WO2012000559A1

WO2012000559A1 - Structure for strengthening concrete and method for producing a structure for strengthening concrete

Info

Publication number: WO2012000559A1
Application number: PCT/EP2010/059406
Authority: WO
Inventors: Leoforos Dimos Kalteziotis
Original assignee: Sidenor Sa
Priority date: 2010-07-01
Filing date: 2010-07-01
Publication date: 2012-01-05
Also published as: PL2588677T3; CY1117733T1; EP2588677B1; ES2576790T3; EP2588677A1

Abstract

A structure for strengthening concrete comprises at least one bended mesh formed of a pre-formed mesh consisting of lateral bars arranged in parallel and assembly bars arranged in parallel, the assembly bars being arranged perpendicular to the lateral bars and connecting the lateral bars, and an outer cage formed of a pre-formed mesh consisting of lateral bars arranged in parallel and assembly bars arranged in parallel, the assembly bars being arranged perpendicular to the lateral bars and connecting the lateral bars. The at least one bended mesh is placed inside the outer cage such that all assembly bars of the at least one bended mesh are enclosed by lateral bars of the outer cage.

Description

STRUCTURE FOR STRENGTHENING CONCRETE AND METHOD FOR PRODUCING A STRUCTURE FOR STRENGTHENING CONCRETE

The present invention relates to a structure for

strengthening concrete and a method for producing a

structure for strengthening concrete.

Structures for strengthening concrete are known in the prior art. These structures are used for strengthening buildings, for example, against forces resulting from a storm, an earthquake or a tsunami. The structures provide a lateral reinforcement for concrete, i.e. they prevent concrete from expanding laterally, when subjected to loads.

It is known to form strengthening structures by bending a pre-formed mesh. The pre-formed mesh consists of

horizontally arranged lateral reinforcement bars to which vertically arranged assembly bars are fixedly connected. Fig. 1 is a perspective view such a pre-formed mesh which comprises a plurality of lateral reinforcement bars 1 to which a plurality of assembly bars 2 are connected, the assembly bars 2 being arranged perpendicular to the lateral reinforcement bars 1 (Note that Fig. 1 is a perspective view so that the bars 1, 2 are not viewed in parallel) .

Fig. 2 shows one lateral reinforcement bar 1 of such a pre^¬ formed mesh seen in a direction of extension of the

assembly bars 2 (not shown in this view) , after the pre^¬ formed mesh has been bended into the intended final shape with hooks 3 at the ends. After bending the pre-formed mesh into the final shape, large diameter longitudinal bars (not shown) are inserted into the corners of the lateral bars 1 such that they extend substantially parallel to the

assembly bars 2, for reinforcement in the longitudinal direction. Then, the mesh with the longitudinal bars is embedded in concrete, i.e. the mesh is poured over with concrete. A resulting structure is shown in Fig. 3 where the mesh of the lateral reinforcement bars 1 and assembly bars 2 together with the longitudinal bars 4 is arranged in a block of concrete 5. In this structure, the lateral reinforcement bars 1 absorb lateral forces and the

longitudinal bars 4 absorb longitudinal forces.

It is the object of the invention to provide an improved structure for strengthening concrete and a method for producing such an improved structure.

The object of the invention is achieved with a structure for strengthening concrete and a method for producing a structure for strengthening concrete according to the independent claims.

Further advantageous developments of the invention are subject-matter of the dependent claims.

According to the invention, a structure for strengthening concrete comprises at least one bended mesh formed of a pre-formed mesh consisting of lateral bars arranged in parallel and assembly bars arranged in parallel, the assembly bars being arranged perpendicular to the lateral bars and connecting the lateral bars, and an outer cage formed of a pre-formed mesh consisting of lateral bars arranged in parallel and assembly bars arranged in

parallel, the assembly bars being arranged perpendicular to the lateral bars and connecting the lateral bars. In the structure the at least one bended mesh is placed inside the outer cage such that all assembly bars of the at least one bended mesh are enclosed by lateral bars of the outer cage. Accordingly, the structure as described above is constituted of at least two members each of which is formed of a pre-formed mesh, and which are inserted into each other. Thus, forces in the lateral direction of the

structure are absorbed from both the lateral reinforcement bars of the at least one bended mesh and the lateral reinforcement bars of the outer cage. As a result, the structure has excellent reinforcement properties, in particular when being subjected to lateral loads. Moreover, since each of the at least one bended mesh and the outer cage can be formed of a pre-formed mesh bended at a

plurality of positions (can be formed of a complex member) , an extremely complex final structure can be achieved.

