Matting and stapling (harping) process for repairing cracks within a structure and associated device.

Abstract

The present invention relates to a method for repairing a cracked structure which comprises the steps of 1) opening a crack in said structure, 2) stapling (harping) with the installation of at least one metal device (1) of the staple type so that the two ends of said metal device (1) are located on either side of said crack and 3) matting with the filling of the crack and covering said at least one metal device (1) with a mortar, in which the metal device (1) consists of at least two elongated metal profiles (2) together forming the same plane (A), said at least two metal profiles (2) having a spacing (E) of at least 0.5 centimeters between them and curved ends (4) outside the plane (A) and, considering the two faces of said plane (A), having the same orientation,where each metal profile (2) incorporates in its length at least one fold (3) which is positioned in the plane (A) and whose apex is associated with the adjacent metal profile (2) by an association point (5), which at least one fold (3), with its corresponding association point (5), together allow the device (2) to be stiffened and the spacing (E) to be maintained between the two metal profiles (2) which they contribute to associating. Figure for the abstract: Fig. 3,

Description

Title of the invention: Method of matting and stapling (harping) for repairing cracks within a structure and associated device. Technical field

[0001] The invention relates to the field of construction and, more specifically, to a method of matting and stapling (harping) for repairing cracks in a structure. Prior art

[0002] When the ground on which a structure rests undergoes differential settlements, the structural rigidity of this structure may not be able to absorb these variations if their amplitude is too great. Such variations result from the shrinkage and swelling of the earth (e.g. clay). Also, and beyond its structural limits, the structure will develop cracks. Naturally, the profile of these cracks will depend on the very constitution of the structure (masonry, reinforced concrete, etc.).

[0003] Such cracks constitute a danger since they weaken the associated structure and their development, if not controlled, can lead to the collapse of the structure.

[0004] Currently, and due to climate change, we are observing in many regions of the world, particularly in France, a clear increase in periods of drought, both in their length and in their amplitude. This climatic evolution naturally leads to a clear increase in the phenomena of ground settlement, which phenomena are themselves responsible for a clear increase in the appearance of cracks in structures in the regions concerned.

[0005] Faced with this problem, crack treatment is traditionally carried out by matting and stapling (harping) to recreate the continuity of the structures and restore the monolithic nature of the treated structures. This treatment can be combined with underpinning in certain situations and thus makes it possible to consolidate the structure of the cracked structures to compensate for the weaknesses resulting from the appearance of cracks.

[0006] In detail, this treatment consists of opening the crack before carrying out a matting step which corresponds to filling it using special mortars, called shrinkage-compensated mortars.

[0007] Prior to this matting step (filling the crack) and in order to recreate the original monolithism, a stapling step is carried out (one can also speak of a harping step) which consists of placing metal staples, perpendicular to the treated crack and in a groove (opening) of sufficient length which will then be embedded in the mortar used during the step consecutive matting.

[0008] Such staples have always been made directly on site from often rusty rebars of all sections. These rebars are first cut into segments of sufficient length (generally around 50 centimetres), the two ends of these segments are then bent in the same orientation. The two curved ends will then resemble two "claws" which are directed towards the inside of the wall, when the staple is installed, and which will contribute to maintaining the staple over time and therefore to that of the repair.

[0009] Now, the repairs made during these projects often prove to be of poor quality and rarely durable, sometimes with staples being torn off or even broken. The reasons for these failures have been little studied and are currently largely unknown within the profession. To try to remedy this, technological developments have targeted special mortars and their formulation. Summary of the invention

[0010] After the matting / staple (harping) processes remained unchanged for decades, the inventor succeeded in developing a new "staple" type device, the use of which makes it possible to obtain repairs to cracked structures that prove solid and stable over time. An explanation for this clear improvement could result from the very good rigidity combined with the very good load-bearing capacity of the developed device.

