JP2020101010A - Bearing wall - Google Patents

Abstract

To provide a bearing wall allowing a wall to become a kind of the bearing wall as remaining an opening in a wall of a building or being in a state with the opening.SOLUTION: In an existing structural plane 10 in a rectangular shape in a front view formed with two right and left existing columns 1 and 2 and existing horizontal members 3 and 4 in an existing building, a bearing wall 100 is formed by securing reinforcement posts 20 on the existing columns 1 and 2 with securing means 30, and by attaching reinforcement metals 40 on at least two positions of joint portions 5 of four positions of the joint portions 5 between the existing columns 1 and 2 and the existing horizontal members 3 and 4.SELECTED DRAWING: Figure 1

Description

The present invention relates to load bearing walls.

BACKGROUND ART With respect to wooden and steel-framed buildings, for example, remodeling including seismic reinforcement of buildings constructed based on the old seismic resistance standard has been actively performed. In seismic retrofitting, non-bearing walls are made to be bearing walls by installing braces inside the walls of buildings and attaching face materials such as structural plywood to the construction surface. However, in the method of making a bearing wall by attaching brace or face material to the construction surface, openings such as windows interfere with the brace or are blocked by the face material. There is a problem that the existing openings must be sacrificed.

Here, a bearing wall has been proposed in which structural face members are attached to a framework composed of a vertical axis member and a horizontal axis member of a structural frame, and gusset plates are arranged at four corners of the frame ( For example, see Patent Document 1).

JP, 2005-207204, A

Even in the load bearing wall described in Patent Document 1, since the face material completely closes the framework, if an opening exists inside the framework before the load bearing wall is formed, this opening is formed by the face material. It will be completely blocked.

The present invention has been made in view of the above problems, and provides a load bearing wall that can be made to be a load bearing wall while leaving an opening existing in a wall of a building or in a state having an opening. The purpose is to

In order to achieve the above object, one mode of the load bearing wall according to the present invention is
In an existing building surface of a rectangular shape in a front view formed by two existing pillars on the left and right and an existing horizontal member in an existing building, an attachment pillar is fixed to the existing pillar through a fixing means, and the existing pillar Reinforcing metal fittings are attached to at least two of the four connections of the existing horizontal member.

According to this aspect, while reinforcing the existing columns of the wooden or steel building with the added columns, the reinforcing metal fittings are attached to at least two ports among the four ports of the existing structure having a rectangular shape in front view. Due to this, even if there is an opening inside the existing construction surface, it is possible to make the existing construction surface a bearing wall without closing the opening. Here, "at least two joints" means, among four joints (four corners), two joints on the upper left and right sides, for example, two joints on the upper left side and the lower right, and all the four corners. It includes a connection. By reinforcing at least two joints at the four corners with the reinforcing metal, the rectangular structure surface can be surface-wise reinforced against earthquakes. Further, for example, by fixing the additional column to the existing column that has deteriorated with the fixing means, it is possible to improve the proof stress of the column, which is a component of the load bearing wall.

If the joint of the existing structure is only reinforced with the reinforcing metal, only the bearing capacity of the bearing wall will be improved, so the bearing capacity of the existing column will be the bearing strength of the joint against the horizontal force at the time of earthquake. It is unable to keep up and thus lead to failure of existing pillars that have dilapidated before the reinforced joint's bearing capacity was fully exerted. Therefore, this time, if an attempt is made to reinforce the joint with the reinforcing metal to the extent that the existing pillar is not damaged, only weak joint reinforcement can be performed according to the proof stress of the aged pillar.

Like the load bearing wall of this aspect, it is possible to form a load bearing wall having a sufficient load bearing value by both reinforcing existing columns with added columns and reinforcing the joints on the construction surface with reinforcing metal. it can. Then, by applying the load bearing wall of this aspect to an existing building, it is possible to make the building earthquake resistant without reducing the openings of the existing building.

Another aspect of the bearing wall according to the present invention is the first form in which the existing horizontal member is an existing beam above the existing column and an existing base below the existing column, and the upper and lower sides of the existing column. The present invention is characterized in that it has any one of the second forms consisting of existing beams in.

According to this aspect, the bearing wall (first form) on the first floor structure (vertical structure) that uses the existing beams and the existing foundation as the horizontal members, and the second floor and above that has the upper and lower existing beams as the horizontal members. It is possible to provide a load bearing wall in which existing columns are reinforced with splints and the joints of the bearing surfaces are reinforced with reinforcing metal in any of the bearing walls (second form) on the floor.