Preferably, the lateral bars of the at least one bended mesh and the outer cage cross each other seen in the direction of extension of their assembly bars. With this construction, the reinforcement property is further

increased, also in the direction of extension of the assembly bars.

Preferably, portions of lateral bars of the at least one bended mesh defining a part of its outer circumference and portions of lateral bars of the outer cage defining a part of its outer circumference overlap each other seen in the direction of extension of their assembly bars. I.e. the portions of lateral bars of the at least one bended mesh and the outer cage are arranged one upon the other when looking at the structure in the direction of extension of the assembly bars. This has the advantage that the at least one bended mesh cannot be pulled out of the outer cage in the direction of extension of the assembly bars, but is held in the same. Accordingly, the structure is easy to handle and to mount. Preferably, the at least one bended mesh, when seen in the direction of extension of their assembly bars, has in one direction the same extension as the outer cage and has in a direction perpendicular to the one direction a smaller extension as the outer cage. This means that the at least one bended mesh flushes with the outer cage in the one direction so that, on the one hand, the at least one pre^¬ formed mesh cannot be pulled out of the outer cage (i.e. is securely held inside the outer cage) , and, on the other hand, the manageability of the whole structure may be improved. Further, the lateral bars of the at least one bended mesh do not project from the lateral bars of the outer cage in the lateral direction, thereby improving the usability of the structure.

Preferably, at least two bended meshes are inserted into each other such that their lateral bars cross each other seen in the direction of extension of their assembly bars. With at least two bended meshes inserted into each other and placed inside the outer cage, the reinforcement

capabilities of the whole structure are further increased, especially in the lateral direction of the structure.

Alternatively or additionally, it is also possible to arrange at least two bended meshes such that their lateral bars do not cross each other, and preferably also do not overlap with each other, seen in the direction of extension of their assembly bars. It is also possible to combine the at least two bended meshes having their lateral bars crossed with each other with one or more further bended meshes the lateral bars of which do not cross (and

preferably also do not overlap) with this at least two bended meshes having their lateral bars crossed with each other. In this regard, the lateral bars of the one or more further bended meshes can also cross with each other. Preferably, a total bending angle through which the lateral bars of the at least one bended mesh are bent is equal to or more than 90°. Preferably, a total bending angle through which the lateral bars of the outer cage are bent is equal to or more than 360°. This ensures a very high lateral reinforcement capability, in particular against lateral loads. Note that the above angles can be selected arbitrary as appropriate, e.g. a total bending angle through which the lateral bars of the at least one bended mesh are bent can be equal to or more than 180°, 270°, 360°, 450°, 540°, etc., and a total bending angle through which the lateral bars of the outer cage are bent can be equal to or more than 450°, 540°, 630 etc. In this respect, the lateral bars can be bent at a plurality of different positions. Also note that the total bending angle includes bending angles for forming attachment portions at the respective ends of the lateral bars for longitudinal bars to be inserted into the final structure in the longitudinal direction

(direction of extension of the assembly bars thereof) . In this respect, it is generally pointed out that longitudinal bars cannot only be placed at the above attachment portions but in arbitrary corners (e.g. in all corners) formed by the longitudinal bars of the structure.

Preferably, the outer cage is of a rectangular outer shape seen in the direction of extension of its assembly bars, wherein at least one assembly bar is arranged at each side. With this configuration, the structure is easy to handle and provides good stability when being arranged in use- position in order to be filled with concrete.

Alternatively, one or more sides of the outer cage can be free of assembly bars.

Preferably, a portion of the outer cage which has been bent after insertion of the at least one bended mesh is provided with at least one assembly bar. This configuration further ensures that the at least one bended mesh is securely held inside the outer cage.

