EP2603649A1

EP2603649A1 - Use of a textile material as a safety barrier to protect users of any type of construction on the occurrence of damage to structural and non-structural elements

Info

Publication number: EP2603649A1
Application number: EP11767059.6A
Authority: EP
Inventors: Roberto Fenzi
Original assignee: LENZI EGISTO SpA
Current assignee: FF S.R.L.
Priority date: 2010-08-10
Filing date: 2011-08-10
Publication date: 2013-06-19
Also published as: WO2012020302A9; US20130139469A1; WO2012020302A1; IT1401321B1; ITMI20101534A1

Abstract

The present invention relates to the use of a textile material as a safety barrier for reducing harm to people in the event of failure of structural and non" structural elements of any type of construction. In particular, the present invention relates to a method for containing a non - structural clay building element which may be deformed following breakage of the same due to a collapse. Finally, the present invention relates to a method for imparting safety to people who are inside an environment confined by the presence of at least one non- structural element. According to the invention, a layer of fabric comprising a weft and a warp is applied on said structural or non - structural element.

Description

150 844/nl5

Title: "Use of a textile material as a safety barrier to protect users of any type of construction on the occurrence of damage to structural and non- structural elements" .

DESCRIPTION

The present invention relates to the use of a textile material as a safety barrier for reducing harm to people in the event of damage to structural and nonstructural elements of any type of construction. In particular, the present invention relates to a method for containing a non- structural clay building element following the breakage thereof. Finally, the present invention relates to a method for imparting safety to people who are inside an environment confined by the presence of at least one non- structural element.

The civil engineering sector is the branch of engineering dedicated to the design of constructions and infrastructures intended for civil use and, therefore, all related fields: environmental, building, geotechnical , infrastructural , hydraulic and structural engineering, and urban and land use planning.

The above-mentioned constructions consist of a "load- bearing structure" (structural part) and all accessory "non- load-bearing" parts (non- structural parts) .

The resistant structure (or load-bearing structure or more simply structure) of a construction (e.g. a residential dwelling, bridges and viaducts, industrial buildings) is the part of the construction itself which is expressly intended to absorb the loads and external forces the construction is subject to during its working lifetime.

The expression "non-structural part" means all those elements which, though they belong to a construction, do not have the task of absorbing working loads, e.g. flooring, screeds, insulation, false-ceilings, masonry panels, masonry walls, partitions (walls dividing interior spaces) , curtain walls (walls that "close off" the building, separating the interior space from the outside, of varying thickness) , decoration, parapets, plaster and installations.

During the lifetime of a construction, both the "structural" and "non-structural" parts can undergo damage, which may be ascribable both to the normal use thereof and resulting wear and to exceptional events such as, for example, bursts, explosions, impacts or earthquakes .

Moreover, during the lifetime of a construction, it may happen that the latter needs to undergo modifications of a structural and non-structural nature or is called upon to withstand greater loads than those for which it was originally designed, and that failures manifest themselves over time as a result, for example, of an incorrect initial design.

Following any of the above-described events, the load- bearing structure of the construction, consisting of structural elements, will have to be restored and/or reinforced in order to prevent the collapse of the construction itself.

A known method for strengthening and structurally reinforcing a construction is to apply fibre-reinforced materials with a continuous fibre polymer matrix (also known as fibre-reinforced composites or FRP) on the structural elements.

The expression "structural strengthening" is used to indicate all building interventions aimed at restoring or preventively increasing the strength of existing construction work.

FRP fibre-reinforced composites (in short FRP composites) are composite materials consisting of reinforcement fibres embedded in a polymer matrix. These composites are available in different geometries, such as pultruded sheets, used for example to reinforce elements having regular surfaces. In FRP fibre- reinforced composites the fibres play a role as load- bearing elements both in terms of strength and stiffness, whereas the matrix, in addition to protecting the fibres, acts as an element for transferring stresses among the fibres and, if necessary, between the latter and the structural element the composite has been applied to. The majority of FRP composites consist of fibres which possess high strength and stiffness, whereas the strain at break thereof is lower than that of the matrix.

It is important to distinguish the matrices, used in the impregnation of the fibres, from the adhesives, which are instead used for the application of pultruded laminates to the surfaces to be reinforced.

