expert in the design / build / consulting for the construction of Mass Gravity Gabion Retaining Walls .
