Reinforcement structure of wooden structure member and reinforcement method of wooden structure member

Abstract

To provide reinforcement structure of a wooden structure member and a reinforcement method of a wooden structure member that can easily and accurately reinforce a through hole according to a plan when forming the through hole in a wooden structure member and can exert sufficient strength to prevent cracking.SOLUTION: A reinforcement structure 10 of a wooden structure member 3 having a through hole 3h includes a reinforcement layer 11 formed by a fiber sheet 12 placed along an inner wall 3s of the through hole 3h and adhered to the inner wall 3s.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a reinforcement structure for a wooden structural member and a method for reinforcing a wooden structural member. [Background technology]

[0002] Buildings with multiple floors are sometimes constructed using wood. In such wooden buildings, when it is desired to make the ceiling height of each floor as high as possible within the limited height restrictions of the building, through holes are sometimes drilled in wooden structural members such as beams to allow for the passage of piping for plumbing facilities such as toilets, bathrooms, and kitchens on upper floors, as well as wiring for electrical equipment. When a through hole is provided in a wooden structural member as described above, cracks may occur on the inner wall of the through hole due to the load acting on the wooden structural member. If the wooden structural member is, for example, a beam and the through hole is provided through the beam in the width direction, the cracks may occur from the inner wall of the through hole and progress along the length of the beam into the wooden structural member. Therefore, to prevent such cracks from occurring, the area around the through hole in the wooden structural member may be reinforced.

[0003] In this regard, Patent Document 1 discloses a wooden structural member reinforcement structure that reinforces the area around a horizontal opening in a wooden beam. In this wooden structural member reinforcement structure, long screws that can be installed without pre-holes are screwed into the wooden beam from the long side surfaces (top and bottom surfaces) where no openings are formed, and penetrate into the wooden beam beyond the area where splitting is expected to occur along the long side of the wooden beam. In the configuration of Patent Document 1, as described above, the periphery of the opening is reinforced by screwing long screws into wooden structural materials. However, if there are knots, for example, around the opening, the knots are harder than the surrounding area, so when the long screws are screwed in, they may hit the knots, be blocked by the knots, or the trajectory of the screw may be shifted. As such, in Patent Document 1, it may be difficult to screw the long screws in accurately as planned. If the long screws are not placed in the planned positions, the reinforcing effect of the long screws will not be fully realized, and as a result, there is a possibility that the opening will crack despite the placement of the long screws. When forming through holes in wooden structural members, there is a need for a reinforcement structure for wooden structural members and a reinforcement method for wooden structural members that can easily and accurately reinforce the through holes according to plan, and that can exert sufficient strength to prevent the occurrence of splitting. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-160737 Summary of the Invention [Problem to be solved by the invention]

[0005] The problem that the present invention aims to solve is to provide a reinforcing structure for a wooden structural member and a reinforcing method for a wooden structural member that, when forming a through hole in a wooden structural member, can easily and accurately reinforce the through hole according to plan, and that can exert sufficient strength to prevent the occurrence of cracks. [Means for solving the problem]

[0006] The present invention provides a reinforcing structure for a wooden structural member having a through hole, the reinforcing structure comprising a reinforcing layer formed by providing a fiber sheet along the inner wall of the through hole and adhering it to the inner wall. When a wooden structural member has a through hole, a load acting on the wooden structural member can cause a crack to form from the inner wall of the through hole to the inside of the wooden structural member. In such a case, the crack can be caused by a tensile force acting on the inner wall of the through hole in the tangential direction of the edge of the through hole. In the above-described configuration, the reinforcing structure of the wooden structural member has a reinforcing layer formed by providing a fiber sheet along the inner wall of the through-hole and adhering it to the inner wall of the through-hole. Therefore, even if a tensile force acts on the inner wall of the through-hole and attempts to cause a crack, the reinforcing layer formed along the inner wall of the through-hole and adhering it to the inner wall resists the tensile force and prevents the crack from occurring. The reinforcing layer described above can be formed simply by adhering a fiber sheet along the inner wall of the through-hole. Therefore, reinforcement can be easily achieved. In particular, the reinforcing layer is formed on the inner wall of the through-hole, i.e., on the surface of the wooden structural member. Therefore, even if knots or other imperfections are present inside the wooden structural member, they do not affect the reinforcement as planned. This allows the reinforcement to be performed exactly as planned. Therefore, a wooden structural member reinforced in this way will have sufficient strength as anticipated in the reinforcement plan. In this way, when a through hole is formed in a wooden structural member, the through hole can be reinforced easily and accurately according to plan, and a reinforcement structure for a wooden structural member can be provided that exhibits sufficient strength and suppresses the occurrence of cracks.

[0007] In one aspect of the present invention, the fiber sheet is provided so as to cover the inner wall of the through hole over the entire area in the circumferential direction of the through hole. According to the above-described configuration, the fiber sheet is arranged to cover the inner wall of the through hole over the entire circumferential area of ​​the through hole, so that cracking can be suppressed regardless of which part of the inner wall of the through hole is prone to occur.

