Reinforcing structure

Abstract

To provide a reinforcing structure or the like capable of efficiently preventing cracking of a wooden beam.SOLUTION: A reinforcing structure 10 reinforces a wooden beam having a through hole 25 penetrating a beam body 2 in a beam width direction. In the reinforcing structure 10, a belt-like fiber reinforcing sheet 3 is provided around the through hole 25 on a side surface 21 of the beam body 2 in a beam axial direction, and the fiber reinforcing sheet 3 is disposed on the side surface 21 so as to cross positions in 4 directions a1 to a4 inclined by 45° with respect to the beam axial direction H from a center C of the through-hole 25, and is disposed on the side surface 21 along the sides of a rectangle R having apexes on the upper, lower, right and left sides of the through-hole 25.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a reinforcing structure for a wooden beam. [Background technology]

[0002] In recent years, the use of wooden materials as beams in buildings has been increasing. Drilling through-holes in these wooden beams to run plumbing and other equipment has the advantage of making effective use of the space above the ceiling and reducing the height of floors.

[0003] However, drilling through holes in wooden beams is expected to reduce the strength of the beam. Therefore, Patent Document 1 discloses a reinforcing structure for wooden beams with through holes, in which fiber reinforcing sheets are provided on both sides of the through holes in the beam axial direction on the side surfaces of the wooden beam, thereby preventing the reduction in the strength of the wooden beam. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6482224 Summary of the Invention [Problem to be solved by the invention]

[0005] FIG. 11 is a schematic diagram of a wooden beam 100 having a through hole 101. It is known that stress generated around the through hole 101 of the wooden beam 100 due to a vertical load or the like increases at a position a on the side surface of the wooden beam 100 in the beam axis direction, which is inclined at approximately 45° from the center C of the through hole 101 to the beam axis direction H, and that there is a high possibility that a crack (split) 102 in the beam axis direction will occur in the wooden beam 100 starting from this position ("Study on the Strength of Glulam Beams with Circular Holes," Okamoto et al., Transactions on Structural Engineering, Architectural Institute of Japan, Vol. 85, No. 775, pp. 1199-1208, September 2020).

[0006] In this regard, the reinforcement structure described in Patent Document 1 involves providing fiber reinforcement sheets in the beam depth direction on both sides of the through hole in the beam axis direction, which is not necessarily an effective measure to prevent cracks such as those described above.

[0007] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a reinforcement structure etc. that can efficiently prevent cracks in wooden beams. [Means for solving the problem]

[0008] In order to solve the above problems, the present invention provides a reinforcing structure for a wooden beam having a through hole that penetrates the beam body in the beam width direction, characterized in that a strip-shaped fiber reinforcing sheet is provided around the through hole on the side surface of the beam body in the beam axis direction, and the fiber reinforcing sheet is arranged on the side surface so as to cross four positions inclined at 45° from the center of the through hole to the beam axis direction, and is arranged on the side surface in a direction along the sides of a rectangle having vertices above, below, left and right of the through hole.

[0009] In this invention, strip-shaped fiber reinforcement sheets are provided on the side of the wooden beam body in a direction along the sides of a rectangle with vertices at the top, bottom, left, and right of the through-hole, and these fiber reinforcement sheets are arranged so as to cross a position inclined at 45° from the center of the through-hole to the beam axis direction. This allows reinforcement against the cracks mentioned above to be performed with a relatively small area of ​​fiber reinforcement sheets near the through-hole, and effectively prevents the occurrence and progression of cracks.

[0010] It is desirable that the fiber reinforcement sheet be provided so as to be continuous between both side surfaces of the beam body in the beam axis direction. This makes it possible to easily reinforce both sides of the beam body.

