JP7298158B2 - Lower end structure of bearing wall - Google Patents

Description

The present invention relates to a lower end structure of a load-bearing wall, and more particularly, a pair of columns whose column bases are joined on a foundation, and a lower frame member horizontally arranged between the column bases of the columns. It relates to the lower end structure of the load-bearing wall to which the structural face material is stuck as.

Conventionally, a structural surface is provided on the outdoor side of a wooden framework, which is formed by a foundation provided on a foundation, a pair of pillars erected on the foundation, and a beam erected on the upper end of the pillar. Load-bearing walls in which materials are fixed with nails or the like are known (for example, Patent Document 1). When a horizontal shear force is applied to a building, each load-bearing wall placed in the building resists the horizontal shear force. A compressive force is applied to the column base of the column. In the case where the load-bearing walls are arranged vertically, the pull-out force and compression force applied to the load-bearing walls on the upper floor will be 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 base.

Then, in order to prevent the pedestal from being pulled out by the pulling force applied to the pedestal, the pedestal hardware is joined to the anchor bolt partially embedded in the foundation, and the pedestal part of the column is joined to the pedestal hardware. structure is known. In such a structure, since the column base and the foundation are joined together without a wooden base, the stress against the pull-out force to the column base can be increased. In addition, among such column base metal fittings, there has also been proposed one in which plates are extended sideways and the end portions of the base are connected to each other (for example, Patent Document 2).

Japanese Unexamined Patent Application Publication No. 2012-202112 Japanese Unexamined Patent Application Publication No. 2017-20236

By the way, the foundation provided on the foundation is arranged for the purpose of supplementing the construction accuracy of the foundation. Therefore, if the construction accuracy of the foundation is high, it is not always necessary to provide the foundation. In the case of a structure without a base, a large gap can be formed in the part where the base was provided in the past, which is advantageous for ventilation under the floor and inside the wall, and the gap blocks the path of the dovetail. Therefore, the anti-termite property can be enhanced.

Even if the base is not provided as described above, it is necessary to arrange the lower frame member between the column bases, which serves as the foundation for the lower end portion of the structural panel. The lower frame member is laid between the column bases, and both ends thereof are fixed to the side surfaces of the column bases. When the lower frame member is fixed to the side of the column base in this way, when a horizontal shear force is applied to the building, a pull-out force is applied to the column base portion of the column, and a horizontal shear force is also applied from the lower frame member. It joins the pedestal of the column. Therefore, loads in the pull-out direction and the shear direction are applied to the column base at the same time, and there is a problem that the load that the column base can bear is extremely reduced compared to the case where the column base is borne in one direction.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a load-bearing wall lower end structure capable of reducing the load in the horizontal shear direction applied to a column base.

The lower end structure of the load-bearing wall of the present invention includes a pair of metal column bases fixed to a foundation with a space therebetween, a pair of columns whose column bases are fixed to the column base metals, and column bases of the columns. a lower frame member disposed between; a structural face member fixed to at least the column and the outdoor side surface of the lower frame member; and a fixing fixing both ends of the lower frame member to the side surface of the column base and a member, wherein the end faces of the lower frame member in the length direction are in contact with the column base metal fitting and the side surface of the column base portion, respectively, and the lower frame member is the side surface of the column base portion. Both ends are fixed to the foundation, and it is erected above the top of the foundation with a predetermined distance, and a gap of the predetermined distance is formed between the top of the foundation and the lower surface of the lower frame member , The lower surface of the lower frame member is arranged at a position lower than the lower end surface of the pillar , and the upper surface of the lower frame member is arranged at a position higher than the lower end surface of the pillar .

According to the lower end structure of the load-bearing wall of the present invention, when a horizontal load is applied to the building, a vertical load in the pull-out direction is applied to the column base of the column that constitutes the load-bearing wall, and the lower frame member is applied to the column base. A horizontal shear force is also applied, but since the lengthwise end face of the lower frame member is in contact with the column base metal, the horizontal load of the lower frame member is received by the column base metal fixed to the foundation. , the horizontal shear force applied to the column base can be reduced. Therefore, since the joint between the column base and the column base metal bears only the vertical load in the drawing direction, it bears a larger load than when the loads in the drawing direction and the shear direction are combined. be able to.

