JP2020111917A - Lower end structure of bearing wall - Google Patents

Abstract

To provide a lower end structure of a bearing wall capable of reducing the load in a horizontal shear direction applied to a column base part.SOLUTION: A lower end structure 1 of a bearing wall includes: a pair of pieces of column base hardware 3 that are fixed to a foundation 2 at a distance from each other; a pair of columns 5 in which a column base part 51 is fixed to the column base hardware 3; a lower frame member 7 that is placed between the column base parts 51 of the columns 5; and a structural panel 8 that is fixed to at least the column 5 and the outside of the lower frame member 7. The lengthwise end faces of the lower frame member 7 are brought into contact with the pieces of column base hardware 3 respectively.SELECTED DRAWING: Figure 1

Description

The present invention relates to a lower end structure of a load-bearing wall, and particularly to a base having a pair of pillars whose pillar bases are joined on a foundation and a lower frame member horizontally arranged between the pillar bases of the pillars. The present invention relates to a lower end structure of a load bearing wall to which a structural face material is attached.

Conventionally, a structural surface is provided on the outdoor side surface of a wooden frame formed by a base provided on a foundation, a pair of pillars erected on the base, and a beam erected on the upper ends of the pillars. A bearing wall in which a material is fixed with a nail or the like is known (for example, Patent Document 1). When a horizontal shearing force is applied to a building, each load-bearing wall arranged in the building resists the horizontal shearing force, and the pulling direction force is applied to the column base of one of the columns forming the load-bearing wall, and the other A compressive force is applied to the column base of the column. When the load bearing walls are arranged vertically, the pulling force and compression force applied to the load bearing walls on the upper floor are also transmitted to the load bearing walls on the lower floor. A large pull-out force and a large compressive force are applied to the column bases of No.

Then, to prevent the column base from being pulled out by the pulling force applied to the column base, connect the column base metal to the anchor bolt partially embedded in the foundation, and connect the column base of the column to the column base metal. The structure is known. In such a structure, since the wooden base is not used for the connection between the column base and the foundation, the stress against the pulling force to the column base can be increased. Further, among such column pedestals, there has been proposed one in which plates are respectively extended laterally and the ends of the base are connected (for example, Patent Document 2).

JP, 2012-202112, A JP, 2017-20236, A

By the way, the base provided on the foundation is arranged for the purpose of supplementing the construction accuracy of the foundation. Therefore, if the foundation construction accuracy is high, it is not always necessary to provide a foundation. When the base is not provided, the part where the base is conventionally installed can be made a large gap, which is advantageous for ventilation under the floor and inside the wall, and the gap blocks the path of the ant path. Therefore, the ant repellency can be enhanced.

Even if the base is not provided as described above, it is necessary to dispose the lower frame material, which is the base of the lower end portion of the structural surface material, between the column bases. The lower frame member is installed between the column bases, and both ends thereof are fixed to the side surfaces of the column bases, respectively. When horizontal shear force is applied to the building when the lower frame material is fixed to the side surface of the column base in this way, pulling force is applied to the column base part of the column, and also horizontal shear force from the lower frame material. It will be added to the pillar base. Therefore, a load in the pull-out direction and a load in the shearing direction are simultaneously applied to the column base, and there is a problem that the load that can be carried by the column base is extremely reduced as compared with the case where the load is one direction.

Therefore, it is an object of the present invention to provide a lower end structure of a load bearing wall that can reduce the load in the horizontal shearing direction applied to a column base.

The lower end structure of the load-bearing wall of the present invention is a pair of pillar pedestals that are fixed to a foundation with an interval between each other, a pair of pillars in which a column base is fixed to the pillar pedestal, and a column base of the pillar. And a structural face material fixed to the outdoor side surface of at least the column and the lower frame member, and the end face in the length direction of the lower frame member is a column leg metal fitting, respectively. Is abutted against.

