Method for producing a modular netting and modular netting for use in geotechnical applications

Abstract

Method for producing a modular netting, comprising the following steps: arranging at least two wires of metallic material; for each wire, making a plurality of bends that define a path in alternating directions, each change of direction defining a bending zone; for each wire, folding the wire back on itself so that the two portions of the wire are side by side; thus, first pairs of bending zones, defined by two bending zones of the same wire but belonging to adjacent portions, being brought close together; placing the two wires folded back on themselves side by side so that second pairs of bending zones, defined by a bending zone of one wire and a corresponding bending zone of the other wire, are brought close together; crossing the bending areas of the pairs, thus defining a plurality of crossing areas, and join the free ends of the wire.

Description

[0001] DESCRIPTION

[0002] METHOD FOR PRODUCING A MODULAR NETTING AND MODULAR NETTING FOR USE IN GEOTECHNICAL APPLICATIONS

[0003] Technical field

[0004] The present invention relates to a method for producing a modular netting, in particular with diagonal meshes, and a modular netting. The present invention finds application in geotechnical applications, for example in the field of protection against natural hazards.

[0005] The present invention finds particular, but not exclusive, application as a high-strength rhomboidal mesh for solutions such as rockfall or avalanche barriers, for covering rock faces to prevent rockfalls, for three-dimensional stabilization of land, embankments, levees, tunnels, and road constructions, and in general for any other civil and geotechnical use where it is necessary to install a metal netting that is resistant and durable.

[0006] Background art

[0007] It is known to use different types of metal nettings in the technical field of civil construction, for example as a separating element between two different properties or as a fencing and confining element for animals. However, the nettings designed for these applications do not have sufficient strength and durability, both in terms of impact and corrosion resistance, for use in applications such as rockfall barriers or avalanche barriers, or for covering rock faces to prevent rockfalls.

[0008] A further area of application is road construction. In particular, the nettings with diagonal mesh obtained with the method proposed here are widely used for retention of debris in environments subject to the risk of landslides, rockfalls and similar.

[0009] In other words, the present invention can be used for the construction of protective barriers suited to preventing debris of various kinds from damaging people and / or things.

[0010] These nettings, also called rockfall nettings, play a fundamental role in preventing road accidents and in keeping travel regular on roads, railways,infrastructures in general and in protecting people or things in residential areas.

[0011] In accordance with the prior art, the nettings used for rockfall barriers are substantially of four types:

[0012] - metal rope nettings with studded diagonal mesh;

[0013] - metal wire nettings with intertwined diagonal mesh;

[0014] - linked ring nettings with rings of various diameter;

[0015] - metal rope nettings with omega mesh.

[0016] The known solutions for rockfall nettings provide for upper and lower terminations of the wires at which coupling between the modules occurs. This means that each module has two points of discontinuity. These are weak points of the system, particularly in certain types of applications where these panels are hanging from ropes.

[0017] Disclosure of the invention

[0018] In this context, the technical task underlying the present invention is to propose a method for producing a modular netting and a modular netting, which overcome the aforementioned drawbacks of the prior art.

[0019] In particular, an object of the present invention is to provide a method for producing a modular netting that has fewer weak points than the known nets.

[0020] Another object of the present invention is to provide a method for producing a modular netting and a modular netting, that simplifies storage and management of the component warehouse in general.

[0021] The defined technical task and the specified objects are substantially achieved by a method for producing a modular netting, comprising the following steps:

[0022] arranging at least two wires of metallic material, each wire extending between two free ends thereof;

[0023] for each of said at least two wires, obtaining a plurality of bends that define a path in alternating directions, each change in direction defining a bending zone;for each of said at least two wires, bending the wire on itself so that the two free ends of the wire are close to each other and two portions of the wire are side by side;

[0024] after having obtained a plurality of bends and after having bent the wire on itself, a plurality of first pairs of bending zones, defined by two bending zones of the same wire, but belonging to side-by-side portions, being close to each other;

[0025] placing side by side said at least two wires bent on themselves, so that a plurality of second pairs of bending zones, defined by a bending zone belonging to one wire and a corresponding bending zone belonging to another wire, are close to each other;

[0026] crossing the bending zones of the pairs with each other, thus defining a plurality of crossing zones;

[0027] after having crossed the bending zones with each other, joining the free ends of the wire.

