BEARING WALL OF WOODEN HOUSE

TECHNICAL FIELD

The present invention relates to a bearing wall of a wooden house capable of maintaining satisfactory seismic resistance while allowing installation of a window.

BACKGROUND ART

In a wooden house, bearing walls are provided to meet the required wall quantity, so that the wooden house can withstand horizontal force during an earthquake or a typhoon. This type of bearing wall is configured by bridging a brace over an opening between adjacent column members in a framework, or sticking a structural plywood so as to cover the entire opening between adjacent column members in a framework.

In general, it is impossible to attach a brace or a structural plywood as described above in a part where a window is installed, it is difficult to maintain satisfactory seismic resistance, and the wall is often not accepted as a bearing wall. For this reason, installation of a window may be restricted in order to meet the required wall quantity.

Therefore, in recent years, a bearing wall capable of maintaining satisfactory seismic resistance while allowing installation of a window has been proposed as disclosed in Patent Literature 1, for example. In this bearing wall, an aseismic glass unit panel formed by integrating a base wood member and a glass plate with each other so that external force can be transmitted is attached to a window installation opening formed between adjacent column members in a framework so as to increase the wall quantity with the in-plane rigidity of the glass plate, that is, to cause the glass plate to function as a structural face plate, so that satisfactory seismic resistance is maintained.

CITATION LIST
Patent Literature

Patent Literature 1: Japanese Patent Application Laid-Open No. 2009-293367

SUMMARY OF THE INVENTION
Technical Problems

However, regarding the above bearing wall, a window to be installed in the window installation opening is limited to a structure such as a fixed window, for example, in which a base wood member and a glass plate are integrated with each other so that external force can be transmitted, it is difficult to install an openable window such as a double sliding window, for example, and there is a problem that the versatility is poor.

An object of the present invention is to provide a bearing wall capable of solving the above problems and maintaining satisfactory seismic resistance while allowing installation of various windows.

Solutions to the Problems

To solve the above-mentioned problems, a bearing wall 1 according to the present invention partitions into a plurality of openings 13 and 14 in a vertical direction between adjacent column members 3 by bridging at least one beam member 11 that serves as a window lintel or a window sill between intermediate portions of the adjacent column members 3 in a framework 2 of the wooden house, and the bearing wall has a structural plywood 50 stuck onto an opening 14 other than a window installation opening 13 among the openings 13 and 14, wherein both end portions of the beam member 11 are tied to intermediate portions of the adjacent column members 3 via metal joints 20, and a peripheral end portion of the structural plywood 50 is fixed to the opening 14 with a nail or a screw.

Specifically, the beam member 11 has a beam height of 150 mm and a beam width of 120 mm. In addition, a peripheral end portion of the structural plywood 50 is fixed to the opening 14 with nails or screws by driving nails or screws at a ratio of nine nails or screws per 1 m along a peripheral end portion of the structural plywood 50. Further, horizontal frame members 10 and 12 having a cross-sectional area smaller than a cross-sectional area of the beam member 11 are bridged between upper end portions or lower end portions of the adjacent column members 3, so that the horizontal frame members 10 and 12 serve as a base for installing a window 40 or fixing the structural plywood 50 with nails or screws.

Advantageous Effects of Invention

In a bearing wall of the present invention, a beam member (structural material) is used as a window lintel or a window sill so that both end portions of the beam member are tied to intermediate portions of adjacent column members in a framework via metal joints, and a peripheral end portion of a structural plywood is fixed to the opening with nails or screws, and therefore the resistance to horizontal force during an earthquake or a typhoon can be increased, and satisfactory seismic resistance can be maintained regardless of the type of window to be installed in a window installation opening.

In particular, the cross-sectional area of the beam member is increased (beam height 150 mm×beam width 120 mm) so that the beam member itself or the joint between the beam member and the column member becomes unlikely to be destroyed, or the pitch of nails or screws for fixing a structural plywood is made rough (a ratio of nine nails or screws per 1 m) to prevent excessive rise of the load imposed on the bearing wall so that flexure fracture of the column member becomes unlikely to occur, and it is therefore possible to obtain a tenacious structure having deformation extensibility significantly improved.

Moreover, regarding a horizontal frame member bridged between upper end portions or lower end portions of adjacent column members, since large force is not likely to act and the possibility of fracture is low even if horizontal force is applied during an earthquake or a typhoon, the cross-sectional area is made smaller than that of the beam member that serves as the window lintel or the window sill, which makes it possible to reduce the material cost.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view of a bearing wall in one embodiment according to the present invention.

