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Snow netsSnow nets:

• Adapt themselves to the acting loads

• Cover a wide range of snowthicknesses(2.5 m – 4.0 m).

• Are l ightweight structures(approx. 70 kg/m).

• Do not interrupt the continuityof the blanket of snow

• Also resist dynamic type impact(fal l ing rock masses) even thoughthey are not designedfor this purpose

• May be adapted to any typeof ground al ignment

• Have a low visual impact

The inhabitants of mountainous areas have always beenaf fec ted by the r isk of avalanches. The need to l i vea longs ide th i s th reat has led to a t tempts to mi t iga tethe r i sk by cons t ruc t ing in t r i ca te sys tems o f a r t i f i c ia ls t ructures.

The de fores ta t ion , somet imes ind i sc r iminate, o f someareas and the development of tourist infrastructures hasresu l ted, on the one hand, in the reduct ion of natura lbarr iers to the tr iggering of snow instabi l i ty phenomenaand, on the other, to an increase in the need to guaranteethe safety due to a d i f fe rent use of the te r r i tory - notto ment ion the need to p ro tec t res ident ia l a reas androads and ra i lway l ines.

Snow bar r ie rs enab le a cons iderab le reduct ion o f th i sr isk.

The mesh snow nets a re des igned in order tos t a b i l i s e t h e l a y e r o f s n o w a t t h e p o t e n t i a lavalanche detachment zone, thereby preventingtriggering of the avalanche.

The l a ye r o f snow exe r t s a p re s su re wh i ch mus t beabsorbed by the nets and transmitted to the ground bymeans of a system of posts and anchors. The f lex ib i l i tyof the system results in a reduction of the pressure exertedby the snow on the structure in a parallel direction to theslope. The stress depends on the slope angle, the thicknessof the layer of snow, the environmental condit ions andthe exposure of the slope itself.

The snow barrier structures act on the s l ipp ing ands l id ing mechanisms of the layer o f snow in a downhi l ld i rect ion, creat ing a “stagnat ion zone” on the ups lopes ide character ised by compress ion forces which absorba part of the dangerous shear forces in the weak layersand l imit the propagat ion of the shear f ractures. In thisway t he r e i s a r educ t i on i n t he shea r f o r ce s and aconsequent increase in the stabil ity of the layer of snow.

The snow barr iers must be posit ioned in the area of thepotent ia l detachment of the snow. I t may be necessaryto instal l var ious rows of structures, on the upslope anddownslope s ides of a potent ia l fa i lure point . This l imitsthe propagat ion of the shear fa i lu re and the resu l t ingmovement of the mass of snow.

Mesh snow nets may be eas i l y adapted to groundsurface irregularities and therefore represent an excellentsolution even in situations where the ground alignmentis very variable, where it would be very diff icult to adoptmore r ig id st ructures.

A n a d va n t a g e o f m e s h s n o w n e t s i s t h e r educedenv i ronmenta l impact due to the i r l im i ted v i s ib i l i t y,dur ing both the winter and summer.

These barr iers consist of a few components which makethem both simple and eff icient: steel tubular struts, steelcab le pane l s, s tee l mesh f i t ted to ma in cab le pane l s,ups lope and downs lope anchors (as wel l as end po intanchors) in order to guarantee the stability of the system.

An avalanche occurs when a mass of snow suddenlystar ts to move downhi l l due to a breakdown of thesnow’s equi l ibr ium condit ions. The movement of thesnow may be the resu l t o f natura l causes (e.g . thewind) or accidental reasons (e.g. skiers on the slope,etc . ) . As i t moves downhi l l the ava lanche may dragother snow with i t , becoming increasingly large, andit can travel at speeds of more than 300 km/h. Almostal l mountain val leys may be considered to be subjectto th is hazard.

“A va l a n c h e h a z a r d ” m e a n s t h e p o s s i b i l i t y o f adangerous event occurr ing, maybe in a remote areahigh up in the mountains, where there are no personso r o b j e c t s : t h e r e i s a c l e a r h a z a r d b u t n o r i s k .

However, “avalanche r isk” means that there is a realhaza rd and the re a re pe r sons o r ob j e c t s a t r i s k .

SINGLE BRACEDOWNSLOPEANCHOR

SINGLE BRACE

SINGLE BRACE

SINGLE BRACE

INSTALLATION

N E W : B A F U O M O L O G AT I O N ! ! !

OM snow nets have been certified by theSwis s Fede ra l I n s t i tu te fo r Snow andAvalanches of DAVOS, approved by theFederal Expert Commission on Avalanchesand Rockfall (EKLS) and have obtained thehomologation of the Federal Office for theEnvironment (BAFU-FOEN) in March 2009.

An avalanche occurs when a mass of snow suddenlystar ts to move downhi l l due to a breakdown of thesnow’s equi l ibr ium condit ions. The movement of thesnow may be the resu l t o f natura l causes (e.g . thewind) or accidental reasons (e.g. skiers on the slope,etc . ) . As i t moves downhi l l the ava lanche may dragother snow with i t , becoming increasingly large, andit can travel at speeds of more than 300 km/h. Almostal l mountain val leys may be considered to be subjectto th is hazard.

“A va l a n c h e h a z a r d ” m e a n s t h e p o s s i b i l i t y o f adangerous event occurr ing, maybe in a remote areahigh up in the mountains, where there are no personso r o b j e c t s : t h e r e i s a c l e a r h a z a r d b u t n o r i s k .