[0008] In another aspect of the present invention, the reinforcing layer is formed so that it is thicker in areas of the inner wall of the through hole where cracking is expected to occur when stress is applied to the wooden structural member than in areas other than those areas. According to the above configuration, the reinforcing layer is formed so that it is thicker in areas of the inner wall of the through hole where cracking is expected to occur when stress is applied to the wooden structural member than in areas other than those areas, thereby more efficiently suppressing cracking of the inner wall of the through hole.

[0009] In another aspect of the present invention, the reinforcing structure of a wooden structural member comprises a plurality of the fiber sheets, each of which is arranged so that its end in the circumferential direction of the through hole overlaps with another of the fiber sheets. When a reinforcing layer is formed by adhering one fiber sheet to the inner wall of a through-hole, the length of the fiber sheet to be adhered at one time becomes long, which may reduce workability. In contrast, in the above-described configuration, the reinforcing layer includes multiple fiber sheets, so the length of the fiber sheets bonded at one time can be shortened, which makes it easier to handle the fiber sheets and improves workability. Furthermore, since each of the plurality of fiber sheets is provided such that its end in the circumferential direction of the through hole overlaps with another fiber sheet, the reinforcing layer can be made thicker in the overlapping fiber sheet portions than in other portions, thereby more efficiently suppressing cracking of the inner wall of the through hole, particularly in the portions where the reinforcing layer is formed to be thicker.

[0010] In another aspect of the present invention, the fiber sheet is provided so that the direction in which the fibers extend coincides with the circumferential direction of the through holes. According to the above-described configuration, the fiber sheet is provided so that the direction in which the fibers extend coincides with the circumferential direction of the through-hole, and therefore, even if a tensile force acts on the inner wall of the through-hole, the tensile force is suppressed by the resistance of the fibers that extend in the circumferential direction of the through-hole. Therefore, the through hole can be reinforced efficiently.

[0011] In another aspect of the present invention, the wooden structural member is a beam, and the through-hole is provided so as to penetrate the beam in the width direction of the beam. According to the above-described configuration, when a through hole is formed in a beam, the through hole can be reinforced easily and accurately according to a plan.

[0012] The present invention also provides a method for reinforcing a wooden structural member having a through hole, which comprises providing a fiber sheet along the inner wall of the through hole and adhering it to the inner wall to form a reinforcing layer. In the above-described method for reinforcing wooden structural members, as already explained with respect to the reinforcement structure of wooden structural members, when through holes are formed in the wooden structural members, the through holes can be reinforced easily and accurately according to plan, and sufficient strength can be exerted to prevent cracks from occurring. [Effects of the Invention]

[0013] According to the present invention, when a through hole is formed in a wooden structural member, it is possible to easily and accurately reinforce the through hole according to plan, and it is possible to provide a reinforcement structure for a wooden structural member and a reinforcement method for a wooden structural member that can exert sufficient strength and suppress the occurrence of cracks. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a front view of a beam-column structure having a wooden structural member with a through hole. [Figure 2]10 is an explanatory diagram of a crack that occurs at the through hole when a through hole is provided in a beam. FIG. [Figure 3] 2 is a front view of a reinforcement structure for a wooden structural member according to an embodiment of the present invention, and is an enlarged view of the portion viewed from the arrow A in FIG. [Figure 4] FIG. 4 is a cross-sectional view taken along the line II in FIG. 3. [Figure 5] 2 is a front view of a reinforcement structure for a wooden structural member according to an embodiment of the present invention, and is an enlarged view of the portion viewed from the arrow B in FIG. [Figure 6] 1 is an explanatory diagram of a force application device used in a performance evaluation experiment regarding the reinforcement structure of the wooden structural member of the above embodiment. FIG. [Figure 7] 10 is a graph showing the relationship between deflection at the center of the beam and load in a case where the through-hole is not reinforced, which was used as a comparative example in the performance evaluation experiment. [Figure 8] 10 is a graph showing the relationship between deflection at the center of the beam and load when the through-hole is reinforced according to the embodiment, used as an example in the performance evaluation experiment. [Figure 9] 10 is a graph showing the relationship between the load and the strain measurement results obtained by a strain gauge provided across the crack at the portion where the crack occurs in the comparative example. [Figure 10] 10 is a graph showing the relationship between the load and the strain measurement results obtained by a strain gauge provided across the crack at the portion where the crack occurs in the above example. [Figure 11] FIG. 2 is a front view of a reinforcement structure for a wooden structural member according to a first modified example of the above embodiment. [Figure 12] FIG. 10 is a front view of a reinforcement structure for a wooden structural member according to a second modified example of the above embodiment. [Figure 13] FIG. 10 is a front view of a reinforcement structure for a wooden structural member according to a third modified example of the above embodiment. [Figure 14] FIG. 10 is a front view of a reinforcement structure for a wooden structural member according to another modified example of the above embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a front view of a beam-column frame having wooden structural members with through holes. The column-and-beam frame 1 of the building comprises columns 2 and beams 3. A pair of columns 2 are erected adjacent to each other. The beam 3 is stretched across the space between the pair of columns 2 that are adjacent to each other. In such a column-beam structure 1, for example, when the beam 3 is constructed of wood as a wooden structural member, a through hole 3h may be drilled in the beam 3 so as to penetrate the beam 3 in the width direction DW perpendicular to the length direction DL and height direction DH of the beam 3 in order to pass piping for plumbing facilities such as toilets, bathrooms, kitchens, etc. located on the floor above the beam 3, and wiring for electrical equipment, etc.