One of the main functions of a matrix in a composite is to "hold together" the fibres (reinforcement) , thereby assuring cohesion between the fibres of a same layer and between adjacent layers.

Adhesives, on the other hand, perform the function of connecting the element to be reinforced to the composite and transferring forces between them.

The matrices most widely used to manufacture FRP fibre- reinforced composites are polymers based on thermosetting resins. The most widespread thermosetting resins are epoxies . Polyester or vinyl ester resins are also employed.

The fibres most widely used for the production of composites for structural reinforcement are glass, carbon and aramid fibres.

The use of FRP fibre-reinforced composites for the structural reinforcement of reinforced concrete (RC for short) , prestressed reinforced concrete (PRC for short) and masonry structures is well known.

The load-bearing structure of RC and PRC buildings consists of columns, beams, walls, stairways and floors and is thus the part of a construction that carries the weight of all the elements making up the building, supporting and supported (e.g. walls, floors, furniture, etc.), and transfers it onto the foundations .

A mechanical system composed of beams connected to each other and to the ground (through columns) is called a "frame" . This system represents one of the most important structural arrangements used in construction. Walls are structural elements for supporting other elements (in a manner analogous to columns) .

Floors are constructive elements which horizontally divide the spaces of a building; they are flat two- dimensional structures loaded perpendicular to their plane, with a prevalent unidirectional strength behaviour (bending strength under vertical load) .

In buildings with a masonry load-bearing structure, the walls serve to transfer the weight of the overlying structures to the ground. Based on the entity of the load it must support, the wall must be more or less thick.

The masonry can be made, for example, with solid or perforated clay blocks, concrete blocks or natural stone blocks. Said elements are generally assembled by means of mortar, which achieves the adhesion.

FRP composites for external structural reinforcement or strengthening of structures can be classified into two categories .

The first relates to pre-formed systems which are prepared in the factory by pultrusion or lamination. The pre-formed composites can be used both for external reinforcement, glued to the structural element to be reinforced, or as internal reinforcement elements (bars for reinforced concrete structures) totally or partially replacing traditional steel reinforcements or surface reinforcing bars (e.g. bars installed in proximity to the surface) .

The second relates to systems impregnated on site, which consist of sheets of fibres that are impregnated with a resin. However, the systems impregnated on site pose a drawback given by the fact that it is not possible to estimate a priori, with sufficient accuracy, the final thickness of the laminate, and it is thus advisable to use pre-formed systems.

Therefore, the use of systems impregnated on site is strongly limited by the above-mentioned applicative limits .

Strengthening by means of FRP is achieved by "gluing" the composite material to the structural element that needs to be reinforced. The strengthening operation consists in compensating for the inadequate strength of a structural element by means of the composite material, which, based on its physical -mechanical characteristics and the method of application, is capable of developing a certain degree of strength. The gluing, achieved using adhesives, must be carried out in such a way that forces can be correctly transferred between the element to be reinforced and the composite.

Correct adhesion of the composite to the substrate is of fundamental importance to ensure that the reinforcement is efficacious.

Experimental tests have shown that one of the collapse modes most frequently observed in reinforced elements such as RC beams or masonry panels, with sheets or layers of FRP composites, consists in a premature failure at the adhesive interface due to a loss of adherence, usually indicated with the term "debonding" . Debonding can manifest itself within the adhesive, between the concrete and adhesive, in the concrete or within the reinforcement composite. Therefore, debonding represents a major limit to the use of these composite materials.

Experimental results have demonstrated that debonding occurs within the weaker adherent, generally represented by the material making up the element to be reinforced, with consequent detachment of a more or less thick layer of RC or masonry in contact with the resin which joins the sheets on one side and the existing substrate on the other. Once debonding occurs, the reinforcement will cease taking up any load because of the detachment .

Therefore, debonding represents a major limit to the use of these composite materials.

Another limit posed by composite materials is given by durability. The term durability means the capacity of the composite material to maintain the mechanical characteristics of interest constant over time.

The main problems which involve durability are environmental actions and load transfer modes. Environmental actions have an impact both on the resins and fibres of the various FRP composites, which will degrade, thus exhibiting impaired mechanical properties after exposure to certain environmental factors, such as temperature, humidity, UV rays, chemical agents, etc. The mechanical properties of some FRP composites may also degrade as a result of fatigue, which is a mechanical phenomenon whereby a material subjected to variable loads over time (in a regular manner or under random "cyclic loading") is damaged until breaking, even though the maximum intensity of the loads in question is significantly lower than the ultimate load of the material itself under static conditions.

