Structural node for buildings and constructions

Abstract

A structural node (1) for buildings and constructions, constituted by at least two intersecting structural units (2, 3, 4) made of concrete provided with reinforcement; each of the structural units (2, 3, 4) comprises a reinforcement constituted by elements (5) made of composite material based on fibers chosen from glass fibers, basalt fibers and carbon fibers, arranged according to a predefined geometry; at the region of intersection (6) of the structural units (2, 3, 4), the reinforcement of the concrete comprises additional members (7) made of ductile material which are arranged according to a predetermined configuration made of ductile material which are arranged according to a predetermined configuration and are provided with appendages (7a) which protrude within the structural units (2, 3, 4).

Description

[0001] STRUCTURAL NODE FOR BUILDINGS AND CONSTRUCTIONS

[0002] The present invention relates to a structural node for buildings and constructions.

[0003] A structural node is a part of a building in which structural elements (such as foundations, beams, pillars, etc.) mutually intersect.

[0004] Nodes are generally among the parts of a building and / or construction that are subject to the greatest stress if external events such as earthquakes, explosions and the like occur.

[0005] The use of reinforced concrete structural elements, in which structural reinforcement components are present inside the concrete block to provide better mechanical performance, is well known. More frequently, steel reinforcement components (steel bars mutually interconnected to constitute an internal reinforcement grid) are used which allow to increase the mechanical resistance of concrete structural elements to bending, torsion, and tensile stresses.

[0006] However, steel significantly affects the weight of the built structure and is highly susceptible to oxidation and corrosion (especially in aggressive environments).

[0007] For this reason, the use of composite bars based on glass fibers (such constructive solutions provide for the use of basalt fibers and carbon fibers) is becoming widespread; said bars combine excellent mechanical performance with low specific gravity and high corrosion resistance, even in aggressive environments.

[0008] However, the intrinsic fragility of glass makes this type of reinforcement bar scarcely suitable for all applications where significant deformations are possible.

[0009] The low ductility means that the composite material of the type described above is unable to absorb much energy through deformation before reaching the breaking point. This is particularly critical in seismic areas or in applications subject to dynamic loads, since low ductility can compromise the structure's ability to absorb and dissipate energy during events such as earthquakes or intense vibrations, increasing the risk of catastrophic failure.

[0010] The aim of the present invention is to solve the above problems by proposing a structural node for buildings and constructions that is scarcely prone to corrosion, even in aggressive environments, and suitable for installation in seismic regions.

[0011] Within this aim, an object of the invention is to propose a structural node for buildings and constructions that is not prone to corrosion, even in aggressive environments, and suitable for applications subject to dynamic loads.

[0012] Another object of the invention is to propose a structural node for buildings and constructions that allows to limit the overall weight of the structural components that intersect in the node, with respect to traditional structural components made of reinforced concrete with steel bars.

[0013] Another object of the invention is to propose a structural node for buildings and constructions that allows to identify, through signs detectable by visual or instrumental examination, traces of deformations that could lead to subsequent structural stability and safety problems.

[0014] Another object of the invention is to propose a structural node for buildings and constructions that reduces the risk of brittle collapse of the structure.

[0015] Another object of the invention is to propose a structural node for buildings and constructions that can dissipate a large amount of energy during seismic events.

[0016] A further object of the present invention is to provide a structural node for buildings and constructions that has modest costs, is relatively simple to provide in practice and of safe application.

[0017] This aim and these and objects that will become more apparent hereinafter are achieved by a structural node for buildings and constructions according to claim 1.

[0018] Further characteristics and advantages of the invention will become better apparent from the description of a preferred but not exclusive embodiment of a structural node for buildings and constructions, illustrated by way of non-limiting example in the accompanying drawings, wherein:

[0019] Figure 1 is a schematic sectional front view, taken along a transverse plane, of a possible embodiment of a structural node for buildings and constructions in general, related to a node between the foundations and a pillar, according to the present invention;

[0020] Figure 2 is a schematic sectional front view, taken along a transverse plane, of a possible embodiment of a structural node for buildings and constructions in general, related to a node between a pillar and two intersecting beams, according to the present invention;

[0021] Figure 3 is a schematic sectional front view, taken along a transverse plane, of a possible embodiment of a structural node for buildings and constructions in general, related to a node between a pillar and a beam, according to the present invention.

[0022] With reference to the figures, a structural node for buildings and constructions is generally designated by the reference numeral 1.

[0023] The structural node 1 according to the invention is constituted by at least two intersecting structural units 2, 3, 4 made of concrete provided with reinforcement.

[0024] The structural units 2, 3, 4 may be constituted by the foundations 2, at least one pillar 3 and at least one beam 4; the nodes 1 according to the invention may therefore be nodes 1 between the foundations 2 and a pillar 3, nodes 1 between a pillar 3 and at least one beam 4 and, although of lesser interest (but applicable at some roofs), nodes 1 between intersecting beams 4.

