JP2008308820A - Bearing wall structure of conventional framework wooden building - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing wall structure which increases a wall magnification by fixing structural plywood between columns of a conventional framework wooden building, which can obtain the high wall magnification by using general structural plywood, without use of a special structural face material, and which is excellent in constructibility without use of a brace. <P>SOLUTION: An outer peripheral portion of the structural plywood 6 with a thickness of 9 mm or more is fixed at an interval of 100 mm or less to a framework member such as the column 1, a sill 2 and a beam 3 by means of a screw 7 with a quality level equivalent to or exceeding a material standard SWCH18A, without use of the brace, so that the wall magnification can be set at 4.0 or more. A joint between the framework members is reinforced with a reinforcing metal 8, so as to obtain necessary strength. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a load-bearing wall structure for seismic reinforcement of a conventional framed wooden building during renovation.

  As a typical structural form of a wooden building, there are a structure by a conventional shaft construction method and a structure by a two-by-four method.

  In contrast to the two-by-four method, which has a planar resistance mechanism, the conventional shaft assembly method is based on a linear resistance mechanism using a shaft assembly such as a column or a beam. Although the assembly method is superior, the two-by-four method is generally advantageous for earthquakes.

  In addition, with the revision of earthquake resistance standards, existing wooden buildings need to be seismically strengthened. Traditionally, buildings with a conventional frame construction method have been reinforced by bracing the part surrounded by pillars and beams, but wall reinforcement by structural face materials such as structural plywood is recognized, and high wall magnification In order to achieve this, it is common to use braces and structural face materials in combination.

  Conventionally, for a bearing wall of a conventional wooden framed wooden building, a wall magnification of 2.5 can be obtained by nailing a structural plywood with a thickness of 7.5 mm or more with a N50 nail at intervals of 15 cm or less. Has been. In reinforcement by bracing, a wall magnification of 2.0 is obtained by attaching a predetermined bracing.

  Therefore, in order to secure a wall magnification of 4.5, a wall magnification of 2.0 is added to the wall magnification of 2.5 of the structural plywood to obtain a wall magnification of 4.5, that is, bracing is indispensable. It was.

  However, reinforcement by bracing needs to be firmly fixed when attaching the end of the bracing to a joint such as a column and a beam, and since stress concentrates on this joint, it is necessary to reinforce that part. Various kinds of construction hardware have been developed to reinforce such joints and fix braces, but there are limits to the installation and reinforcement of only narrow joints, making the installation work complicated, and mounting brackets and reinforcements. There is a problem that the cost of hardware is also increased.

  On the other hand, Patent Document 1 uses a fiber reinforced mortar composite board instead of a structural wooden plywood or a structural wooden panel in a conventional wooden house, thereby increasing service life, improving earthquake resistance, and fire resistance. A technique for improving performance is described.

  In addition, Patent Document 2 relates to seismic reinforcement of a wooden building constructed by a conventional construction method. As a structural surface material, MDF (medium fiberboard) is laminated integrally on the front and back surfaces of a structural plywood to provide strength. A technique is described in which a wall magnification is set to 3.56 times by using a plate-like member having an increased height and fastening to a shaft assembly with screws. In this case, the screw interval is about 150 mm.

  Further, in Patent Document 3, a gap is provided between the upper surface of the foundation constituting the bearing wall and the lower end surface of the structural plywood, and an edge of the floor material is provided on the upper surface of the foundation. Receiving material that can be placed on the floor, eliminates the need for a floor receiving member on the base to support the flooring material, facilitates the construction of the floor, and is joined to both the structural plywood and the flooring material And connecting the structural plywood and the floor surface material via the receiving material, and providing an intermediate column that connects the intermediate part of the beam and the base, reinforcing the frame material with this intermediate column, thereby 3 times or more magnification The technology of ensuring the proof stress of the proof stress wall in the bearing wall is described.

JP-A-11-107366 JP 2000-291130 A JP 2006-090036 A JP 2006-037394 A JP 2002-061316 A

  As mentioned above, in the seismic reinforcement of conventional conventional wooden framed wooden buildings, bracing is indispensable when trying to secure a large wall magnification of 4.5 or more, including reinforcement of joints. However, there is a problem that the cost is increased.

  Moreover, although the technique of patent document 1 and patent document 2 aimed at the improvement of wall magnification by improvement of a structural surface material, in addition to the cost as a structural surface material increasing, the wall magnification obtained is It is not sufficient, and bracing is necessary to ensure a larger wall magnification.

