WALL

The present invention relates to a structure for strengthening a longitudinally extending concrete wall .

A typical existing structure for strengthening a longitudinally extending concrete wall is shown in Fig . 1 being a top view of the structure. The dimension A of the structure in the longitudinal direction A is considerably larger than the dimension B of the structure in the width (transverse) direction. The structure basically consists of a first face Fl and a second face F2. Each face Fl, F2 consists of vertical bars V and horizontal bars H forming a grid . In many cases, the two grids are held together using specifically shaped transverse reinforcements R, as exemplified in Fig . 1. The transverse reinforcements are e. g . known under the names "S-bars", "cross-ties", "transverse links", etc. An example of an "S-bar" transverse reinforcement is illustrated in Fig . 2. Further, Fig . 3 schematically shows a resulting structure with two faces which are connected to each other by means of four "S-bars".

The use of the transverse reinforcements enables, before being concreted, a self- support and rigid stand of the structure. Furthermore, while and after being concreted, the transverse reinforcements enable an accurate and stable positioning of the two faces Fl and F2 in concrete walls. Further, in particular in structures used in earthquake-prone areas, the transverse reinforcements enhance the overall structural performance of the wall during a critical seismic event.

However, the transverse reinforcements in the above example are manually fixed to the two faces at a construction site, wherein, during fixing the transverse reinforcements, the two faces have to be held always in correct position. This is extremely labor-intensive, resulting in high costs. Thus, it is the object of the invention to provide a structure for strengthening a longitudinally extending concrete wall, which is easier to put up at a construction site, thereby lowering costs.

The object of the invention is achieved with a structure for strengthening a longitudinally extending concrete wall according to claim 1.

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

According to the invention, a structure for strengthening a longitudinally extending concrete wall comprises a plurality of wallcages which are arranged in series along a longitudinal direction so as to be aligned in the longitudinal direction, each wallcage having a first face consisting of vertical bars arranged in parallel, a second face consisting of vertical bars arranged in parallel, and a plurality of reinforcement portions, wherein the first face and the second face are arranged at a distance in parallel to each other, the reinforcement portions extend between the first face and the second face and connect the first face and the second face with each other, and the reinforcement portions are integrally connected to the first face and/or the second face.

Since the reinforcement portions are integrally connected to the first face and/or second face (i.e. since the reinforcement portions are unified/formed with the first face and/or the second face in advance), it is not required to manually fix the reinforcement portions to at least one of the first face and the second face. Accordingly, labor and costs can be reduced . Further, even if the reinforcement portions are connected to only one of the first face and the second face, the structure can be easily assembled, since the two faces can be leaned against each other with the reinforcement portions ensuring the correct distance between them. In case the reinforcement portions are integrally connected to the first face and the second face, each wallcage is completely self-supporting, so that, for putting up the structure, the wallcages only have to be arranged in series so as to be aligned in the longitudinal direction (i.e. so that their longitudinal direction corresponds to the longitudinal wall extension direction). Preferably, a spatial density of the reinforcement portions in the structure is equal to or more than 4/m ² , and more preferably equal to or more than 10/m ² , seen in the direction perpendicular to the first face and the second face (in other words, in a side view, perpendicular to the to the first face and the second face, in an area of lm ² , at least 4 (or at least 10) reinforcement portions are provided). In cases where the reinforcement portions are not defined as number of bars per m ² , it is possible to define a horizontal and vertical spacing arrangement for the reinforcement portions (i.e. the provision of the reinforcement portions of specific vertical spacing at specific distances along the direction of the wall) according to a structural analysis. Preferably, the reinforcement portions are arranged at equal distances in the vertical direction and/or horizontal direction. Nevertheless, it is also possible to arrange them at irregular intervals in the vertical direction and/or horizontal direction.

The above configuration allows a very stable reinforcement of the structure in the transverse direction, which is especially necessary in earthquake-prone areas. Specifically, when a spatial density of the reinforcement portions in the structure is adequate, during an earthquake, the reinforcement portions provide a sufficient restraint against buckling of the longitudinal reinforcement (i.e. the longitudinal extending bars) and aid the cooperation between vertical and horizontal bars.

Preferably, the reinforcement portions are arranged at one end of each wallcage in the longitudinal direction or at both ends of each wallcage in the longitudinal direction. This allows an easy integration of the reinforcement portions.