[0016] FIG. 2 is an explanatory diagram of a crack that occurs at the through-hole when a through-hole is provided in a beam. The beam 3 has its end portion 3e supported by the column 2, and supports a load from above across the entire length of the beam 3, centered on the central portion 3c. Therefore, as shown in Figure 2, shear deformation occurs in the beam 3, displacing the central portion 3c downward relative to the end portion 3e. As a result, a tensile force TF acts in a diagonal direction connecting the upper left and lower right of the through hole 3h around the through hole 3h shown on the left side of Figure 2. Here, in the upper right portion of the through hole 3h, i.e., the portion of the through hole 3h located on the upper side of the beam central portion 3c, the diagonal direction in which this tensile force TF acts roughly coincides with the circumferential direction C in which the inner wall 3s of the through hole 3h extends, and therefore a tensile force acts on the inner wall 3s of the through hole 3h in that portion. Therefore, in that portion, there is a possibility that a crack will occur from the inner wall 3s of the through hole 3h toward the inside of the beam 3, i.e., toward the beam central portion 3c, as if the inner wall 3s of the through hole 3h is torn. Similarly, in the lower left part of the through hole 3h, i.e., the part of the inner wall 3s of the through hole 3h located on the lower side of the beam end 3e of the through hole 3h, a tensile force acts in the circumferential direction C of the through hole 3h, causing the inner wall 3s of the through hole 3h to tear, and there is a possibility that a crack will occur from the inner wall 3s of the through hole 3h toward the inside of the beam 3, i.e., the beam end 3e. On the other hand, a compressive force CF acts in a diagonal direction connecting the upper right and lower left of the through hole 3h around the through hole 3h shown on the left side of Figure 2. As a result, a compressive force acts in the circumferential direction C of the through hole 3h at the lower right and upper left parts of the through hole 3h, i.e., at the part of the through hole 3h located on the lower side of the beam center part 3c and the part of the through hole 3h located on the upper side of the beam end part 3e, on the inner wall 3s of the through hole 3h, and therefore, cracking is unlikely to occur in the inner wall 3s of the through hole 3h.

[0017] Similarly, in the through hole 3h shown on the right side of Figure 2, cracking may occur in the portion of the through hole 3h located on the upper side of the beam center 3c and the portion of the through hole 3h located on the lower side of the beam end 3e. Similarly, cracking is unlikely to occur in the portion of the through hole 3h located on the lower side of the beam center 3c and the portion of the through hole 3h located on the upper side of the beam end 3e.

[0018] In this way, when a through hole 3h penetrating in the width direction DW is provided in a wooden structural member such as a beam 3, cracks may occur in the inner wall 3s of the through hole 3h. In the reinforcement structure 10 for a wooden structural member of this embodiment, the through hole 3h is reinforced to prevent cracks from occurring. In the following description, the region of the inner wall 3s of the through hole 3h where cracking is expected to occur when stress acts on the wooden structural member (beam 3 in this embodiment) is referred to as the cracking expected region R. In particular, in this embodiment, the cracking expected region R includes the first cracking expected region R1 located on the upper side of the beam center portion 3c of the through hole 3h, and the second cracking expected region R2 located on the lower side of the beam end portion 3e of the through hole 3h. The reinforcement structure 10 for wooden structural members suppresses cracking in these cracking expected regions R (R1, R2). Furthermore, in the following description, a region different from the cracking expected region R, where cracking is unlikely to occur when stress acts on the wooden structural member (beam 3 in this embodiment), is referred to as the cracking non-expected region T.

[0019] In this embodiment, the first assumed splitting region R1 is a 90-degree angle range from the direction from the center of the through hole 3h toward the beam center portion 3c along the length direction DL to a vertically upward direction, and the second assumed splitting region R2 is a 90-degree angle range from the direction from the center of the through hole 3h toward the beam end portion 3e along the length direction DL to a vertically downward direction. In this embodiment, the through-hole 3h is circular. However, the shape of the through-hole 3h is not limited to a circle, and it may have other shapes such as an ellipse or a rectangle. In such cases, the same explanation as in this embodiment is also applicable.