  The thing of patent document 3 differs in the structure from the conventional earthquake-proof reinforcement structure, and construction is complicated, and also the wall magnification obtained is not sufficient, and bracing is necessary to secure a larger wall magnification. Become.

  On the other hand, the inventor of the present application, as a result of repeated studies in order to solve the problems as described above, a structural plywood having a predetermined thickness or more with a screw having a predetermined material or more and pulling resistance, It was found that seismic reinforcement with a wall magnification of 4.5 or more is possible without using braces by fastening at intervals shorter than the conventional general intervals.

  That is, the present invention provides a large wall magnification with a general structural plywood without using a special structural face material in seismic reinforcement of a conventional framed wooden building, and does not require bracing and is easy to construct. It is also intended to provide an excellent bearing wall structure.

  The invention according to claim 1 of the present application is the bearing wall structure in which the wall magnification is increased by fastening the structural plywood between the columns of the conventional wooden framed wooden building, and the outer peripheral portion of the structural plywood having a thickness of 9 mm or more This is characterized in that the wall magnification is set to 4.0 or more without using a brace by fixing it with a material standard SWCH18A or a screw having a quality equal to or higher than that at an interval of 100 mm or less with respect to the shaft assembly. To do.

  As the structural plywood itself, a commercially available general structural plywood can be used, but a standard thickness of 7.5 mm is insufficient, and in the present invention, a wall having a thickness of 9 mm or more is used. The magnification can be 4.0 or more, usually 4.5 or more. The upper limit of the thickness is not particularly defined, but if it is too thick, the contribution to the seismic strength is not so much, but it is difficult to fix with screws, so 15 mm or less is desirable.

  The dimensions of commercially available structural plywood include, for example, 900 mm × 1800 mm, 910 mm × 1820 to 2730 mm, and the like, but it is possible to select one that is easy to use according to the dimensions of the shaft set to be reinforced. it can. Regarding the strength and the like of the structural plywood, there is a distinction between the first grade and the second grade, but the first grade is preferable.

  The fixing interval of the structural plywood to the shaft set is not enough at 150 mm as a reference, and in the present invention, the fixing interval of the outer peripheral portion of the structural plywood is set to 100 mm or less. Further, the round nail is loosened by the action of the pulling force, and the wall magnification of 4.0 or 4.5, which is the condition of the present invention, cannot be secured. For portions other than the outer peripheral portion to be fastened to cross members such as studs and other vertical members in the shaft assembly, or cross members such as trunks, the fixing interval is not necessarily 100 mm or less.

  Further, in the present invention, in order to secure the wall magnification of 4.0 or 4.5, the drawing resistance by the screw thread portion is an indispensable element, but material strength corresponding to the drawing resistance is required. Therefore, we decided to use the material standard SWCH18A or a screw having quality equivalent to or better than this. Further, the screw must be prevented from damaging the shaft assembly material, such as cracking, but such a quality is also a condition in order to obtain a required fastening strength even with a relatively short screw.

  There are cases where the structural plywood is fixed to the shaft assembly with screws, either directly on a shaft assembly material such as a pillar, or via a receiving material along the pillar.

  Under the above conditions, a wall magnification of 4.0 or 4.5 can be achieved without attaching a brace by attaching a reinforcing hardware to the joint of the shaft assembly. Various types of reinforcing hardware have been used in the past, but it is only necessary to select one that can secure the required strength, is compact, and does not hinder the work of fixing the structural plywood to the shaft assembly.

  Claim 2 is a bearing wall structure of a conventional framed wooden structure according to claim 1, wherein the screw has a tip screw formed at the tip side, a neck screw formed at the root of the head, and the neck The length of the screw is shorter than the length of the tip screw, and the screw pitch of the neck screw is smaller than the screw pitch of the tip screw.

  As described above, in the present invention, the conventional round nail is insufficient, and a screw is used. However, by using a screw having a neck screw pitch smaller than the screw pitch of the tip screw, it can be used for a shaft assembly of a structural plywood or the like. It is possible to prevent the shaft assembly or the like from being cracked and to securely fix the structural plywood.

  Such screws are also described in, for example, Patent Document 4 (Japanese Patent Laid-Open No. 2006-037394).

  A third aspect of the present invention provides the bearing wall structure of a conventional wooden framed wooden building according to claim 1 or 2, wherein a viscoelastic body formed in a tape shape is interposed between the frame member and the structural plywood. It is characterized by that.

