MaccaferriGabions

I River training I Earth control and soil conservation r Retaining structures Landscaping u Lining of canals a Marine works Rockfall protectio

Gabion baskets an ancient concept in a modern form... Although it is known that gabions have been used from ancient times, it is only in the last few decades that their widespread use has led them to become an accepted

construction material in civil engineering. Modern technology has made possible the manufacture of these reliable and sound products, using mild steel wire mesh.

The wire is woven into an hexagonal pattern, with double twist joints which prevent the whole mesh from unravelling should a wire break or be cut.

...supported today by laboratory tests. Research into the behaviour of gabions and Reno mattresses has been carried out in both full and model scales at: Fig. 1 - U.S.A. - Colorado Hydraulic Laboratory at the Engineering Research Centre, Colorado State University.

Fig. 2 - FRANCE - Grenoble SOGREAH Ingenieurs Conseils. Fig. 3 - HOLLAND - Rotterdam Delft Hydraulic Laboratory at Hartel Kanaal. Fig. 4 - ITALY - Bologna University of Bologna Laboratorio di Scienza delle Costruzioni.

Fig. 5 - ITALY - Bologna Officine Maccaferri SpA Factory, in cooperation with Bologna University's Laboratorio di Tecnica delle Costruzioni.

I Advantages of Maccaferri gabion and Reno mattress structures Flexibility An outstanding advantage of tine gabion is its flexibility. Its double-twist hexagonal mesh construction permits it to tolerate differential settlement without fracture, fig. 6. This property is especially important when a structure is on unstable ground or in an area where scour from waves or currents can undermine i t

Strength The strength and flexibility of the steel wire hexagonal mesh from which gabions and mattresses are made is utilized to withstand and absorb the forces generated by retained earth or flowing water.

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Permeability Hydrostatic heads do not develop behind gabion structures because of their permeable nature. Their ability to combine drainage and retention functions make them ideal structures for slope stabilization, fig. 7.

Durability A Maccaferri gabion or Reno mattress is a heavy monolithic gravity unit able to withstand earth thrust. Its efficiency increases instead of decreasing with age since further consolidation takes place as silt and soil collect in the voids and vegetation establishes itself (fig. 8-9).

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Economy Gabion installations are more economical than rigid or semi-rigid structures for a number of reasons. The following are the most important ones: • Little maintenance is required. • Gabion construction is simple, does not require skilled labour. • Suitable stone fill is available normally on site or from nearby quarries. • Minimum foundation preparation is required, the surface needs to be only reasonably plane. • No costly drainage provision is required, as gabions are permeable.

Ecology Because gabions permit the growth of vegetation and maintain the existing environment, they provide attractive and natural building blocks for decorative landscaping.

Description of the l\/laccaferri box gabion Zinc c o a t e d box gabions Box g a b i o n s consist of rectangular units, f a b r i c a t e d f r o m a double-twist, hexagonal m e s h of soft a n n e a l e d , heavily zinc c o a t e d wire. The wire quality a n d t h e zinc c o a t i n g m e e t all international specifications. The m e s h panels are reinforced at all edges w i t h wires of a larger d i a m e t e r t h a n that used for m a n u f a c t u r i n g the m e s h , to s t r e n g t h e n t h e m and to facilitate c o n s t r u c t i o n . G a b i o n s may be divided into cells by fitting d i a p h r a g m s w h i c h have t h e f u n c t i o n of reinforcing t h e structure and m a k i n g a s s e m b l y a n d e r e c t i o n easier.

Zinc c o a t e d box gabions with P V e sleeve The c h a r a c t e r i s t i c s of t h e s e p r o d u c t s are similar t o t h o s e of t h e z i n c - c o a t e d gabions; h o w e v e r t h e wire, prior to m a n u f a c t u r i n g t h e m e s h , is c o a t e d w i t h a 0.4 t o 0.6 m m t h i c k special PVC (polyvinyl chloride) continuous sheath. A complete protection against possible c o r r o s i o n is t h u s o b t a i n e d m a k i n g t h e g a b i o n s suitable for use in marine or p o l l u t e d e n v i r o n m e n t s . D i a p h r a g m s are always r e c o m m e n d e d w h e n gabions are s u b j e c t to c o n t i n u o u s stress c a u s e d by w a v e m o t i o n , or high w a t e r velocity, etc. Filled w i t h s t o n e , gabions b e c o m e a large, flexible a n d p e r m e a b l e building b l o c k f r o m w h i c h a b r o a d range of s t r u c t u r e s m a y be built.