[0025] Each of the structural units 2, 3, 4 comprises a reinforcement constituted by elements 5 made of composite material based on fibers chosen from glass fibers, basalt fibers, and carbon fibers, arranged according to a predefined geometry.

[0026] At the intersection region 6 of the structural units 2, 3, 4, the concrete reinforcement comprises further members 7 made of ductile material arranged according to a predetermined configuration and provided with appendages 7a which protrude into the structural units 2, 3, 4.

[0027] At the node 1, the reinforcement function of the reinforcement is entrusted to the members 7 made of ductile material, while for the rest of the structural units 2, 3, 4 it is entrusted to the elements 5.

[0028] In this way, since the greatest deformations occur at the node 1 during seismic events or in applications subject to dynamic loads, it is essential to ensure that said node is able to dissipate energy by deforming, furthermore tolerating even considerable deformations.

[0029] For this reason, inside the node the reinforcement is constituted by the members 7, which are made of ductile material, i.e., capable of undergoing significant plastic deformation before fracture. A ductile material can bend or elongate considerably under load without breaking and dissipate energy when subjected to cyclic loads such as, for example, an earthquake. In the context of reinforced concrete, the ductility of the reinforcement members 7 is crucial for structural safety, as it allows the structure to absorb and dissipate energy during dynamic loads such as earthquakes, show visible signs of deformation before failure, providing warning of possible structural problems, and reduce the risk of brittle collapse.

[0030] At the node 1 according to the invention, instead, the reinforcement elements 5 are interrupted so as to ensure that they are not affected by the deformations that may occur at node 1 (thus giving the members 7 the task of exclusively mechanically reinforcing the node 1 in the region of intersection of intersecting structural units 2, 3, 4).

[0031] By virtue of this embodiment, it is possible to provide structural units 2, 3, 4 having a low specific gravity (lower than structural units reinforced with metal alloy bars) and high resistance to corrosion (even in aggressive environments, such as the marine environment or specific industrial applications) and to ensure that the same, at the relative structural nodes 1 where they intersect, do not have problems such as sudden failure (since glass fibers and basalt fibers tend to break abruptly when subjected to excessive loads; although to a lesser extent, carbon fibers can also break abruptly beyond a threshold stress) and poor energy dissipation capacity (increasing the risk of structural damage).

[0032] Such units 2, 3, 4 intersect in respective structural nodes 1 where structural reinforcement is ensured by the members 7, which instead offer the advantages described above.

[0033] It is specified that conveniently, the ductile material may be of a type chosen from metals, metal alloys, polymeric materials, natural materials, and combinations thereof.

[0034] In particular, the chosen metal alloy may be steel; however, the use of different metals and metal alloys is not excluded: so-called shape memory alloys (SMA) and shape memory metals are of great importance.

[0035] The elements 5 made of composite material based on glass fibers can instead be advantageously glass fiber reinforced polymers, abbreviated as GFRP.

[0036] In particular, glass fibers of the type which is alkali-resistant will be preferred.

[0037] As already mentioned, the (alternative or combined) use of reinforcement fibers such as basalt fibers and carbon fibers is not excluded in any case.

[0038] The polymers preferably chosen to provide the elements 5 may be of a type selected from thermosetting polymers, such as vinyl esters, epoxies, polyesters, and thermoplastic polymers, such as polyurethanes and acrylics.

[0039] The members 7 made of ductile material are preferably arranged within the structural units 2, 3, 4 at a greater depth, therefore at a greater distance from the external surface of said units 2, 3, 4, than the outermost layer of elements 5 made of composite material based on glass fibers and / or basalt fibers and / or carbon fibers that are present.

[0040] The predetermined configuration for the members 7 made of ductile material comprises respective members 7 made of ductile material arranged parallel to the direction of extension of each structural unit 2, 3, 4: said members 7 are substantially crossed (at least in pairs originating from different units 2, 3, 4) and, at least in pairs, partially overlap at the region of intersection 6 of the structural units 2, 3, 4.

[0041] The predefined geometry of the elements 5 made of composite material based on glass fibers and / or basalt fibers and / or carbon fibers comprises instead respective elements 5 arranged parallel to the direction of extension of each structural unit 2, 3, 4.

[0042] The elements 5 arranged parallel to the direction of extension of each structural unit 2, 3, 4 face and are proximate to the appendages 7a that protrude within the structural units 2, 3, 4 of the members 7 made of ductile material.