[0020] Figure 3 is a front view of the reinforcement structure for a wooden structural member in this embodiment, and is an enlarged view of the portion viewed from the arrow A in Figure 1. Figure 4 is a cross-sectional view of the portion viewed from the arrow II in Figure 3. In Figure 3 and Figure 5, which will be used in later explanations, split cracks CR that may generally occur when the through-hole 3h is "not" reinforced are shown by virtual lines (two-dot chain lines) to clearly show the relationship between the structure of the reinforcement structure 10 for a wooden structural member and the position of the split cracks CR. The reinforcing structure 10 for a wooden structural member has a reinforcing layer 11 provided on the inner wall 3s of the through hole 3h. The reinforcing layer 11 is formed by providing a fiber sheet 12 along the inner wall 3s of the through hole 3h and adhering it to the inner wall 3s. In this embodiment, the fiber sheet 12 is made of aramid fiber. The fiber sheet 12 may be made of a fiber material other than aramid fiber, such as carbon fiber. In this embodiment, the fiber sheet 12 used has a thickness of, for example, about 1 mm. The fiber sheet 12 may have a thickness different from the above, for example, a thicker fiber sheet 12. The fiber sheet 12 is provided so that the extending direction of the fibers coincides with the circumferential direction C of the through hole 3h, and is adhered to the inner wall 3s of the through hole 3h with an adhesive. In this embodiment, the fiber sheet 12 is provided so as to cover the entire area of ​​the through hole 3h in the circumferential direction C of the through hole 3h.

[0021] The fiber sheet 12 is adhered to the inner wall 3s of the through hole 3h with an adhesive (not shown). A two-component epoxy resin adhesive, for example, is preferably used as the adhesive because it is easy to apply. When the fiber sheet 12 is adhered to the inner wall 3s of the through hole 3h, the entire fiber sheet 12 is impregnated with the adhesive. Therefore, the reinforcing layer 11 is formed such that the fiber sheet 12 is embedded in a layer of hardened adhesive, and the fiber sheet 12 and the adhesive are integrated as a whole.

[0022] In this embodiment, there are provided a plurality of fibrous sheets 12. More specifically, the fibrous sheet 12 includes a first fibrous sheet 12A and a second fibrous sheet 12B. The first fiber sheet 12A is adhered to the inner wall 3s of the through hole 3h within an angular range of 270 degrees in the circumferential direction C of the through hole 3h, centered on the center CO of the through hole 3h, from a first direction D1 extending from the center CO of the through hole 3h along the longitudinal direction DL toward the central portion 3c of the beam, through a second direction D2 extending vertically upward counterclockwise around the center CO of the through hole 3h, and a third direction D3 extending along the longitudinal direction DL toward the end portion 3e of the beam, and finally to a fourth direction D4 extending vertically downward. In this way, the first fiber sheet 12A is adhered to the inner wall 3s of the through hole 3h in an area including the first anticipated cracking area R1 located on the upper side of the beam center portion 3c of the through hole 3h, the second anticipated cracking area R2 located on the lower side of the beam end portion 3e of the through hole 3h, and the non-anticipated cracking area T located in the upper left of Figure 3 between the first anticipated cracking area R1 and the second anticipated cracking area R2, where cracking is unlikely to occur.

[0023] The second fiber sheet 12B is adhered to the inner wall 3s of the through hole 3h within an angular range of 270 degrees in the circumferential direction C of the through hole 3h centered on the center CO of the through hole 3h, from a third direction D3 extending from the center CO of the through hole 3h along the longitudinal direction DL toward the beam end 3e, through a fourth direction D4 extending vertically downward counterclockwise around the center CO of the through hole 3h, and through a first direction D1 extending along the longitudinal direction DL toward the beam center 3c, and finally to a second direction D2 extending vertically upward. In this way, the second fiber sheet 12B is adhered to the inner wall 3s of the through hole 3h in an area including the second anticipated cracking area R2 located on the lower side of the beam end portion 3e of the through hole 3h, the first anticipated cracking area R1 located on the upper side of the beam center portion 3c of the through hole 3h, and the non-anticipated cracking area T located at the bottom right in Figure 3 between the first anticipated cracking area R1 and the second anticipated cracking area R2, where cracking is unlikely to occur.

[0024] FIG. 5 is a front view of the reinforcing structure for a wooden structural member according to this embodiment, and is an enlarged view of the portion seen from the arrow B in FIG. The right side of the beam 3 shown in Fig. 5 has a configuration obtained by flipping the left side of the beam 3 shown in Fig. 3. That is, when the right side of the beam 3 shown in Fig. 5 is viewed from the back, more specifically from the depth direction of the paper surface of Fig. 5, the right side of the beam 3 shown in Fig. 5 has a configuration that matches the left side of the beam 3 shown in Fig. 3. Therefore, in this case, the same explanation as for the left side of the beam 3 shown in Fig. 3 is possible. Specifically, the first fiber sheet 12A is adhered to the inner wall 3s of the through hole 3h within an angular range of 270 degrees in the circumferential direction C of the through hole 3h, centered on the center CO of the through hole 3h, from a first direction D1 extending from the center CO of the through hole 3h along the longitudinal direction DL toward the central portion 3c of the beam, through a second direction D2 extending vertically upward clockwise around the center CO of the through hole 3h, and a third direction D3 extending along the longitudinal direction DL toward the end portion 3e of the beam, and finally to a fourth direction D4 extending vertically downward. In this way, the first fiber sheet 12A is adhered to the inner wall 3s of the through hole 3h in an area including the first anticipated cracking area R1 located on the upper side of the beam center portion 3c of the through hole 3h, the second anticipated cracking area R2 located on the lower side of the beam end portion 3e of the through hole 3h, and the non-anticipated cracking area T located in the upper right corner of Figure 5 between the first anticipated cracking area R1 and the second anticipated cracking area R2, where cracking is unlikely to occur.