[0011] Consequently, a first object of the invention relates to a method of repairing a cracked structure which comprises the steps of:

[0012] o opening of a crack in said work;

[0013] o stapling (harping) with the installation of at least one metallic device (1) of the staple type so that the two ends of said metallic device are located on either side of said crack; and

[0014] o matting with the filling of the crack and covering said at least one metallic device (1) with a mortar;

[0015] Characterized in that the metal device (1) is made up of at least two elongated metal profiles (2) together forming the same plane (A), said at least two metal profiles (2) having:

[0016] - a spacing (E) of at least 0.5 centimeters between them; and

[0017] - curved ends (4) outside the plane (A) and, considering the two faces of said plan (A), showing the same orientation;

[0018] where each metal profile (2) integrates in its length at least one fold (3) which is positioned in the plane (A) and whose top is associated with the adjacent metal profile (2) by an association point (5), which at least one fold (3) with its corresponding association point (5) together allow the device (2) to be stiffened and maintain the spacing (E) between the two metal profiles (2) which they help to associate.

[0019] The present invention also relates to a device as described above.

[0020] Finally, a third object relates to the use of a device as defined above for repairing cracks in a structure by matting / stapling. Brief description of the drawings

[0021] [Fig.l] schematizes a preferred 3D embodiment of a metallic device according to the invention.

[0022] [Fig.2] shows a schematic side view of this same preferred embodiment of a metal device according to the invention.

[0023] [Fig.3] shows a schematic view from above of this same preferred embodiment of a metal device according to the invention. Description of the embodiments

[0024] By opening the crack, we mean the widening of this crack. Typically, such an opening step aims for said crack to have a width of at least one centimeter, preferably a width of at least two centimeters and, particularly preferably, at least five centimeters. Such widening is essential to allow good penetration of the mortar during the matting step, which good penetration constitutes a guarantee of stability of the repair over time. Such an opening step can be carried out with methods well known to those skilled in the art using motorized tools (e.g.: grinder or grooving machine) or not (e.g.: chisel and hammer).

[0025] During the stapling step, the devices according to the invention are preferably placed in such a way that each device according to the invention makes an angle of 45 to 135° with the crack, preferably that each device according to the invention is positioned perpendicular to the crack. Such positioning makes it possible to obtain optimal efficiency for maintaining the crack over time.

[0026] During the stapling step, the devices are preferably placed at regular intervals along the crack. An interval of 30 to 80 centimeters will be chosen, preferably an interval of 40 to 60 centimeters, typically an interval of around 50 centimeters.

[0027] Conventionally, this stapling step can be carried out with devices according to the invention having the same length. It has now been established that installing devices of different lengths, so that two successive devices do not have the same length, ensures better resistance of the crack repair over time.

[0028] Advantageously, the devices according to the invention are installed in such a way that two devices installed successively have a different length.

[0029] Ideally, this stapling step is preceded by the creation, preferably perpendicular to the crack, of at least one groove for each metal device, a groove whose dimensions allow said at least one device according to the invention to be accommodated. Such grooves are made using methods well known to those skilled in the art. If such grooves were made with a chisel in the past, they are now made with a grinder or a grooving machine (generally equipped with diamond discs). In relation to the dimensions of this groove, a width of at least 3 cm, preferably at least 5 cm, and a depth of at least 5 cm, preferably at least 7 cm, will be chosen. As regards the length of the groove, it is at least 5 cm longer than that of the device according to the invention which it accommodates, preferably its length is at least 10 cm longer than that of the device according to the invention which it accommodates.

[0030] The matting step with the filling of the crack is carried out using methods well known to those skilled in the art. It is preferably carried out using a shrinkage-compensated mortar and, particularly preferably, using a non-shrinkage mortar. Such a mortar is formulated so as to avoid the formation of (micro)cracks during its drying. Examples of such shrinkage-compensated mortar include SIKAGROUT-217 or 234 (SIKA), 704 CLAVEX+ HP (PAREXLANKO), SCEL CALAGE (PRB), WEBERCELL HP (WEBER), GROUTMIX CA (AXON), etc. Examples of such non-shrinkage mortar include the non-shrink mortar from SELTEX or TILLMAN, or MASTERFLOW 544 (SIKA). In connection with this matting step, the filling is carried out leaving a gap of at least one centimeter, in order to receive the finishing coating.

[0031] As regards the metallic nature of the device according to the invention, this means a device made of any suitable metal or metal alloy (e.g.: aluminum or steel).