In the case of the construction of a non-structural element such as a wall (or a masonry panel) , the latter is in practice constructed by assembling bricks with mortar; these are arranged starting from a first surface or lower floor until arriving at a second surface or upper floor. However, in proximity to said second surface or upper floor the wall is not anchored or fixed to the upper floor. The same applies for the outer parts of the wall (shoulders) , which are not in practice anchored or fixed to other existing walls or surrounding columns . Therefore, should a catastrophic event occur, said walls risk collapsing with extreme ease, causing damage to property and injury to people who are in the vicinity of said walls.

It thus becomes necessary to have a method for securely anchoring a construction comprising one or more nonstructural elements, such as masonry walls, partitions or panels to the surrounding structures and making it safer without modifying the normal installation thereof, without adding weight to the non- structural element and without imparting stiffness and strength to the construction.

It may also happen that non- structural elements such as curtain walls and partitions undergo breakage despite remaining connected to the load-bearing structures.

In particular, it becomes necessary to have a material which, once applied in contact with a non-structural clay building element, such as, for example, a curtain wall or a partition, is capable of containing the clay parts that could form following the collapse of the non-structural element itself in the event of breakage. By virtue of their "continuous" nature, FRP fibre- reinforced composite materials prevent the elements to be reinforced they are applied to from breathing.

This lack of breathability represents a major limit to the application of FRP composites, especially in residential buildings. Therefore, it is inadvisable to apply a composite material on a masonry panel having a large surface area.

It is thus necessary to have a material and a method for applying the same which is capable of overcoming the limits and drawbacks of the composites present on the market .

Moreover, it becomes necessary to have a material which, once applied in contact with a non- structural element, is capable of imparting greater safety to the environment where said non-structural element is present so as to assure greater safety for the people who are inside said environment.

For example, in the event of pieces breaking away from the bottom of a floor or other ceiling failures, it would be useful to be able to contain and hold back the debris, which would otherwise fall into the room below and could cause physical harm to the occupants.

A subject matter of the present invention relates to a method for containing a non- structural element having the characteristics as set forth in the appended independent claim.

Another subject matter of the present invention relates to a method for imparting safety to people in a room having the characteristics as set forth in the appended independent claim.

Another subject matter of the present invention relates to the use of a textile material as a safety barrier having the characteristics as set forth in the appended independent claim.

Other preferred embodiments of the present invention will be illustrated below in the present description without limiting the scope of the invention in any way. Table 1 shows the data related to the tests for determining the bending tensile strength.

Figure 1 shows a graph related to the determination of bending tensile strength performed on a hollow flat block without any reinforcement or textile material

(block S) according to the present invention.

Figure 2 shows a graph related to the determination of bending tensile strength performed on a hollow flat block having a layer of textile material (block lB-1) according to the present invention on one outside face

(lower face) .

Figure 3 shows a graph related to the determination of bending tensile strength performed on a hollow flat block having a layer of textile material (block 2B) according to the present invention on two outside faces . Figure 4 shows a photograph related to the determination of bending tensile strength performed on a hollow flat block (see graph in figure 1) .

Figure 5 shows a photograph related to the determination of bending tensile strength performed on a hollow flat block (see graph in figure 2) .

Figure 6 shows a photograph related to the determination of bending tensile strength performed on a hollow flat block having a layer of fabric according to the present invention on the two outside faces (see graph in figure 3) .

After lengthy research and experimentation, the Applicant selected a category of textile materials capable of providing a suitable answer to the above- mentioned drawbacks.

In the context of the present invention, "textile material" means a fabric having a weft and a warp, as described hereunder.

In the context of the present invention, "fabric" or "textile material" is not meant to include a composite material, such as, for example, an FRP composite.

The textile material or fabric of the present invention is characterised in that it has an "elastic" strength that favours a "ductile" break of a non- structural element, in contrast with FRP composites, which favour a "brittle" break. A brittle break is what occurs with a sudden failure, in an unexpected manner, without leaving the occupants any possibility of finding shelter. The material of our invention, in contrast, is based on an "elastic" strength that favours a "ductile", more progressive break that allows time for anyone who is inside the construction at the time the breakage occurs to react and escape if necessary. This is the revolutionary and innovative concept of this invention .