[0025] In addition, the second fiber sheet 12B is adhered to the inner wall 3s of the through hole 3h within an angular range of 270 degrees in the circumferential direction C of the through hole 3h centered on the center CO of the through hole 3h, from a third direction D3 extending from the center CO of the through hole 3h along the longitudinal direction DL toward the beam end 3e, through a fourth direction D4 extending vertically downward clockwise around the center CO of the through hole 3h, and a first direction D1 extending along the longitudinal direction DL toward the beam center 3c, and finally to a second direction D2 extending vertically upward. In this way, the second fiber sheet 12B is adhered to the inner wall 3s of the through hole 3h in an area including the second anticipated cracking area R2 located on the lower side of the beam end portion 3e of the through hole 3h, the first anticipated cracking area R1 located on the upper side of the beam center portion 3c of the through hole 3h, and the non-anticipated cracking area T located at the lower left in Figure 5 between the first anticipated cracking area R1 and the second anticipated cracking area R2, where cracking is unlikely to occur.

[0026] In both through holes 3h of the beam 3 shown in Figures 3 and 5, the first fiber sheet 12A and the second fiber sheet 12B are provided as described above, so that the end 12e of each of the multiple fiber sheets 12 in the circumferential direction C of the through hole 3h overlaps with the end of the other fiber sheet 12. In particular, in this embodiment, the first fiber sheet 12A and the second fiber sheet 12B are provided so as to overlap each other in each of the first assumed split region R1 and the second assumed split region R2. In the overlapping portion of the first fiber sheet 12A and the second fiber sheet 12B, the second fiber sheet 12B is disposed radially inward of the through-holes 3h relative to the first fiber sheet 12A.

[0027] In this way, the reinforcing layer 11 is formed so that in the expected cracking area R, more fiber sheets 12 are layered and the reinforcing layer 11 is thicker than in the non-expected cracking area T, which is an area different from the expected cracking area R. As already explained, in the expected cracking region R, there is a possibility that the inner wall 3s of the through hole 3h will tear, causing a crack CR to occur from the inner wall 3s of the through hole 3h toward the center 3c of the beam or the end 3e of the beam. However, in this embodiment, as described above, a reinforcing layer of sufficient thickness is formed in the expected cracking region R, so that the occurrence of a crack CR is efficiently suppressed.

[0028] Next, a method for reinforcing the above-mentioned wooden structural member will be described. To reinforce a wooden structural member (beam 3) having a through hole 3h as described above, a fiber sheet 12 is placed along the inner wall 3s of the through hole 3h and adhered to the inner wall 3s to form a reinforcing layer 11.

[0029] More specifically, first, the first fiber sheet 12A is adhered to the inner walls 3s of the through-holes 3h. To do this, first, approximately 3 / 4 of the amount of adhesive required to bond one fiber sheet 12 is applied within an angular range of 270 degrees in the circumferential direction C of the through hole 3h, centered on the center CO of the through hole 3h, to which the first fiber sheet 12A will be bonded. Next, the first fiber sheet 12A is attached onto the applied adhesive, and the adhesive is impregnated into the first fiber sheet 12A with a spatula. Thereafter, about 1 / 4 of the required amount of adhesive is applied to the surface of the first fiber sheet 12A and then cured.

[0030] Next, the second fiber sheet 12B is bonded to the inner walls 3s of the through-holes 3h and the first fiber sheet 12A. To do this, first, approximately 3 / 4 of the amount of adhesive required to bond one fiber sheet 12 is applied to the inner wall 3s of the through hole 3h and the surface of the first fiber sheet 12A already bonded to the inner wall 3s of the through hole 3h, within an angular range of 270 degrees in the circumferential direction C of the through hole 3h, centered on the center CO of the through hole 3h, to which the second fiber sheet 12B will be bonded. Next, the second fiber sheet 12B is attached onto the applied adhesive, and the second fiber sheet 12B is impregnated with the adhesive using a spatula. Thereafter, about 1 / 4 of the required amount of adhesive is applied to the surface of the second fiber sheet 12B and then cured.