[0028] According to one aspect, the steps of obtaining a plurality of bends and of bending the wire on itself occur in a manner that, following the extension of the wire, each bending zone of the first pairs is followed and / or preceded by at least one bending zone that is not close to a corresponding bending zone of the other portion.

[0029] According to one aspect, after having placed side by side said at least two wires bent on themselves, following the extension of the wire each bending zone of the first pairs is followed and / or preceded by at least one bending zone of the second pair.

[0030] According to one aspect, the step of crossing the bending zones with each other occurs first crossing at least a part of the second pairs and then at least a part of the first pairs.

[0031] According to one aspect, the bending zones of the first pairs are separate from the bending zones of the second pairs.

[0032] According to one aspect, the free ends are joined by means of one or more pressed sleeves.According to one aspect, the wire can be a stand-alone element or part of a bundle of wires or part of a strand or part of a rope.

[0033] According to one aspect, each wire is made of high-strength steel with an ultimate tensile strength between 1370 MPa and 1960 MPa.

[0034] The defined technical task and the specified objects are substantially achieved by a modular netting for use in geotechnical applications, for example in the field of protection against natural hazards, comprising a plurality of modules intertwined with each other,

[0035] each module comprising at least one metal wire bent on itself so as to define two side-by side portions and having free ends joined together, wherein said at least one wire comprises, along its extension, a plurality of bending zones defining a path in alternating directions,

[0036] wherein the bending zones are configured so as to define:

[0037] - first pairs of bending zones, consisting of a bending zone belonging to the first portion and a bending zone belonging to the second portion of the same wire, and

[0038] - second pairs of bending zones, consisting of a bending zone of one module and a corresponding bending zone of an adjacent module, wherein the bending zones of the first and second pairs are crossed with each other so as to define crossing zones that stably connect the modules to each other,

[0039] wherein the netting defines meshes alternately delimited by:

[0040] - two crossing zones obtained by crossing first pairs of bending zones, and

[0041] - two crossing zones obtained by crossing second pairs of bending zones.

[0042] According to one aspect, each wire is made of high-strength steel having an ultimate tensile strength between 1370 MPa and 1960 MPa.

[0043] According to one embodiment, each module comprises at least one rope in turn comprising a plurality of metal wires.

[0044] According to one aspect, the ropes have a diameter between 3 mm and12 mm, preferably between 4 mm and 6 mm.

[0045] Brief description of drawings

[0046] Further features and advantages of the present invention will become more apparent from the indicative and thus non-limiting description of a preferred but non-exclusive embodiment of a method for producing a modular netting and a modular netting, as illustrated in the appended drawings in which:

[0047] - Figure 1 illustrates an intermediate step in creating a netting module of a method for producing a modular netting, according to the present invention;

[0048] - Figures 2a-2e illustrate an example of an embodiment of bending of a wire to obtain an open module of a method for producing a modular netting, according to the present invention;

[0049] - Figures 3-5 illustrate three steps of a method for producing a modular netting, according to the present invention, in which crossing is applied between bending zones of adjacent modules and between bending zones of the same module;

[0050] - Figures 6a and 6b illustrate an enlargement of a first type of crossing zone and a second type of crossing zone, respectively;

[0051] - Figures 7a-7c illustrate different embodiments of the locking means.

[0052] Detailed description of preferred embodiments of the invention The present invention relates to a method for producing a modular netting 1 comprising the following steps.