According to the lower end structure of the bearing wall of the present invention, the lower frame member is erected above the top end of the foundation with a predetermined distance therebetween, so that a gap is formed between the top end of the foundation and the lower frame member. Since it is possible to block the ant trails climbing up from the foundation, it is possible to enhance the anti-termite property. In addition, since the lower surface of the lower frame member is located at a position lower than the lower end surface of the column , the end portion of the lower frame member can be brought into contact with the column base metal even if the column base metal has a normal shape. It is possible to reduce the cost of the load-bearing wall because there is no need to provide special column base hardware. Further, since fixing members are provided for fixing both ends of the lower frame member to the side surfaces of the column base, the lower frame member can be used as a base for attaching the structural surface member.

FIG. 4 is a partially omitted front view for explaining the lower end structure of the load-bearing wall; FIG. 4 is a partially omitted perspective view for explaining the lower end structure of the load-bearing wall. (A) is a partially enlarged front view for explaining the column base portion of the lower end structure of the load-bearing wall, and (B) is a perspective view illustrating the configuration of the column base hardware. FIG. 4 is a front view showing the configuration of a load-bearing wall in which the bottom structure of the load-bearing wall is formed; A front view and an 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. A front view and an abbreviated enlarged view for explaining the load on 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 conventional load-bearing wall is arranged.

An embodiment of the present invention will be described below with reference to FIGS. 1 to 6. FIG. As shown in FIG. 4, the load-bearing wall 4 in the lower end structure 1 of the load-bearing wall of this embodiment includes 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 fittings 3. , a horizontal member 6 such as a beam erected on the column head 52 of the column 5, and a lower frame member 7 arranged between the column bases 51 of the column 5. The load-bearing wall 4 is formed by fixing the structural panel 8 to the outdoor side surface of the rectangular wooden framework 10 formed by the pair of pillars 5, the horizontal member 6, and the lower frame member 7 with nails 80 or the like. , which bears the horizontal shear force. 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 foundation 2 of the present embodiment is a raised portion on the outer periphery of the foundation 2. Although not shown, the lower portion is buried below the ground line, and reinforcing bars (not shown) are buried therein. As shown in FIGS. 1 and 3A, anchor bolts 11 are embedded in the foundation 2 so that a portion thereof protrudes upward from the top end. Anchor bolts 11 are embedded in the foundation 2 at a pitch of 1 m, for example, in order to fix the column base hardware 3 . In addition, as shown in FIG. 1, the anchor bolt 11 has a flange-shaped enlarged diameter portion 12 at the portion embedded in the foundation 2 so as to resist the pull-out 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 has a bolt groove in a portion protruding upward from the top end of the foundation 2, and fixes the column base hardware 3 by screwing a fixing nut 13 thereto.

As shown in FIG. 3B, the column base metal 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 projecting upward from the lower plate 31. A base portion 34 having a connection leg portion 32 and an upper plate 33 which is a horizontal flat plate fixed to the upper end of the connection leg portion 32, and a flat plate shape projecting upward from the base portion 34, and a column base A connecting portion 36 in which three drift holes 35 for fixing the portion 51 are formed side by side is provided. An insertion hole 37 having a diameter larger than that of 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. A tool can be inserted when fastening. The column base hardware 3 is fixed to anchor bolts 11 protruding above the top 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 FIG. 1 and FIG. 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 so that the center in the height direction is positioned 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 end faces in the length direction of the lower frame member 7 are in contact with the edges of the upper plate 33 of the base portion 34 of the metal column base 3 . One piece 91 of the L-shaped fixing member 9 is fixed to the upper surface of the lower frame member 7 with a screw 38, and the other piece 92 is fixed to the side surface of the column base portion 51 with a screw 38. are fixed to the column bases 51 respectively, and the lower frame member 7 is constructed between the column bases 51 .

The column 5 has a slit 53 extending upward from the lower end thereof into which the connecting portion 36 of the column base metal fitting 3 can be inserted, and penetrates from one side surface of the column base portion 51 to the other side surface. Three horizontal through-holes 54 are formed perpendicularly to the slit 53 as shown. With the connection portion 36 inserted into the slit 53 of the column base portion 51, the drift hole 35 of the connection portion 36 is aligned with the horizontal through hole 54 of the column base portion 51, and a drift pin (not shown) is inserted into the horizontal through hole 54 and the horizontal through hole 54 of the column base portion 51. The column base portion 51 and the column base hardware 3 are joined by inserting them into the drift holes 35 .