[0031] The reinforcing structure 10 for a wooden structural member as described above is a reinforcing structure 10 for a wooden structural member (beam 3) having a through hole 3h, and has a reinforcing layer 11 formed by a fiber sheet 12 arranged along the inner wall 3s of the through hole 3h and adhered to the inner wall 3s. When a through hole 3h is provided in a wooden structural member, a split CR may occur due to a load acting on the wooden structural member (beam 3) from the inner wall 3s of the through hole 3h, progressing into the wooden structural member. In such a case, the split CR may occur when a tensile force acts on the inner wall 3s of the through hole 3h in the tangential direction of the edge of the through hole 3h. In the above-described configuration, the reinforcing structure 10 for a wooden structural member has a reinforcing layer 11 formed by providing a fiber sheet 12 along the inner wall 3s of the through hole 3h and adhering it to the inner wall 3s of the through hole 3h. Therefore, even if a tensile force acts on the inner wall 3s of the through hole 3h and a split CR occurs, the reinforcing layer 11, which is formed along the inner wall 3s of the through hole 3h and adhered to the inner wall 3s, resists the tensile force and suppresses the split. The reinforcing layer 11 described above can be formed simply by adhering the fiber sheet 12 along the inner wall 3s of the through hole 3h. This allows for easy reinforcement. In particular, the reinforcing layer 11 is formed on the inner wall 3s of the through hole 3h, i.e., on the surface of the wooden structural member. This prevents the presence of knots or other imperfections inside the wooden structural member from preventing the reinforcement from being completed as planned, allowing the reinforcement to be completed exactly as planned. Therefore, a wooden structural member reinforced in this way will have sufficient bearing strength as anticipated in the reinforcement plan. In this way, when a through hole 3h is formed in a wooden structural member, the through hole 3h can be reinforced easily and accurately according to plan, and a reinforcement structure 10 for a wooden structural member can be provided that exhibits sufficient strength and can suppress the occurrence of splitting CR.

[0032] In particular, the reinforcing layer 11 is adhered only to the inner wall 3s of the through hole 3h. That is, when reinforcing the wooden structural member, the reinforcing layer 11 does not appear on, for example, the side surface 3a and the underside 3b (see FIG. 4) of the beam 3 that face the interior side. This prevents the appearance of the wooden structural member from being damaged by the reinforcement.

[0033] The fiber sheet 12 is provided so as to cover the inner wall 3s of the through-hole 3h over the entire area in the circumferential direction C of the through-hole 3h. According to the above-described configuration, the fiber sheet 12 is arranged to cover the inner wall 3s of the through hole 3h over the entire circumferential direction C of the through hole 3h, so that it is possible to suppress cracking CR regardless of which part of the inner wall 3s of the through hole 3h is prone to cracking.

[0034] In addition, the reinforcing layer 11 is formed so that it is thicker in the area (expected cracking area R) of the inner wall 3s of the through hole 3h where cracking CR is expected to occur when stress acts on the wooden structural member (beam 3) than in the area other than the area R (non-expected cracking area T). According to the above-described configuration, the reinforcing layer 11 is formed so that it is thicker in the area (expected cracking area R) of the inner wall 3s of the through hole 3h where cracking CR is expected to occur when stress acts on the wooden structural member (beam 3) than in the area other than the area R (non-expected cracking area T), thereby more efficiently suppressing the occurrence of cracking CR in the inner wall 3s of the through hole 3h.

[0035] The reinforcing structure 10 for a wooden structural member also includes a plurality of fiber sheets 12, each of which is arranged such that an end 12e in the circumferential direction C of the through-hole 3h overlaps with another fiber sheet 12. If one attempts to form a reinforcing layer 11 by adhering one fiber sheet 12 to the inner wall 3s of the through hole 3h, the length of the fiber sheet 12 to be adhered at one time becomes long, which may reduce workability. In contrast, in the above-described configuration, the reinforcing layer 11 includes a plurality of fiber sheets 12, so the length of the fiber sheets 12 bonded at one time can be shortened, which makes it easier to handle the fiber sheets 12 and improves workability. Furthermore, each of the plurality of fiber sheets 12 is provided so that the end 12e in the circumferential direction C of the through hole 3h overlaps with another fiber sheet 12, so that the reinforcing layer 11 can be made thicker in the portion where the fiber sheets 12 overlap than in other portions. Therefore, it is possible to more efficiently suppress the occurrence of splitting CR on the inner wall 3s of the through hole 3h, particularly in the portion where the reinforcing layer 11 is formed to be thick.

[0036] The fiber sheet 12 is provided so that the direction in which the fibers extend coincides with the circumferential direction C of the through-holes 3h. According to the above-described configuration, the fiber sheet 12 is provided so that the extending direction of the fibers coincides with the circumferential direction C of the through-hole 3h. Therefore, even if a tensile force acts on the inner wall 3s of the through-hole 3h, the tensile force is suppressed by the fibers extending in the circumferential direction C of the through-hole 3h, which resist the tensile force. Therefore, the through-hole 3h can be reinforced efficiently.

[0037] The wooden structural member is a beam 3, and the through-hole 3h is provided so as to penetrate the beam 3 in the width direction DW of the beam 3. According to the above-described configuration, when the through-hole 3h is formed in the beam 3, the through-hole 3h can be reinforced easily and accurately according to a plan.