FIG. 2 is a perspective view of a bearing wall.

FIG. 3 is a front view showing a state that a window of a bearing wall and the structural plywood are not installed.

FIG. 4A is an exploded perspective view showing a joint via the metal joint of a beam member and a column member.

FIG. 4B is an erection perspective view showing a joint via the metal joint of a beam member and a column member.

FIG. 5 is a view showing a shearing test result of a bearing wall.

FIG. 6 is a view showing a shearing test result of a bearing wall in the comparative example.

FIG. 7 is a front view showing a state that a window and the structural plywood of a bearing wall are not installed in the comparative example.

FIG. 8 is a front view showing a state that a window and the structural plywood of a bearing wall are not installed according to another embodiment.

FIG. 9 is a front view showing a state that a window and the structural plywood of a bearing wall are not installed according to another embodiment.

FIG. 10 is a front view showing a state that a window and the structural plywood of a bearing wall are not installed according to another embodiment.

DESCRIPTION OF EMBODIMENTS

The following description will explain embodiments of the present invention in detail with reference to the drawings. As shown in FIGS. 1 and 2, a bearing wall 1 of a wooden house according to an embodiment of the present invention is partitioned into two openings 13 and 14 in the vertical direction between adjacent column members 3 constituting a framework 2 by bridging a window lintel 10 as a horizontal frame member between upper end portions of the adjacent column members 3 constituting the framework 2, bridging a beam member 11 that serves as a window sill between intermediate portions of the adjacent column members 3 constituting the framework 2, and bridging a base member 12 as a horizontal frame member between lower end portions of the adjacent column members 3 constituting the framework 2. As shown in FIG. 3, it is to be noted that an upper end portion of each column member 3 is fixed to a beam member 4 constituting the framework 1 via a column head metal fitting 15, and a lower end portion of each column member 3 is fixed to a rising portion of a cloth foundation 5 via a column base metal fitting 16.

The window lintel 10 is made of a square timber having a vertical cross section height of 60 mm and a horizontal width of 120 mm, and both end portions thereof are fixed to upper end portions of the adjacent column members 3 with nails or screws. Similar to the window lintel 10, the base member 12 is made of a square timber having a vertical cross section height of 60 mm and a horizontal width of 120 mm, and both end portions thereof are fixed to lower end portions of the adjacent column members 3 with nails or screws. On the other hand, the beam member 11 that serves as a window sill is made of a square timber having a vertical cross section height (beam height) of 150 mm and a horizontal width (beam width) of 120 mm, and both end portions thereof are tied to intermediate portions of the adjacent column members 3 via metal joints 20.

As shown in FIGS. 4A and 4B, each metal joint 20 includes a plate-shaped column-side fixing portion 23 formed by bending a metal plate into a U-shape in a plan view, and a pair of right and left plate-shaped beam-side fixing portions 24 protruding from both end portions in the vertical direction of the column-side fixing portion 23. A plurality of bolt insertion holes 25 are formed at the column-side fixing portion 23 at an interval in the vertical direction. At each beam-side fixing portion 24, a substantially V-shaped pin receiving groove 26 that opens upward, and a pin insertion hole 27 are formed at an interval in the vertical direction.

The column members 3 and the beam member 11 that serves as a window sill are tied using the metal joints 20 as follows. It is to be noted that a pair of bolt through holes 30 are formed at an intermediate portion of each column member 3 at an interval in the vertical direction. At an end portion of the beam member 11, a pair of slits 31 that open to the upper and lower surfaces and the end surface of the beam member are formed at an interval in the lateral direction. Furthermore, a pair of pin through holes 32 are formed at an end portion of the beam member 11 at an interval in the vertical direction so as to be orthogonal to the slit 31.

