Gabions, as used in modern engineering practice, are compartmented,
rectangular containers made of galvanized or PVC coated steel hexagonal
wire mesh, and filled with stone. The compartments, or cells, of equal
capacity are formed by a factory-inserted wire netting dividers or
diaphragms. These diaphragms add strength to the container and help
retain its rectangular shape during the filling operation. Diaphragms
also provide assurance that the fill will be equally divided and prevent
shifting of fill.
The gabions are then tied together to form
a gabion structure. These structures provide numerous advantages:
Flexibility
Flexibility is an important benefit of any
gabion structure. The double-twist hexagonal mesh construction permits
it to tolerate differential settlement without fracture.
Durability
Gabions support plant growth which
provides a living coating for the wire mesh and stones, adding to their
durability. Generally, the wire mesh is needed for the first few years
of the structure’s life, because the voids between stones fill with
soil, silt, and plant roots which act as a bonding agent for the
stones. Additionally, the double twisted hexagonal mesh won’t unravel
if cut.
Strength
Steel wire hexagonal mesh has strength and
flexibility to withstand forces generated by water and earth masses, and
the pervious nature of the gabion allows it to absorb and dissipate much
of that energy. This is evident on coast protection installations where
gabion structures remain effective long after a massive rigid structure
fails.
Permeability
Gabion walls are pervious to water and
stabilize slopes by the combined action of draining and retaining,
precluding the development of hydrostatic pressure behind the gabion
wall. Drainage is accomplished by gravity, as well as evaporation as
the porous structure permits air circulation through it. As plant
growth develops within the structure, the process of transpiration
assists in removing moisture from the backfill - a much more efficient
system than weep holes in standard masonry walls.
Economy
Gabion systems are more economical than
rigid or semi-rigid structures for the following reasons:
+ Require little maintenance
+ Installations does not require skilled
labor
+ Stone fill is available on site or from
nearby quarries
+ Requires little or no foundation
preparation, as the surface needs
to be only reasonably level and
smooth
+ Gabions are porous, requiring no costly
drainage provision.
Landscaping
The use of gabions in decorative
landscaping is limited only by the creativity of the landscaper.
Gabions permit growth of vegetation and help maintain the natural
environment of the area and have been effectively and economically used
in parks, along highways, along stream banks and ponds, rock gardens,
terraces, and patios.
Rockfall Netting is manufactured from
galvanized or PVC coated Gabion wire. Sold in rolls it is attached to
extremely steep rock slopes. If rocks are dislodged, the netting allows
the rock to fall but stops it from rolling into the traffic right of
way.
