Patent Description:
In particular, the present invention relates to a method and a kit for the building and construction industry that can be used for the structural reinforcement of existing building structures at the convergence area between beams and columns.

The beam-column node, i.e. the area of the load-bearing structure where the vertical and horizontal load-bearing partitions converge, represents a particularly critical area in reinforced concrete buildings. This area, in fact, being more subject to loads and stresses, must be monitored and if necessary reinforced in order to adequately resist and guarantee the safety of the building work.

Nowadays, the reinforcement (or confinement) of the nodes in the concrete structures is usually made by means of composite materials or through metal elements made ad hoc with specific dimensions for each node. In the latter, more widespread case, customised metal reinforcement structures are in fact designed and manufactured according to the specific dimensional parameters obtained by the analysis of the node in question. Each reinforcement structure/reinforcement is therefore designed (typically with the support of calculation and analysis software) and manufactured tailor-made for the specific application; this necessarily entails significant construction and installation costs.

The Applicant has also noted that not all known the node reinforcement techniques to date allow for easy intervention from outside the building, but require breaking elements surrounding the node (e.g.: infills, screeds, secondary partitions).

The need to break some of the surrounding elements in order to effectively install the reinforcement thus entails a high degree of invasiveness in maintenance operations that is often not acceptable; think for example of residential buildings.

Furthermore, the use of custom-made metal components requires accurate dimensional surveying and design work, which is often the cause of very long lead times due to the lengthy product design and manufacturing process.

Furthermore, the Applicant has seen how the use of chemical resins to anchor the connectors for fixing the metal components to the node to be reinforced, requires careful cleaning of the holes, the respect of a specific waiting time necessary for the product to harden, and the use of special equipment to apply the correct tightening torque (necessary to obtain adequate seismic certification of the anchorage) before proceeding with the subsequent works. <CIT> discloses a method for reinforcing a reinforced concrete beam-column node and a kit for use in the method of reinforcing a reinforced concrete beam-column node.

In this context, the technical task underlying the present invention is to propose a method and a kit for reinforcing a reinforced concrete beam-column node that overcomes one or more of the drawbacks of the known technique mentioned above.

In particular, aim of the present invention is to make available a method for reinforcing a reinforced concrete beam-column node that is practical and efficient, allowing the design and production process to be optimised and the installation process to be made easier and faster.

A further aim of the present invention is to make available a kit for use in the method of reinforcing a reinforced concrete beam-column node according to the present invention that is modular, ready-to-use, easy to fabricate and versatile in use, allowing it to be adapted to different applications in a practical and efficient manner, without the need for ad hoc sizings.

The specified technical task and objects are substantially achieved by a method and a kit for reinforcing a reinforced concrete beam-column node, comprising the technical features set forth in one or more of the appended claims.

Specifically, in a first aspect as defined in claim <NUM>, the present invention provides a method for reinforcing a reinforced concrete beam-column node comprising the following steps:.

In other words, in this step the node is inspected and the necessary information is gathered (e.g. the dimensions of the area to be intervened on and the depth of the concrete cover to be removed, if any) for choosing the correct type of reinforcement assembly to be assembled and subsequently installed.

Preferably, the method then comprises a step of removing an outer concrete cover layer so as to create an intervention surface wherein the reinforcement bars inside the node are exposed. In fact, every reinforced concrete structure laid in a workmanlike manner provides for a reinforcement consisting of reinforcement bars (longitudinal bars and stirrups) incorporated within a concrete casting, which once cured covers and protects the reinforcement externally (the so-called "concrete cover"). The concrete cover layer, however, tends to detach locally over the years, for various reasons, exposing the reinforcement to external agents that deteriorate it. It is therefore often necessary to remove the deteriorated layer, thus defining an intervention surface that is rearward with respect to the outer edge of the wall of the node, and to restore it with a new one at the end of the reinforcement operation. b) Arrangement of two steel reinforcement plates at an intervention surface of the node, preferably having a thickness less than the outer concrete cover layer removed, and connection of the two reinforcement plates to each other so as to make a reinforcement assembly shaped to be arranged at the intervention surface.