  Examples of the viscoelastic body formed into a tape shape include those described in Patent Document 5 (Japanese Patent Laid-Open No. 2002-061316) and the like. There is "Seismic tape".

  The tape-shaped viscoelastic material is attached to the surface of the shaft assembly before fastening the structural plywood, and then the structural plywood is fastened with screws on top of it. The earthquake resistance is further improved. Especially in a large earthquake, the energy absorption effect and deformation suppression effect are high.

  A fourth aspect of the present invention is the bearing wall structure of a conventional wooden frame wooden building according to the first, second, or third aspect, wherein the joints between the frame members are reinforced with reinforcing hardware. .

  As mentioned above, various types of reinforcement hardware have been used in the past, and they are essentially indispensable for seismic reinforcement. However, the required strength can be ensured and the structure is made of compact plywood. What is necessary is just to select the thing which does not interfere with the operation | work which fastens to an assembly.

  According to the load-bearing wall structure of the present invention, in the seismic reinforcement of a conventional framed wooden building, 4.0 or more, substantially 4 without using a brace or using a special structural face material. Since a large wall magnification of .5 or more is obtained and the structure is simplified, material processing is easy, workability is excellent, and a bearing wall having a required strength can be realized at low cost.

  For comparison with the present invention, FIG. 2 shows a conventional example when the wall magnification is 4.5 times. In this example, a reinforcement frame 18 attached to a brace 19 and a corner, etc. for a frame of a conventional wooden frame structure composed of left and right pillars 1, a lower base 2 and an upper beam 3, etc. Thus, a wall magnification of 2.0 is secured, and a structural surface material such as a structural plywood 16 is attached by a nail 17 to secure a wall magnification of 2.5. It is what.

  In this case, it is supposed that the structural plywood 16 having a thickness of 7.5 mm or more is nipped and fixed at a distance P of 150 mm or less.

  However, as shown in FIG. 2, when the brace 19 is arranged, it is in contact with the inter-column 4 and the trunk tether 5, fixed to the column beam joint, and in contact with the reinforcing hardware 18 (actually several different reinforcements). It is usually necessary to use hardware together.

  On the other hand, FIG. 1 shows the load-bearing wall structure of the present invention, and the wall magnification can be 4.5 or more without using braces. FIG. 3 and FIG. 4 show one form of the screw 7 and the reinforcing hardware 8 used in the embodiment of FIG.

  That is, in the present invention, a structural plywood 6 having a general thickness of 9 mm or more is used in the present invention, and the outer peripheral portion thereof is screwed at an interval of 100 mm or less with respect to a shaft assembly such as the pillar 1, foundation 2, beam 3. Fasten with 7. The example shown in the figure is a case where the structural plywood 6 of 900 mm × 1800 mm and the structural plywood 6 of 900 mm × 900 mm are vertically attached, as in the case of FIG. 2 showing the conventional example. There is no particular limitation on the size of the. For example, wall reinforcement in the form of using a commercially available structural plywood of 900 mm × 2700 mm or 910 mm × 2730 mm is also possible.

  The screw 7 is made of a material having a higher strength than that of a normal nail material, and is a screw having a quality equivalent to or higher than the material standard SWCH18A.

The screw 7 shown in FIG. 3 is of a commercially available material standard SWCH18A, a tip screw 7b is formed on the tip side, a neck screw 7c is formed at the root of the head 7a, and the length of the neck screw 7c is the shorter than the length of the tip screw, and thread pitch p ₂ of the neck screw 7c is smaller than the thread pitch p ₁ of the tip screw 7b. Further, a plurality of protrusions 7d are formed on the back side of the head portion 7a, that is, at the root portion, and when fastened, the surface of the structural plywood 6 can be bitten and the screws 7 can be prevented from loosening.

  By using such screws 7, the structural plywood 6 is not easily cracked when the structural plywood 6 is fastened to the shaft assembly or the like, and the structural plywood 6 can be firmly secured to the shaft assembly or the like. it can.

  The reinforcing metal member 8 shown in FIG. 4 is an L-shaped reinforcing metal member in which the plate-like column-side joint portion 8a is longer than the plate-like beam or the base-side joint portion 8b. Along the inside of the mouth portion, the screw hole 8e is attached through a screw.