[0053] In the first place, at least two wires 2 of metallic material are prepared. The wire 2 extends between two free ends.

[0054] As will be clearer below, each wire 2 will define a module of the netting 1. The module will be defined in its final version only after coupling with the adjacent modules.

[0055] According to the present invention, it is specified that the wire 2 is the minimum configuration that can be used to produce the netting 1. The wire can, in fact, be a stand-alone element or part of a bundle of wiresoverlapped and joined to each other or also part of a strand or part of a rope. Regardless of this, the steps of the method which will be described below do not vary.

[0056] According to one aspect, the metal wires are made of high-strength steel. Each wire is made of steel with an ultimate tensile strength greater than 1370 MPa, preferably equal to or greater than 1500 MPa. The ultimate tensile strength may be even higher, for example preferably equal to or greater than 1700 MPa, for example approximately 1750 MPa, or 1860 MPa. Preferably, the ultimate tensile strength may be equal to or greater than 1900 MPa, for example approximately 1960 MPa.

[0057] Preferably, the ultimate tensile strength is between 1370 MPa and 1960 MPa.

[0058] Successful experiments have been carried out with metal wires having a ultimate tensile strength of 1770 MPa, which corresponds to the preferred version.

[0059] It should be noted that the above values refer to the ultimate tensile strength of the wire material.

[0060] These values should be considered illustrative, but not limiting, of the invention, which can be implemented with wires other than those described in detail herein.

[0061] For each wire 2, a plurality of bends is obtained on the wire 2 that define a path in alternating directions, each change in direction defining a bending zone 3.

[0062] In accordance with an embodiment, the plurality of bends defines a path with broken line or polyline. As will be clearer below, this results in a geometry of the basic module of the polygonal type, for example diagonal. In the embodiment illustrated, the plurality of bends defines a path with alternating angles. In other words, the wires are bent in order to have a zig-zag shape, in which each bending zone consists substantially of a vertex.

[0063] As will be clearer below, this results in a geometry of the basic module ofthe diagonal type.

[0064] In accordance with an alternative embodiment, the wires are bent to have a wavy pattern, i.e. the bending zones 3 are rounded.

[0065] As will be clearer below, this results in a geometry of the basic module of the semi-circular type.

[0066] For each wire 2, the method comprises a bending of the wire 2 on itself so that the two free ends of the wire 2 are close to each other and two portions 2a, 2b of the wire 2 are side by side.

[0067] In particular, such bending occurs substantially into a “U” shape.

[0068] It is noted that the free ends of the wire 2, although close to each other, remain free in this step.

[0069] After having obtained the plurality of bends and after having bent the wire 2 on itself, a plurality of first pairs of bending zones 3 is obtained, defined by two bending zones 3 of the same wire 2, but belonging to side-by-side portions 2a, 2b, being close to each other.

[0070] In fact, it should be noted that obtaining the bends that define a path in alternating directions results in several bending zones 3 projecting from one side, whereas others project from the opposite side, relative to an original rectilinear extension of the wire 2.

[0071] Bending the wire 2 on itself means that several bending zones 3 of the first portion 2a are close to bending zones 3 of the second portion 2b.

[0072] In particular, the aforementioned step of obtaining the bends of the wire 2 that define a path in alternating directions and bending of the wire 2 on itself result in the formation of an intermediate version of what will be a module of the netting 1. The wire 2 is still in its open state. In fact, as just said, the free ends of the wire 2 are still free.

[0073] Opportunely, the module is formed on the basis of the quantity and length necessary for the final mesh.

[0074] In particular, bending of the wire 2 on itself occurs relative to an intermediate bending point on the wire 2. The two portions 2a, 2b are the consecutive parts of the wire 2 which are ideally divided by such bendingpoint. It is noted that no specific order in which to perform the step of making the bends on the wire 2 and the step of bending it on itself is envisaged, since the order thereof can be exchanged indiscriminately. In a non-limiting example of an embodiment of the method, shown in Figures 2a-2e, these steps occur in an overlapping manner. In other words, during the step of bending the wire 2 on itself, the bends that define a path in alternating directions are obtained in different sub-steps.