[0032] Advantageously, the device according to the invention, and its constituent elements, will be made of steel, preferably of a steel intended for construction as defined for example by standard NF A 35 027 relating to steel products for reinforced concrete. As such, the device according to the invention may optionally have a surface treatment (e.g. galvanization), so as to limit oxidation phenomena. Now and preferably, the device according to the invention will be made of stainless steel.

[0033] Advantageously still, the device according to the invention will have a non-smooth surface condition (e.g. grooves). Indeed, such a non-smooth surface condition is likely to improve the adhesion of said device with the mortar used during the filling (or matting) step. Advantageously still, the device according to the invention will be made of high-adhesion steel.

[0034] The device according to the invention has a length ranging from 20 to 120 centimeters, preferably from 30 to 80 centimeters and, particularly preferably, from 35 to 70 centimeters. Typically, a device having a length of 35, 50 or even 70 centimeters will be chosen.

[0035] Now concerning the detail of the separate metal profiles constituting the device according to the invention, there will be at least two of them, but they may possibly be 3, 4 or even more. In such a case, said 3, 4 or even more metal profiles will always together form only one and the same plane (A). Now and preferably, the device according to the invention will only comprise two separate metal profiles.

[0036] These metal profiles can have any suitable section, which section can be circular, square, ovoid, rectangular, etc.

[0037] Regardless of the nature of the section, these metal profiles must have a tensile strength of at least 250 MPa, preferably at least 350 MPa.

[0038] Advantageously, the metal profiles have a circular section. Typically, said metal profiles take the form of reinforcing bars whose diameter will be in the range from 4 to 12 mm, preferably from 5 to 11 mm and, particularly preferably, from 5 to 9 mm.

[0039] Preferably, the metal profiles take the form of 6 and / or 8 mm rebar, typically 6 mm rebar.

[0040] The ends of the metal profiles constitute “claws” (4) whose function is to ensure the anchoring of the device according to the invention within the structure and, by the same token, the bearing capacity of the latter.

[0041] The ends (4) of the metal profiles form an angle (C) of between 45 and 135° with the plane (A) defined by the rest of the at least two metal profiles and have the same orientation relative to this plane (A), preferably they form an angle of between 70 and 120° and, particularly preferably, between 80 and 100°. Typically, ends forming an angle of 90° will be chosen to be used.

[0042] Each of the ends of the metal profiles constituting a claw will have a sufficient length to allow the device according to the invention to be anchored within the structure. Typically, the length of each claw is between 1 and 15 cm, preferably between 2 and 5 cm. Ideally, a claw length of 2.5 cm will be chosen.

[0043] If the distance between two metal profiles is at least 0.5 centimeters, a distance of between 0.5 and 10 centimeters may be chosen, preferably a distance of between 1 and 5 cm and, particularly preferably, a distance between 1 and 2 centimeters.

[0044] In connection with the at least one fold (3) of each metal profile (2), this is similar to a notch (in the shape of a triangle) in the length of the metal profile. Such a fold (3) can also be described as a bending angle or bending angle. It can be produced by methods well known to those skilled in the art. Such a fold (3) can in particular be produced with a press, a bending machine or with a framing machine. Typically, such a fold (3) takes the form of an angle (B) of between 20 and 160°, preferably an angle (B) of between 45 and 135°, typically an angle of 125°. Ideally, all the folds (3) of the metal profiles (2) within the same device according to the invention (1) take the form of an angle (B) having a single and same value.

[0045] The association point (5) between the top of each fold (3) and an adjacent metal profile can be produced by a method well known to those skilled in the art. Typically, such an association point (5) can consist of a welding point, preferably produced by arc or MIG welding.

[0046] Advantageously, each fold is at least 1 cm away from the ends of the metal profiles, preferably each fold is at least 2 cm away from these ends. Such a distance is desirable so that each fold, with its corresponding association point, best ensures its function of support and rigidity.

[0047] Advantageously still, the device according to the invention will comprise at least 1 fold in one of these at least two metal profiles per length of 25 cm and at most 1 fold in one of these at least two metal profiles per length of 8 cm. Preferably, the distance between the association points (5) between two metal profiles will be in the range from 8 to 25 cm, preferably from 10 to 20 cm and, ideally, of the order of 15 cm.