Since the lower frame member 7 is erected at a distance from the top end of the foundation 2, the dovetail path running along the foundation 2 is blocked by the gap between the top end of the foundation 2 and the lower frame member 7, thereby The termite resistance of the wall 4 can be enhanced. In addition, since the end surface of the lower frame member 7 in the length direction is in contact with the upper plate 33 of the base portion 34 of the column base metal 3, the horizontal shear force generated in the axial direction of the lower frame member 7 is reduced to the column base metal. Since it is received by the foundation 2 via the 3, it is possible to suppress the horizontal load from being applied to the column base portion 51 from the lower frame member 7. - 特許庁

The horizontal member 6 is, for example, a wooden beam provided between the first and second floors of the building. A capital fitting (not shown) is provided on the capital 52 of the pillar 5 and joined to the horizontal member 6 . In the present embodiment, the fitting is of a beam beam, and the upper end of the column 5 and the bottom surface of the horizontal member 6 are joined. 5 may be joined together.

As described above, the pair of pillars 5, the horizontal member 6, and the lower frame member 7 form the rectangular wooden framework 10. As shown in FIG. Then, the load-bearing wall 4 is formed by fixing the structural panel 8 to the outdoor side surface of the wooden framework 10 with nails 80 or the like. The structural face member 8 is, for example, plywood, and is fixed by driving nails 80 into the underlying wooden framework 10 at a pitch of 150 mm. Since the bearing wall 4 resists the horizontal shear force applied to the building and suppresses deformation, an axial pull-out force is generated on one of the columns 5 . Further, 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 FIGS. 5 and 6, in the case of a three-story building in which a high-performance load-bearing wall 4 with a large horizontal shear force that can be borne is continuously formed over three levels, The pull-out force generated on the pillar 5 on the upper floor is also transmitted to the lower floor, and a relatively large pull-out 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 portion 51 and does not contact the column base metal fittings 3 as shown in the column base portion 51 of the conventional bearing wall 4a in FIG. , a vertical pull-out force, and a 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 is extremely low. Therefore, for example, it is necessary to take measures such as changing the load-bearing wall 4 on the third floor to one with lower performance. The degree of freedom in planning decreases, such as the number of places where parts can be installed.

However, in the column base portion 51 of this embodiment shown in FIG. It is possible to suppress 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 this embodiment is joined to the side surface of the column base 51 by the fixing member 9, but by reducing the horizontal shearing force transmitted to the column base 51, the shear of the column base 51 is reduced. A load applied in a direction can be reduced, and a high-performance load-bearing wall 4 with a larger shear force can be arranged. Therefore, since an excessive load does not occur on the column base 51, high-performance load-bearing walls 4 can be arranged, for example, over three stages, and the degree of freedom in planning, such as installing a large opening, can be increased. can.

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

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

1 Lower end structure of bearing wall 2 Foundation 3 Column base hardware 4 Bearing wall 5 Column 7 Lower frame member 8 Structural face member 9 Fixing member 51 Column base

Claims (1)

a pair of column base metal fittings spaced apart from each other and fixed to the foundation;
a pair of columns whose column bases are fixed to the column base hardware;
a lower frame member arranged between the column bases of the columns;
a structural face member fixed to at least the pillar and the outdoor side surface of the lower frame member;
a fixing member for fixing both ends of the lower frame member to the side surface of the column base;
with
The end faces in the length direction of the lower frame member are in contact with the column base hardware and the side surface of the column base, respectively,
Both ends of the lower frame member are fixed to the side surfaces of the column base, and the lower frame member is erected at a predetermined distance from the top end of the foundation so that the top end of the foundation and the lower surface of the lower frame member are separated from each other. A gap of the predetermined distance is formed between
The lower surface of the lower frame member is arranged at a position lower than the lower end surface of the pillar , and the upper surface of the lower frame member is arranged at a position higher than the lower end surface of the pillar . Bottom structure of the wall.

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