[0075] In particular, these operations are performed on the wire 2 in the order:

[0076] - arranging the wire in a substantially rectilinear position;

[0077] - identifying an intermediate point on the wire 2 such as to divide the wire 2 in an imaginary way into a consecutive first portion 2a and second portion 2b;

[0078] - bending the first portion 2a relative to an intermediate point, so that it is inclined relative to the second portion 2b;

[0079] - obtaining the plurality of bends that define a path in alternating directions in both the portions 2a, 2b, one after the other (preferably, first in the first portion 2a just bent);

[0080] - bending the second portion 2b relative to the intermediate position, so that it is alongside the first portion 2a, on the opposite side relative to the intermediate position.

[0081] Preferably, the first portion 2a is bent substantially by 90° relative to the rectilinear extension of the wire 2 before bending.

[0082] As is evident, in this embodiment, bending of the portions 2a, 2b to define a path in alternating directions occurs during the steps that result overall in a bending of the wire 2 on itself.

[0083] It is nonetheless possible to provide for the use of alternative embodiments which, starting from the stretched wire 2, obtain a wire 2 on which the aforementioned bends are made and that is bent on itself.

[0084] In the preferred embodiment, the two portions 2a, 2b are two halves of the wire 2. In other words, the wire 2 is bent at the midpoint thereof.

[0085] The method then continues with the placing side by side of two wires 2bent on themselves, so that a plurality of second pairs of bending zones 3, defined by a bending zone 3 belonging to one wire 2 and a corresponding bending zone 3 belonging to another wire 2, are close to each other.

[0086] It is specified that the bending zones 3 of the first pair (which are close together between portions 2a, 2b of the same wire 2) are separate from the bending zones 3 of the second pair (which are close together between different and side-by-side wires 2).

[0087] Preferably, the steps of obtaining a plurality of bends and of bending the wire 2 on itself occur in a manner that, following the extension of the wire 2, each bending zone 3 of the first pairs is followed and / or preceded by at least one bending zone 3 that is not close to a corresponding bending zone 3 of the other portion 2a, 2b.

[0088] Preferably, after having placed side by side the two wires 2 bent on themselves, following the extension of the wire 2 each bending zone 3 of the first pairs is followed and / or preceded by at least one bending zone 3 of the second pair.

[0089] For example, in the case of a zig-zag pattern as illustrated in the figures, an alternating sequence of one bending zone 3 belonging to a first pair and one bending zone 3 belonging to a second pair is obtained. In this case, with the wire 2 being bent on itself, it can be observed that, alternately, a bending zone 3 of the first portion 2a is close to a bending zone 3 of the second portion 2b, whereas the next one is not. When the two bent wires 2 are placed side by side, it can be observed that the bending zones 3 are alternating: one belongs to the second pair (i.e. it is close to the bending zone 3 of the other wire 2), the other belongs to the first pair (therefore, it is close to the bending zone 3 of the other portion of the same wire 2).

[0090] The method provides, at this point, for crossing the bending zones 3 of the pairs with each other, thus defining a plurality of crossing zones 4.

[0091] In this manner, two adjacent wires 2 (two modules) are coupled with each other.In light of the above, it is possible to distinguish the crossing zones 4 between a first type, obtained by crossing bending zones 3 of a first pair, and a second type, obtained by crossing bending zones 3 of a second pair.

[0092] In other words, the first type of crossing zone 4 is obtained by crossing a bending zone 3 of the first portion 2a of a wire 2 and a bending zone 3 of the second portion 2b of the same wire 2.

[0093] An example of the first type of crossing zone 4 is illustrated in an enlargement in Figure 6a.

