WO2007030836A1

WO2007030836A1 - Concrete reinforcement structure and process for making the same

Info

Publication number: WO2007030836A1
Application number: PCT/VN2006/000005
Authority: WO
Inventors: Duc Thang Do
Original assignee: Duc Thang Do
Priority date: 2005-09-06
Filing date: 2006-08-21
Publication date: 2007-03-15

Abstract

The present invention relates to a concrete reinforcement structure and process for making the same with low initial investment, high quality and low price. To attain the above purpose, process for making a concrete reinforcement structure according to the invention comprises the steps of: welding the transverse bars (5) having bent ends (6) to longitudinal bars (3, 4) with a spot welding machine to form a mesh; transforming said mesh into V-shape to obtain a girder having cross- section of V-shape and the bent ends (6) of said transverse bars orthogonal with the center axis (C) of V-shape; preparing a lower plate (2) with convex indentation (7, 8) in predetermined places; locating said girder on lower plate; and welding bent ends (6) of the transverse bars to lower plate (2). Thereby, it is possible to obtain reinforcement structure comprising a lattice-like girder in inverted V-shape connected with the lower plate (2) by welding.

Description

CONCRETE REINFORCEMENT STRUCTURE AND PROCESS FOR MAKING THE SAME

Technical Field

The present invention relates to a building construction and more particularly, the invention provides a concrete reinforcement structure for concrete slaps or walls that allow producing a concrete slap in an industrial scale and making light-weighted and low-cost concrete slaps, shortening the time of building process and carefully controlling the quality of the buildings. This invention also discloses the process for making this concrete reinforcement structure.

Description of Related Art

The concrete reinforcement structures are widely used in building of the civil and industrial construction due to their high load bearing capacity and duration of use. Conventionally, the concrete reinforcement structures are produced by laying a reinforcement system in the form of steel wire mesh on the formwork supported by pillars, the formwork is surrounded by casing to form an open space and concrete is poured into this space and rammed. After concrete is completely hardened and reaches a required strength, the casing, formwork and pillars are removed to form a concrete floor or wall. The reinforcement systems usually comprise longitudinal and transverse bars disposed in a predetermined interval and tied with each other by a thin steel wire to form a mesh with rectangular or square netting. Depending on the required strength of the concrete slaps, two meshes can be bound together by spacer bars to form a three-dimensioned reinforcement structure.

One of the drawbacks of this conventional reinforcement is that the reinforcement is usually prepared in-situ, the steel bars are tied together by hand, therefore the labour cost is high and the time for preparing is very long. Moreover, since the bars are tied by hand, the size of mesh is unstable, even does not satisfy with the requirements, therefore badly affect to the quality of the construction. Moreover, this conventional method requires high cost for preparing formwork and pillar system before pouring concrete into and the cost for their removing afterward.

It is known that a concrete reinforcement was disclosed in British Patent No. 1344896 published on January 23, 1974. As shown in the drawings of Fig. 1 to Fig. 4 and Claim 1 of this Patent, the concrete reinforcement comprises several inverted V- sectioned lattice-like girder with longitudinal bars and diagonals, and a lower mesh- like reinforcement with longitudinal and transverse bars and the diagonals are brought outside of the longitudinal bars of the girder and in diagonal direction of the girder on side view, the diagonals have bent ends, which are engaged below the longitudinal bars of the mesh. The characterizing features of this structure are that the ends of the diagonals are bent outwards, and these diagonals are pre-loaded to engage between the longitudinal mesh bars and then remain stressed, and therefore, there is no need to use steel wire to tie the girder to the mesh, and the bottom longitudinal bars of girder are disposed on the diagonals bearing on the transverse mesh bars, and therefore the engagement of the girder and the mesh is stable.

The above-mentioned reinforcement structure has several advantages in comparison with conventional structure in that the structure can be prefabricated and thereby it is possible to reduce manpower in assembling the structure to their place in the building construction. However, this Patent did not disclose any information relating to the process of manufacture of reinforcement structure. Accordingly, (1) if the lower mesh is prepared by hand, some of the labour cost for making the mesh will still be needed, and since the intervals between the longitudinal mesh bars are unstable, the positioning of the girder to the mesh will be unstable too, and (2) if the lower mesh is engaged with the girder in advance, then due to low resilient property of the construction steel, even when the girders are engaged with the mesh in stressed state, the structure may be deformed during their transportation from factory to the construction site and positioning to their places in the construction. Furthermore, since the girder is just engaged with the mesh, it is difficult to ensure a force- transmitting connection between the girder and the mesh. Moreover, the cost for preparing formwork and pillar system before pouring concrete into and the cost for their removing afterward can not be avoided.