First, the column-side fixing portion 23 of a metal joint 20 is brought into contact with an intermediate portion of a column member 3 so that the bolt insertion holes 25 are overlapped with the bolt through holes 30 of the column member 3. From this state, bolts 35 are inserted into the bolt through holes 30 and the bolt insertion holes 25 that correspond to each other, and nuts 36 are screwed into tip portions of the bolts 35 and tightened to fix the column-side fixing portion 23 of a metal joint 20 to an intermediate portion of the column member 3. Then, an end portion of the beam member 11 is brought into contact with an intermediate portion of the column member 3 by inserting the beam-side fixing portions 24 of the metal joint 20 into the slits 31. At this time, a drift pin 37 is inserted into an upper pin through hole 32 of the beam member 11 in advance, and the drift pin 37 is dropped into the pin receiving grooves 26 of the beam-side fixing portions 24 so as to temporarily fix the beam member 11 to the beam-side fixing portions 24 so that a lower pin through hole 32 of the beam member 11 and the pin insertion holes 27 of the beam-side fixing portions 24 correspond to each other. From this state, an end portion of the beam member 11 is fixed to the beam-side fixing portions 24 of the metal joint 20 by inserting a drift pin 37 into the pin through hole 32 and the pin insertion holes 27 that correspond to each other. As a result, the intermediate portion of the column member 3 and the end portion of the beam member 11 are tied to each other via the metal joint 20.

As shown in FIGS. 1 and 3, the upper opening 13 is constituted of a square frame-shaped portion surrounded by the adjacent column members 3, the window lintel 10, and the beam member 11 that serves as a window sill, and a window 40 is installed in the upper opening 13. That is, the upper opening 13 serves as a window installation opening.

As shown in FIGS. 1 and 2, the window 40 is a double sliding window in which a pair of paper sliding doors 42 are slidably attached to a window frame 41, and is fitted into the window installation opening 13 and installed by fixing with nails or screws. It is to be noted that the window 40 is not limited to a double sliding window, and may be any kind of window such as a fixed window, a sash window, an outward opening window, a folding window, and a bay window.

As shown in FIGS. 1 and 3, the lower opening 14 is constituted of a square frame-shaped portion surrounded by the adjacent column members 3, the beam member 11 that serves as a window sill, and the base member 12, a half column 45 and studs 46 are extended between the beam member 11 and the base member 12 in the lower opening 14, and a square structural plywood 50 is stuck. Although upper and lower end portions of the half column 45 and the studs 46 are fixed to the beam member 11 and the base member 12 with nails or screws, it is to be noted that the upper and lower end portions may be fixed via metal joints.

The structural plywood 50 is fixed to the lower opening 14, that is, the adjacent column members 3, the beam member 11 that serves as a window sill, and the base member 12 with nails by driving nails 51 at a ratio of nine nails per 1 m (a pitch of approximately 120 mm) along a peripheral end portion thereof. Moreover, nails 51 are appropriately driven also into portions of the structural plywood 50 with which the half column 45 or the studs 46 come into contact, and fixing to the half column 45 or the studs 46 with nails is also achieved. It is to be noted that a small gap 47 is provided between the beam member 4 and the window lintel 10 constituting the framework 2, and a strip-shaped plywood 52 is laid across the beam member 4 and the window lintel 10 and fixed with nails so as to close the gap 47.

As described above, since the beam member 11 that is a structural material having a large cross-sectional area is used as a window sill, and both end portions of the beam member 11 are tied with intermediate portions of the adjacent column members 3 in the framework 2 via the metal joints 20, fracture of the beam member 11 itself or the joints between the beam member 11 and the column members 3 are less likely to occur in the above bearing wall 1. Moreover, since the structural plywood 50 is fixed to the lower opening 14 with nails at a rough nail pitch (at a pitch of approximately 120 mm), it is possible to prevent excessive rise of the load imposed on the bearing wall 1 to reduce the bending load of the column member 3 (to prevent excessive force from acting from the joints between the beam member 11 and the column members 3 to the intermediate portion of the column members 3), and to increase the resistance to horizontal force during an earthquake or a typhoon while preventing flexure fracture of the column members 3. As a result, a tenacious structure having deformation extensibility significantly improved is obtained, and satisfactory seismic resistance can be maintained.

Moreover, regarding the window lintel 10 and the base member 12 as horizontal frame members bridged between upper and lower end portions of the adjacent column members 3, since large force is not likely to act and the possibility of fracture is low even when horizontal force is applied during an earthquake or a typhoon, the cross-sectional area is made smaller than that of the beam member 11 that serves as a window sill, which makes it possible to reduce the material cost.

Although not shown in the figures, it is to be noted that the above bearing wall 1 is provided with an interior material stuck onto the indoor side thereof and an exterior material stuck onto the outdoor side thereof, except for the part where the window 40 is installed.