The textile materials or fabrics of the present invention have characteristics of elasticity that may vary from 5 to 40% of elongation according to standard UNI EN ISO 13934-1:2000. Preferably, the elasticity may vary within a range comprised from 8 to 35% of elongation; even more preferably within a range comprised from 10 to 30% of elongation.

In a preferred embodiment, the fabrics of the present invention have characteristics of elasticity that may vary from 12 to 25% of elongation according to standard UNI EN ISO 13934-1:2000.

In another preferred embodiment, the fabrics of the present invention have characteristics of elasticity that may vary from 15 to 20% of elongation according to standard UNI EN ISO 13934-1:2000. The textile material is a fabric which comprises at least a weft and at least a warp. The fabric is obtained by weaving weft yarns and warp yarns.

Preferably, the weft comprises or, alternatively, consists of at least one high- strength fibre yarn. In a preferred embodiment, said fibre is selected from the group comprising polyester fibres, polyethylene fibres, aramid, polypropylene and polyolefin fibres and the like. In another preferred embodiment, said fibre is selected from the group consisting of polyester fibres, polyethylene fibres, aramid, polypropylene and polyolefin fibres and the like.

Preferably, the warp comprises or, alternatively, consists of at least one high-strength fibre yarn. In a preferred embodiment, said fibre is selected from the group comprising polyester fibres, polyethylene fibres, aramid, polypropylene and polyolefin fibres and the like. In another preferred embodiment, said fibre is selected from the group consisting of polyester fibres, polyethylene fibres, aramid, polypropylene and polyolefin fibres and the like.

In a preferred embodiment, said weft and/or said warp can further comprise at least one metal thread selected from the group comprising steel and copper threads and the like having a diameter comprised from 0.05 mm to 1 mm. Preferably, the diameter is comprised from 0.10 to 0.80 mm.

In another preferred embodiment, said weft and/or said warp can further comprise at least one metal thread selected from the group comprising steel and copper threads and the like having a diameter comprised from 0.15 mm to 0.60 mm. Preferably, the diameter is comprised from 0.20 to 0.50 mm.

In a preferred embodiment, the weft and/or warp comprise a metal thread of steel having a diameter comprised from 0.10 mm to 0.50 mm; preferably 0.20 mm. In a preferred embodiment, the weft and/or warp comprise a metal thread of copper having a diameter comprised from 0.10 mm to 0.50 mm; preferably 0.20 mm. The high-strength fibre yarns can be used both in a single ply of only one of the high-strength fibres selected from the group comprising polyester fibres, polyethylene fibres, aramid, polypropylene and polyolefin fibres and the like, such as steel, copper and the like, and in a yarn composed of a number of yarn elements of the above fibres (twisted yarn) , possibly reinforced with filaments of a metallic nature. The count of singly ply yarns or those resulting from the twisting of a number of elements have a final count greater than 500 deniers . There exists no upper limit, since yarns that are extremely thick, but have a density proportioned to the overall weight of the fabric, could be advantageously used without modifying the final result. It is in fact well known in the art that the tensile strength of a fabric depends on the total number of centinewtons/dtx for a flat section of fabric, generally stated over 5 cm.

In a preferred embodiment, the textile material of the present invention can be a simple weft and warp fabric, with plain weave, simple twill and other simple textile structures .

In a preferred embodiment, the weft can be made with one or more yarns of high- strength fibres of the same or different types, possibly twisted together, as stated previously for the warp.

This type of orthogonal fabric is produced by means of a manufacturing process known to persons skilled in the art using textile machines of the loom type commonly present in the sector.

The textile materials of the present invention have a weight comprised from 200 g/m² to 3000 g/m² when they are produced with a weft and warp of high-strength fibres. For example, a fabric made with 4 warp threads per centimetre, with a resulting count of 6600 den, has a weight of 640 g/m², and 4.5 weft threads per centimetre, with a resulting count of 6600 den.