[0011] It is desirable that two of the fiber reinforcement sheets intersect at the top surface of the beam body and are arranged in an upside-down V shape on both sides of the beam body to surround the upper part of the through hole, and that another two of the fiber reinforcement sheets intersect at the bottom surface of the beam body and are arranged in a V shape on both sides of the beam body to surround the lower part of the through hole. This allows for easy installation of the fiber-reinforced sheets, and efficient reinforcement using four fiber-reinforced sheets. Furthermore, by intersecting the fiber-reinforced sheets above and below the through-holes, the cross-sectional loss caused by the through-holes can be compensated for, increasing the strength of the beam body.

[0012] It is also desirable that the corners of the cross section of the beam body perpendicular to the beam axis direction are chamfered, and that the fiber reinforcement sheet is arranged so as to cross the chamfered corners. This prevents the fiber-reinforced sheet from bending at right angles at the corners of the cross section of the beam body, thereby suppressing damage to the fiber-reinforced sheet at those corners.

[0013] It is desirable that the fiber reinforcement sheet be placed in a groove provided in the beam body. This prevents the fiber reinforcement sheet from lifting off the surface of the beam body, making it easier to apply a fire-retardant layer to the beam body.

[0014] It is desirable that the fiber reinforcement sheet be arranged on the side of the beam body so as to contact the outer periphery of the through hole. This allows the fiber reinforcement sheet to be installed without any gaps in the through holes on the side of the beam body, thereby enhancing the reinforcing effect. [Effects of the Invention]

[0015] According to the present invention, a reinforcement structure or the like can be provided that can efficiently prevent cracks in wooden beams. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 shows a wooden beam 1. [Figure 2]FIG. [Figure 3] 2 is a development view of the side surface 21, top surface 22 and bottom surface 23 of the beam body 2. FIG. [Figure 4] 3A and 3B are diagrams showing examples of arrangement of a fiber-reinforced sheet 3. FIG. [Figure 5] FIG. [Figure 6] FIG. [Figure 7] FIG. [Figure 8] FIG. 2 is a diagram showing a reference example of the arrangement of a fiber-reinforced sheet 3. [Figure 9] FIG. 2 is a diagram showing a reference example of the arrangement of a fiber-reinforced sheet 3. [Figure 10] FIG. 2 is a diagram showing a reference example of the arrangement of a fiber-reinforced sheet 3. [Figure 11] 1 is a diagram showing an outline of a wooden beam 100. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

[0018] (1. Wood beam 1) Figures 1(a) and (b) are diagrams showing a wooden beam 1 having a reinforcement structure 10 according to an embodiment of the present invention. Figure 1(a) is a diagram showing a side view of the wooden beam 1 in the beam axis direction, and Figure 1(b) is a diagram showing a cross section of the wooden beam 1 perpendicular to the beam axis direction. Figure 1(b) is a cross section taken along line AA in Figure 1(a). The beam axis direction corresponds to the left-right direction in Figure 1(a) and the normal direction to the paper surface in Figure 1(b).

[0019] The wooden beam 1 has a beam body 2, a fiber reinforcing sheet 3, a fire-resistant coating 5, a fire-retardant layer 6, etc. The reinforcing structure 10 reinforces the beam body 2 of the wooden beam 1 with the fiber reinforcing sheet 3.

[0020] The beam body 2 is a load-bearing part that mainly bears the load of the wooden beam 1, and is formed in a beam shape from wooden material. The cross section of the beam body 2 that is perpendicular to the beam axis direction is rectangular, but this is not limited to this.

[0021] The above-mentioned wooden materials are laminated timber with the fiber direction aligned with the beam axis, but are not limited to this. For example, other wooden materials with the fiber direction aligned with the beam axis or beam depth direction, such as CLT (Cross Laminated Timber), may also be used. The beam depth direction corresponds to the up-down direction in Figures 1(a) and (b).

[0022] The beam body 2 has a through hole 25. The through hole 25 is provided so as to penetrate the beam body 2 in the beam width direction. The beam width direction is a direction perpendicular to the beam axis direction and the beam depth direction, and corresponds to the normal direction to the paper surface of FIG. 1(a) and the left-right direction of FIG. 1(b). The through hole 25 is for passing equipment piping and the like, and in this embodiment is formed in the center of the wooden beam 1 in the beam depth direction, and has a circular cross section. However, the position and shape of the through hole 25 are not particularly limited.