[0094] In other words, the second type of crossing zone 4 is obtained by crossing a bending zone 3 of a wire 2 and a corresponding bending zone 3 of the other wire 2.

[0095] An example of the second type of crossing zone 4 is illustrated in an enlargement in Figure 6b.

[0096] Preferably, first the bending zones 3 of the second pairs (therefore, two different wires 2) are crossed with each other. After this, the bending zones 3 of the first pairs (therefore, two portions of the same wire) are crossed with each other.

[0097] In particular, this occurs for one pair at a time, preferably following a direction that goes from the bending point towards the free ends, which are on the opposite side.

[0098] It is specified that the netting 1 is defined by meshes delimited between two crossing zones 4 of the first type and meshes delimited between two crossing zones 4 of the second type.

[0099] After obtaining the crossings, the method provides for joining the free ends of the wire 2.

[0100] With this step, a mesh module in its closed state is defined, formed of the wire 2 bent on itself, intertwined with the adjacent ones and with the joined free ends.

[0101] Locking of the free ends occurs by means of one or more locking elements 5, preferably by means of a pressed sleeve. This closure represents aconsiderable simplification from a construction viewpoint and guarantees a very good tightness of the joint. The pressed sleeve constitutes the locking means 5.

[0102] Alternatively, the locking means 5 consists of studs. Alternatively, the locking means 5 consists of binding knots.

[0103] In other words, the module can be closed with one, two or more sleeves or similar cable closing systems, pressed or mechanical, welded, etc.

[0104] According to one embodiment, the steps of the method described above occur on strands or on ropes.

[0105] Strand means an element of the rope formed of a set of wires helically wound in the same direction in one or more layers around a centre.

[0106] Rope means a stranded wire rope (set of various strands helically wound in one or more layers around a core) or a single-layer rope (stranded wire rope formed of a single layer of strands helically wound around a core). According to the preferred embodiment, the steps of the method described above are performed on ropes with spiral constructions.

[0107] The ropes may have a diameter between 3 mm and 12 mm, more preferably between 4 mm and 6 mm. Preferably, the metal wires of each rope or strand have the same nominal diameter.

[0108] Preferably, the ropes may have a 1x4, 1x7, 1x19, or 1x37 construction. For clarity, the formulation AxB indicates the number of strands with A and the number of wires with B.

[0109] Preferably, the ropes may have a diameter between 3 mm and 12 mm with a 1x4, 1x7, 1x19, or 1x37 construction. More preferably, the ropes may have a diameter between 4 mm and 6 mm with a 1x4, 1x7, 1x19, or 1x37 construction.

[0110] These values are to be considered exemplary, not limiting to the invention, which can be made with wires different from those described here in detail. As specified above, the netting of the present invention defines so-called rhomboidal or diagonal meshes.

[0111] For example, it is possible to create rhomboidal meshes with diagonaldimensions ranging from approximately 80 x 80 mm to approximately 250 x 250 mm with an acute angle of the rhomboidal mesh that can be between 70° and 90°, preferably 90°.

[0112] The values expressed for the meshes are to be considered within a tolerance of ±10%.

[0113] Successful experiments have been carried out with 4 mm diameter spiral rope with a 1x7 construction, with steel having a nominal strength of 1770 Mpa, tested with results >140 kN / m.

[0114] Preferably, the wires 2 of the netting 1 may have a corrosion protection coating. This coating may be applied either individually to each wire 2 or, alternatively, to the already formed strand. The protective coating may be of a generally known type, for example metallic, such as a zinc and aluminum alloy commercially known as Galfan, or plastic, for example polyethylene, polyvinyl chloride, or polyamide, ora combination thereof. The present invention also relates to a modular netting 1, defined in structural terms by the characteristics described below. The netting 1 is preferably obtained by the method described above.

[0115] The netting 1 comprises a plurality of modules intertwined with each other. Each module is formed by at least one metal wire 2 bent on itself so as to define two side-by-side portions 2a, 2b. The wire 2 extends between two free ends.