The embodiments that envisage the use of one or more metal threads in the weft and/or warp have a weight comprised from 250 g/m² to 3500 g/m². For example, a fabric called "948 PL HT IRON STRONG" produced with 6 warp threads per centimetre of twisted yarn composed of HT polyester and a metallic filament of steel with a diameter of 0.20 mm, and a weft of the same thread with 4.5 weft insertions per centimetre, has a weight of 950 g/m². Woven with a plain weave structure, the fabric thus composed, evaluated according to standard UNI EN ISO 113934-1:2000, has an average maximum warp strength of 5864 N over 50 mm of fabric, with an average elongation of 26% and a strength per linear metre of 117,30 KN/mt lin. In the weft it has an average maximum strength of 5494 N over 50 mm, an elongation of 24% and a strength per linear metre of 110 KN/Ml.

According to another embodiment of a fabric, called "948 KE IRON STRONG", produced with 4 warp threads per centimetre of twisted yarn composed of two 3300 den aramid yarns and a metallic filament of steel with a diameter of 0.20 mm twisted together, and a weft with 4.5 insertions per centimetre of the same thread, it has a weight of 950 g/m². Woven with a plain weave structure, the fabric thus composed, evaluated according to standard UNI EN ISO 113934-1:2000, has an average maximum warp strength of 7950 N over 50 mm of fabric, with an average elongation of 11,8% and a strength per linear metre of 159 KN/mt lin.

In the weft it has an average maximum strength of 6850 N over 50 mm, an elongation of 10.5% and a strength per linear metre of 137 KN/Ml .

The textile material in fabric form of the present invention has valid application in constructions and residential buildings.

A mechanical system composed of beams connected to each other and connected to the ground (through columns) is called a "frame" . This system represents one of the most important structural arrangements used in constructions and residential buildings.

Walls are constructive elements that vertically divide the spaces of a building, whereas floors are constructive elements that horizontally divide the spaces of a building.

The walls can be structural elements for supporting other elements (in a manner analogous to columns) or, alternatively, they can be non-structural elements. Examples of non-structural elements are partitions, walls or panels of masonry made with perforated bricks and curtain walls. Floors are flat two-dimensional structures loaded perpendicular to their plane, with a prevalent unidirectional strength behaviour (bending strength under vertical load) . The floors are anchored to the beams and/or to the walls. The load-bearing structure of the floor can be made of wood, reinforced concrete or steel with the presence of other materials, such as brick elements.

Stairways are constructive elements for vertically connecting two different heights.

In buildings with a masonry load-bearing structure, the walls (structural elements) serve to transfer the weight of the overlying structures to the ground. Based on the entity of the load it must support, the wall must be more or less thick. The weight, from the top of the wall, is distributed throughout the thickness thereof, exerting a homogeneous pressure on the section of the structure.

The material of the present invention is applied on the masonry walls or panels, be they either structural elements or non-structural elements, on floors and on stairways .

For example, in the case of the construction of a masonry panel (or masonry wall) , the latter is in practice constructed by assembling bricks with mortar; these are arranged starting from a first surface or lower floor until arriving at a second surface or upper floor .

In a preferred embodiment, once the masonry wall or panel has been built, the textile material can be anchored thereto by means of a glue or a substance with adhesive properties or by means of mechanical fixing means, such as, for example, nails, screws or other fastening means .

Preferably, the textile material can be placed over the entire surface of the panel or, alternatively, only on a given portion thereof.

Advantageously, once placed over the surface of the masonry panel or wall, the textile material can also be anchored to said first surface or lower floor and/or to said second surface or upper floor where the masonry wall or panel have been built.

In a preferred embodiment, the textile material is anchored onto the entire lower surface or floor, the entire surface of the masonry panel or wall and the entire upper surface or floor. In practical terms, in an environment confined and delimited by a first and a second surface situated at a certain distance from each other and connected to each other by a masonry wall or panel, said surfaces and said masonry panel or wall is completely clad by applying a textile material of the present invention on the outside surface thereof.

Alternatively, the textile material is anchored onto a part of the lower surface or floor, a part of the surface of the masonry panel or wall and a part of the upper surface or floor.

During their working lifetime, masonry walls or panels, be they structural elements or non- structural elements, can be subject to forces, generated for example by a seismic event, which act perpendicular to the midplane thereof, and by forces which act parallel to said plane .