[0023] The fiber reinforced sheet 3 is a strip-shaped sheet provided on the surface of the beam body 2, which reinforces the beam body 2 and suppresses the occurrence and progression of the cracks described above. An aramid fiber sheet with known structural performance is used as the fiber reinforced sheet 3. The fiber reinforced sheet 3 is narrow, for example, about 10 cm wide, and has a thickness of, for example, 1 mm or less. However, the material and dimensions of the fiber reinforced sheet 3 are not limited to these. For example, a carbon fiber reinforced sheet can also be used as the fiber reinforced sheet 3. Details of the reinforced structure 10 using the fiber reinforced sheet 3 will be described later.

[0024] The fire-resistant coating 5 is a tubular member provided on the inner surface of the through-hole 25. The fire-resistant coating 5 is formed of, for example, mortar or wood material impregnated with a fire retardant, but is not limited to these. By providing the fire-resistant coating 5, the beam body 2 is prevented from being exposed to the inner surface of the through-hole 25.

[0025] The fire-retardant layer 6 is a plate-like member provided to cover the side surface 21 and bottom surface 23 of the beam body 2 in the beam axis direction. The fire-retardant layer 6 is a part for stopping the combustion of the wooden beam 1 in the event of a fire, etc., and is formed from wood material impregnated with a fire-retardant agent, but is not limited to this. The fire-retardant layer 6 is omitted from the top surface 22 of the beam body 2 because it comes into contact with a concrete slab (not shown), etc., but in some cases the fire-retardant layer 6 may be provided.

[0026] The fire-retardant layer 6 on the side surface 21 of the beam body 2 has an opening 61 at a position corresponding to the inner periphery of the fire-resistant coating 5. The fire-retardant layer 6 is continuous with the fire-resistant coating 5 at the outer periphery of the opening 61. It is also possible to provide a substitute fire layer or decorative material made of wood on the outside of the fire-retardant layer 6.

[0027] (2. Reinforcement structure 10 using fiber reinforcement sheet 3) 2(a) and (b) are perspective views showing the beam body 2 with the fire-retardant layer 6 omitted, and show a pair of side surfaces 21 of the beam body 2. FIG.

[0028] In this embodiment, on the side surface 21 of the beam body 2, the periphery of the through hole 25 is reinforced using four fiber reinforcement sheets 3 (3-1 to 3-4), thereby preventing cracks originating from the through hole 25 in the beam axis direction (the fiber direction of the beam body 2). These fiber reinforcement sheets 3 are arranged around the through hole 25 so as to be inclined with respect to the beam axis direction. The arrangement of the fiber reinforcement sheets 3 is the same on both side surfaces 21 of the beam body 2.

[0029] As shown in Fig. 2(a), the fiber-reinforced sheets 3-1 to 3-4 are arranged on the side surface 21 of the beam main body 2 so as to cross four directions a1 to a4 inclined at 45° from the center C of the through hole 25 with respect to the beam axis direction H. As shown in Fig. 2(b), the fiber-reinforced sheets 3-1 to 3-4 are arranged on the side surface 21 of the beam main body 2 in directions along the sides of a rectangle R having vertices above, below, left, and right of the through hole 25. Furthermore, the fiber-reinforced sheets 3-1 to 3-4 are arranged on the side surface 21 of the beam main body 2 so as to contact the outer periphery of the through hole 25.