[0038] Furthermore, the reinforcing method for a wooden structural member (beam 3) as described above is a reinforcing method for a wooden structural member having a through hole 3h, and includes forming a reinforcing layer 11 by providing a fiber sheet 12 along the inner wall 3s of the through hole 3h and adhering it to the inner wall 3s. In the above-described method of reinforcing a wooden structural member, as already explained with respect to the reinforcement structure 10 for a wooden structural member, when forming a through hole 3h in the wooden structural member, the through hole 3h can be reinforced easily and accurately according to plan, and sufficient strength can be exerted to suppress the occurrence of splitting CR.

[0039] In particular, in the above-described method for reinforcing a wooden structural member, the reinforcement work is completed simply by adhering the fiber sheet 12 to the inner wall 3s of the through hole 3h. There is no need to process the wooden structural member for reinforcement. Therefore, the reinforcement work can be easily performed not only at the factory where the wooden structural member is manufactured, but also after the wooden structural member is erected. It is conceivable that, after the wooden structural member is erected, it may become necessary to urgently add more through holes 3h due to changes in the routing of wiring or piping, etc. Even in such a case, the reinforcement work of the through holes 3h can be easily performed on-site, allowing construction to proceed smoothly.

[0040] (Performance evaluation experiment) Next, the content and results of a performance evaluation experiment conducted on the above-described reinforcement structure 10 for wooden structural members will be described. First, as in the above embodiment, a beam 3 was assumed as a wooden structural member. The test specimen was assumed to be a medium- to large-scale wooden office building, with a span of 8000 mm, a beam depth of 600 mm, and a beam width of 120 mm. The test specimen was made of larch laminated timber (different grades). One through hole 3h was drilled in the test specimen at the beam end 3e. The diameter of the through hole 3h was 300 mm. The above-described test specimen was prepared as a comparative example. In addition, an aramid fiber sheet was bonded to the inner wall 3s of the through hole 3h as in the above embodiment, and this was prepared as an example.

[0041] FIG. 6 is an explanatory diagram of the force application device used in the performance evaluation experiment. The test was a four-point bending test, and monotonic loading was performed, assuming a condition in which bending moment and shear force act simultaneously. Displacement gauges S1, S2, and S3 were installed above each of the two support points that support the wooden structural member from below, and below the center of the wooden structural member, respectively. In addition, strain gauges U1 and B1 were installed in the areas around the through hole 3h corresponding to the first assumed splitting area R1 and the second assumed splitting area R2, respectively, in positions that would straddle the area when a split occurs.

[0042] Fig. 7 is a graph showing the relationship between deflection and load at the center of the beam when the through-hole is not reinforced, used as a comparative example. Fig. 8 is a graph showing the relationship between deflection and load at the center of the beam when the through-hole is reinforced according to the above embodiment, used as an example. In Fig. 8, the results of the comparative example shown in Fig. 7 are overlaid with dashed lines. In the comparative example shown in FIG. 7, cracking occurs when the load reaches 90 kN, and when the load reaches 104.2 kN, the cracking progresses and the strength decreases. In contrast, in the example shown in Figure 8, the strength begins to decrease only when the load reaches 151.7 kN. This shows that the example can support a load that is approximately 45% greater than that of the comparative example.

[0043] Fig. 9 is a graph showing the relationship between load and the results of strain measurement by a strain gauge installed across the crack in the area where the crack occurs in the comparative example. Fig. 10 is a graph showing the relationship between load and the results of strain measurement by a strain gauge installed across the crack in the area where the crack occurs in the example. In Fig. 10, the results of the comparative example shown in Fig. 9 are overlaid with dashed lines. 10, the strain when a certain load is applied is smaller in the example than in the comparative example. This shows that the provision of the reinforcing layer 11 on the inner wall 3s of the through hole 3h reduces the tensile force acting around the through hole 3h.

[0044] (Modification of the embodiment) In the above embodiment, the reinforcing layer 11 is formed by adhering two fiber sheets 12, the first fiber sheet 12A and the second fiber sheet 12B, to the inner wall 3s of the through hole 3h, but this is not limited to this. FIG. 11 is a front view of a reinforcement structure for a wooden structural member according to a first modified example of the above embodiment. In the reinforcement structure 10C for a wooden structural member of this modified example, one fiber sheet 12C is used. Specifically, the fiber sheet 12C is provided along the inner wall 3s of the through hole 3h over an angular range of 630 degrees in the circumferential direction C around the center CO of the through hole 3h so as to pass through the inner wall 3s corresponding to the first assumed split region R1 and the second assumed split region R2 twice each, and is adhered to the inner wall 3s to form a reinforcing layer 11C.

[0045] FIG. 12 is a front view of a reinforcement structure for a wooden structural member according to a second modification of the above embodiment. In this modified example of a reinforcement structure 10D for a wooden structural member, six fiber sheets 12D are used. Each fiber sheet 12D is formed to a length that, when installed along the inner wall 3s of the through hole 3h, covers the inner wall 3s over an angular range of 90 degrees in the circumferential direction C centered on the center CO of the through hole 3h. Two fiber sheets 12D are installed doubly in the first assumed split region R1 and the second assumed split region R2. One fiber sheet 12D is installed in the non-assumed split region T.