During a catastrophic event, such as, for example, an earthquake, the forces which act perpendicular to the midplane cause the panels to collapse by simple overturning, or as a result of vertical bending or horizontal bending. Whereas the forces parallel to the midplane induce mechanisms of breakage due to combined compressive and bending stress and shear stress in the plane of the panel .

In practical terms, as a result of these forces, the masonry wall or panel will be divided into smaller parts, which, by falling, cause injury to people and damage to property.

Thanks to the mechanical properties it possesses, in particular its elastic properties, the textile material of the present invention is capable of containing (holding together) the parts of the panel which have originated from the original intact panel following the catastrophic event (breakage due to collapse) and preventing said parts from causing injury to people or damage to property.

A subject matter of the present invention relates to a method for containing a non-structural brick element which can be deformed following breakage of the same due to a collapse, said method comprising at least a step in which a layer of textile material is applied on said non- structural element.

Another subject matter of the present invention relates to a method for imparting safety to people who are in an environment confined by the presence of at least one non- structural element, said method comprising at least a step in which a layer of textile material is applied on said non-structural element.

Advantageously, the textile material of the present invention can be applied underneath, or inside, the cladding of the masonry wall and/or panel. In this manner, the textile material will prevent any brick elements that might originate from perpendicular forces, parallel forces or in any case forces that can cause breakage, from being expelled outward, into the adjacent rooms. Consequently, the textile material of the present invention is capable of thus protecting the occupants against highly dangerous, and sometimes lethal, events.

Advantageously, when the textile material of the present invention is applied continuously from the wall to the floor above, the textile material binds the wall itself to the floor, preventing "out-of-plane overturning" of the wall in the event of forces perpendicular thereto.

Advantageously, when the textile material of the present invention is applied continuously from the floor to the walls below, the textile material will ensure that, in the event of sections breaking away from the bottom of the floor or other ceiling failures, the debris originating therefrom will be contained and held back and thus not fall into the environment below, where it could cause physical harm to the occupants. In this case, the textile material of the present invention, despite not increasing the structural strength of the floor itself (it does not support the structure) , is capable of containing the debris, enabling people to seek shelter. This fact is confirmed by figures 5 and 6 , from which it may be seen that at the end of the bending tensile strength test there is no expulsion of debris from the flat hollow block but rather a containment thereof thanks to the elastic properties of the textile material used.

Unlike FRP composites, the textile material of the present invention achieves important advantages thanks to its elasticity. In fact, FRP composites are used to reinforce the load-bearing structure by adding "strength" to the structure. The composites are hence materials stiffened with various types of resins and hardened in such a way as to have mechanical performances similar to those of the various structural components of the construction, which have fundamentally "rigid" reactions without any substantial elongation. This logic is also correct, because they must react in a manner that is similar to, or in any case homogeneous with, that of the various components of the construction in order to be able to adequately add the strength they are intended to give to the construction. If they underwent greater elongations, the construction would end up breaking apart before the reinforcement has started to transfer its share of strength to the structural element (construction) . If they were stiffer, and less elastic, the force would first break the reinforcement and then the construction, separating the two strengths thereof and making each effective only for its own part. That is why it is important for these structural reinforcements to exert their peak strength simultaneously (optimal solution) with the peak strength of the part to be reinforced, elongation being equal. For this reason, even when they are used to bind non- structural elements, they must be stiffened with resins.

In contrast with all that has been stated above, the materials of the present invention make elasticity an essential characteristic.

Advantageously, having a weight in grams/square metre comprised from 300 to 3500 g/square metre and at the same time highly elastic properties, the textile material can avoid adding weight to the structural elements and non- structural elements it is applied on while assuring the required performance.

The textile material of the present invention does not increase the static strength of the construction comprising the non-structural elements it is applied on, even though it improves the characteristics thereof by adequately binding the various elements which form the construction. The textile material of the present invention performs an action that is in a certain sense "complementary" to that of FRP composite materials, in that the latter are all aimed at reinforcing the structural and non- structural parts and better binding them together so as to increase the static strength of the construction. Notwithstanding this reinforcement and increase in strength, when stresses exceed the combined strength of the building part and reinforcement, these may in any case collapse and break apart, resulting in a serious hazard to the safety of occupants .

In contrast, the textile material of the present invention does not bring about any enhancement of the static strength characteristics of the structures of the construction (see experimental part) , but rather acts as a barrier for containing any debris that comes detached when the various building parts collapse or break as a result of any type of extraordinary event, be it an earthquake, a structural failure or an explosion .