In the lower end structure of the load bearing wall of the present invention, the lower frame member is erected on the upper side with a predetermined distance from the top end of the foundation, and the lower surface of the lower frame member is lower than the lower end surface of the column member. It is characterized by further comprising a fixing member which is arranged at a lower position and which fixes both ends of the lower frame member to the side surfaces of the column base portion, respectively.

According to the lower end structure of the load bearing wall of the present invention, when a horizontal load is applied to a building, a vertical load in the pulling direction is applied to the column base portion of the column forming the load bearing wall, and from the lower frame material to the column base portion. Horizontal shearing force is also applied, but since the end face in the length direction of the lower frame material contacts the column base metal, the horizontal load of the lower frame will be received by the column base metal fixed to the foundation. The horizontal shearing force applied to the column base can be reduced. Therefore, since the joint between the column base and the column base bears only the vertical load in the pulling direction, it bears a larger load than in the case where the loads in the pulling direction and the shearing direction are combined. be able to.

According to the lower end structure of the load-bearing wall of the present invention, the lower frame member is installed on the upper side with a predetermined distance from the top end of the foundation, so that a gap is formed between the base top end and the lower frame member, Since it is possible to block the ant trail that rises from the foundation, it is possible to improve the ant resistance. Further, since the lower surface of the lower frame member is arranged at a position lower than the lower end surface of the column member, even if the shape of the regular column pedestal is the same, the end of the lower frame member should be brought into contact with the column pedestal member. Since there is no need to provide a special column pedestal, the cost of the bearing wall can be reduced. Since the fixing members for fixing both ends of the lower frame member to the side surfaces of the column base are provided, the lower frame member can be used as a base when the structural face member is attached.

The partially omitted front view explaining the lower end structure of a load bearing wall. The partially omitted perspective view explaining the lower end structure of a load bearing wall. (A) is a partially enlarged front view illustrating a column base portion of a lower end structure of a load bearing wall, and (B) is a perspective view showing a configuration of a column base metal fitting. The front view which shows the structure of the bearing wall in which the lower end structure of the bearing wall is formed. The front view and the abbreviated enlarged view for explaining the load of the load bearing wall when a horizontal load is applied to a three-story building in which the load bearing wall having the lower end structure of the load bearing wall of the present invention is arranged. The front view and the abbreviated enlarged view which explain the load of the bearing wall when a horizontal load is applied to the building of three floors in which the bearing wall having the lower end structure of the conventional bearing wall is arranged.

Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 6. The load-bearing wall 4 in the lower end structure 1 of the load-bearing wall of the present embodiment includes, as shown in FIG. 4, a pair of column base metal fittings 3 fixed to the foundation 2 and a pair of columns 5 fixed to the column base metal fitting 3. The horizontal member 6 such as a beam installed on the pillar head portion 52 of the pillar 5 and the lower frame member 7 arranged between the pillar base portions 51 of the pillar 5. Then, the load bearing wall 4 is obtained by fixing the structural face material 8 to the outdoor side surface of the rectangular wooden frame set 10 formed by the pair of pillars 5, the horizontal member 6, and the lower frame member 7 with the nail 80 or the like. , Bears the horizontal shear force. Further, both ends of the lower frame member 7 are fixed to opposite side surfaces of the column base portion 51 by L-shaped fixing members 9.

The base 2 of the present embodiment is an outer peripheral rising portion of the base 2, and although not shown, the lower part is buried below the ground line, and a reinforcing bar (not shown) is buried inside. In addition, as shown in FIGS. 1 and 3A, an anchor bolt 11 is embedded in the foundation 2 so that a part thereof projects upward from the top end. The anchor bolts 11 are embedded in the foundation 2 at a pitch of, for example, 1 m in order to fix the column base metal piece 3. As shown in FIG. 1, the anchor bolt 11 has a flange-shaped enlarged diameter portion 12 in a portion embedded in the foundation 2 so as to resist the pulling force generated in the column base portion 51. However, for example, the portion embedded in the foundation 2 may be curved in a J shape, an L shape, or the like. The anchor bolt 11 is provided with a bolt groove in a portion projecting upward from the top end of the base 2, and the fixing nut 13 is screwed to fix the column base metal piece 3.