The present invention provides that the two reinforcement plates are to be selected from a predetermined set of modular reinforcement plates made of steel according to the characteristic dimension parameters detected. In other words, it is not necessary to size the plates ad hoc but it is sufficient to trace within the already existing set which one might be the most suitable one for the specific node in question.

Each reinforcement plate has a main portion mainly developing along a longitudinal direction and at least two parallel arms branching off from the main portion in the same direction mainly developing along respective transverse directions perpendicular to the longitudinal direction. In other words, the arms develop perpendicular to the main portion, which will typically be arranged in a vertical position.

Each arm then has a plurality of connecting holes that serve to carry out the connection between plates. c) Positioning of the reinforcement assembly on the intervention surface and drilling a plurality of holes in the node through selected openings, not overlapping in use the reinforcement bars of the node (so that the reinforcement bars are not compromised), of a plurality of openings made in the main portions of the respective reinforcement plates, each hole extending perpendicularly within the node with respect to the intervention surface.

In other words, the reinforcement plates are used as a template for the holes to be drilled through the openings that are not aligned with the reinforcement bars in the node. d) Fitting a plurality of dry connectors within said plurality of holes through the selected openings.

Advantageously, the fitting of dry connectors is practical and immediate, optimising the entire reinforcement process.

Preferably, moreover, the invention may provide, in the case of prior removal of the outer concrete cover layer, the application of a layer of mortar so as to restore the removed outer concrete cover layer, thus incorporating the reinforcement assembly, even more preferably the application of a first layer of bedding mortar on which the reinforcement assembly is laid and a second layer of cover mortar to restore the concrete cover. Once the node has been reinforced by fastening the plates through the connectors, the layer of mortar solidifies the whole covering the plates and the connectors installed in the intervention surface to restore the initial concrete cover and even out the initial encumbrance of the node.

The invention therefore makes it advantageously possible to operate directly from the outside of the structure to be reinforced, guaranteeing the continuity of use of the building, without using ad hoc metal components with specific dimensions for each node, and envisaging the use of dry connectors that allow for a rapid and simplified installation of the reinforcement.

Thanks to the present invention, the reinforcement intervention is therefore quick from an execution point of view and simple from a design point of view.

In a second aspect as defined in claim <NUM>, the invention provides a kit for use in the method of reinforcing a reinforced concrete beam-column node according to the present invention, comprising:.

The kit further comprises connecting means and a plurality of steel extensions, each configured to connect.

Each extension has a sequence of connecting holes arranged along a main development direction of the extension for connecting selected connecting holes of the arms with respective connecting holes of the steel extensions so that the extensions can be interposed between the two reinforcement plates or between one of said reinforcements plates with one of said modular steel angular plates.

The kit proposed by the present invention is therefore ready to use and does not need any ad hoc design, as it can be easily adapted to any node thanks to a set of modular reinforcement plates.

In addition, the use of dry connectors reduces the number of components needed for laying, ensuring immediacy and simplicity in the installation process.

The dependent claims correspond to different embodiments/implementations of the invention.

Further features and advantages of the present invention will become clearer from the indicative, and therefore non-limiting, description of a preferred, but not exclusive, embodiment/implementation of a method and a kit for reinforcing a reinforced concrete beam-column node, as illustrated in the accompanying drawings.

With reference to the attached figures, N denotes as a whole a reinforced concrete beam-column node at the convergence area between a beam T and a column P, while <NUM> denotes as a whole a reinforcement assembly that is installed in the node N to reinforce it.

The method for reinforcing the node N comprises a preliminary step a) of identifying the node N to be reinforced and detecting dimensional parameters characteristic of the node N.