Further, in another aspect of the load bearing wall according to the present invention, the attachment columns fixed to each of the left and right existing columns are arranged inside the existing configuration surface. A second form arranged on the outside, a third form in which one of the addition columns is arranged outside the existing construction surface, and the other of the addition columns is arranged inside the existing construction surface, It is characterized by having either.

According to this aspect, the first form in which the left and right pillars are arranged inside the existing structure, the second form arranged outside the existing structure, and one is inside the existing structure and the other is It is possible to cover all the reinforcement forms of the third form, which are arranged outside the existing construction surface, by the added columns.

Further, in another aspect of the load bearing wall according to the present invention, the reinforcing metal object is arranged in four positions on the inside, above, below, left and right of the existing construction surface, and on the upper left and right sides inside the existing construction surface. A second mode in which two locations are provided, two locations on the lower left and right outside the existing construction surface, a total of four locations, and a third configuration, which is disposed on the upper left and right locations inside the existing construction surface. The present invention is characterized in that it has any one of a form and a fourth form arranged at one of upper left and right and one lower left and right inside the existing structure.

According to this aspect, the first mode in which the reinforcing metal members for reinforcing at least two positions of the joint are arranged at four positions on the upper, lower, left, and right sides inside the existing structure, and two positions on the upper, left, and right sides inside the existing structure. And a second form that is arranged at two places on the lower left and right sides of the outside, a third form that is arranged at two places on the upper left and right sides of the inside of the existing structure, and one of the upper left and right sides inside the existing structure. It is possible to cover all the reinforcement forms by the reinforcement metal object of the fourth form arranged at one place and at any one of the lower left and right.

Another aspect of the bearing wall according to the present invention is characterized in that it has an opening inside the existing structure.

According to this aspect, while reinforcing the existing pillar with the added pillar, the reinforcing metal fittings are attached to at least two of the four joints of the existing construction surface of the rectangular shape in the front view. Inside the surface, a load bearing wall having openings such as a sliding window and a sweep window can be formed. In addition to the window, the opening includes a piloty space in which a wall does not exist between the existing columns on the left and right, which are reinforced by the column. In addition, when the existing structure surface before reinforcement has an opening, both the existing pillar is reinforced by the splint pillar while leaving this opening, and the joint of the structure surface is reinforced by the reinforcing metal object. When the existing construction surface is a non-bearing wall, the bearing wall can be made a bearing wall.

Further, in another aspect of the load bearing wall according to the present invention, the reinforcing metal object is configured such that a plurality of rectangular steel pipes are arranged in parallel with each other in an axial direction thereof, and diagonal lines of respective cross sections of the rectangular steel pipes are aligned with each other. The corners that are in contact with are joined together,
It is characterized in that the rectangular steel pipe is directly or indirectly fixed to the existing column, the additional column, and the existing horizontal member.

According to this aspect, the plurality of square steel pipes have their axial directions parallel to each other, and the corner portions that are in contact with each other are connected to each other so that the diagonal lines of the respective cross sections are straight, so that the reinforcing metal article is configured, and thus the earthquake occurs. When a horizontal force or the like at the time acts on the building, the cross section of each rectangular steel pipe is deformed into a rhombus, and seismic energy can be effectively absorbed. That is, by utilizing both the rigidity and the tenacity of the rectangular steel pipe, it is possible to firmly reinforce the joint in a mode having the deformability and to make the existing construction surface a bearing wall. Here, "the square steel pipe is directly or indirectly fixed to the existing column, the additional column, and the horizontal member" means that the end portion of the plurality of square steel pipes to be joined to each other. The existing square steel pipe is directly joined to the existing column by bolting or welding, or multiple rectangular steel pipes that are joined to each other are joined to the base plate, and the base plate is joined to the existing column by bolting or welding. It includes a configuration in which a square steel pipe is indirectly joined to an existing column or the like by being directly joined.

As can be understood from the above description, according to the load bearing wall of the present invention, it is possible to make the wall a load bearing wall while leaving the opening existing in the wall of the building or in the state having the opening.