The method for producing a structure for strengthening concrete according to the invention comprises the steps of a) providing at least one bended mesh formed of a pre^¬ formed mesh consisting of lateral bars arranged in parallel and assembly bars arranged in parallel, the assembly bars being arranged perpendicular to the lateral bars and connecting the lateral bars, b) providing an opened outer cage formed of a pre^¬ formed mesh consisting of lateral bars arranged in parallel and assembly bars arranged in parallel, the assembly bars being arranged perpendicular to the lateral bars and connecting the lateral bars, c) inserting the at least one bended mesh into the

opened outer cage, and

d) closing the outer cage.

According to this method, a structure as described above can be provided, i.e. a structure consisting of at least two members each of which absorbs loads in the lateral direction of the structure. Thus, with this method it is possible to produce a structure for strengthening concrete having excellent reinforcement capabilities. Furthermore, it is possible to produce highly complex structures for strengthening concrete very easily and with a very low number of steps. This results in low manufacturing costs.

Preferably, in step d) the outer cage is closed such that the lateral bars of the outer cage enclose all assembly bars of the at least one bended mesh. Preferably, in step d) , the opened outer cage is closed by bending the lateral bars of the opened outer cage along at least one axis substantially parallel to its assembly bars. This way of closing is very easy to achieve and may reduce the manufacturing costs.

Preferably, a total bending angle through which the lateral bars are being bent in step d) for closing the outer cage is equal to or more than 90°. Note that this angle can be selected arbitrary as appropriate for closing the outer cage, and can be e.g. equal to or more than 180°. In this respect, the lateral bars can be bended at a plurality of different positions.

Preferably, a portion of the opened outer cage being bent over in step d) is provided with at least one assembly bar. This ensures that the at least one bended mesh is securely held inside the closed outer cage.

Preferably, in step c) , the at least one bended mesh is inserted into the opened outer cage in a direction

substantially parallel to a plane formed by a lateral bar of the outer cage. I.e. the at least one bended mesh is inserted from the side of the opened outer cage. As a result, the structure is easy to assemble.

Preferably, in step a) , the at least one bended mesh is provided by bending the lateral bars of the pre-formed mesh at a plurality of positions along axis parallel to its assembly bars. Preferably, in step b) , the at least one outer cage is provided by bending the lateral bars of the pre-formed mesh at a plurality of positions along axis substantially parallel to its assembly bars. This is a very easy way of providing the at least one bended mesh/the outer cage. Thus it may be possible to keep manufacturing costs low.

Preferably, a total bending angle through which the lateral bars are being bent in step a) is equal to or more than 90°. Preferably, a total bending angle through which the lateral bars are being bent in step b) is equal to or more than 360°. This may lead to a superior reinforcing

capability of the resulting structure. The total bending angle referred to above is not limited to these angles, and a total bending angle can assume another value, especially a higher value. Preferably, the bending is performed in two different directions, on the one hand, clockwise and, on the other hand, counterclockwise.

Preferably, in step b) , the lateral bars of the pre-formed mesh are being bent from one end side of the lateral bars along plural axis substantially parallel to the assembly bars so as to form a partial cage with a portion of the lateral bars at the other end side projecting outwardly from the partial cage. Due to the formation of a partial cage, the reinforcing capability of the structure is further increased. In this respect, the portion of the lateral bars at the other end side projecting outwardly from the partial cage can itself be a cage structure, i.e. form a partial cage, and can be formed in the same manner as described above.

Preferably, a total bending angle through which the lateral bars are being bent to form the partial cage is equal to or more than 90°, preferably equal to or more than 180°, 270° or 360°. With these total bending angles, very good

strengthening capabilities may be achieved. Preferably, in step d) , for closing the outer cage, the portion of the lateral bars at the other end side

projecting outwardly from the partial cage is being bent over or the portion of the lateral bars including the partial cage is being bent over. This may ensure an easy closing of the outer cage. In the second case, the portion of the lateral bars including the partial cage can be bent over such that the partial cage projects into the interior of the at least one bended mesh seen in a direction of extension of their assembly bars (i.e. such that the portion of the lateral bars forming the partial cage and lateral bars of the at least one bended mesh cross each other) .