Preferably, the detection step can be carried out by visual inspection or by means of special instrumentation, e.g. a pacometer.

Preferably, the dimensional parameters characteristic of the node N may comprise: node N width, node N height, concrete cover thickness and reinforcement bar layout (not visible in the attached figures).

The method then preferably comprises a step of removing the outer concrete cover layer C so as to create an intervention surface S wherein the reinforcement bars inside node N (not illustrated in the attached figures) are exposed.

Preferably the removal step comprises a sub-step of removing a layer of rust from the exposed reinforcement bars, even more preferably by means of brushing or sandblasting.

Preferably, the removal step is carried out by means of mechanical milling or hydrodemolition.

It should be noted that in the attached figures, reference is made to an implementation of the method in which the step of removing the concrete cover layer was envisaged, although this step may be considered optional for the implementation of the method in the event that the concrete cover layer is in good condition and therefore does not need to be removed.

The method then comprises a step b) of arranging two steel reinforcement plates <NUM> at an intervention surface (S) of the node (N), preferably having a thickness less than the outer concrete cover layer C removed, if any, so that, after being installed in the node N - as will be clearer from the description that follows - the overall volume of the reinforced N is not altered compared to the initial one (because they are incorporated in the new concrete cover layer).

The reinforcement plates <NUM> are selected from a set of modular steel reinforcement plates <NUM>, illustrated by way of example in <FIG>, based on the characteristic dimension parameters detected.

In other words, thanks to the present invention, it is possible to choose, within a set of reinforcement plates <NUM> already carried out, which pair of plates <NUM> best suits the dimensional characteristics of the node N detected, bearing in mind that the two plates <NUM> may be connected by simple overlapping or by means of extensions and/or angular profiles, as will be better understood in the continuation of the description.

In fact, the method envisages the connection/assembly of the two reinforcement plates <NUM> to each other so as to make the reinforcement assembly <NUM> shaped to, i.e. suitable to, be arranged at the intervention surface S.

Preferably the connection is made by means of bolting.

With reference to <FIG>, in particular, each reinforcement plate <NUM> has a main portion <NUM> mainly developing along a longitudinal direction Y and at least two parallel arms <NUM> (three in number in the example of <FIG>) branching off from the main portion <NUM> in the same direction mainly developing along respective transverse directions X perpendicular to the longitudinal direction Y, each arm <NUM> having a plurality of connecting holes <NUM>.

Through the plurality of connecting holes, the connection between the two reinforcement plates <NUM> can be carried out.

Preferably step b) comprises a sub-step of arranging a steel angular plate <NUM>, preferably having a thickness less than the outer concrete cover layer C removed, even more preferably equal to the thickness of the reinforcement plates <NUM>.

In particular, the angular plate <NUM> is selected from a set of modular steel angular plates <NUM>, illustrated by way of an example in <FIG>, according to the characteristic dimension parameters detected.

With reference to <FIG>, the angular plate <NUM> has an angular portion <NUM> comprising two side wings <NUM> that are mutually tilted, preferably by a right angle, mainly developing along a respective longitudinal direction K (parallel in use to the longitudinal direction Y of the main portion <NUM> of the reinforcement plates <NUM>), and at least two parallel arms <NUM> (three in number in the example of <FIG>) branching off from each side wing <NUM> in the same direction mainly developing along respective transverse directions J perpendicular to the longitudinal direction K (parallel in use to the transverse directions X of the arms <NUM> of the reinforcement plates <NUM>).

In particular, each arm <NUM> has a respective plurality of connecting holes <NUM> adapted to connect with the respective connecting holes <NUM> of the arms <NUM> of the plates <NUM> by means of bolting to carry out the connection between the two reinforcement plates <NUM>.

The user selects certain connecting holes <NUM> of the arms <NUM> to be connected to respective connecting holes <NUM> of the arms <NUM> according to the dimensional parameters characteristic of the node N so that the angular plate <NUM> is interposed between the two reinforcement plates <NUM>, as illustrated in <FIG>.