It is a front view of an example of the bearing wall according to the embodiment, which is formed by converting an existing structural surface that is a non-bearing wall into a bearing wall. It is a perspective view showing the state where an example of a reinforcement metal object is attached to a joint. (A) is a schematic view of a reinforcing metal piece at all times, and (b) and (c) are schematic diagrams showing a state in which the reinforcing metal piece is deforming and resisting repeated horizontal force acting during an earthquake. .. It is a figure showing a list of load bearing walls concerning a plurality of embodiments.

Hereinafter, a load bearing wall according to an embodiment will be described with reference to the accompanying drawings. In the present specification and the drawings, substantially the same components may be denoted by the same reference numerals to omit redundant description.

[Bearing wall according to the embodiment]
An example of the bearing wall according to the embodiment will be described with reference to FIGS. 1 to 3. Here, FIG. 1 is a front view of an example of a bearing wall according to the embodiment, which is formed by converting an existing structural surface that is a non-bearing wall into a bearing wall. Further, FIG. 2 is a perspective view showing a state in which an example of the reinforcing metal piece is attached to the joint. Further, FIG. 3(a) is a schematic diagram of the reinforcing metal piece at all times, and FIGS. 3(b) and 3(c) show that the reinforcing metal piece is deformed and resists repeated horizontal force acting during an earthquake. It is a schematic diagram which shows the state which exists.

The load-bearing wall 100 is formed by the two existing columns 1 and 2 on the left and right sides and the existing horizontal members 3 and 4 on the upper and lower sides of the existing building. The column 20 is fixed to each of the above by means of the fixing means 30, and the reinforcing metal 40 is attached to the existing columns 1 and 2 and the upper and lower existing horizontal members 3 and 4 at four joints 5 which are the corners. It is composed by.

The existing building is a wooden house, the existing columns 1 and 2 are formed of wooden columns, and the existing horizontal members 3 and 4 are formed of wooden beams. For example, the existing columns are constructed based on the old earthquake resistance standard. It is a building that needs to be renewed for more than 30 years. In addition, an opening A such as a sliding window exists inside the existing construction surface 10 and does not have a brace necessary as a load bearing wall, and is compared with a surface material attached to the existing construction surface 10. The existing structural surface 10 is a non-bearing wall that cannot be regarded as a bearing wall due to the presence of the relatively large opening A. The existing building may be a steel framed building that needs renewal.

The existing construction surface 10 shown in the figure is the construction surface (vertical construction surface) of the first floor of the building. Therefore, the existing horizontal cross member 3 on the upper side is the second floor floor beam, and the existing horizontal cross member 4 on the lower side is the base of the first floor. (Beam). When the existing construction surface 10 is a construction surface on the second floor or higher of the building, both the upper and lower existing horizontal members 3 and 4 are floor beams.

As with the existing columns 1 and 2, the wooden added columns 20 are arranged inside the existing structure 10 for the left and right existing columns 1 and 2, respectively, and a plurality of fixing means including lag screws, screws, nails, and the like. They are fixed to each other by 30. In the bearing wall 100 of the illustrated example, the reinforcing metal fittings 40 are attached to all the joints 5 at the four corners of the existing construction surface 10 having a rectangular shape in plan view.

In the joint 5, the reinforcing metal 40 is fixed to the added column 20 and the existing horizontal members 3 and 4 by a plurality of fixing means 50 including lag screws, screws, nails and the like. As described above, in the bearing wall 100 of the illustrated example, inside the existing structural surface 10 that is a non-bearing wall, two additional columns 20 are fixed to the existing columns 1 and 2, and four reinforcing metal pieces 40 are provided at four corners. The bearing wall is made by the remodeling construction attached to the joint 5.

By attaching the reinforcing metal members 40 to at least two ports 5 on the existing construction surface 10 which is rectangular in plan view, it is possible to make the existing construction surface 10 a bearing wall. In addition to the form in which the reinforcing metal 40 is attached to all the four joints 5 as in the illustrated example, the reinforcing metal 40 can be attached to the three joints 5 or the two joints 5.

As shown in detail in FIG. 2, the reinforcing metal member 40 includes an L-shaped metal base plate 41 in a front view, and a plurality of short-width rectangular steel pipes 42 (three in the illustrated example). The base plate 41 has two metal pieces 41a that are formed by bending one metal piece and are orthogonal to each other. One surface of the rectangular steel pipe 42 located at the end is brought into contact with each of the metal pieces 41a and joined to each other by welding.