[0116] According to one aspect, the metal wires are made of high-strength steel. Each wire is made of steel with an ultimate tensile strength greater than 1370 MPa, preferably equal to or greater than 1500 MPa. The ultimate tensile strength may be even higher, for example preferably equal to or greater than 1700 MPa, for example approximately 1750 MPa, or 1860 MPa. Preferably, the ultimate tensile strength may be equal to or greater than 1900 MPa, for example approximately 1960 MPa.

[0117] Preferably, the ultimate tensile strength is between 1370 MPa and 1960 MPa.

[0118] Successful experiments have been carried out with metal wires having aultimate tensile strength of 1770 MPa, which corresponds to the preferred version.

[0119] It should be noted that the above values refer to the ultimate tensile strength of the wire material.

[0120] These values should be considered illustrative, but not limiting, of the invention, which can be implemented with wires other than those described in detail herein.

[0121] The two free ends of the wire 2 are brought close to each other as a result of bending the wire 2 on itself and are joined together by locking means 5, thereby defining the module in a closed configuration.

[0122] Along its extension, the wire 2 comprises a plurality of bending zones 3 defining a path in alternating directions. The plurality of bending zones 3 is such that, with respect to an ideal rectilinear extension of the wire 2, some bending zones 3 project from one side while others project from the opposite side.

[0123] According to one embodiment, the plurality of bending zones 3 defines a polyline path. In particular, the wire 2 may have a substantially zig-zag configuration, in which each bending zone 3 substantially consists of a vertex.

[0124] According to an alternative embodiment, the bending zones 3 are rounded and define a wavy pattern of the wire 2.

[0125] In particular, bending of the wire 2 on itself occurs at an intermediate bending point. The two portions 2a, 2b are consecutive parts of the wire 2 ideally divided by such bending point.

[0126] In the preferred embodiment, the two portions 2a, 2b are two halves of the wire 2. In other words, the wire 2 is bent at its midpoint.

[0127] The configuration of the bent wire 2 determines the presence of first and second pairs of bending zones 3. The first pairs of bending zones 3 consist of a bending zone 3 belonging to the first portion 2a and a bending zone 3 belonging to the second portion 2b of the same wire 2, which are close to each other. The second pairs of bending zones 3 consist of abending zone 3 of a wire 2 of one module and a corresponding bending zone 3 of an adjacent module.

[0128] It is specified that the bending zones 3 of the first pairs are distinct from the bending zones 3 of the second pairs.

[0129] Preferably, following the extension of the wire 2, each bending zone 3 belonging to a first pair is followed and / or preceded by at least one bending zone 3 belonging to a second pair.

[0130] In the embodiment with a zig-zag pattern, an alternating sequence of bending zones 3 belonging to first pairs and bending zones 3 belonging to second pairs is obtained.

[0131] The bending zones 3 of the first and second pairs are crossed with each other so as to define a plurality of crossing zones 4. It is possible to distinguish a first type of crossing zone 4, obtained by crossing bending zones 3 belonging to a first pair, and a second type of crossing zone 4, obtained by crossing bending zones 3 belonging to a second pair.

[0132] In other words, the first type of crossing zone 4 is obtained by crossing a bending zone 3 of the first portion 2a of a wire 2 with a bending zone 3 of the second portion 2b of the same wire 2.

[0133] In other words, the second type of crossing zone 4 is obtained by crossing a bending zone 3 of a wire 2 with a corresponding bending zone 3 of an adjacent module.

[0134] Preferably, the crossing zones 4 are distributed along the netting in such a way that crossing zones of the first type and crossing zones of the second type alternate.

[0135] The netting 1 defines a plurality of meshes alternately delimited by two crossing zones 4 of the first type and by two crossing zones 4 of the second type.

[0136] According to one embodiment, the meshes are of the rhomboidal or diagonal type.