In other words, the arms <NUM> of one side wing <NUM> are connected to the arms <NUM> of a first reinforcement plate <NUM> and the arms <NUM> of the other side wing <NUM> are connected to the arms <NUM> of a second reinforcement plate <NUM>, so that the transverse directions X, J are parallel.

Preferably, step b) comprises a sub-step of arranging at least two steel extensions <NUM>, visible in <FIG>, preferably having a thickness less than the outer concrete cover layer C of the node N, even more preferably equal to the thickness of the reinforcement plates <NUM> and/or to the thickness of the angular plate <NUM>.

Each extension <NUM> has a sequence of connecting holes <NUM> arranged along a main development direction of the extension (parallel in use to the transverse direction X of the arms <NUM>).

As illustrated in <FIG>, the connection between the two reinforcement plates <NUM> can thus be carried out by connecting selected connecting holes <NUM> of the arms <NUM> with respective connecting holes <NUM> of the extensions <NUM> so that the extensions <NUM> are interposed between the two reinforcement plates <NUM>.

In other words, the extension <NUM> is connected on the one hand to a first reinforcement plate <NUM> and on the other hand to a second reinforcement plate <NUM>, so that the main development direction of each extension <NUM> is parallel to the respective transverse directions X of distinct arms <NUM> of distinct reinforcement plates <NUM> connected on opposite sides.

As illustrated in <FIG>, preferably the method can also comprise the step of connecting the extensions <NUM> on the one hand to the arms <NUM> of the reinforcement plates <NUM> and on the other hand to the arms of the angular plate <NUM>. In other words, the extensions <NUM> can also be used for the angular nodes N, interposing respectively as a connection between the two reinforcement plates <NUM> and the angular plate <NUM>.

Preferably, step b) may comprise a sub-step of coupling a steel support plate (not illustrated), preferably having a thickness equal to the steel support plates <NUM>, to the main portion <NUM> of one of the two support plates <NUM> so that at least one opening <NUM> of the main portion <NUM> is overlapped and aligned with a respective opening of the support plate.

The support plate can advantageously be used as a compensation thickness for the space between one of the two reinforcement plates <NUM> and the intervention surface S.

Once the reinforcement assembly <NUM> has been assembled, whether it is simply composed of two overlapped plates <NUM> (as illustrated in <FIG>) or of two plates <NUM> connected by extensions <NUM> (as illustrated in <FIG>) or of plates <NUM> connected by the use of angular plate <NUM> (as illustrated in <FIG>) or again of two plates connected to the angular plate <NUM> by means of extensions <NUM> (as illustrated in <FIG>), the method according to the present invention comprises a subsequent step c) of arranging the reinforcement assembly <NUM> on the intervention surface S.

In this step, a plurality of holes, not visible in the attached figures, is drilled in the node N through selected openings <NUM>, not overlapping in use the reinforcement bars of the node N, of a plurality of openings <NUM> made in the main portions <NUM> of the respective reinforcement plates <NUM>.

In particular, each hole is drilled in the thickness of the node N, developing perpendicularly to its interior with respect to the intervention surface S, so that the holes are perpendicular in use to the reinforcement plates <NUM>. Preferably, drilling is carried out by means of a hammer drill, while the dry anchoring of the connectors by means of an impact wrench.

Subsequently, the method envisages a step d) in which a plurality of dry connectors <NUM> are fitted within the plurality of holes drilled and fitting them through the selected openings <NUM>.

In other words, the connectors <NUM> are simply fitted into node N to connect the two reinforcement plates <NUM> to the node N.

Preferably, the method may then envisage, subsequent to step d), a step of applying a layer of mortar until the outer concrete cover layer C removed is restored and incorporating the reinforcement assembly <NUM> so as to solidify the whole and restore the initial volume of the node N, as illustrated for example in <FIG>.