There is another reinforcement structure provided by Kosteel M&C Co., Ltd., South Korea, and has structure similar to the structure disclosed in French Patent No. FR279350 published on 20.10.2000. In comparison with the structure of British Patent No. 1344896, instead of using a lower mesh, the South Korea's company makes use of a steel plate or strip having convex indentation on its surface to increase the strength and serve as base for welding the girder thereto. The girder in this structure also has an inverted V-shape comprising three (3) longitudinal bars, but instead of using diagonals, it uses two sinuous steel wires, the upper apexes of which are welded to the sides of the upper longitudinal bar along their length and the lower apexes are bent outwardly in order to be placed on the convex indentation of lower plate while two other longitudinal bars are welded outside of the sinuous steel wire.

This structure allows using lower steel plates as a formwork, thereby the cost for preparation of the formwork and to remove them afterward can be eliminated. However, this structure is very complicated to manufacture. It requires locating the upper apexes of the sinuous wire on the opposite sides of the upper longitudinal bar before welding. Therefore, there is a need to use special apparatus or machine with high cost to perform this operation. That means the investment for manufacturing apparatus are very high making the cost of the reinforcement structure increase. Moreover, it is necessary to use several girders on the lower plate. In one embodiment that has been put into the market by Kosteel M&C Co., Ltd., three girders are used on the plate which is 60cm in width. That means the quantity of material to be used increases, making the cost of the reinforcement structure even higher.

Disclosure of the Invention

In order to cope with the above problems, the present invention is made and the purpose of the invention is to provide a concrete reinforcement structure having simple structure, low material expenses, easy to make and, therefore, low manufacturing cost while sufficiently satisfying the requirements of high strengthened concrete slaps.

In order to attain the above purposes, according to the first aspect of the invention as cited in Claim 1, there is provided a concrete reinforcement structure comprising a lattice-like girder having an inverted V-shape formed by longitudinal bars inside the V-shape and transverse bars bringing outside of said longitudinal bars, two opposite ends of said transverse bars are bent outside and connected with a lower plate, characterized in that, the lower plate is a steel plate having convex indentations and the bent ends of the transverse bars are orthogonal to the center axis of the V- shape to form a leg of the girder for placing on the lower plate and welded to the lower plate on said convex indentations.

According to one of the embodiments of the invention, the transverse bars are located orthogonal to longitudinal bars.

Since the reinforcement structure is simple, easy to produce and does not require investment in an expensive manufacturing apparatus, it is possible to reduce the cost of the structure according to the invention.

According to another embodiment of the invention, the transverse bars are located inclined to longitudinal bars so that the apex of the V-shapes of two adjacent transverse bars are located on longitudinal bar at apex of the V-shapes and the bent ends of said transverse bars is located near to the bent ends of next transverse bar on the lower plate.

It is clearly that positioning the transverse bars inclined to the longitudinal bars make the process of manufacturing becomes more complicated but it can be easily solved by a process according to the invention as described latter, while the load bearing of the concrete slap mounded by using this structure can be remarkably increased with such arrangement.

According to still another embodiment of the invention, structure comprises additional convex indentations formed on the lower plate in places other than said convex indentations. Since the girder is positioned stably on the lower plate and firmly welded to this lower plate and the additional convex indentation the force-transmitting connection between lower plate and the girder is improved. This allows increasing the rigidity of the structure and decreasing the number of girder to be used on lower plate having the same width as that of the known structure and therefore, decreasing the material cost for making the structure according to the invention.

The next purpose of the invention is to provide a process for making a concrete reinforcement structure that allows producing such a structure with simple apparatus and at low cost.

In order to attain the above purposes, according to the second aspect of the invention as cited in Claim 6, there is provided a process for making a concrete reinforcement structure comprising the steps of: welding the transverse bars having bent ends to longitudinal bars with a spot welding machine to form a mesh; transforming said mesh into V-shape to obtain a girder having cross-section of V- shape and the bent ends of said transverse bars orthogonal with the center axis of V- shape; preparing a lower plate with convex indentation in predetermined positions; locating said girder on lower plate; and welding bent ends of the transverse bars to the lower plate.