[0137] For example, rhomboidal meshes may be provided with diagonal dimensions between approximately 80 x 80 mm and approximately 250 x250 mm, with an acute angle between 70° and 90°, preferably approximately 90°, with a tolerance of ±10%.

[0138] According to an alternative embodiment, when the bending zones 3 are rounded, the meshes may have a substantially semi-circular geometry. According to the present invention, it is specified that the wire 2 represents the minimum configuration that can be used for a module of the netting 1. The wire may in fact be a stand-alone element, or part of a bundle of overlapped and joined wires, or part of a strand, or part of a rope. Regardless of this, the structural characteristics of the netting 1 described above remain unchanged.

[0139] Preferably, the locking means 5 comprise at least one pressed sleeve. This closure represents a considerable simplification from a construction viewpoint and ensures very good joint tightness.

[0140] Alternatively, the locking means 5 consist of studs. Alternatively, the locking means 5 consist of binding knots.

[0141] In other words, the module may be closed with one, two or more sleeves or similar rope-closing systems, pressed or mechanical, welded, etc.

[0142] According to one embodiment, the netting modules 1 comprise strands or ropes.

[0143] By strand is meant an element of the rope formed by a set of wires helically wound in the same direction in one or more layers around a centre.

[0144] By rope is meant a stranded wire rope (a set of several strands helically wound in one or more layers around a core) or a single-layer rope (a stranded wire rope composed of a single layer of strands helically wound around a core).

[0145] In the preferred embodiment, the netting modules 1 comprise ropes with spiral constructions.

[0146] The ropes may have a diameter between 3 mm and 12 mm, more preferably between 4 mm and 6 mm.

[0147] Preferably, the ropes may have a 1x4, 1x7, 1x19 or 1x37 construction. Forclarity, the formulation AxB indicates the number of strands with A and the number of wires with B

[0148] Preferably, the ropes may have a diameter between 3 mm and 12 mm with a 1x4, 1x7, 1x19 or 1x37 construction. More preferably, the ropes may have a diameter between 4 mm and 6 mm with a 1x4, 1x7, 1x19 or 1x37 construction.

[0149] These values are to be considered exemplary and not limiting of the invention, which may be made with wires different from those described in detail herein.

[0150] As specified above, the netting of the present invention defines so-called rhomboidal or diagonal meshes.

[0151] For example, rhomboidal meshes may be provided with diagonal dimensions ranging from approximately 80 x 80 mm to approximately 250 x 250 mm, with an acute angle between 70° and 90°, preferably 90°. The values expressed for the meshes are to be considered within a ±10% range.

[0152] Successful experiments have been carried out with a 4 mm diameter spiral rope with a 1x7 construction, with wires having a nominal ultimate tensile strength of 1770 MPa, tested with results > 140 kN / m. Expectations for other types are proportional to the mesh size and to the breaking strength of the rope.

[0153] The present invention also relates to a rockfall or avalanche protection barrier system. As known, this is an engineering structure designed to intercept and stop falling rocks, protecting infrastructures and people.

[0154] The system comprises the netting 1.

[0155] The characteristics of a method for producing a modular netting and a modular netting for use in geotechnical applications, according to the present invention, are clear from the description, as are the advantages. In particular, each netting module is defined by a single wire (or by a joined bundle of wires or by a strand or by a rope) bent on itself and closed at the free ends only after being coupled to another netting module.Furthermore, in the bending zones the two adjacent netting modules are reciprocally fixed by means of a single reciprocal winding.

[0156] This allows a modular netting to be obtained on which each module has only one point of discontinuity (join between the two free ends), rather than the two of the prior art.

[0157] Furthermore, the end closure performed with a pressed sleeve rather than the sleeved holes of the prior art represents a considerable simplification from a construction viewpoint and guarantees a very good seal of the join.