Applications R I V E R TRAINING

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Applications E A R T H C O N T R O L AND S O I L C O N S E R V A T I O N

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Fig. 14 - REPUBLIC OF CAPE VERDE. Series of structures for soil conservation in Santiago Island.

RETAINING S T R U C T U R E S

Fig. 15 - SAUDI ARABIA. PVC coated gabion wall near Dahran.

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Fig. 16 - SWITZERLAND. Retaining wall for the protection of the railway near Aipnach.

LANDSCAPING

Fig. 18 - CANADA - Quebec. River wall to a city parlc along the St. Lawrence in Candiac.

RETAINING S T R U C T U R E S

B R I D G E AND C U L V E R T P R O T E C T I O N S

Fig. 17 - BRASIL - S. Paulo. Bridge abutments on Turvo river, near S. José dos Campos.

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M A R I N A S AND S E A S H O R E P R O T E C T I O N

Fig. 19 - CANADA - Quebec. Marina walls at Matane; the work was carried out using PVC coated gabions. 5

Description of the l\/laccaferri Reno mattress Zinc c o a t e d Reno mattress The Reno mattress is a special form of gabion with a large plan area/thickness ratio. It is fabricated from a similar but smaller doubie-twist hexagonal mesh of that used to manufacture the gabions. The wire characteristics are the same. Diaphragms are spaced usually at 1.00 m centres, and a continuous panel of mesh forms the base, the side and the end walls of the unit to obtain an open-topped multicell container. The same mesh is used for the base, diaphragms, and the separate lid. All panel edges are selvedged with a wire of larger diameter than that used for the mesh, so as to strengthen the structure. Zinc c o a t e d Reno mattress with P V C sleeve The wire of the Reno mattress can be coated with PVC in the same manner as that for gabions.

Applications R I V E R TRAINING

Fig. 22 - U.S.A. - New York. Gabion bank protection near Buffalo.

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SOIL CONSERVATION

Fig. 23 - ITALY - Tuscany. Drainage ciiannei to stabilize a slope near Florence.

Applications

Fig. 24 - IRAQ. Revetment of the Razaza drainage channel near Kerbala.

CULVERT PROTECTION

Fig. 25 - U.S.A. - Maryland, Lining of a stream near Frederick, along highway A40.

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Fig. 26 - CANADA - Ontario. Culvert protection near Cornwali.

I M P E R M E A B L E LINING O F D A M S

Fig. 28 - Reno mattresses can be seaied by fiot poured sand aspiialt mastic, in order to provide an impermeable revetment to dams, reservoirs, channels, etc.

BRIDGE PROTECTION

Fig. 27 - AUSTRALIA, Protection of abutments of tfie "Sfieridan" Bridge, State Highvïay No. 2.

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MARINAS AND S E A S H O R E P R O T E C T I O N

Fig. 29 - U.K. - Dawlish Warren. Protection of the sand spit at the mouth of the Exe river with PVC-coated Reno mattress. 7

Description of the l\/laccaferri sacic gabion These consist of a single sheet of mesh, which forms a cylinder open either at one end or at the side. The characteristics of mesh, wire, zinc coating and PVC coating are identical to those of the box gabions.

Applications

Fig. 31 - ITALY-Lombardy. Assembly of a sack gabion using a special maciiine.

Fig. 32 - BRASIL - S. Paulo. Sack gabion foundation for a bank protection wall on the Tamanduatéi river.

Fig. 33 - ITALY - Emiiia-Romagna. Closing a breach of the Po river, near Ferrara.

Fig. 34 - IRAQ. Sack gabion foundation for a bank revetment on the Tigris river

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I Description of l\/laccaferri ^ rockfall protection netting Wire mesli netting is often used to prevent rocl