Preferably, the reinforcement portions are integrally connected to (or unified/integrally formed with) connecting portions connecting the vertical bars of the first face with each other and/or the vertical bars of the second face with each other. In this respect, the connecting portions are preferably assembly bars which are arranged perpendicular to the vertical bars and connect the vertical bars with each other. Preferably, each wallcage is further provided with horizontal bars for horizontal reinforcement of each wallcage/the structure. A diameter of a cross-section of a horizontal bar for reinforcement is generally larger than a diameter of a cross- section of a connection portion/assembly bar. The horizontal bars can be provided in addition to the connecting portions/assembly bars or alternatively to them.

In a preferred aspect of the invention, the reinforcement portions are integrally connected to (or unified/integrally formed with) the horizontal bars. This enables, on the one hand, a very stable wallcage, and, on the other hand, an easy integration of the reinforcement portions.

Preferably, the horizontal bars connect the vertical bars of the first face with each other (so as to form a mesh face) and/or connect the vertical bars of the second face with each other (so as to form a mesh face). As a result of this configuration, a self-supporting cage is provided in an easy manner.

Preferably, each wallcage is made by bending a single pre-formed mesh configured by bars arranged perpendicular to each other (i.e. a plurality of first bars arranged in parallel and a plurality of second bars arranged in parallel, wherein the plurality of first bars is arranged perpendicular to the plurality of second bars). As a result, the wallcage can be easily manufactured at low production costs.

In another preferred aspect of the invention, the reinforcement portions are, at one end thereof, integrally connected to at least one face of the first face and the second face, and are engaged, at the other end thereof, with a vertical bar of at least the other face of the first face and the second face. The engagement of the other end of the reinforcement portions with the vertical bar is preferably achieved by bending the reinforcement portions around the vertical bar.

In this aspect, preferably reinforcement portions of a wallcage engage with a vertical bar of an adjacent wallcage. Nevertheless, the configuration can also be such that reinforcement portions of a wallcage engage only with a vertical bar/vertical bars of itself.

In this aspect, further preferably the first face includes reinforcement portions integrally connected thereto and the second face includes reinforcement portions integrally connected thereto, the first face including the reinforcement portions integrally connected thereto is made by bending a single pre-formed mesh of bars arranged perpendicular to each other, and the second face including the reinforcement portions integrally connected thereto is made by bending a single pre-formed mesh of bars arranged perpendicular to each other. Thus, since each cage is configured by two pre-formed meshes which are appropriately bent, each cage can be easily manufactured at low costs.

In this aspect, preferably the first face is displaced in the longitudinal direction with respect to the second face. Alternatively, the first face is arranged so as to correspond/match with the second face in the longitudinal direction.

Preferably, adjacent wallcages overlap each other, seen in the direction of extension of the vertical bars. As a result, it is possible to easily achieve a desired length of the structure. Further, the overall stability of the structure is improved. Here, adjacent wallcages overlap each other preferably such that reinforcement portions of one cage lie within an adjacent cage, seen in the direction of extension of the vertical bars. This further improves the overall stability of the structure.

Preferably, identical wallcages are used in the structure. This keeps the manufacturing costs low. Nevertheless, it also possible to use non-identical wallcages in the structure.

Preferably, the first face and second face have the same dimensions in the horizontal direction and/or vertical direction, which makes it easy to combine adjacent wallcages. Alternatively, it is possible that the first face and the second face have different dimensions in the horizontal direction and/or vertical direction. Preferably, the reinforcement portions extend perpendicular to the first face and the second face.

Preferably, the diameter of the cross-section of each reinforcement portion is at least 8mm. This provides an excellent strength of the structure especially in the transverse direction of the structure.

Preferably, the structure has an outer shape of an elongate rectangular, seen in the direction of extension of the vertical bars. Typically, the dimension of the structure in the transverse direction ranges from 150mm to 300mm, but may be larger, even exceeding 1000mm in some special applications.

In summary, the structure according to the invention provides in particular the following advantages:

- All wallcage shapes provide adequate anti-buckling restraint to the vertical bars and ensure that all constituents work as a unit providing optimum reinforcement characteristics in a high-intensity seismic event.

- Using the structure comprising the wallcages results in significant labor cost savings originating from the faster placing of the proposed entities but also of any remaining (optional) horizontal bars that are required to complete the wall's reinforcement.