The rectangular steel pipes 42 are arranged such that the axis lines L1 passing through the hollows are parallel to each other and the diagonal lines of the rectangular steel pipes 42 are aligned with a common straight line L2. They are integrated by being joined at.

As shown in FIG. 2, the width dimension of the base plate 41 is about the same as the width dimension of the existing columns 2, the additional columns 20, the existing horizontal members 4, etc. The length dimension is larger than the entire length dimension of the three rectangular steel pipes 42 joined together, that is, the projected dimension when the three rectangular steel pipes 42 are attached to the port 5 as a cane. doing. Further, the width dimension of the square steel pipe 42 is set shorter than the width dimension of the base plate 41, and the square steel pipe 42 is attached at the center position of the base plate 41 in the width direction. A plurality of insertion holes (not shown) are formed in the base plate 41, and the fixing means 50 such as a lag screw is inserted through each of the insertion holes, so that the base plate 41 and the supporting columns 20 and the existing horizontal member 4 are inserted. Etc. are fixed.

Here, when a horizontal force is repeatedly applied in the left-right direction at the time of an earthquake to the continuous reinforcing metal piece 40 shown in FIG. 3( a ), the reinforcing metal piece 40 has a rectangular steel pipe 42, which is its constituent element. By making use of both the rigidity and the tenacity that it has, it is possible to strongly reinforce the joint 5 in a mode having a deformability.

For example, as shown in FIG. 3B, when a horizontal force H1 at the time of an earthquake acts in the right direction on the paper surface, the post 20 is deformed and tilted to the right due to the deformation of the structure. At this time, the base plate 41 is not damaged by its own rigidity, but is deformed so as to be inclined to the right in the same manner as the deformation of the construction surface. Due to this deformation of the base plate 41, the central angle of the two metal pieces 41a becomes smaller than 90 degrees at all times, and the diagonal lengths of the three rectangular steel pipes 42 joined to each other are shorter than the normal length t3. The length is t4.

However, since the rectangular steel pipes 42 have rigidity and have a hollow structure and are excellent in deformability, the rectangular steel pipes 42 are crushed in a diagonal direction so as to satisfy the short diagonal length t4. It transforms into a rhombus.

As described above, when the horizontal force H1 at the time of an earthquake acts and the reinforcing metal piece 40 is deformed so as to be crushed inward, the reinforcing metal piece 40 is damaged due to the rigidity of the base plate 41 and the plurality of rectangular steel pipes 42. While the deformation is suppressed, the reinforcing metal pieces 40 can follow the deformation of the structure surface without being detached from the structure surface due to their deformability. Therefore, the reinforcing metal 40 reinforces the joint 5 of the existing construction surface 10, and the bearing wall 100 is formed.

On the other hand, as shown in FIG. 3C, when the horizontal force H2 at the time of the earthquake acts in the left direction of the paper surface, the post 20 is deformed due to the deformation of the construction surface and is inclined to the left side this time. .. At that time, the base plate 41 is deformed so as to be inclined to the left side similarly to the deformation of the construction surface without being damaged by its own rigidity. Due to the deformation of the base plate 41, the central angle of the two metal pieces 41a becomes larger than 90 degrees at all times, and the diagonal lengths of the three rectangular steel pipes 42 joined to each other are longer than the usual length t3. The length is t5.

However, since the rectangular steel pipes 42 have rigidity and have a hollow structure and are excellent in deformability, each of the rectangular steel pipes 42 is stretched in the diagonal direction so as to satisfy the long diagonal length t5. It transforms into a diamond.

In this way, even when the horizontal force H2 at the time of an earthquake acts and the reinforcing metal article 40 is deformed so as to be stretched outward, the rigidity of the base plate 41 and the plurality of rectangular steel pipes 42 causes damage to the reinforcing metal article 40. While being restrained, due to their deformability, the reinforcing metal object 40 can follow the deformation of the structure surface without being detached from the structure surface.

In this way, the reinforcing metal member 40 has a plurality of short-width rectangular steel pipes 42 joined to each other and the base plate 41 to which the rectangular steel pipes 42 located at the ends are joined and are directly attached to the joint 5. As a result, the joint 5 of the existing construction surface 10 is reinforced in a manner having deformation performance and rigidity, and sufficient seismic resistance is given to the existing construction surface 10. Although the reinforcing metal piece 40 in the illustrated example has the form having the base plate 41, the reinforcing metal piece may be formed only by a plurality of rectangular steel pipes 42 which are not provided with the base plate and are joined to each other. In this embodiment, an insertion hole is opened in the side surface of the rectangular steel pipe 42 located at the end, and the fixing means is fixed to the spit column 20 or the like via the insertion hole, so that the square steel pipe 42 is fixed to the splint column 20 or the like. Will be directly fixed.