With such a process, the manufacturing of the reinforcement structure having the features described in the first aspect of the invention can be performed by simple apparatus which are easy to make such as spot welding machine for making the mesh, rolling machine for performing the mesh into the V-shaped girder and another spot welding machine to weld the girder to lower plate. Consequently, it is possible to reduce the initial investment and reduce the cost of the product. Besides, the process also allows increasing productivity and an automatization the process of manufacturing. Therefore, the cost of the product can be further reduced.

According to the next embodiment of the invention, steps of transforming the mesh into V-shape is performed by a rolling machine or by a metal sheet folding machine. Thereby, the initial investment can be further reduced. Brief Description of the Drawings

The above and other purposes and advantages of the invention will be further described hereinafter by the way of their preferred embodiments with the reference to the attached drawings, in which:

Fig. 1 is a front view showing a reinforcement structure according to the invention;

Fig. 2 is a side view of the reinforcement structure according to one of embodiment of the invention;

Fig. 3 is a perspective view illustrating the reinforcement structure shown in Fig. 2;

Fig. 4 is a perspective view illustrating the reinforcement structure according to another embodiment of the invention;

Fig. 5 is a perspective view illustrating the reinforcement structure shown in Fig. 4;

Fig. 6 is a perspective view illustrating the mesh before transforming into V- shape, in which Fig. 6a shows a mesh for forming structure in Fig. 2 and Fig. 3, and Fig. 6b shows a mesh for forming structure in Fig. 4 and Fig. 5;

Fig. 7 is a perspective view illustrating the step of transforming the mesh into a V-shape girder according to the process of making a reinforcement structure according to the invention;

Fig. 8 is a perspective view illustrating the step of welding the V-shape girder on the lower plate according to the process of making a reinforcement structure according to the invention; and

Fig. 9 is a perspective view illustrating an arrangement of the reinforcement structure according to the invention into their position in the building construction.

Detailed Description of the Preferred Embodiments of the Invention

Referring to drawing from Fig. 1 to Fig. 3, a reinforcement structure according to the invention comprises two lattice-like girders 1 in the form of an inverted V-shape with the height of H and the width of W welded to a lower plate 2 and located apart from each other by interval L on the lower plate 2. Each of the girders 1 is formed by a longitudinal bar 3 on the apex of V-shape and at least two longitudinal bar 4, each on one side of the V-shape and the V-shape transverse bars 5, which are is bringing over outside of the longitudinal bars 3, 4 and located at equal intervals along of the girder 1. However, the number of the longitudinal bars 4 on each side of the V-shape may be more than two. The opposite ends 6 of the transverse bars 5 are bent outwardly so that they perpendicular to the center axis C of the V- shape to form a base of the girder 1 allowing to locate it on the lower plate 2 and welded thereto.

The lower plate 2 is a steel plate having convex indentations 7, which runs along the length of the lower plate and is formed in positions corresponding with the ends 6 of the girder 1 to increase its strength and facilitate the welding of the ends 6 of the girder 1 to the lower plate 2. Furthermore, an additional convex indentation 8 is also formed on the lower plate 2 in the space between the girders 1 and/or inside of the V-shaped girder 1. Two opposite edges 9 of the lower plate 2 are folded in opposite directions, one edge is folded upwardly while the other edge is folded downwardly so that one edge of the lower plate can be engaged with the other edge of the next lower plate to form a surface that is substantially planar and without the gap therebetween.

In the above structure, since the ends 6 of the transverse bars 5 are formed on the same plane, they together form a base to facilitate the positioning and firmly welding the girder 1 to the lower plate 2. This contributes to increasing e a load bearing capacity of the concrete slaps using this reinforcement structure.

The reinforcement structure according to another embodiment of the invention is shown in Fig. 4 and Fig. 5. In general, the reinforcement structure according to this embodiment is similar to the one shown in Fig. 1 to Fig. 3 except the fact that the transverse bars 5 are located inclined to longitudinal bars 3, 4 so that the apex of the V-shape of two adjacent transverse bars 5 are located side-by-side with each other on the longitudinal bar 3 at the apex of the V-shape and the bent ends of the transverse bar 5 are located side-by-side with the bent ends of the following transverse bar 5 on the lower plate. Preferably, the transverse bars 5 are inclined at the angle of 45° to the longitudinal bars 3, 4.