[0046] FIG. 13 is a front view of a reinforcement structure for a wooden structural member according to a third modified example of the above embodiment. The reinforcement structure 10E for a wooden structural member of this modified example uses two fiber sheets 12E and two fiber sheets 12F. The fiber sheet 12E is thicker than the fiber sheet 12F, for example, twice as thick. When the fiber sheets 12E and 12F are provided along the inner wall 3s of the through hole 3h, they are each formed to a length that covers the inner wall 3s over an angular range of 90 degrees in the circumferential direction C centered on the center CO of the through hole 3h. One fiber sheet 12E is provided in each of the first assumed split region R1 and the second assumed split region R2. One fiber sheet 12F is provided in each of the two non-assumed split regions T.

[0047] The reinforcing structures 10C, 10D, 10E for wooden structural members shown as the first to fourth modified examples as described above are all configured, similarly to the above embodiment, to have reinforcing layers 11C, 11D, 11E formed by arranging fiber sheets 12C, 12D, 12E (, 12F) along the inner wall 3s of the through hole 3h and adhering them to the inner wall 3s. In addition, as in the above embodiment, the reinforcing layers 11C, 11D, and 11E are formed so that they are thicker in the area (expected cracking area R) of the inner wall 3s of the through hole 3h where cracking CR is expected to occur when stress acts on the wooden structural member (beam 3) than in the area other than the area R (non-expected cracking area T). Therefore, similarly to the above embodiment, it is possible to efficiently suppress the occurrence of cracks CR in the inner wall 3s of the through hole 3h.

[0048] (Another modified example of the embodiment) The reinforcement structure for wooden structural members and the reinforcement method for wooden structural members of the present invention are not limited to the above-mentioned embodiments and modifications described with reference to the drawings, and various other modifications can be considered within the technical scope.

[0049] For example, the reinforcing layer 11G of the reinforcement structure 10G for a wooden structural member shown in Fig. 14 is configured such that the fiber sheet 12D provided in the crack-prone region T is removed from the reinforcement structure 10D for a wooden structural member described using Fig. 12 as the second modified example, and no fiber sheet 12 is provided in the crack-prone region T. In this way, in cases where it is considered that there is an extremely small possibility of a crack CR occurring in the crack-prone region T, the reinforcing layer 11G does not need to be provided in the crack-prone region T. In the above embodiment, the wooden structural member is a beam 3, but this is not limiting. The wooden structural member may be, for example, a pillar or a bearing wall having a through-hole, and a fiber sheet may be provided along the inner wall of the through-hole and adhered to the inner wall to form a reinforcing layer. In the above embodiment, the through holes 3h are provided to pass piping and wiring related to electrical equipment, but this is not limiting. The through holes 3h may be provided, for example, to improve the design of the wooden structural member.

[0050] In addition to this, it is possible to select and discard the configurations given in the above embodiment and each modified example, or to change them to other configurations as appropriate. [Explanation of symbols]

[0051] 3 Beam (wooden structural member) 12e End 3h Through hole C circumferential direction 3s Inner wall CR Warisaki 10, 10C~10G Reinforcement structure of wooden structural members DH Height direction 11, 11C~11G Reinforcement layer DW width direction 12, 12A~12F Fiber sheet DL length direction 12A First fiber sheet (fiber sheet) 12B Second fiber sheet (fiber sheet) R, R1, R2: Expected cracking area (area where cracking is expected to occur) T Non-splitting area (area different from the splitting area)

Claims

1. A reinforcement structure for a wooden structural member having a through hole, a fiber sheet provided along the inner wall of the through hole and bonded to the inner wall, thereby forming a reinforcing layer; A reinforced structure for wooden structural members.

2. The fiber sheet is provided so as to cover the inner wall of the through hole over the entire area in the circumferential direction of the through hole.

2. The reinforcement structure for a wooden structural member according to claim 1.

3. The reinforcing layer is formed so as to be thicker in a region of the inner wall of the through hole where cracking is expected to occur when stress is applied to the wooden structural member than in a region other than the region.

3. The reinforcement structure for a wooden structural member according to claim 1 or 2.

4. A plurality of the fiber sheets are provided, Each of the plurality of fiber sheets is provided such that an end portion in the circumferential direction of the through hole overlaps with another fiber sheet.

2. The reinforcement structure for a wooden structural member according to claim 1.

5. The fiber sheet is provided so that the extending direction of the fibers coincides with the circumferential direction of the through-holes.

2. The reinforcement structure for a wooden structural member according to claim 1.

6. The wooden structural member is a beam, The through-hole is provided so as to penetrate the beam in the width direction of the beam.

2. The reinforcement structure for a wooden structural member according to claim 1.

7. A method for reinforcing a wooden structural member having a through hole, comprising: A fiber sheet is provided along the inner wall of the through hole and adhered to the inner wall to form a reinforcing layer. A method for reinforcing a wooden structural member, comprising:

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