[0048] Thus, and for a device having a length of 50 centimeters, there will typically be between 2 and 5 folds, preferably between 3 and 4 folds distributed between the two metal profiles.

[0049] Figures 1 to 3 illustrate a particular embodiment in which the device according to the invention is made up of two adjacent metal profiles (2), of the same length of the order of 50 centimeters and together forming a plane (A). The two metal profiles (2) have a spacing (E) of the order of two centimeters. The two ends of the two metal profiles (2) are furthermore curved at the same angle (C) with respect to the plane (A) (of the order of 90°) to form claws (4) of a length of approximately 3 centimeters. The different folds (3) within the metal profiles (2) form an angle (B) having the same value, which is of the order of 125° in this embodiment. Now, the two metal profiles (2) have a different number of folds (3) in this case. A first metal profile The metal profile (2) has two folds (3), which folds (3) are located near its ends (a little more than 5 centimeters). The second metal profile (2) has only one fold (3) which is located towards its center. This different distribution of the folds (3) between the two metal profiles allows, when they are associated by the association points (5) at the top of each fold (3), to obtain a good distribution of the folds (3) over the entire length of the device so as to ensure very good support of the profiles between them and very good overall rigidity.

Claims

Claims

1. A method for repairing a cracked structure which comprises the steps of: - opening a crack in said structure; - stapling with the installation of at least one metal device (1) of the staple type so that the two ends of said metal device (1) are located on either side of said crack; and - matting with the filling of the crack and covering said at least one metal device (1) with mortar; Characterized in that the metal device (1) consists of at least two elongate metal profiles (2) together forming the same plane (A), said at least two metal profiles (2) having: - a spacing (E) of at least 0.5 centimeters between them; and - curved ends (4) outside the plane (A) and, considering the two faces of said plane (A), having the same orientation;Where each metal profile (2) incorporates in its length at least one fold (3) which is positioned in the plane (A) and whose apex is associated with the adjacent metal profile (2) by an association point (5), which at least one fold (3), with its corresponding association point (5), together make it possible to stiffen the device (2) and to maintain the spacing (E) between the two metal profiles (2) which they contribute to associating.;

2. The method according to claim 1, characterized in that, during the stapling step, the metal devices (1) are placed at regular intervals along the crack and so that two successive metal devices (1) have a different length.

3. The method according to any one of the preceding claims, characterized in that the metal device (1), and its constituent elements, is made of steel, preferably stainless steel.

4. The method according to any one of the preceding claims, characterized in that the metal device (1) comprises only two separate metal profiles (2).

5. The method according to the preceding claim, characterized in that the at least two metal profiles have a tensile strength of at least 250 MPa, preferably at least 350 MPa.

6. The method according to any one of the preceding claims, ca- characterized in that the metal device (1) has a length ranging from 20 to 120 centimeters, preferably from 30 to 80 centimeters and, particularly preferably, ranging from 35 to 70 centimeters.

7. The method according to any one of the preceding claims, characterized in that each at least one fold (3) takes the form of an angle (B) between 20 and 160°, preferably an angle (B) between 45 and 135°, typically an angle of 125°.

8. The method according to any one of the preceding claims, characterized in that the association point (5) is a welding point.

9. A metal device (1) of the staple type characterized in that it is made up of at least two elongated metal profiles (2) together forming the same plane (A), said at least two metal profiles (2) having: - a spacing (E) of at least 0.5 centimeters between them; and - curved ends (4) outside the plane (A) and, considering the two faces of said plane (A), having the same orientation; Where each metal profile (2) integrates in its length at least one fold (3) which is positioned in the plane (A) and whose apex is associated with the adjacent metal profile (2) by an association point (5), which at least one fold (3), with its corresponding association point (5), together allow the device (2) to be stiffened and the spacing (E) to be maintained between the two metal profiles (2) which they contribute to associating.

10. A use of a staple-type device for repairing cracks in a work by matting / stapling characterized in that said device is as defined in claim 9.

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