Claims

CLAIMS1. Method for producing a modular netting (1), comprising the following steps:arranging at least two wires (2) of metallic material, each wire (2) extending between two free ends thereof;for each of said at least two wires (2), obtaining a plurality of bends that define a path in alternating directions, each change in direction defining a bending zone (3);for each of said at least two wires (2), bending the wire (2) on itself so that the two free ends of the wire (2) are close to each other and two portions (2a, 2b) of the wire (2) are side by side;after having obtained a plurality of bends and after having bent the wire (2) on itself, a plurality of first pairs of bending zones (3), defined by two bending zones (3) of the same wire (2), but belonging to side-by-side portions (2a, 2b), being close to each other;placing side by side said at least two wires (2) bent on themselves, so that a plurality of second pairs of bending zones (3), defined by a bending zone (3) belonging to one wire (2) and a corresponding bending zone (3) belonging to another wire (2), are close to each other;crossing the bending zones (3) of the pairs with each other, thus defining a plurality of crossing zones (4);after having crossed the bending zones (3) with each other, joining the free ends of the wire (2).

2. The method according to claim 1, wherein the steps of obtaining a plurality of bends and of bending the wire (2) on itself occur in a manner that, following the extension of the wire (2), each bending zone (3) of the first pairs is followed and / or preceded by at least one bending zone (3) that is not close to a corresponding bending zone (3) of the other portion (2a, 2b).

3. The method according to claim 1 or 2, wherein after having placed side by side said at least two wires (2) bent on themselves, following theextension of the wire (2) each bending zone (3) of the first pairs is followed and / or preceded by at least one bending zone (3) of the second pair.

4. The method according to any one of the preceding claims, wherein the step of crossing the bending zones (3) with each other occurs first crossing at least a part of the second pairs and then at least a part of the first pairs.

5. The method according to any one of the preceding claims, wherein the bending zones (3) of the first pairs are separate from the bending zones (3) of the second pairs.

6. The method according to any one of the preceding claims, wherein the free ends are joined by means of one or more pressed sleeves.

7. The method according to any one of the preceding claims, wherein the wire (2) can be a stand-alone element or part of a bundle of wires or part of a strand or part of a rope.

8. The method according to any one of the preceding claims, wherein each wire (2) is made of high-strength steel with an ultimate tensile strength between 1370 MPa and 1960 MPa.

9. Netting (1) obtained by means of the method according to any one of the preceding claims.

10. Modular netting (1) for use in geotechnical applications, for example in the field of protection against natural hazards, comprising a plurality of modules intertwined with each other,each module comprising at least one metal wire (2) bent on itself so as to define two side-by side portions (2a, 2b) and having free ends joined together,wherein said at least one wire (2) comprises, along its extension, a plurality of bending zones (3) defining a path in alternating directions, wherein the bending zones (3) are configured so as to define:- first pairs of bending zones, consisting of a bending zone belonging to the first portion (2a) and a bending zone belonging to the second portion (2b) of the same wire, and- second pairs of bending zones, consisting of a bending zone of one module and a corresponding bending zone of an adjacent module, wherein the bending zones of the first and second pairs are crossed with each other so as to define crossing zones (4) that stably connect the modules to each other,wherein the netting (1) defines meshes alternately delimited by:- two crossing zones obtained by crossing first pairs of bending zones, and- two crossing zones obtained by crossing second pairs of bending zones.

11. Netting (1) according to claim 10, wherein each wire (2) is made of high-strength steel having an ultimate tensile strength between 1370 MPa and 1960 MPa.

12. Netting (1) according to claim 10 or 11, wherein each module comprises at least one rope in turn comprising a plurality of metal wires (2).

13. Netting (1) according to claim 12, wherein the ropes have a diameter between 3 mm and 12 mm, preferably between 4 mm and 6 mm.

14. Rockfall or avalanche protection barrier system comprising the netting (1 ) according to any one of claims 10 to 13.

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