Therefore, a subject matter of the present invention relates to the use of a textile material as a safety barrier for reducing harm to people in the event of failure of structural and non-structural elements of any type of construction comprising at least one nonstructural element.

Moreover, the application of the textile material of the present invention is extremely simple, and also cost-effective, since by binding the various structural and/or non-structural elements of the construction, it makes the entire construction as a whole safer.

As has been amply discussed above, the application of FRP composite materials requires them to be directly coupled to the constructive part they have to reinforce, directly upon the latter and without any interposed component such as plaster or the like, in order to avoid the phenomenon of debonding.

Therefore, when such reinforcements are applied on existing constructions, it is necessary to remove the plaster from the walls. Removing plaster and restoring the parts to be reinforced to an unfinished state is sometimes the principal cost.

In contrast, the textile material of the present invention is applied in various ways, e.g.: i) directly in plaster specially applied on the wall, in the case of new constructions, ii) on top of old, pre-existing plaster already on the wall, or iii) incorporated in new plaster applied on top of pre-existing plaster, in the case of renovation of a wall.

The non- structural element comprises a midplane and said breakage through collapse is caused by a force which acts perpendicular and/or parallel to said midplane of said non- structural element. Said forces perpendicular to the midplane induce the breakage of the non- structural element. Said forces parallel to the midplane induce the breakage of the non- structural element. The fabric of the present invention is capable of reducing/containing the damage caused by nonstructural elements.

The fabric of the present invention differs from composite materials, such as, for example, FRP composites made with glass fibre or carbon fibre, because it is endowed with high ductility deriving from the fabric's characteristics of elasticity. Thus the fabrics of the present invention are capable of withstanding large shifts of non- structural elements without breaking because they are elastic fabrics, unlike the composite materials, which are rigid materials and, therefore, once applied to the nonstructural elements they break.

Advantageously, the fabric of the present invention can be applied directly on the non-structural element without the use of a glue or fixing means, simply by applying the fabric together with the plaster.

Experimental part

The Applicant tested several textile materials, such as the ones specified below.

Fabric 1: called "948 PL HT IRON STRONG", having the characteristics described above.

Fabric 2: called "948 KE IRON STRONG", having the characteristics described above.

Tests were carried out on 6 hollow clay blocks with and without the textile material of the present invention. Specifically, the bending tensile strength was determined for 6 hollow clay blocks (test 1 - Table 1) having the following characteristics:

- No. 1 25x100x6 cm block with a 1.5 cm layer of gauged mortar on one face (25x100 cm) , identified as "S" . - No. 2 25x100x6 cm blocks with a 1.5 cm layer of gauged mortar, coupled with fabric x, on one face (25x100 cm), identified as "lB-1" and "1B-2" .

- No. 1 25x100x6 cm block with a 1.5 cm layer of gauged mortar, coupled with fabric x, on two faces (25x100 cm) , identified as "2B" .

- No. 1 25x100x6 cm block with a 1.5 cm layer of gauged mortar, coupled with fabric y, on one face (25x100 cm) , identified as "1G" .

- No. 1 25x100x6 cm block with a 1.5 cm layer of gauged mortar, coupled with fabric y, on two faces (25x100 cm) , identified as "2G" .

The bending tensile strength was determined for the 6 blocks (test 1) using a Galdabini/Metrocom universal test machine mod. PM60 with a lOkN load cell and following the reference standard UNI EN 772-6, which provides for a static scheme with a beam simply rested on supports spaced apart 80 cm and load concentrated at the midpoint. The results are shown in Table 1.

Table 1: Determination of bending tensile strength for 6 hollow clay blocks.

Block Test conditions Bending

tensile strength

S No fabric 3059 N lB-1 With a layer of fabric 1 2675 N

positioned on the lower face

1B-2 With a layer of fabric 1 4356 N

positioned on the upper face

1G With a layer of fabric 2 3215 N

positioned on the lower face

2B With 2 layers of fabric 1, 3079 N

one positioned on the lower face and one on the upper face 2G With 2 layers of fabric 1, 3230 N one positioned on the lower face and one on the upper face

The experimental graphs (see figure 1 and figure 3) illustrate the increase in ductility of the hollow clay blocks (block S and block 2B in figure 1 and figure 3) following the application of fabric 1 of the present invention .