[0043] The node 1 according to the invention provides for the combined use of elements 5 (generally bars) made of composite material reinforced with glass fibers and / or basalt fibers and / or carbon fibers and members 7 (generally bars) made of steel in the region of intersection 6 of the structural units 2, 3, 4. The steel members 7, which have greater ductility (with respect to the elements 5), are used internally, ensuring greater concrete cover (concrete layer covering the members 7 themselves) and therefore greater durability of the component (since there is no risk of a portion of steel becoming exposed to the external environment, the risk of said member 7 being exposed to a corrosive agent present in the atmosphere is substantially eliminated). The steel reinforcement, constituted by the members 7, is anchored to node 1 and extends throughout the plastic deformation region of the hinge (understood as the structural hinge to which the node 1 can be approximated in the event of high stresses that cause deformations thereof). The elements 5 (bars made of GFRP or, generically, composite material), positioned more to the outside of the units 2, 3, 4, are not anchored to the node 1 (in the region 6) and therefore perform their reinforcing action only beyond the region 6, which is particularly critical as regards deformations in the event of an earthquake. This ensures that the hinge (meaning the structural hinge to which the node 1 can be approximated in the event of high stresses causing deformations thereof) made of reinforced concrete has a deformation and dissipation capacity similar to that of traditional structures, combining the advantages of both materials to improve the overall performance of the structure. The solution can be adopted both for cast-in-place structures and for wet nodes of prefabricated structures.

[0044] Advantageously, the present invention solves the problems set out above by proposing a structural node 1 for buildings and constructions that is scarcely susceptible to corrosion, even in aggressive environments, and is suitable for installation in seismic regions.

[0045] Conveniently, the structural node 1 according to the invention is scarcely susceptible to corrosion, even in aggressive environments, and is suitable for applications subject to dynamic loads.

[0046] Favorably, the structural node 1 according to the invention allows to limit the overall weight of the structural components (such as the units 2, 3, and 4) that intersect in the node 1 with respect to traditional structural components made of reinforced concrete with steel bars.

[0047] Advantageously, the structural node 1 according to the invention allows to identify, through signs detectable by visual or instrumental examination, traces of deformations (which remain after a seismic event or other type of stress that has subjected the node 1 to deformations) that could cause subsequent structural stability and safety problems.

[0048] Positively, the structural node 1 according to the invention allows to reduce the risk of brittle collapse of the structure. Usefully, the structural node 1 according to the invention can dissipate a large amount of energy during seismic events.

[0049] Validly, the structural node 1 according to the invention is relatively simple to provide in practice and modest in cost: these characteristics make the node 1 according to the invention an innovation of safe application.

[0050] The invention thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims; all the details may furthermore be replaced with other technically equivalent elements.

[0051] In the exemplary embodiment shown, individual characteristics, given in relation to specific examples, may actually be interchanged with other different characteristics that exist in other exemplary embodiments.

[0052] In practice, the materials used, as well as the dimensions, may be any according to the requirements and the state of the art.

[0053] The disclosures in Italian Patent Application No. 102024000013414 from which this application claims priority are incorporated herein by reference.

[0054] Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly, such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.

Claims

CLAIMS1. A structural node for buildings and constructions of the type constituted by at least two intersecting structural units (2, 3, 4) made of concrete provided with reinforcement, characterized in that each of said structural units (2, 3, 4) comprises a reinforcement constituted by elements (5) made of composite material based on fibers chosen from glass fibers, basalt fibers and carbon fibers, arranged according to a predefined geometry, said elements (5) being arranged parallel to the direction of extension of each structural unit (2, 3, 4) except in said region of intersection (6) of said structural units (2, 3, 4), in that at the intersection region (6) of said structural units (2, 3, 4) said reinforcement of said concrete comprises additional members (7) made of ductile material which are arranged according to a predetermined configuration and are provided with appendages (7a) which protrude within said structural units (2, 3, 4), said elements (5) arranged parallel to the direction of extension of each structural unit (2, 3, 4) facing and being proximate to said protruding appendages (7a) within said structural units (2, 3, 4) of said members (7) made of ductile material, and in that said members (7) made of ductile material are arranged within said structural units (2, 3, 4) at a greater depth, therefore at a greater distance from the outer surface of said units (2, 3, 4), with respect to the outermost layer of elements (5) made of composite material based on fibers chosen from glass fibers, basalt fibers, and carbon fibers present in said units (2, 3, 4).

2. The structural node according to claim 1, characterized in that said ductile material is of a type chosen from metals, metal alloys, polymeric materials, natural materials, and combinations thereof.

3. The structural node according to the claim 2, characterized in that said metal alloy is steel.

4. The structural node according to one or more of the precedingclaims, characterized in that said elements (5) made of composite material are glass fiber reinforced polymers, in acronym GFRP.

5. The structural node according to claim 4, characterized in that said glass fibers are alkali-resistant and said polymers are of a type selected from thermosetting polymers, such as vinyl ester, epoxy, polyester and equivalents, and thermoplastic polymers, such as polyurethanes, acrylics and equivalents.

6. The structural node according to one or more of the preceding claims, characterized in that said intersecting structural units (2, 3, 4) are of the type chosen from foundations (2), pillars (3) and beams (4).

7. The structural node according to one or more of the preceding claims, characterized in that said predetermined configuration of said members (7) made of ductile material comprises respective members (7) made of ductile material which are arranged parallel to the direction of extension of each structural unit (2, 3, 4), said members (7) substantially crossing each other and, at least in pairs, partially overlapping at the intersection region (6) of said structural units (2, 3, 4).

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