With this structure, load-bearing capacity of the reinforcement structure according to the invention can be further increased. This allows using a light concrete slurry (density of approx. 800 kg/m³) to make the concrete slaps.

Process for making the reinforcement structure according to the invention will be described hereinafter with reference to the drawings from Fig. 6 to Fig. 8.

As shown in Fig. 6, the first step of the process comprises welding the transverse bars 5 having the bent ends 6 to the longitudinal bars 3, 4 to form a mesh. The bent angle of the ends 6 to the transverse bar 5 is calculated so that after bending the mesh into V-shape as described later, the ends 6 will be perpendicular to the center axis C of the V-shape. In case of the reinforcement structure according to the first embodiment of the invention shown in Fig. 1 to Fig. 3, the transverse bars 5 are substantially straight (see Fig. 6a), while in case of the reinforcement structure according to the second embodiment of the invention shown in Fig. 4 and Fig. 5, the transverse bars 5 has a substantially V-shape, in which the apex of the V-shape of two next transverse bars located on the central longitudinal bar 3, and the bent ends 6 of the transverse bars 5 are located next to the bent ends 6 of the following transverse bar 5 alternatively (see Fig. 6b).

Conveniently, if the welding is performed by a spot welding machine (not shown in Figures) in which the longitudinal bars 3, 4 are fed into the welding machine step by step, the interval of which corresponds to the distance between the transverse bars 5 as desired, then the transverse bars 5 is fed onto the longitudinal bars 3, 4 and are welded thereto by clamps of the spot welding machine. This allows the welding the transverse bars 5 onto longitudinal bars 3, 4 be quickly with high quality and facilitate the automatization of the process.

Next, in the second step of the process as shown in Fig. 7, the obtained mesh is transformed into the V-shape girder 1 by the rolling machine. In general, the rolling machine comprises a series of rolls 10 having outer appearance of V-shape which serves as upper mould and a V-shape rack 11 surrounding the rolls and serves as a lower mould. The mesh obtained in the first step is fed into the rolling machine in the state that the central longitudinal bar 3 comes into the apex of the V-shape of the rack 11. Therefore, after passing the rolling machine, the planar mesh obtained in the first step will be transformed into the V-shape girder 1, in which the longitudinal bar 3 will be located at the apex of the V-shape, side bars 4 will be located inside of V- shape and the bent ends 6 extends outwardly and perpendicular to the center axis C of the V-shape as shown in Fig. 1. Number of rolls 10 and the appearance of each roll should be selected so that after passing the rolling machine, the V-shape of the girder 1 remains stable state.

The using of the rolling machine as described above can be applied to the mesh with unlimited length. For the mesh with limited lengths due to the reason that the longitudinal bars 3, 4 having diameter of 10mm or more are usually supplied in the form of bars with the length of 12m, it is possible to use a folding machine similar to the steel trip folding to transform the mesh shown in Fig. 6 into the girder 1. That is the known apparatus can be used for producing the girder according to the invention and therefore the initial investment can be reduced.

In the third step of the process, the lower plate 2, in general comprising of a steel plate or strip having convex indentation 7, 8 and folded edges 9 is prepared. The lower plate 2 may not be prepared at the same time or in order of steps of process but in advance. It should be noted that the convex indentation 7 is formed in positions, the interval of which is a little larger than the width W of the girder 1 and along the lower plate 2 where the girder 1 will be placed on as described below, and the additional convex indentation 8 can be formed with any form and in any other positions on the lower plate 2 in order to improve its strength.

Next, in the fourth step of the process shown in Fig. 8, the V-shape girder 1 is put on the lower plate 2 so that the bent ends 6 of the transverse bars 5 lied on the convex indentation 7 of the lower plate 2; and the final step is to weld the bent ends 6 of the transverse bars 5 on the girder 1 to the lower plate 2 to obtain the reinforcement structure according to the invention. The above described allows an automatization of the process and producing the reinforcement structure according to the invention by using simple apparatus and machines which are easy to make. Hence, the reinforcement structure according to the invention can be produced with high productivity, low initial investment, and therefore the manufacturing cost can be reduced.

The method of using the reinforcement structure according to the invention will be described with reference to Fig. 9. As shown in this figure, the reinforcement structures are prefabricated in a factory and transported to the construction site and then, arranged into the position in the building so that two ends of the of the reinforcement plate are supported on the girder 12 of the building and the edges 9 of the two adjacent plates engaged with each other to form a substantially planar surface without a gap therebetween.