- In case the reinforcement portions are integrally connected to the connecting portions/assembly bars connecting the vertical bars, the connecting portions/assembly bars themselves enhance the horizontal reinforcement of the structure. Accordingly, if certain requirements for the horizontal reinforcement have to be fulfilled, such as a necessary area of steel requirement, the connecting portions/assembly bars may be deemed to contribute to fulfill the requirement and, thus, less horizontal bars have to be assembled/tied to the structure in order to complete the reinforcement of the wall. This also results in a reduction of labor and costs. The invention will be described in more detail on the basis of preferred embodiments with reference to the drawings.

Fig. 1 shows a known structure for strengthening a longitudinally extending concrete wall.

Fig. 2 shows a known S-shaped transverse reinforcement.

Fig. 3 schematically shows a resulting structure with two faces which are connected to each other by means of four "S-bars".

Fig. 4a is a schematic top view of a structure for strengthening a longitudinally extending concrete wall according to a first embodiment.

Fig. 4b is a schematic explosive top view of wallcages which form the structure shown of Fig . 4a.

Fig. 5 is a top view of a wallcage used in the structure shown in Fig. 4a.

Fig. 6 is a schematic perspective view of the wallcage shown in Fig . 5.

Fig. 7 is a schematic front view of a pre-formed mesh which is to be bent so as to produce the wallcage as shown in Figs. 5 and 6.

Fig. 8 is a schematic top view of the pre-formed mesh shown in Fig . 7.

Fig. 9a is a schematic top view of a structure for strengthening a longitudinally extending concrete wall according to a second embodiment.

Fig. 9b is a schematic explosive top view of wallcages which form the structure shown of Fig . 9a.

Fig. 10 is a top view of a wallcage used in the structure shown in Fig . 9a. Fig. 11 is a schematic perspective view of the wallcage shown in Fig . 10.

Fig. 12 is a schematic front view of a pre-formed mesh which is to be bent so as to produce the wallcage as shown in Figs. 10 and 11.

Fig. 13 is a schematic top view of the pre-formed mesh shown in Fig . 12.

Fig. 14a is a schematic top view of a structure for strengthening a longitudinally extending concrete wall according to a third embodiment.

Fig. 14b is a schematic explosive top view of wallcages which form the structure shown of Fig . 14a.

Fig. 15 is a schematic top view of two wallcage halves configuring a wallcage of the structure shown in Fig . 14a.

Fig. 16 is a schematic perspective view of a wallcage half shown in Fig . 15.

Fig. 17 is a schematic front view of a pre-formed mesh which is to be bent so as to produce the wallcage half as shown in Figs. 16.

Fig. 18 is a schematic top view of the pre-formed mesh shown in Fig . 17.

Fig. 19a is a schematic top view of a structure for strengthening a longitudinally extending concrete wall according to a fourth embodiment.

Fig. 19b is a schematic explosive top view of wallcages which form the structure shown of Fig . 19a.

Fig. 20 is a top view of a wallcage used in the structure shown in Fig . 19a. First embodiment

A first embodiment of the structure for strengthening a longitudinally extending concrete wall according to the invention is shown in Fig. 4a being a top view of the structure and in Fig . 4b being a schematic explosive top view of wallcages which form the structure shown of Fig . 4a. As can be gathered from the Figs., the structure comprises a plurality of identical wallcages Wl which are arranged in series along a longitudinal direction so as to be aligned in the longitudinal direction (i.e. the longitudinal direction of the wallcages corresponds to the longitudinal extension direction of the wall which is to be reinforced by the structure). As can be gathered from Figs. 5 and 6, each wallcage Wl has a first face 1 consisting of vertical bars V arranged in parallel, a second face 2 consisting of vertical bars V arranged in parallel, and a plurality of reinforcement portions 3. The reinforcement portions 3 which extend perpendicular to the first and second faces 1, 2 (which are arranged in parallel at a distance) are integrally connected to the first face 1 and the second face 2 by means of connecting portions 4. Specifically, in this embodiment, the connecting portions 4 are assembly bars which extend in the horizontal direction and which integrally connect the vertical bars V of both faces 1, 2 with each other. The reinforcement portions 3 are integrally connected (in particular integrally formed) with the assembly bars such that the reinforcement portions 3 are arranged at both ends of the wallcage Wl in the longitudinal direction.

In this embodiment, each wallcage Wl is made by bending a single pre-formed mesh schematically shown in Figs. 7 and 8. Specifically, the pre-formed mesh configured by bars arranged perpendicular to each other is bent by 90° around each of the dashed lines, thereby forming the wallcage Wl as shown in Figs. 5 and 6.