Preferably, the at least one bended mesh is inserted in step c) into the partial cage such that their lateral bars cross each other seen in a direction of their assembly bars. This further improves the strengthening capability.

Preferably, in step a) , at least two bended meshes are being provided and are inserted into each other such that their lateral bars cross each other seen in the direction of extension of their assembly bars, and in step c) , the at least two bended meshes with their lateral bars crossing each other are being inserted into the opened outer cage. The provision of such at least two bended meshes may further enhance the reinforcement capability of the whole structure .

Preferably, the structure for strengthening concrete produced according to the method of the invention is the structure as referred to above.

The invention will be described in more detail on the basis of preferred embodiments with reference to the drawings. Fig. 1 is a perspective view of a known pre-formed mesh.

Fig. 2 is a view of a lateral reinforcement bar of a known bended pre-formed mesh in the direction of extension of an assembly bar (not shown in the drawing) .

Fig. 3 is a schematic perspective view of a known structure for strengthening concrete.

Figures 4A to 4C show steps for producing a structure for strengthening concrete according to a first embodiment of the invention.

Figures 5A to 5D show steps for forming a structure for strengthening concrete according to a second embodiment.

Fig. 6 shows a bended mesh according to the invention.

Fig. 7 shows another bended mesh according to the

invention .

Fig. 8 shows bended mesh according to the invention.

Fig. 9A shows a structure for strengthening concrete according to the invention. Fig. 9B shows a bended mesh and an outer cage for forming the structure of Fig. 9A before assembly .

Fig. 10A shows another structure for strengthening concrete according to the invention. Fig. 10B shows two bended meshes and an outer cage for forming the structure of Fig. 10A before assembly. Fig. 11A shows another structure for strengthening concrete according to the invention. Fig. 11B shows two bended meshes and an outer cage for forming the structure of Fig. 11A before assembly.

Fig. 12A shows another structure for strengthening concrete according to the invention. Fig. 12B shows two bended meshes and an outer cage for forming the structure of Fig. 12A before assembly.

Fig. 13A shows another structure for strengthening concrete according to the invention. Fig. 13B shows two bended meshes and an outer cage for forming the structure of Fig. 13A before assembly.

Figures 14A to 14C each show a possible shape of a partial cage according to the invention.

At first, the structure for strengthening concrete and the method for producing such a structure is explained with reference to Figures 4A to 4C.

Fig. 4A shows a bended mesh 10 and an outer cage 20 before assembly. Both, the bended mesh 10 as well as the outer cage 20 are formed of a pre-formed mesh as shown in Fig. 1, i.e. of a pre-formed mesh consisting of a plurality of lateral bars arranged in parallel and a plurality of assembly bars arranged in parallel, wherein the assembly bars are arranged perpendicular to the lateral bars and are connecting the lateral bars.

Specifically, the bended mesh 10 is formed by bending lateral bars 12 of the pre-formed mesh (only one lateral bar 12 is shown Figures 4A to 4C) at seven positions around axes substantially parallel to assembly bars 11 thereof (Figs. 4A to shows the bended mesh 10 in the direction of extension of the assembly bars 11), 5-times by a bending angle of approximately 90° and 2-times by a bending angle of approximately 45°, wherein the bending is performed clockwise and counter-clockwise. Methods and apparatuses for bending pre-formed meshes are known from the prior art, for example from the application WO 2006/079639 Al of the applicant, the whole content of which is herewith

incorporated by reference. The longitudinal bars 12 are bended such that the resultant bended mesh 10 has a

rectangular outer shape and forms two substantially closed rectangular loops seen in the direction of extension of its assembly bars 11. The end bendings 13 of each lateral bar 12 (portions at the end being bended by 45°) constitute respective attachment portions for longitudinal bars (not shown) to be inserted in the direction of extension of the assembly bars 11 after completion of the structure. As pointed out before, longitudinal bars cannot be placed only at the above mentioned attachment portions, but in

arbitrary corners formed by the lateral bars of the

structure. Further, all assembly bars 11 (5 in this

embodiment) are arranged near one end side in the

longitudinal direction of the bended mesh 10. This is important in view of a later insertion of the bended mesh 10 into the outer cage 20.