Advantageously, if the girder 12 is also a hollow girder as shown in Fig. 9 and the concrete pouring for the slaps and girder 12 takes place simultaneously. Consequently, it is possible to obtain a slap with flush top and bottom, that is, the viewer can not observe the girder 12 after the slaps are completed. This may bring up an aesthetic effect for the building and facilitate the arranging interior facilities afterward.

After the reinforcement plates are properly supported by pillars or columns and suiTOunded by formwork, a light concrete slurry (with the density approx. 800 kg/m³) is poured into the space formed thereby and rammed. The formwork can be removed when the concrete hardened and reach the required strength.

Example

As an experiment, the inventor has made a concrete slap by using the reinforcement structure according to the second embodiment of the invention as described and shown in Fig. 4 and Fig. 5. The girder 1 is formed with the high H (see Fig. 1) of 180mm and the width W of 150mm. The longitudinal bar 3 at the apex of V-shape has diameter of 20mm and the longitudinal bar 4 on both sides of the V- shape has diameter of 16mm, the transverse bar 5 has diameter of 10mm, the angle of inclination of the transverse bar 5 to the longitudinal bars 3, 4 is 45°, lower plate 2 is a steel strip having the thickness of 0,5mm, the length of 4m and the width of 630mm. Two girders 1 are arranged on the lower plate at a distance L of 300mm.

Next, the above reinforcement structure is surrounded by a formwork from four sides and poured with a light concrete slurry (with the density approx. 800 kg/m³) to form a concrete slap with the dimension of 4m x 0,63m x 0,2m.

After 16 days from pouring, the received concrete slap is subjected to a statistic loading test for determining a deformation at the Institute of building construction structure of Vietnam. The test was carried out by loading the weights, each of which weighted approx. 25kg, on the slap supported on both ends, and the deformation of the slap was measured by using a portable deformation measuring apparatus under the trademark of MASTEST, made by Italy, a deflectometer with accuracy of 10^"2 mm and microscope with magnification of 4Ox, made by Russia. The loading is made step by step, each step comprises putting 8 weighted pieces, equivalent to 200kg on the slap and to maintain this state at least 10 minutes before the next loading until reach the last loading of 2400kg, equivalent to 1000 kg/m² and the last loading is also maintained within 10 minutes. Then, unloading is carried out to zero with a magnitude of two steps, that means in each of unloading comprises of removing 16 weighted pieces, equivalent to 400kg. Each unloading is carried out with the interval of 5 minutes and the data of displacement or deformation is recorded.

As a result of the test, the following data was recorded.

Upon the 8^th loading, equivalent to 1600 kg or 667kg/m², a slit of 0,08mm starts appearing on the slap tested. The width of the slit increases to 0,15mm upon the last loading; equivalent to 2400kg or 1000kg/m² but the structure of the slap is not destroyed. At the same time, when the unloading is completed (to zero), the slip disappears.

With regard to the displacement, at the last loading the deflection of the slap is 9,58mm and when the unloading is completed (to zero), the deflection of the slap is 0,67mm. That means the permanent deflection comprises about 7% of maximum measured deflection. That is, a load-bearing ability of the slap using the reinforcement structure according to the invention satisfies the requirement of the concrete slaps that are usually used in civil and industrial construction.

Effects of the Invention

With the structure according to the first aspect of the invention, it is possible to produce a reinforcement structure that is simple, easy in manufacture and allow to substantially shortening the time of erection of the construction.

Furthermore, in the structure according to one of the embodiments of the invention, since the transverse bars are located inclined to longitudinal bars so that two apexes of the V-shape of two adjacent transverse bars lie side-by-side on the longitudinal bar at the apex of the V-shape and the bent ends of the transverse bars lied side-by-side with the bent ends of the next transverse bar on the lower plate, the load-bearing capacity of the structure according to the invention can be substantially improved.

Moreover, since the load-bearing capacity between the lower plate 2 and the girder 1 can be increased and the girders 1 are stably located on the lower plate 2. It is possible to reduce number of the girder and hence to reduce the cost of the products. Indeed, for the lower plate having the width of 60cm, it is enough to use two girders while Kosteel M&C Co., Ltd of Korea needs three girders for the same width of the lower plates. This allows reducing the material to be used and therefore to further reduce the cost of the products.