For completing the structure, the wallcages Wl are placed, at first, such that they overlap each other, seen in the direction of extension of the vertical bars (as illustrated in Fig . 4a). Specifically, the wallcages Wl are laterally shifted into one another. In this state, vertical bars OV (see Fig. 4a) are then inserted into the overlapping portions and tied or welded to adjacent wallcages such that the adjacent wallcages Wl are coupled/fixed to each other. Optionally, horizontal bars fulfilling specific strength requirements and having a larger cross-sectional diameter than the connecting portions can be assembled/tied to the wallcages Wl in order to further reinforce the wallcages Wl .

- The completed structure comprises along the shown length L 64 reinforcement portions 3 (eight reinforcement portions 3 along the longitudinal direction x eight reinforcement portions 3 along the vertical direction).

In the above embodiment, the reinforcement portions 3 are integrally connected to connecting portions 4 in the form of assembly bars. As a modification of the above example, the reinforcement portions 3 can be integrally connected to horizontal bars fulfilling specific strength requirements, having a larger cross- sectional diameter than the connecting portions 4, and connecting the vertical bars with each other. I.e. in this case, each wallcage comprises the horizontal bars only without any other connecting portions or horizontal extending assembly bars.

Second embodiment

A second embodiment of the structure for strengthening a longitudinally extending concrete wall according to the invention is shown in Fig. 9a being a top view of the structure and in Fig . 9b being a schematic explosive top view of wallcages which form the structure shown of Fig . 9a .

Same as in the first embodiment, the structure according to the second embodiment comprises a plurality of identical wallcages W2 which are arranged in series along a longitudinal direction so as to be aligned in the longitudinal direction. As shown in Fig . 10 and 11, each wallcage W2 has a first face 1 consisting of vertical bars V arranged in parallel, a second face 2 consisting of vertical bars V arranged in parallel, and a plurality of reinforcement portions 3. The reinforcement portions 3 which extend perpendicular to the first and second faces 1, 2 being arranged in parallel are integrally connected to the first face 1 and the second face 2 by means of connecting portions 4. Also, in the second embodiment, the connecting portions 4 are assembly bars which extend in the horizontal direction and which integrally connect the vertical bars V of both faces 1, 2 with each other.

Differently to the first embodiment, the reinforcement portions 3 are integrally connected (in particular integrally formed) with the assembly bars such that the reinforcement portions 3 are arranged at only one end of the wallcage W2 in the longitudinal direction (the left end in Figs. 9a, 9b).

Further, in this embodiment, each wallcage W2 is made by bending a single preformed mesh schematically shown in Figs. 12 and 13. Specifically, the preformed mesh configured by bars arranged perpendicular to each other is bent by 90° around each of the dashed lines, thereby forming the wallcage W2 as shown in Figs. 10 and 11.

For completing the structure, the wallcages W2 are placed, at first, such that they overlap each other, seen in the direction of extension of the vertical bars (as illustrated in Fig . 9a). Specifically, the wallcages W2 are laterally shifted into one another, wherein the portion into which the reinforcement portion of an adjacent wallcage W2 is shifted, is free from vertical bars. In the overlapping state, vertical bars OV are then inserted into the overlapping portions and tied or welded to that wallcage which receives the reinforcement portion of an adjacent wallcage W2, so that the adjacent wallcages W2 are coupled/fixed to each other. Optionally, horizontal bars fulfilling specific strength requirements and having a larger cross-sectional diameter than the connecting portions can be assembled/tied to the wallcages W2 in order to further reinforce the wallcages W2.

The completed structure comprises along the shown length L 56 reinforcement portions 3 (four reinforcement portions 3 along the longitudinal direction x fourteen reinforcement portions 3 along the vertical direction). Third embodiment

A third embodiment of the structure for strengthening a longitudinally extending concrete wall according to the invention is shown in Fig . 14a being a top view of the structure and in Fig . 14b being a schematic explosive top view of wallcages which form the structure shown of Fig . 14a. Same as in the first and second embodiments, the structure according to the third embodiment comprises a plurality of identical wallcages W3 which are arranged in series along a longitudinal direction so as to be aligned in the longitudinal direction. In Fig. 14a only a single cage W3 is fully shown, as can be gathered also from 14b (only the cage which is configured by the two halves which are shown to the full extent in Fig. 14b).