[0030] Each of the fiber-reinforced sheets 3-1 to 3-4 is provided so as to be continuous between both side surfaces 21 of the beam body 2. More specifically, the fiber-reinforced sheets 3-1 and 3-2 intersect at the top surface 22 of the beam body 2 and are provided on both side surfaces 21 of the beam body 2 in an upside-down V-shape so as to surround the upper part of the through-hole 25. Both end portions of the fiber-reinforced sheets 3-1 and 3-2 are folded between each side surface 21 and the bottom surface 23 of the beam body 2 and fastened to the bottom surface 23. In contrast, the fiber-reinforced sheets 3-3 and 3-4 intersect at the bottom surface 23 of the beam body 2 and are provided so as to be V-shaped so as to surround the lower part of the through-hole 25 on both side surfaces 21 of the beam body 2. Both end portions of the fiber-reinforced sheets 3-3 and 3-4 are folded between each side surface 21 and the top surface 22 of the beam body 2 and fastened to the top surface 22.

[0031] As a result, on both side surfaces 21 of the beam body 2, the fiber reinforced sheets 3-1, 3-2, 3-3, and 3-4 are respectively arranged at the upper left, upper right, lower left, and lower right of the through hole 25. The fiber reinforced sheets 3-1 and 3-3 intersect on the left side of the through hole 25, and the fiber reinforced sheets 3-2 and 3-4 intersect on the right side of the through hole 25.

[0032] The fiber-reinforced sheet 3 is adhered to the surfaces (side surface 21, top surface 22, and bottom surface 23) of the beam body 2 with an adhesive. The adhesive is, for example, an epoxy resin-based adhesive, and does not particularly need to be used in conjunction with screws, nails, etc.; the fiber-reinforced sheet 3 can be fixed using only the adhesive. Each of the fiber-reinforced sheets 3-1 to 3-4 may be configured by stacking multiple layers of sheets as needed.

[0033] Figure 3 is a development of the side surface 21, top surface 22, and bottom surface 23 of the beam body 2 in Figure 2. In this embodiment, the fiber-reinforced sheet 3 is linear in the development, and the fiber-reinforced sheet 3 does not meander or distort, making it easy to install.

[0034] The wooden beam 1 is manufactured in a factory or the like by adhering a fiber reinforcement sheet 3 to the surface of a beam body 2 having through holes 25, and attaching a fire-resistant coating 5 and a fire-retardant layer 6 to the beam body 2. The finished wooden beam 1 is then transported to the construction site and used.

[0035] As described above, in the reinforcement structure 10 of this embodiment, strip-shaped fiber reinforcement sheets 3 are provided on the side surface 21 of the beam body 2 of the wooden beam 1 in a direction along the sides of a rectangle R having vertices at the top, bottom, left, and right of the through-hole 25. These fiber reinforcement sheets 3 are arranged so as to cross the positions a1 to a4, which are inclined at 45° from the center C of the through-hole 25 relative to the beam axis direction H. This allows reinforcement against cracks to be performed using a relatively small area of ​​fiber reinforcement sheets 3 near the through-hole 25, effectively preventing the occurrence and progression of cracks. This allows the diameter of the through-hole 25 relative to the beam depth of the wooden beam 1 to be increased, lowering the hurdle for forming the through-hole 25 in the wooden beam 1. As a result, the flexibility of the arrangement of equipment piping and the like is improved, allowing for the reduction of the building's floor height and the effective use of the space above the ceiling.

[0036] In this embodiment, the fiber reinforcement sheet 3 is provided continuously between both side surfaces 21 of the beam body 2, so that both side surfaces 21 of the beam body 2 can be easily reinforced.

[0037] In particular, in this embodiment, two fiber-reinforced sheets 3-1 and 3-2 intersect at the top surface 22 of the beam body 2 and are provided on both side surfaces 21 of the beam body 2 in an upside-down V-shape so as to surround the upper part of the through-hole 25, and another two fiber-reinforced sheets 3-3 and 3-4 intersect at the bottom surface 23 of the beam body 2 and are provided on both side surfaces 21 of the beam body 2 in a V-shape so as to surround the lower part of the through-hole 25. This allows the fiber-reinforced sheets 3 to be easily installed, and reinforcement by the four fiber-reinforced sheets 3 can be efficiently performed. Furthermore, by intersecting the fiber-reinforced sheets 3 above and below the through-hole 25, the fiber-reinforced sheets 3 function as tensile members above and below the through-hole 25, thereby compensating for the cross-sectional loss caused by the through-hole 25 and increasing the strength of the beam body 2.