The outer cage 20 which is shown in the open state in Fig. 4A is formed of a pre-formed mesh the lateral bars 22 of which having been bent at ten positions along axes

substantially parallel to its assembly bars 21, 8-times by a bending angle of approximately 90° and 2-times by a bending angle of approximately 45°. In particular, the lateral bars 22 have been bent from one end side thereof in order to form a partial cage 24 having a rectangular shape and forming three substantially closed rectangular loops, seen in the direction of extension of the assembly bars 21. Further, a portion 25 of the lateral bars 22 at their other end side projects outwardly (sideways) from the partial cage 24, wherein this projecting portion 25 itself is angled by 90°. Like the end bendings 13 of the mesh 10, the end bendings 23 of the lateral bars 22 constitute

respective attachments portions for longitudinal bars. The assembly bars 21 of the partial cage 24 are arranged near one end of the partial cage 24 in its longitudinal

direction (in the lower portion of the partial cage 24 in Fig. 4A) for enabling an insertion of the bended mesh 10 into the middle part of the outer cage 24, as will be described later.

Generally speaking, the assembly bars of a bended mesh (or a plurality of bended meshes) and of an opened outer cage have to be arranged such that there are no assembly bars connected to those portions of the respective lateral bars crossing each other or overlapping each other (seen in the direction of extension of the assembly bars) , when

inserting the bended mesh into the opened outer cage, i.e. the path of insertion needs to be free of assembly bars.

In the next step, shown in Fig. 4B, the bended mesh 10 is inserted from the opening formed by the projecting portion 25 into the partial cage 24. Concretely, the bended mesh 10 is inserted into the middle portion of the partial cage 24 until a portion of the lateral bars 12 of the bended mesh 10 defining the outer circumference of the bended mesh 10 at one end side in the longitudinal direction of the bended mesh 10 overlaps/flushes with a portion of the lateral bars 22 defining the outer circumference of the partial cage 24 at the width side thereof. It is possible to determine this position by means of the assembly bars 11 preventing a further insertion of the bended mesh 10 when abutting against the lateral bars 22. In the inserted state all assembly bars 11, 21 are substantially parallel to each other, and all lateral bars 12, 22 are substantially parallel to each other and arranged alternately on top of each other in the direction of extension of the assembly bars 11, 21.

Then, with the bended mesh 10 thus being inserted into the partial cage 24, the lateral bars 22 constituting the portion 25 are bent at one position around an axis

substantially parallel to the assembly bars 21 by a bending angle of 90° for closing the outer cage 20, thereby

completing the structure for strengthening concrete. The completed structure is shown in Fig. 4C. As can be gathered from Fig. 4C, the lateral bars 22 of the outer cage 20, in particular those portions of the lateral bars 22 which define its square outer circumference, enclose all assembly bars 11 of the bended mesh 10. Furthermore, each of the four outer sides of the closed outer cage 20 is provided with at least one assembly bar 21. Alternatively, one or more sides of the closed outer cage can be free of assembly bars. Also, the portions of the lateral bars 12 defining the outer circumference of the bended mesh 10 at the other end side (right end side in Fig. 4) flush and overlap with corresponding portions of the lateral bars 22 defining the outer circumference of the outer cage 20. In other words, those portions alternately lie on top of each other in the direction of extension of the assembly bars 11, 21. Apart from that, the lateral bars 12 of the bended mesh 10 and the lateral bars 22 of the outer cage 20 cross each other at a plurality of positions (nine positions in this embodiment) seen in the direction of extension of their assembly bars 11, 21. The completed structure is then provided with longitudinal bars, i.e. longitudinal bars are inserted into the

attachment portions 13, 23 and optionally into further corners formed by the lateral bars of the structure, and then the structure is poured over with concrete.

Figures 5A to 5D show steps of producing a structure for strengthening concrete according to a further embodiment.