As shown in FIG. 3(B), the column base metal member 3 is formed by a lower plate 31 having a fixing hole 30 into which the anchor bolt 11 is inserted, and a cross-shaped cross section that projects upward from the lower plate 31. A base portion 34 having a connecting leg portion 32 and an upper plate 33 which is a horizontal flat plate fixed to the upper end of the connecting leg portion 32, and a flat plate-like shape projecting upward from the base portion 34. The connection portion 36 is formed by arranging three drift holes 35 for fixing the portion 51. An insertion hole 37 having a larger diameter than the fixing hole 30 is formed in the upper plate 33 of the base portion 34 at a position overlapping the fixing hole 30 of the lower plate 31 when viewed from above, and the fixing nut 13 is attached to the anchor bolt 11. A tool can be inserted when fastening. The column base metal fitting 3 is fixed to an anchor bolt 11 protruding above the top end of the foundation 2 at a pitch of 1 m, for example.

The lower frame member 7 is a wooden square member, and as shown in FIGS. 1 and 2, both ends have a length that abuts against the pair of column base metal members 3. The lower frame member 7 is installed on the upper side with a predetermined distance from the top end of the foundation 2, and the lower surface of the lower frame member 7 is arranged at a position lower than the lower end surface of the column 5. For example, the lower frame member 7 is arranged such that the center in the height direction is located at the boundary between the lower end of the column 5 and the upper plate 33 of the base portion 34 of the column base metal fitting 3. Both lengthwise end faces of the lower frame member 7 are in contact with the edges of the upper plate 33 of the base portion 34 of the column base metal member 3, respectively. Then, one piece 91 of the L-shaped fixing member 9 is fixed to the upper surface of the lower frame member 7 with the screw 38, and the other piece 92 is fixed to the side surface of the column base 51 with the screw 38, so that the lower frame member 7 Are fixed to the column bases 51, and the lower frame member 7 is installed between the column bases 51.

In the pillar 5, a slit 53 into which the connecting portion 36 of the pillar pedestal 3 can be inserted is formed in the pillar pedestal 51 from the lower end upward, and penetrates from one side surface of the pillar pedestal 51 to the other side surface. Thus, three horizontal through holes 54 orthogonal to the slit 53 are formed. With the connecting portion 36 inserted in the slit 53 of the column base portion 51, the drift hole 35 of the connecting portion 36 and the horizontal through hole 54 of the column base portion 51 are aligned, and the drift pin (not shown) is connected to the horizontal through hole 54 and The column base 51 and the column base metal fitting 3 are joined by being inserted into the drift hole 35.

Since the lower frame member 7 is erected at a distance from the top end of the foundation 2, the dovetail that passes through the foundation 2 is blocked by the gap between the top end of the foundation 2 and the lower frame member 7, so The anti-termite property of the wall 4 can be enhanced. Moreover, since the end face in the length direction of the lower frame member 7 is in contact with the upper plate 33 of the base portion 34 of the column base metal member 3, the horizontal shearing force generated in the axial direction of the lower frame member 7 is generated. Since it is received by the foundation 2 via 3, it is possible to suppress the horizontal load from being applied from the lower frame member 7 to the column base 51.

The horizontal member 6 is, for example, a wooden beam provided between the first floor and the second floor of the building. An unillustrated stake fitting is provided on the stilt head 52 of the stanchion 5 and is joined to the horizontal member 6. In this embodiment, the beam wins are settled, and the upper end of the pillar 5 and the lower surface of the horizontal member 6 are joined, but in the case of a pillar win such as a through pillar, the side end surface of the horizontal member 6 and the pillar are joined. The side surface of 5 may be joined.