[0038] In addition, in this embodiment, the fiber reinforcement sheet 3 is arranged on the side surface 21 of the beam body 2 so as to contact the outer periphery of the through hole 25, and by installing the fiber reinforcement sheet 3 without any gaps relative to the through hole 25, the reinforcing effect can be enhanced.

[0039] However, the present invention is not limited to the above embodiment. As an example, the arrangement of the fiber-reinforced sheets 3 is not particularly limited as long as the fiber-reinforced sheets 3 are provided on the side surface 21 of the beam body 2 in a direction along the sides of a rectangle R having vertices at the top, bottom, left, and right of the through-hole 25, and the fiber-reinforced sheets 3 are arranged so as to cross positions a1 to a4 inclined at 45° from the center C of the through-hole 25 with respect to the beam axis direction H.

[0040] For example, in the reinforcement structure 10a of FIG. 4, unlike the above-described embodiment, the fiber reinforcement sheets 3 do not cross the top surface 22 or the bottom surface 23 of the beam body 2, but are provided separately on both side surfaces 21 of the beam body 2. Also, on each side surface 21, the fiber reinforcement sheets 3 are arranged so as not to cross each other. Furthermore, each fiber reinforcement sheet 3 is arranged with a slight gap from the outer periphery of the through hole 25. In addition, the angle of the fiber reinforcement sheets 3 with respect to the beam axis direction may be determined arbitrarily, and the length of the fiber reinforcement sheets 3 may be any length as long as the required length for the structure is ensured.

[0041] In the above embodiment, fire resistance is ensured by providing the fire-retardant layer 6 on the side surface 21 and bottom surface 23 of the beam body 2, and covering the outside of the fiber reinforced sheet 3 with the fire-retardant layer 6 is also effective in terms of design. However, depending on the installation location of the wooden beam 1, the fire-retardant layer 6 can be omitted if there are no fire resistance issues, and there is no particular need to cover the outside of the fiber reinforced sheet 3 if there are no design issues.

[0042] 5, grooves 24 may be formed by notching the surface (side surfaces 21, top surface 22, and bottom surface 23) of the beam body 2, and fiber-reinforced sheets 3 may be placed in the grooves 24. The depth of the grooves 24 is determined taking into consideration the thicknesses of the fiber-reinforced sheets 3 and adhesive 7. The grooves 24 are made deeper at locations where the fiber-reinforced sheets 3 intersect than at locations where they do not intersect. Alternatively, the overall depth of the grooves 24 is determined taking into consideration the thicknesses of the fiber-reinforced sheets 3 and adhesive 7 at locations where the fiber-reinforced sheets 3 intersect. This prevents the fiber-reinforced sheets 3 and adhesive 7 from protruding from the surface of the beam body 2, making it easier to install fire-retardant layers 6, etc.

[0043] 6, the four corners of the cross section of the beam body 2a perpendicular to the beam axis direction may be chamfered to form inclined surfaces inclined relative to the side surfaces 21, top surface 22, and bottom surface 23, and the fiber-reinforced sheet 3 may be arranged to cross the inclined surfaces of the corners. This prevents damage to the fiber-reinforced sheet 3 caused by bending at right angles at the corners of the cross section of the beam body 2. Furthermore, since the corners are heated from two directions (for example, the corner between the side surface 21 and bottom surface 23 is heated from both the side surface 21 and bottom surface 23), they are weak points in terms of fire resistance. However, chamfering the corners may eliminate the weak points in terms of fire resistance and reduce the thickness of the fire-retardant layer 6.

[0044] In this embodiment, the fire-resistant coating 5 and the fire-retardant layer 6 are connected in the manner that the fire-retardant layer 6 dominates, and the fire-resistant coating 5 is not exposed on the side of the wooden beam 1a. However, the fire-resistant coating 5 may be connected in the manner that the end of the fire-resistant coating 5 in the beam width direction is exposed on the side of the wooden beam 1a, as shown in Figure 7, which shows a cross section corresponding to Figure 1(b).