At first, as shown in Fig. 5A, two bended meshes 10 and 30 are provided. The bended mesh 10 is the same as shown in Figures 4A to 4C. The mesh 30 is also formed of a pre^¬ formed mesh as described above. In particular, it is formed by bending lateral bars 32 of the pre-formed mesh at a plurality of positions (eight positions) substantially parallel to the axes of its assembly bars 31 into the shape of a "U", wherein each shank of the "U" is formed of a substantially closed loop seen in the direction of

extension of the assembly bars 31. As can be seen from Fig. 5A, all assembly bars 31 of the bended mesh 30 are provided near one longitudinal end of the bended mesh 30 (in the lower portion of the bended mesh 30 in Fig. 5a) . The end portions 33 of the lateral bars 32, which are angled by 45°, form respective attachment portions for longitudinal bars .

In the next step, as depicted in Fig. 5A, the bended mesh 10 and the bended mesh 30 are put into each other, i.e. either the bended mesh 10 is inserted into the bended mesh 30 or vice versa. The resultant structure is a complex cage, wherein the longitudinal axes of the bended mesh 10 and of the bended mesh 30 are arranged perpendicular to each other seen in the direction of extension of the assembly bars 11, 31 arranged in parallel. In the complex cage, the lateral bars 12 and the lateral bars 32 cross each other at twelve positions seen in the direction of extension of the assembly bars 11, 31.

Then, as shown in Fig. 5B, an opened outer cage 40 is provided. The opened outer cage 40 is formed of a pre^¬ formed mesh in the same manner as the outer cage 20. In particular, lateral bars 42 of the pre-formed mesh are bent at one side (right side in Fig. 5B) so as to form a partial cage 44 having a rectangular shape and forming of one substantially closed loop, while at the other end side the lateral bars 42 are angled in 90° and project outwardly from the partial cage 44, thereby forming a projecting portion 45. Besides, the ends of the lateral bars 42 angled in 45° form respective attachment portions 43 for

longitudinal bars.

Next, the complex cage consisting of the bended mesh 10 and the bended mesh 30 is inserted from a side of the opened outer cage (substantially from above in this embodiment) into the opened outer cage 40. Specifically, the complex cage is inserted into a corner of the projecting portion 45 such that all assembly bars 11, 31, 41 are arranged

substantially in parallel, as shown in Fig. 5C, and all lateral bars 12, 32, 42 alternately lie on top of each other in the direction of extension of the assembly bars 11, 31, 41.

In the following step, the lateral bars 42 including the portion forming the outer cage 44 are bended over at one position by 90° such that the outer cage 44 is partly inserted into the bended mesh 30 (i.e. such that the lateral bars 42 and the lateral bars 32 cross each other seen in the direction of extension of the assembly bars) , thereby closing the outer cage 40 and completing the structure for strengthening concrete. The completed structure is shown in Fig. 5D. In the completed structure, the lateral bars 42 of the outer cage 40 (specifically the portions of the lateral bars 42 defining the outer

circumference of the outer cage 40) enclose all assembly bars 11, 31 of the bended meshes 10, 30. Further, the bended mesh 10 has the same outer extension as the outer cage 40 in the direction of the longitudinal extension of the bended mesh 10, and the bended mesh 30 has the same outer extension as the outer cage 40 in the longitudinal direction of the bended mesh 30 (the bended meshes 10, 30 do not project from the outer circumference of the outer cage 40 defined by its lateral bars 42) . Also, portions of the lateral bars 12 of the bended mesh 10 defining the outer circumference at the longitudinal ends of the bended mesh 10 and portions of the lateral bars 42 of the outer cage 40 defining the outer circumference of the outer cage 40 overlap with each other (i.e. are arranged on top of each other in the direction of the extension of the

assembly bars 11, 41) . In the same way, portions of the lateral bars 32 forming the outer circumference of the bended mesh 30 at the longitudinal ends overlap with respective portions of the lateral bars 42. Further, the lateral bars 42 of the outer cage 40 cross the lateral bars 32 of the bended mesh 30 at a plurality positions (four positions in this embodiment) .

The completed structure is then provided with longitudinal bars, i.e. longitudinal bars are inserted into the

attachment portions 13, 33, 43 and optionally into further corners formed by the lateral bars of the structure, and then the structure is poured over with concrete.

Figures 6 to 8 show further possible shapes of bended meshes, which can also be combined with each other. Each of Figures 6 to 8 is a view onto lateral bars of the respective bended mesh in the direction of extension of assembly bars which are not shown.