However, “avalanche r isk” means that there is a realhaza rd and the re a re pe r sons o r ob j e c t s a t r i s k .

SINGLE BRACEDOWNSLOPEANCHOR

SINGLE BRACE

Snow nets:

• Adapt themselves to the acting loads

• Cover a wide range of snowthicknesses(2.5 m – 4.0 m).

• Are l ightweight structures(approx. 70 kg/m).

• Do not interrupt the continuityof the blanket of snow

• Also resist dynamic type impact(fal l ing rock masses) even thoughthey are not designedfor this purpose

• May be adapted to any typeof ground al ignment

• Have a low visual impact

SINGLE BRACE

SINGLE BRACE

INSTALLATION

Forces which actinside a layer of snowand possibledetachment pointsElements characterising the detachment zone

• Slope angle

• Orientation with respect to wind direction

• Exposure to sun’s rays

• Altitude

• Morphology

• Presence of trees

• Surface area of slope

The triangular mesh snow net produced by Officine Maccaferri has beendesigned on the basis of the “Directives for the construction of avalancheprotection works at the detachment zone” edition 2006 issued by UFAFP(Federal Management of Swiss Forests) and FNP (Swiss Federal Institute forStudy of Snow and Avalanches).

Technicalcharacterist icsIt is an elastic and modular structure, consisting of the following mainelements:

a ) containment structure: consisting of triangular shapedpanels made of steel cables. There are two types oftriangular mesh panels: one with the horizontal sideon the ground and the vertex at the top and the otherwith the vertex on the ground and the horizontal sideat the top. The dimensions of the panels vary for eachmodel and depend on the thickness and the specificweight of the layer of snow.

b ) support structure: consisting of steel tubular struts,fixed to the ground at the base by means of a universalball joint and at the top by means of the triangularm e s h p a n e l s a n d t h e d o w n s l o p e b r a c e s .

c ) connection structure: consisting of steel cables todistribute the loads transmitted by the containmentstructure and to transfer the loads to the ground bymeans of the anchoring structure.

d ) anchoring structure and foundation: this transfers tothe ground the loads transmitted by the containment,support and connection structures and, depending onthe element connected, it consists of upslope anddownslope anchors made of double spiral cables orby micro-piles or foundation plates for the struts.

The components of the snow net barrier enable assembly even under harshconditions.The snow net has been designed manufactured and marketed in accordancewith the quality control requirements of ISO 9001.

TUBULAR STRUT

TRIANGULAR MESH

MICRO-PILE

DOWNSLOPE BRACE

DOWNSLOPE SPIRALANCHOR

UPSLOPE SPIRALANCHOR

Tensile zone

Neutral zone

Shear forces

Intermediate weal layer

Tensile zone

Zona neutra

Forza di taglio

Tensile zone

Neutral zone

Shear forces

Compressive zone

Shear forces

Neutral zone

Zona di trazione

Tens i le zone depend ing on the anchor ing o f the snowto the s ide o f the mounta in

Neut ra l zone wi th shear fo rces. Tens i le and compress ivezones depend ing on a g reate r o r lesse r s lope ang le.

Tensile zone depending on the increase in the height of the snow.

Tens i le zone caused by the fo rmat ion o f anin te rmedia te weaker layer fu r ther down the s lope.

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Off ic ine MaccaferriGroup Profi le

Founded in 1879, Officine Maccaferri was soon to become a referenceworldwide in the design and development of advanced solutions forerosion control and reinforcement structures. Over time, however, thecompany has innovated and evolved so that today it is also a reliablepartner for complex civil and environmental engineering applications.This aptitude for technological innovation is the result ofcontinuous dedication, which, alongside experience and technicalknow-how, has enabled the Maccaferri Group to leverage high levelsof efficiency. Concepts transformed into versatile solutions meetour customers specific requirements, whilst maintaining a sustainableenvironmental balance.

Consultancy and partnershipMaccaferri does not just offer its customers simple collaboration buta real partnership which goes beyond merely supplying products.Maccaferri is a partner that works alongside its customers from thevery start. It is a reliable partner thanks to its extensive portfolioof top quality products. As well as versatile solutions that can beadapted to local situations, it makes its technical know-how availableto create a virtual circle in which each factor (products, experience andinnovative practice) is improved by each activity.Maccaferri tackles every project with the aim of identifying, dealingwith and resolving each customer’s actual needs, and the results ofthis attitude produce benefits which can be appreciated over time.

Maccaferri researches, designs and develops solutions for theconstruction, erosion protection and soil stabil isation sectors in over100 countries across the world.The organizational structure has beendesigned to be global and local at the same time. It is made up ofsubsidiary companies which make Maccaferri’s products and designand offer the company’s solutions throughout the world.This ensures greater flexibil ity, a widespread presence and a betterawareness of continued market development.Maccaferri’s presence throughout the world allows the company todeal with problems which results in new know-how that, in turn, feedsinto further innovation for other solutions offered on the market.As well as the parent company in Italy and subsidiaries in France,Britain, Russia and Spain, the company is also active in all f ivecontinents, with over 60 operating companies. Where there is nointernal sales force, there are distributors in all the continents so thatall markets are monitored indirectly.

Organizational Structure

Bureau Veritas Certified Quality System Companywith SINCERT's and UKAS's accreditation

Officine Maccaferri S.p.A.Via Kennedy, 1040069 Zola Predosa (Bologna) - ItaliaTel. ++39 051 6436000Fax ++39 051 6436201e-mail: comes@maccaferri.com

www.maccaferri.com

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