Preferably the outer concrete cover layer C is at least <NUM>.

Preferably, moreover, after step c), in which the holes are drilled using the assembly <NUM> as a template, and before step d), in which the dry connectors <NUM> are fitted, the method may comprise the steps of:.

In other words, to enable better positioning of the assembly <NUM> and better adherence/solidification of the assembly <NUM> on the node N, it is possible to temporarily remove the assembly <NUM> used as a template for drilling the holes and applying a first layer of mortar.

The application of the first layer of mortar allows the intervention surface S to be evened out while protecting the exposed reinforcement bars.

However, the laying of the assembly <NUM> must be carried out quickly before the layer of mortar hardens.

The mortar can be applied manually by trowel or by means of spraying machine, paying attention to the setting speed.

Preferably between the step of removing the assembly <NUM> and the step of applying the first layer of mortar, the method may provide for a step of cleaning the intervention surface S, and a subsequent step of wetting the intervention surface S to saturation (so-called "completely wetting").

Cleaning can be carried out, for example, by means of high-pressure cleaner or compressed air, according to known techniques.

Preferably the assembly <NUM> is made of S355 steel and preferably undergoes a protective treatment, such as a hot-dip galvanising treatment. The present invention according to the second aspect and as defined in claim <NUM> relates to a kit for use in the method of reinforcing a reinforced concrete beam-column node N comprising:.

The kit comprises further connecting means (preferably bolting, not illustrated) and a plurality of steel extensions <NUM>, each configured to connect.

using said plurality of holes <NUM>;
each extension <NUM> having a sequence of connecting holes <NUM> arranged along a main development direction of the extension <NUM> for connecting selected connecting holes <NUM> of the arms <NUM> with respective connecting holes <NUM> of the steel extensions <NUM> so that the extensions <NUM> can be interposed between the two reinforcement plates <NUM> or between one of said reinforcements plates <NUM> with one of said modular steel angular plates <NUM>.

The present invention achieves the proposed aims, overcoming the drawbacks complained about in the known technique, by making available a kit and a method for reinforcing a reinforced concrete beam-column node that envisages using plates and accessories with standardised shapes and dimensions, so that they can be assembled directly in situ, allowing for versatile adaptation to a wide variety of geometries of the nodes, and reducing production-design time and costs.

Claim 1:
Method for reinforcing a reinforced concrete beam-column node (N) comprising the steps of:
a) identifying a beam-column node (N) to be reinforced and detecting dimensional parameters characteristic of said node (N);
b) arranging two steel reinforcement plates (<NUM>) for an intervention surface (S) of the node (N), said reinforcement plates (<NUM>) being selected from a set of modular reinforcement plates (<NUM>) made of steel according to the characteristic dimension parameters detected, and connecting said two reinforcement plates (<NUM>) to each other so as to make a reinforcement assembly (<NUM>) shaped to be arranged at the intervention surface (S),
wherein each reinforcement plate (<NUM>) has a main portion (<NUM>) mainly developing along a longitudinal direction (Y) and at least two parallel arms (<NUM>) branching off from the main portion (<NUM>) in the same direction mainly developing along respective transverse directions (X) perpendicular to the longitudinal direction (Y), each arm (<NUM>) having a plurality of connecting holes (<NUM>) that are used for said connection between the reinforcement plates (<NUM>);
c) arranging the reinforcement assembly (<NUM>) on the intervention surface (S) and drilling a plurality of holes in the node (N) through selected openings (<NUM>), not overlapping in use the reinforcement bars of the node (N), of a plurality of openings (<NUM>) made in the main portion (<NUM>) of the respective reinforcement plates (<NUM>), each hole extending perpendicularly within the node (N) with respect to the intervention surface (S);
d) fitting a plurality of dry connectors (<NUM>) within said plurality of holes through said selected openings (<NUM>).