[0045] 8 shows a reference example of the arrangement of the fiber-reinforced sheet 3, in which the fiber-reinforced sheet 3 is adhered in a cylindrical shape to the inner surface of the through-hole 25 of the beam body 2. The inner surface of the through-hole 25 may be unevenly formed to increase the adhesive strength between the fiber-reinforced sheet 3 and the inner surface of the through-hole 25 by the adhesive. In this case, cracks from the through-hole 25 can be prevented even if the fiber-reinforced sheet 3 is not arranged on the side surface 21 of the beam body 2.

[0046] 9, one fiber-reinforced sheet 3 is provided on both side surfaces 21 of the beam body 2 over the entire length of the beam body 2 in the beam axis direction. In yet another reference example shown in Fig. 10, one fiber-reinforced sheet 3 is provided on both side surfaces 21 of the beam body 2 at a partial position in the beam axis direction of the beam body 2 that includes the through-hole 25. The beam body 2 can also be reinforced by these fiber-reinforced sheets 3.

[0047] 9 and 10 is attached to both side surfaces 21 of the beam body 2 across the bottom surface 23 of the beam body 2, and is then folded between each side surface 21 and the top surface 22 and fastened to the top surface 22. In addition, at positions corresponding to the through holes 25 on the side surfaces 21 of the beam body 2, openings of the same shape as the through holes 25 are provided in the fiber reinforced sheet 3. These openings can be formed simultaneously with the through holes 25 by adhering the fiber reinforced sheet 3 to the surface of the beam body 2 and then cutting the fiber reinforced sheet 3 and the beam body 2 at the same time.

[0048] While the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to these examples. It is clear that those skilled in the art can conceive of various modifications and alterations within the scope of the technical ideas disclosed in this application, and it is understood that these modifications and alterations also fall within the technical scope of the present invention. [Explanation of symbols]

[0049] 1, 1a, 100: Wooden beam 2, 2a: Beam body 3, 3-1 to 3-4: Fiber reinforced sheet 5: Fireproof coating 6: Fire-retardant layer 10, 10a: Reinforcement structure 21: Side 22:Top surface 23: Bottom 24: Groove 25, 101: Through holes 102: Crack

Claims

1. A reinforcement structure for a wooden beam having a through hole penetrating the beam body in the beam width direction, A strip-shaped fiber reinforcement sheet is provided around the through hole on the side surface of the beam body in the beam axis direction, The fiber-reinforced sheet is On the side surface, the through-holes are arranged so as to cross four positions inclined at 45° from the center of the through-hole with respect to the beam axis direction, The reinforcing structure is characterized in that the through hole is arranged on the side surface in a direction along the sides of a rectangle having vertices above, below, left and right of the through hole.

2. 2. The reinforced structure according to claim 1, wherein the fiber reinforcement sheet is provided so as to be continuous between both side surfaces of the beam body in the beam axis direction.

3. The two fiber reinforcement sheets intersect at the top surface of the beam body and are provided on both side surfaces of the beam body in an upside-down V shape so as to surround the upper part of the through hole, A reinforcement structure as described in claim 2, characterized in that two other fiber reinforcement sheets intersect at the bottom surface of the beam body and are arranged in a V-shape on both side surfaces of the beam body to surround the lower part of the through hole.

4. A reinforced structure as described in claim 2, characterized in that the corners of the cross section of the beam body perpendicular to the beam axis direction are chamfered, and the fiber reinforcement sheet is arranged so as to cross the chamfered corners.

5. The reinforced structure according to claim 1, wherein the fiber reinforcement sheet is disposed in a groove provided in the beam body.

6. The reinforced structure according to claim 1 , wherein the fiber reinforcement sheet is disposed so as to contact the outer periphery of the through hole on the side surface.

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