Specifically, Fig. 6 shows a bended mesh where only the lateral bars at the end portions of a pre-formed mesh

(having the configuration as described above) have been bent by a bending angle of about 45° in order to form attachment portions for longitudinal bars.

Fig. 7 shows a bended mesh the lateral bars of which have been bent substantially in the shape of a "U" . One shank of the "U" is formed of two substantially closed loops and constitutes a first rectangular partial cage, and the other shank is formed of one substantially closed loop and constitutes a second rectangular partial cage. Further, with respect to the bending direction, the first partial cage comprises six clockwise bends and the second partial cage comprises four counter-clockwise bends.

The bended mesh of Fig. 8 is the same as that of Fig. 7 except for that each shank of the "U" is formed of two substantially closed loops.

Figures 9A to 13A show different structures for

strengthening concrete according to the invention which can be produced by the method according to the invention, wherein Figs. 9B to 13A shows the respective bended meshes and outer cages before assembly. Each of Figures 9A to 13A and 9B to 13B is a view onto lateral bars of the respective structure in the direction of extension of assembly bars.

The structure of Fig. 9A consists of one bended mesh forming three rectangular substantially closed loops and being inserted into an outer cage. In Fig. 9B the bended mesh is shown before insertion into the outer cage. The structure of Fig. 10A consists of two bended meshes having substantially the shape of the bended mesh 30 and a bended mesh having the shape shown in Fig. 6. Here, the bended mesh having the shape shown in Fig. 6 is inserted into the two bended meshes having substantially the shape of the bended mesh 30. All three bended meshes are inserted into an outer cage forming a partial cage at one side (left side in Fig. 10) . In Fig. 10B the bended meshes are shown before insertion into the outer cage.

The structure of Fig. 11A consists of two adjacent and parallel arranged bended meshes having a rectangular shape and forming one loop (as depicted in Fig. 2) and two bended meshes each having the shape of the bended mesh 30 as described above (in Fig. 11B the bended meshes are shown before insertion into the outer cage) . The two bended meshes having a rectangular shape and forming one loop are inserted into the two bended meshes having the shape of the bended mesh 30 and arranged adjacent and parallel to each other such that they are also arranged adjacent and

parallel to each other in the two bended meshes having the shape of the bended mesh 30. As can be seen from Fig. 11B, the lateral bars of the two bended meshes having a

rectangular shape and forming one loop do neither cross nor overlap with each other seen in the direction of their assembly bars, and also the lateral bars of the two bended meshes having the shape of the bended mesh 30 do neither cross nor overlap with each other seen in the direction of their assembly bars. Further, the lateral bars of each of the two bended meshes having a rectangular shape and forming one loop crosses the lateral bars of both bended meshes having the shape of the bended mesh 30. Further, longitudinal axes of the two bended meshes each having the shape of the bended mesh 30 are perpendicular to longitudinal axes of the two adjacent and parallel arranged bended meshes. All bended meshes are inserted into an outer cage forming a single loop, as shown in Fig. 11A.

Fig. 12A shows a construction consisting of a rectangular outer cage with a partial cage and two bended meshes

(bended like the mesh 30) which are placed inside the outer cage. The two bended meshes are arranged parallel and adjacent to each other, but do not overlap/cross each other. Fig. 12B shows the bended meshes before insertion into the outer cage.

Fig. 13A shows a similar construction to Fig. 11B, with the two bended meshes having the shape of the bended mesh 10 instead of the bended mesh 30. Fig. 13B shows the bended meshes before insertion into the outer cage.

Figures 14A to 14C show different shapes that are

considered to be a "partial cage" according to the

invention. The shape of Fig. 14A is achieved by bending lateral bars of a pre-formed mesh at six positions with a total bending angle of substantially 495° (5x90° + 1x45°) thereby forming two substantially closed loops (seen in the direction of extension of corresponding assembly bars not shown) . The shape of Fig. 14B is achieved by bending lateral bars at four positions with a total bending angle of 315° (3x90° + 1x45°), thereby forming a substantially closed loop. The shape of Fig. 14C is achieved by bending lateral bars at a first position by 90° and at a second position by 45°. The above described structures are merely examples for a partial cage and do not limit the term partial cage in any aspect.