Returning to FIG. 1, according to the bearing wall 100, at least two of the four joints 5 of the existing construction surface 10 of the rectangular front view are reinforced while the existing pillars 1 and 2 of the wooden building are reinforced by the added pillars 20. Since the reinforcing metal fittings 40 are attached to the joints 5 at the locations (four locations in the illustrated example), even when the opening A is present inside the existing construction surface 10, the existing construction surface 10 is not blocked. It is possible to make a bearing wall.

If only the joint 5 of the existing construction surface 10 is reinforced with the reinforcing hardware 40, only the proof stress of the joint 5 of the bearing wall is improved. The proof stress does not catch up with the proof stress of the joint 5, so that the existing columns 1 and 2 that have deteriorated before the proof of the reinforced joint 5 is sufficiently exerted may be damaged. Therefore, if it is attempted to reinforce the joint 5 with the reinforcing hardware 40 to the extent that the existing pillars 1 and 2 are not damaged, this time, only weak joint reinforcement can be performed according to the proof stress of the deteriorated existing pillars 1 and 2. .. On the other hand, by forming the bearing wall 100 both by reinforcing the existing columns 1 and 2 with the additional columns 20 and by reinforcing the joint 5 of the existing construction surface 10 with the reinforcing metal 40, A bearing wall with a sufficient bearing value is obtained. Then, by applying the load bearing wall 100 of the present aspect to an existing building, it is possible to achieve earthquake resistance of the building without reducing the openings A of the existing building. Further, in the renewal construction, a building having the bearing wall 100 having the opening A can be constructed, so that it is possible to construct a building having excellent seismic performance, a high degree of freedom, and an excellent design.

When the opening A is not a sliding window as in the illustrated example but a sweep window, the reinforcing metal members 40 on the lower left and right joints 5 may interfere with the sweep window. Therefore, in such a form, a bearing wall in which the reinforcing metal 40 is attached only to the upper and left joints 5 may be used. Further, even in the piloty structure in which the width dimension of the existing beam 3 is long and a face material or the like is not attached between the left and right existing pillars 1 and 2, the left and right existing pillars 1 and 2 are reinforced by the attachment pillars 20, and, for example, upward. By reinforcing the left and right joints 5 with the reinforcing metal 40, a piloty type bearing wall can be formed.

Next, with reference to FIG. 4, another modification of the load bearing wall 100 shown in FIG. 1 will be described. Here, FIG. 4 is a diagram showing a list of load bearing walls according to a plurality of embodiments, and shows Examples 1 to 12. The first embodiment corresponds to the bearing wall 100 shown in FIG.

The first to fourth embodiments shown in the upper stage show a mode in which the additional columns are attached inside the existing columns on the left and right. As described above, the first embodiment has a form in which the reinforcing metal fittings are attached to the joints at the four corners. On the other hand, in the second embodiment, the reinforcing metal fitting is attached to the inner side of the upper joint, and the reinforcing metal fitting is attached to the outer side of the lower joint. In addition, the third embodiment has a configuration in which the reinforcing metal parts are attached to the inside of only the two left and right upper joints. Further, the fourth embodiment has a mode in which the reinforcing metal fittings are attached to the inside of both the upper right side joint and the lower left side joint. In the first to third embodiments, the span length t1 (beam span) between the left and right existing columns can be set to about 1 m to 4 m, for example. In the fourth embodiment, the span length t2 between the left and right existing columns can be set to, for example, less than 1 m (for example, 910 mm and 455 mm).

Next, in the fifth to eighth embodiments shown in the middle stage, unlike the first to fourth embodiments, the attachment pillars are attached to the outsides of the existing left and right pillars. Is the same as in the first to fourth embodiments.

Further, unlike the first to eighth embodiments, the ninth to twelfth embodiments shown in the lower stage are such that the additional pillars are attached to the outside of the existing pillar on the left side of the paper and the inside of the existing pillar on the right side of the paper. And the mounting form of the reinforcing metal article is the same as in the first to fourth embodiments. It should be noted that it is also possible to adopt a form in which the additional columns are attached to the inside of the existing column on the left side of the paper and the outside of the existing column on the right side of the paper.