Differently to the first and second embodiments, each wallcage W3 according to the third embodiment basically consists of two identical halves as shown in Fig. 15. The first half has a first face 1 consisting of vertical bars V arranged in parallel and a plurality of reinforcement portions 3 which are integrally connected, at one end thereof, to the first face 1 by means of connecting portions 4. In the same manner, the second half has a second face 2 consisting of vertical bars V arranged in parallel and a plurality of reinforcement portions 3 which are integrally connected, at one end thereof, to the second face 2 by means of connecting portions 4. The reinforcement portions 3 extend perpendicular to the first face 1 and the second face 2, respectively, and are formed on both sides of the wallcage W3 in the longitudinal direction, i.e. are formed on both ends of the first face 1 as well as the second face 2 in the longitudinal direction. In this embodiment, the connecting portions 4 are assembly bars which extend in the horizontal direction and which integrally connect the vertical bars V of the respective faces 1, 2 with each other. Fig . 16 is a schematic perspective view of one of the two wallcage halves shown in Fig . 15 (which are identical in this embodiment).

In this embodiment, each wallcage half is made by bending a single pre-formed mesh schematically shown in Figs. 17 and 18. Specifically, the pre-formed mesh configured by bars arranged perpendicular to each other is bent by 90° around each of the dashed lines, thereby forming the wallcage half as shown in Fig . 16.

For completing the structure, the wallcage halves are placed such that they are displaced in the longitudinal direction, i.e. the first face 1 is displaced in the longitudinal direction with respect to the second face 2. Then, the wallcage halves are connected to each other by bending the free ends of the reinforcement portions 3 (which are provided at one end side of the first face 1 in the longitudinal direction) of the first face 1 around a vertical bar V of the second face 2 and bending the free ends of the reinforcement portions 3 (which are provided at one end side of the second face 2 in the longitudinal direction, which end side is opposite to the before mentioned end side of the first face 1 in the longitudinal direction) of the second face 2 around a vertical bar V of the first face 1, as shown in Fig . 14a. As a result, a wallcage W3 is formed . Then, a plurality of wallcages W3 formed in this manner is arranged so as to overlap each other, seen in the direction of extension of the vertical bars (as illustrated in Fig. 14a). Specifically, the wallcages W3 are laterally shifted into one another such that reinforcement portions 3 of adjacent first faces 1 and reinforcement portions 3 of adjacent second faces 2 overlap each other. In this state, the remaining free ends of reinforcement portions 3 of a wallcage W3 are engaged with vertical bars V of an adjacent wallcage W3 by bending, so as to connect adjacent wallcages W3 to each other. Thus, each wallcage half engages with its counterpart half as well as with a half of an adjacent wallcage W3. Moreover, in the overlapping state, vertical bars OV (see Fig . 14a) are inserted into the overlapping portions and tied or welded to the wallcages such that adjacent wallcages W3 are coupled/fixed to each other. Optionally, horizontal bars fulfilling specific strength requirements and having a larger cross-sectional diameter than the connecting portions/assembly bars can be assembled/tied to the wallcages W3 in order to further reinforce the wallcages W3.

The completed structure comprises along the shown length L 64 reinforcement portions 3 (eight reinforcement portions 3 along the longitudinal direction x eight reinforcement portions along the vertical direction). In this embodiment, the reinforcement portions 3 are integrally connected to connecting portions 4 in the form of assembly bars. As a modification, the reinforcement portions 3 can be integrally connected to horizontal bars fulfilling specific strength requirements, having a larger cross-sectional diameter than the connecting portions 4, and connecting the vertical bars of one face 1, 2 with each other.

Fourth embodiment

A fourth embodiment of the structure for strengthening a longitudinally extending concrete wall according to the invention is shown in Fig. 19a being a top view of the structure and in Fig. 19b being a schematic explosive top view of wallcages which form the structure shown of Fig . 19a.

The structure of the fourth embodiment is similar to the third embodiment. In the structure of the fourth embodiment wallcages W4 are used. As shown in Fig . 20, each wallcage WS4 consists of identical halves configured and produced in the same manner as described with respect to the third embodiment. Differently to the third embodiment, a wallcage W4 of the fourth embodiment is configured by two halves which are not displaced with respect to each other in the longitudinal direction, but which are connected to each other by connecting (e.g. tying or welding) the reinforcement portions 3 of the halves to each other.

For completing the structure, the wallcages W4 are placed, at first, such that they overlap each other, seen in the direction of extension of the vertical bars (as illustrated in Fig. 19a). Specifically, the wallcages W4 are laterally shifted into one another. In this state, vertical bars OV (see Fig. 19a) are inserted into the overlapping portions and tied or welded to adjacent wallcages W4 such that the wallcages W4 are coupled/fixed to each other.