Claims

1. A structure for strengthening concrete comprising

at least one bended mesh formed of a pre-formed mesh consisting of lateral bars arranged in parallel and

assembly bars arranged in parallel, the assembly bars being arranged perpendicular to the lateral bars and connecting the lateral bars, and

an outer cage formed of a pre-formed mesh consisting of lateral bars arranged in parallel and assembly bars arranged in parallel, the assembly bars being arranged perpendicular to the lateral bars and connecting the lateral bars,

wherein the at least one bended mesh is placed inside the outer cage such that all assembly bars of the at least one bended mesh are enclosed by lateral bars of the outer cage .

2. The structure according to claim 1, wherein lateral bars of the at least one bended mesh and the outer cage cross each other seen in the direction of extension of their assembly bars.

3. The structure according to claim 1 or 2, wherein

portions of lateral bars of the at least one bended mesh defining a part of its outer circumference and portions of lateral bars of the outer cage defining a part of its outer circumference overlap each other seen in the direction of extension of their assembly bars.

4. The structure according to any one of claims 1 to 3, wherein the at least one bended mesh, seen in the direction of extension of their assembly bars, has in one direction the same extension as the outer cage and has in a direction perpendicular to the one direction a smaller extension as the outer cage.

5. The structure according to any one of claims 1 to 4, comprising at least two bended meshes inserted into each other such that their lateral bars cross each other seen in the direction of extension of their assembly bars, and/or at least two bended meshes arranged such that that their lateral bars do not cross each other, and preferably do not overlap with each other, seen in the direction of extension of their assembly bars.

6. The structure according to any one of claims 1 to 5, wherein

a total bending angle through which the lateral bars of the at least one bended mesh are bent is equal to or more than 90°, and/or

a total bending angle through which the lateral bars of the outer cage are bent is equal to or more than 360°.

7. The structure according to any one of claims 1 to 6, wherein the outer cage is of a rectangular outer shape seen in the direction of extension of its assembly bars, wherein at least one assembly bar is arranged at each side or at least one side is free of assembly bars.

8. A method for producing a structure for strengthening concrete comprising the steps of

a) providing at least one bended mesh formed of a pre-formed mesh consisting of lateral bars arranged in parallel and assembly bars arranged in parallel, the assembly bars being arranged perpendicular to the lateral bars and connecting the lateral bars,

b) providing an opened outer cage formed of a pre^¬ formed mesh consisting of lateral bars arranged in parallel and assembly bars arranged in parallel, the assembly bars being arranged perpendicular to the lateral bars and connecting the lateral bars,

c) inserting the at least one bended mesh into the opened outer cage, and

d) closing the outer cage.

9. The method according to claim 8, wherein in step d) the opened outer cage is closed by bending the lateral bars of the opened outer cage along at least one axis substantially parallel to its assembly bars.

10. The method according to claim 9, wherein a total bending angle through which the lateral bars are being bent in step d) for closing the outer cage is equal to or more than 90°.

11. The method according to any one of claims 8 to 10, wherein in step c) the at least one bended mesh is inserted into the opened outer cage in a direction substantially parallel to a plane formed by a lateral bar of the outer cage .

12. The method according to any one of claims 8 to 11, wherein

in step a) the at least one bended mesh is provided by bending the lateral bars of the pre-formed mesh at a plurality of positions along axes substantially parallel to its assembly bars, and/or

in step b) the outer cage is provided by bending the lateral bars of the pre-formed mesh at a plurality of positions along axes substantially parallel to its assembly bars .

13. The method according to claim 12, wherein a total bending angle through which the lateral bars are being bent in step a) is equal to or more than 90°, and/or

a total bending angle through which the lateral bars are being bent in step b) is equal to or more than 360°.

14. The method according to any one of claims 8 to 13, wherein

in step a) at least two bended meshes are being provided and are inserted into each other such that their lateral bars cross each other seen in the direction of extension of their assembly bars, and

in step c) the at least two bended meshes with their lateral bars crossing each other are being inserted into the opened outer cage.

15. The method according to any one of claims 8 to 14, wherein the produced structure for strengthening concrete is the structure according to any one of claims 1 to 7.