Due to the high load-bearing capacity of the reinforcement structure according to the invention, it is possible to use light concrete (with the density of approx. 800 kg/m³) to make the concrete slap while conventional concrete has a density up to 2500 kg/m³. Therefore, the weight of the building construction can be reduced and it contributes to the reduction of the cost for preparing a building basement.

In addition, by using the reinforcement structure according to the invention, it is possible to obtain a slap with flush top and bottom surfaces with high aesthetic effects. And, by using the lower plate as a part of formwork, the expenses for preparing the formwork and its removing can be eliminated.

The next advantage of the invention lies in the process of manufacturing of the reinforcement structure according to the second aspect of the invention.

With such a process, the manufacturing of the reinforcement structure can be performed with simple and easy to make apparatus and machines such as spot welding machines for making a mesh, rolling machine for transforming the mesh into the V-shape girder and another spot welding machines for welding of the V-shape girder to the lower plate. Consequently, it is possible to reduce the initial investment, and thereby to reduce the cost of the products. In addition, the process is productive and can be automatized. Therefore, the cost of the products can be further reduced.

Furthermore, instead of using a rolling machine, it is possible to use a metal sheet folding machine to transform a mesh into the V-shape girder 1. This allows further reducing the investment for the manufacturing apparatus.

Besides, since the reinforcement structure is prefabricated in the factory the accuracy of the structure is ensured. This allows improving the quality of the reinforcement structure and hence improving the quality of the final products (concrete slaps) irrespective to the skill of the workers.

The invention is described above by the way of its preferred embodiments which serve as illustration example only and the invention is not limited in these preferred embodiments but many other changes, modifications and improvements may be made thereto without departing from the scope of the invention as defined in the following Claims.

Claims

1. A concrete reinforcement structure comprising a lattice-like girder (1) having an inverted V-shape formed by longitudinal bars (3, 4) inside of the V-shape and transverse bars (5) bringing outside of said longitudinal bars (3, 4), two opposite ends (6) of said transverse bars (5) are bent outside and connected with a lower plate (2), characterized in that, the lower plate (2) is a steel plate having convex indentations (7) and said bent ends (6) of the transverse bars (5) are bent orthogonal to the center axis (C) of the V-shape to form a leg of the girder for placing on the lower plate (2) and welded to the lower plate (2) on said convex indentations (7).

2. The structure according to Claim 1, characterized in that, the transverse bars (5) are located orthogonal to longitudinal bars (3, 4).

3. The structure according to Claim 1, characterizing in that, the transverse bars (5) are located inclined to longitudinal bars (3, 4) so that the apex of the V-shapes of two adjacent transverse bar (5) located on longitudinal bar (3) at the apex of the V-shapes and the bent ends (6) of said transverse bars (5) is located near to the bent ends (6) of the next transverse bar (5) on the lower plate (2).

4. The structure according to Claim 3, characterizing in that, the transverse bars (5) are located inclined 45° to longitudinal bars longitudinal bars (3, 4).

5. The structure according to Claim 1, characterizing in that, said structure comprise additional convex indentations (8) form on the lower plate in places other than said convex indentations (7).

6. Process for making a concrete reinforcement structure comprising the steps of:

- welding the transverse bars having bent ends to longitudinal bars with a spot welding machine to form a mesh;

- transforming said mesh into V-shape to obtain a girder having cross-section of V-shape and the bent ends of said transverse bars orthogonal with the center axis of V-shape;

- preparing a lower plate with convex indentation in predetermined positions;

- locating said girder on lower plate so that said bent ends lie on said convex indentation; and

- welding bent ends of the transverse bars to the lower plate.

7. The process according to Claim 6, characterizing in that, in step of welding the transverse bars having bent ends to longitudinal bars to form a mesh, the transverse bars is generally straight and located orthogonal to the longitudinal bars.

8. The process according to Claim 6, characterizing in that, in step of welding the transverse bars having bent ends to longitudinal bars to form a mesh, the transverse bars has V-shape and located so that the apex of said V-shape of two next transverse bars lies side-by-side on the longitudinal bar in the middle of the mesh while the bent ends of said transverse bars located side-by-side with the bent ends of the next transverse bar, alternatively.

9. The process according to Claim 6, characterizing in that, steps of transforming the mesh into V-shape is performed by a rolling machine.

10. The process according to Claim 6, characterizing in that, steps of transforming the mesh into V-shape is performed by a metal sheet folding machine.