  4 includes a stiffening portion 8d obtained by bending a plate material in an out-of-plane direction at a corner portion 8c where the plate-like column-side joint portion 8a and the plate-like beam or base-side joint portion 8b intersect. By forming it, it is a high-strength reinforcement hardware that fits compactly inside the joint between the pillar 1 and the base 2 or the beam 3, and no special processing is required for the shaft assembly material. The fastening of 6 can be performed without any trouble.

  In addition, the above has illustrated the best form, and it is not limited to said things, such as the form of a bis | screw 7 or a reinforcement metal object, Moreover, if necessary, it can use together various reinforcement metal elements conventionally used. it can.

  FIG. 5 shows the test results of the bearing wall of the present invention, in which the outer peripheral portion of the structural plywood having a thickness of 9 mm is fixed to the shaft assembly with a screw of material standard SWCH18A at an interval of 100 mm or less. The test was performed on the body (no bracing), and the vertical axis represents the moment M (kN · m) due to the load, and the horizontal axis represents the deformation angle γ (× 1000 rad).

  Table 1 is a strength calculation table when calculating the wall magnification based on the test results. The wall magnification in this case is calculated as 4.54 which is the minimum value of a, b, c, and d.

  FIG. 6 shows a case where a viscoelastic body 21 formed in a tape shape is interposed between a frame assembly such as a pillar 1, a base 2 and a beam 3 and a structural plywood 6 in the bearing wall structure of the present invention. An arrangement example of the elastic body 21 is schematically shown with a part cut away.

  As the viscoelastic body 21 formed in a tape shape, a commercially available one can be used as described above, and it can be easily applied in the same manner as a general adhesive tape.

  In small and medium-sized earthquakes, the structural plywood 6 and the screws 7 that fix the structure mainly resist the deformation of the shaft. However, for large earthquakes, the contribution of the damping force by the viscoelastic body 21 increases and the viscoelasticity is increased. Energy absorption and deformation suppression effects by the body 21 are effective.

It is a front view which shows the outline | summary of the bearing wall structure of this invention. It is a front view which shows the outline | summary of the load-bearing wall structure using the conventional bracing. 1 shows an example of a screw used in the present invention, (a) is a front view of a screw laid down, (b) is a left side view (screw head), (c) is a right side view ( Screw tip). In one embodiment of the reinforcing hardware used in the present invention, (a) is a plan view in a state where the reinforcing hardware is used in the lower part of the shaft assembly, (b) is a front view seen from the outside of the wall surface, (c) is a right side view (viewed from the inside of the wall surface). It is a graph which shows the test result of the bearing wall of this invention. In the load-bearing wall structure of this invention, it is the front view which showed roughly the example of arrangement | positioning of the viscoelastic body in the case of interposing the viscoelastic body shape | molded in tape shape between a frame assembly and structural plywood.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Pillar, 2 ... Base, 3 ... Beam, 4 Column, 5 ... Body connection, 6 ... Structural plywood, 7 ... Screw, 7a ... Head, 7b ... Tip screw, 7c ... Neck screw, 7d ... Projection, 8 ... Reinforcement hardware, 8a ... Column side joint, 8b ... Beam or foundation side joint, 8c ... Corner, 8d ... Stiffening part, 8e ... Screw hole,
16 ... structural plywood, 17 ... nail, 18 ... reinforcement hardware, 19 ... braiding,
21 ... Tape-like viscoelastic body

Claims (4)

  In a load-bearing wall structure with increased wall magnification by fastening structural plywood between pillars of a conventional wooden framed wooden building, the outer periphery of the structural plywood with a thickness of 9 mm or more is spaced at a distance of 100 mm or less with respect to the shaft assembly With a material standard SWCH18A or a screw with quality equivalent to or better than this, the strength of a conventional wooden framed wooden building is characterized by having a wall magnification of 4.0 or more without using braces. Wall structure.   The screw has a tip screw formed on the tip side, a neck screw is formed at the base of the head, the length of the neck screw is shorter than the length of the tip screw, and the screw pitch of the neck screw is the tip screw. 2. The load-bearing wall structure of a conventional wooden framed wooden building according to claim 1, wherein the bearing wall structure is smaller than the screw pitch.   3. A bearing wall structure of a conventional wooden frame wooden building according to claim 1, wherein a viscoelastic body formed in a tape shape is interposed between the frame member and the structural plywood. . The bearing wall structure for a conventional wooden frame wooden building according to claim 1, 2 or 3, wherein the joint portion between the frame members is reinforced with a reinforcing metal.

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