In this way, a bearing wall that satisfies both the reinforcement of the existing columns on the left and right with the added columns and the reinforcement of at least two of the four locations of the existing construction surface with the reinforcing hardware. Has various forms as shown in FIG.

[Comparative verification of yield strength values of the bearing wall of the present invention and existing bearing walls]
The present inventors have specified the yield strength values of the bearing walls according to Examples 1 to 3 shown in FIG. 4 and performed verification to compare with the bearing strength values of existing bearing walls. In this verification, the load-bearing value of the existing load-bearing wall is shown in "2012 Seismic Diagnosis and Reinforcement Method Guideline and Commentary of Revised Wooden House, 2012.10, page 31" by the Japan Building Disaster Prevention Association. I am referring. Table 1 below shows the specifications and verification results of the examples and comparative examples. In addition, the yield strength value of each example in Table 1 is the yield strength value of the bearing wall with the space 1.82 (m) between the left and right existing columns, and the yield value of each comparative example is the same as that of the embodiment. It is a yield strength value obtained by multiplying each wall standard yield strength value by 1.82 (m).

From Table 1, between the yield strength value of the bearing wall according to each comparative example formed by attaching the brace and the face material to the existing construction surface and the bearing strength value of the bearing wall according to each example not including the brace and the face material It has been demonstrated that there is no significant difference between them. That is, according to the load bearing wall according to the example, it can be seen that the load bearing wall having a sufficient load bearing value can be formed while leaving the opening without blocking the opening of the existing structural surface with the brace or the face material.

In addition, among the examples, the yield value of the bearing wall according to the first embodiment, that is, the bearing wall in which the addition columns are fixed inside the existing columns on the left and right, and the reinforcing metal fittings are attached to the insides of the four corners of the joints. Has been proven to be the highest.

It should be noted that other configurations such as other components may be combined with the configurations and the like described in the above embodiments, and the present invention is not limited to the configurations shown here. .. This point can be changed without departing from the spirit of the present invention, and can be appropriately determined according to the application form.

1,2: existing pillars, 3: existing horizontal members (existing beams), 4: existing horizontal members (existing bases), 5: joints, 10: existing structures, 20: added columns, 30: fixing means, 40: Reinforcing hardware, 41: Base plate, 42: Square steel pipe, 50: Fixing means, 100: Bearing wall, A: Opening, L1: Axis line, L2: Common straight line

Claims (6)

In an existing building surface of a rectangular shape in a front view formed by two existing pillars on the left and right and an existing horizontal member in an existing building, an attachment pillar is fixed to the existing pillar through a fixing means, and the existing pillar A bearing wall, wherein reinforcing metal fittings are attached to at least two of the four positions of the existing horizontal member. Any one of the first mode in which the existing horizontal member is an existing beam above the existing column and an existing base below the existing column, and a second mode consisting of existing beams above and below the existing column. The load-bearing wall according to claim 1, characterized in that: The additional column fixed to each of the left and right existing columns, the first form arranged inside the existing structure, the second form arranged outside the existing structure, one of 3. The third aspect in which the attachment column is disposed outside the existing construction surface, and the other addition column is disposed inside the existing construction surface, The load bearing wall according to 1 or 2. The first form in which the reinforcing hardware is arranged at four positions in the upper, lower, left, and right inside the existing structure, two upper and left positions inside the existing structure, and lower left and right outside the existing structure. The second form is arranged at a total of four places, that is, the third form is arranged on the upper left and right of the inside of the existing structure, and the upper left and right of the inside of the existing structure. The load bearing wall according to any one of claims 1 to 3, wherein the load bearing wall has any one of a fourth form arranged at one place and at any one of two places on the lower left and right sides. The load bearing wall according to any one of claims 1 to 4, wherein the bearing wall has an opening inside the existing construction surface. The reinforcing metal article, a plurality of rectangular steel pipes are arranged in parallel in the respective axial direction, the corner portions are mutually joined so that the diagonal lines of the respective cross-sections of the rectangular steel pipes are in a straight line,
The said square steel pipe is being fixed directly or indirectly with respect to the said existing column, the said addition column, and the said existing horizontal member, The any one of Claim 1 thru|or 5 characterized by the above-mentioned. Bearing wall.

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