As described above, the pair of pillars 5, the horizontal member 6, and the lower frame member 7 form the rectangular wooden frame set 10. Then, the structural face material 8 is fixed to the outdoor side surface of the wooden frame assembly 10 with the nails 80 or the like to form the bearing wall 4. The structural face material 8 is, for example, a plywood, and nails 80 are fixed at a pitch of 150 mm to the wooden framing set 10 as a base. Since the load bearing wall 4 resists horizontal shearing force applied to the building and suppresses deformation, a pulling force in the axial direction is generated in the one column 5. A horizontal shearing force in the axial direction is applied to the horizontal member 6 and the lower frame member 7, which are the upper frame of the load bearing wall 4.

For example, as shown in FIG. 5 and FIG. 6, in the case where the high-performance bearing wall 4 having a large horizontal shearing force that can be borne in a three-story building is continuously formed in three steps above and below, The pulling force generated in the pillar 5 on the upper floor is also transmitted to the lower floor, and a relatively large pulling force is generated on the column base portion 51 of the pillar 5 on the first floor. At this time, an axial force is generated in the lower frame member 7. Therefore, if the end surface of the lower frame member 7 contacts only the column base 51 and does not contact the column base metal 3, as shown in the column base 51 of the conventional bearing wall 4a in FIG. The vertical pulling force and the horizontal shearing force transmitted from the axial direction of the lower frame member 7 are applied to the column base 51, and the stress that the column base 51 can bear becomes extremely low. Therefore, for example, it is necessary to take measures such as changing the load-bearing wall 4 on the third floor to a low-performance wall, and it is necessary to dispose the load-bearing wall 4 at another location in order to compensate for the insufficient wall amount. The degree of freedom of the plan is reduced, such as the number of places where parts can be installed decreases.

However, in the column base portion 51 of this embodiment shown in FIG. 5, the end surface of the lower frame member 7 is in contact with the column base metal member 3, and the axial force generated in the lower frame member 7 is the column base metal member 3. Since it is received by the foundation 2 via the, it is possible to suppress the horizontal shearing force from being transmitted to the column base portion 51 from the axial direction of the lower frame member 7. The end of the lower frame member 7 of the present embodiment is joined to the side surface of the column base 51 by the fixing member 9. However, by reducing the horizontal shearing force transmitted to the column base 51, the shear of the column base 51 is reduced. The load applied in the direction can be reduced, and the high-performance load bearing wall 4 having a larger shearing force can be arranged. Therefore, since the pedestal portion 51 is not excessively burdened, the high-performance bearing wall 4 can be arranged, for example, in the upper and lower three stages, and the degree of freedom in planning such as setting a large opening can be increased. it can.

It goes without saying that the embodiment of the present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the scope of the idea of the present invention.

The lower end structure 1 of the load bearing wall according to the present invention is suitable, for example, as the lower end structure 1 of the load bearing wall of a building in which a plurality of load bearing walls 4 are vertically arranged.

1 Lower end structure of load bearing wall 2 Foundation 3 Pillar pedestal 4 Load bearing wall 5 Pillar 7 Lower frame material 8 Structural face material 9 Fixing member 51 Pillar foot portion

Claims (2)

A pair of pillar pedestals that are fixed to the foundation with a gap between them,
A pair of pillars in which the pillar base is fixed to the pillar base metal fittings,
A lower frame member arranged between the column bases of the columns,
At least a structural face material fixed to the outdoor side surface of the pillar and the lower frame member,
Equipped with
A lower end structure of a load-bearing wall, wherein end surfaces of the lower frame member in the lengthwise direction are respectively brought into contact with a column pedestal. The lower frame member is erected on the upper side with a predetermined distance from the top end of the foundation, and the lower surface of the lower frame member is arranged at a position lower than the lower end surface of the pillar member,
The lower end structure of the load bearing wall according to claim 1, further comprising fixing members that fix both ends of the lower frame member to the side surfaces of the column base.

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