The test performed is called "bending test" and consists in the application of a progressively increasing load distributed over the axis which divides the block in half along its shorter side, and simultaneous measurement of the lowering of the axis. A "brittle" fracture manifests itself suddenly in that the material breaks without showing any deformations that might suggest an imminent collapse and is therefore a very dangerous mechanism.

A "ductile" break on the other hand is a "controlled" break, in that before collapsing the material shows deformations which indicate an imminent break (e.g. formation of cracks, sagging, rotations, etc.) .

For the sake of simplicity reference will be made to the graph shown in figure 1 "Block without reinforcement (S) " and the graph shown in figure 3 "Block with 2 layer reinforcement 2B" (where reinforcement means the potential application of one or two layers of textile material 1 of the present invention) .

The graphs are constructed to show the shift in the point of application of the load on the block on the horizontal x-axis and the value of said load on the vertical y-axis.

In the graph shown in figure 1, corresponding to the bending test on the block without fabric 1, it can be observed that sag increases with load and the test is interrupted on reaching the breaking shift, corresponding to about 1.70 mm under a load of 300 kg. In the graph shown in figure 3 , corresponding to the bending test of the block having fabric 1 on both sides, the point of breakage of the block in relation to shift and load values is practically the same as observed in the first graph. However, the test continued up to a shift of about 120 mm since the block continued to withstand the load of 300 kg, becoming deformed but remaining confined within the fabric 1 placed on the upper and lower faces. The 120 mm measured could presumably have been higher, but the test was stopped at this deformation value because of the constructive limits of the test equipment. As can be seen from the above-mentioned graphs, the textile material of the present invention has an "elastic" strength that favours a "ductile" break, which takes a longer period of time (following a progressive pattern) and allows more time for people who are inside the construction to react and escape. Advantageously, the textile material of the present invention can be validly applied by using a glue or a substance with adhesive properties or mechanical fixing means such as, for example, nails, screws or other fixing means, directly upon the non- structural element, which is preferably free of plaster or any other type of finish.

Moreover, once applied on the structural element or non-structural element, directly on the plaster-free part, the textile material of the present invention represents the finish of the element itself, which does not further need to be plastered or finished.

Claims

1. A method for containing a non-structural clay building element which can be deformed following breakage of the same due to collapse, said method comprising at least a step in which a layer of fabric comprising a weft and a warp is applied on said nonstructural element.

2. The method according to claim 1, wherein said weft and said warp comprise at least one yarn of high- strength fibres.

3. The method according to claim 2, wherein said high- strength fibres are selected from the group comprising polyester fibres, polyethylene fibres, aramid, polypropylene and polyolefin fibres and the like.

4. The method according to any one of claims 1-3, wherein said weft and/or warp can also comprise at least one metal thread selected from the group comprising steel and copper threads and the like having a diameter comprised from 0.05 mm to 1 mm.

5. The method according to claim 4, wherein said weft and/or warp comprise a metal thread of steel or copper having a diameter comprised form 0.10 to 0.50 mm; preferably 0.20 mm.

6. The method according to claim 1, wherein said non- structural clay building element is selected from the group comprising walls, panels, partitions, curtain walls, floors and stairways.

7. The method according to any one of claims 1-6, wherein said layer of fabric is applied to a nonstructural clay building element by using a glue or a substance with adhesive properties or mechanical fixing means, preferably nails, screws or other fixing means, directly upon the non-structural clay building element, preferably, said non-structural clay building element is free of plaster.

8. The method according to any one of claims 1-7, wherein said layer of fabric is applied to a nonstructural clay building element by using a glue or a substance with adhesive properties or mechanical fixing means, preferably nails, screws or other fixing means, directly upon the non- structural clay building element, and directly upon the pre-existing plaster on said nonstructural clay building element.

9. A method for imparting safety to people who are inside an environment confined by the presence of at least one non-structural clay building element, said method comprising at least one step in which a layer of fabric is applied on said non-structural clay building element .

10. A use of a textile material in accordance with claims 1-8, as a safety barrier for reducing harm to people in the event of structural and non-structural failures of any type of construction comprising at least one non-structural clay building element.