FIG. 5 shows a shearing test result of the above bearing wall 1, and FIG. 6 shows a shearing test result of a bearing wall of a comparative example. As shown in FIG. 7, in a bearing wall of the comparative example, it is to be noted that a window sill 11A is made of a square timber having a vertical cross section height (beam height) of 60 mm and a horizontal width (beam width) of 120 mm, both end portions thereof are fixed to intermediate portions of adjacent column members 3 with nails, and a structural plywood is fixed to a lower opening 14 with nails by driving the nails at a pitch of approximately 60 mm along the peripheral end portion thereof. The other configurations are similar to those of the above bearing wall 1. In the shearing test, a load in the horizontal direction was applied to the beam member 4 constituting the framework 2, and the deformation angle with respect to the load at this time was measured. This measurement was performed three times each.

It was confirmed from this shearing test result that, in the above bearing wall 1, the maximum load was suppressed, the wall was tenacious enough not to break until large deformation occurs, and a sufficient short-term allowable shearing strength could be secured, while, in the comparative example, the maximum load increased, deformation did not extend, brittle fracture occurred, and the short-term allowable shearing strength significantly lowered. It is to be noted that the short-term allowable shearing strength is found from the minimum value of yield load (Py), ultimate load and deformation performance (Pux0.2/Ds), ⅔ of maximum load (⅔xPmax), and load at deformation angle 1/120.

FIGS. 8 to 10 show bearing walls 1 according to other embodiments. A bearing wall 1 shown in FIG. 8 is partitioned into two openings 60 and 61 in the vertical direction between adjacent column members 3 by bridging a beam member 11 that serves as a window lintel between intermediate portions of the adjacent column members 3 constituting a framework 2. In addition, a half column 45 and studs 46 are extended between the beam member 4 constituting the framework 1 and the beam member 11 that serves as a window lintel in the upper opening 60, a square structural plywood 50 is stuck, and a window 40 is installed in the lower opening 61. It is to be noted that the other configurations are similar to those of the above bearing wall 1.

A bearing wall 1 shown in FIG. 9 is partitioned into three openings 62, 63, and 64 in the vertical direction between adjacent column members 3 by bridging a window lintel 10 as a horizontal frame member between upper end portions of the adjacent column members 3 constituting a framework 2, and bridging two beam members 11 that serves as a window lintel and a window sill between intermediate portions of the adjacent column members 3 constituting the framework 2. A half column 45 and studs 46 are extended between the upper and lower beam members 11 in the intermediate opening 63, a square structural plywood 50 is stuck, and a window 40 is installed in the upper opening 62 and the lower opening 64. It is to be noted that the other configurations are similar to those of the above bearing wall 1.

A bearing wall 1 shown in FIG. 10 is partitioned into three openings 65, 66, and 67 in the vertical direction between adjacent column members 3 by bridging two beam members 11 that serve as a window lintel and a window sill between intermediate portions of the adjacent column members 3 constituting a framework 2 and by bridging a base member 12 as a horizontal frame member between lower end portions of the adjacent column members 3 constituting the framework 2. In addition, in the upper opening 65, a half column 45 and studs 46 are extended between the beam member 4 constituting the framework 1 and the beam member 11 that serves as a window lintel, and a square structural plywood 50 is stuck. In the lower opening 67, a half column 45 and studs 46 are extended between the beam member 11 and the base member 12 that serves as a window sill, and a square structural plywood 50 is stuck. In the intermediate opening 66, a window 40 is installed. It is to be noted that the other configurations are similar to those of the above bearing wall 1.

Similar to the above bearing wall 1, each of the bearing walls 1 shown in FIGS. 8 to 10 also has a tenacious structure having deformation extensibility significantly improved, and can maintain satisfactory seismic resistance.

Although embodiments of the present invention have been explained above, the invention is not limited to the above embodiments, and various modifications can be made within the scope of the invention. For example, a bearing wall of the present invention is not limited to a bearing wall to be provided on the first floor foundation of a wooden house as described in the above embodiments, and may be provided on an upper floor of a wooden house. In this case, for example, adjacent column members constituting a framework are laid across upper and lower beam members constituting the framework. Moreover, for sticking a structural plywood onto an opening, not only fixing with nails but also fixing with screws may be employed.

DESCRIPTION OF REFERENCE SIGNS

1 bearing wall

2 framework

3 column member

11 beam member

10,12 horizontal frame member

13,61,62,64,66 window installation opening

14,60,63,65,67 opening for sticking the structural plywood

20 metal joint

40 window

50 structural plywood

51 nail

BEARING WALL OF WOODEN HOUSE

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