Laminated wood

Abstract

To provide a laminated wood material having high shear strength while ensuring fire resistance.SOLUTION: A wood laminate 10 of the present invention is a laminated wood made by laminating and adhering multiple sawn boards 11 cut from wood. A reinforcing member 20 extending vertically is provided inside the wood laminate 10, and the bottom edge of the reinforcing member 20 is located a predetermined dimension above the lower end surface of the wood laminate 10. According to the present invention, the wood laminate is provided with a reinforcement 20 extending vertically inside the wood laminate 10, the reinforcement 20 resists slippage between the sawn plates 11, that is, horizontal shear force, so that the shear strength of the woody laminate 10 can be enhanced. The bottom edge of the reinforcement 20 is positioned a predetermined dimension above the bottom surface of the wood laminate 10, so that even if a fire breaks out below the wood laminate 10 and the bottom portion of the wood laminate 10 burns, this heat can be prevented from being transmitted to the upper part of the wood laminate 10 through the reinforcing material 20, and the fire resistance performance of the wood laminate 10 can be ensured.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a laminated wood material formed by laminating and bonding a plurality of boards cut out from wood. [Background technology]

[0002] BACKGROUND ART Conventionally, laminated wood materials, which are made by laminating and gluing together a plurality of boards cut out from wood, have been reinforced (see Patent Documents 1 and 2). Patent Document 1 discloses a laminated lumber in which pieces of wood are glued together with an adhesive. In this laminated lumber, a reinforcing material such as carbon fiber and a spacer are sandwiched between the pieces of wood. Patent Document 2 shows a reinforced laminated timber made of two or more layers of laminated wooden planks. A groove with a semicircular cross section is formed on the joint surface between the wooden planks, and a steel rod-shaped reinforcing material is housed in this groove. The wooden planks are also connected by shear reinforcement bolts that penetrate through the planks in the thickness direction. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 11-10610 [Patent Document 2] Japanese Patent Application Laid-Open No. 2009-30299 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide a laminated wood material that has high shear strength while ensuring fire resistance. [Means for solving the problem]

[0005] The inventors arrived at the present invention by noticing that by installing a reinforcing material containing fire-resistant material or a steel reinforcing material that becomes thinner toward the bottom inside the wood laminate, this reinforcing material acts as a thermal bridge to suppress heat transfer and also serves as a means of shear reinforcement between the boards that make up the wood laminate, making it possible to achieve a wood laminate with high shear strength while maintaining fire resistance. The first invention of the laminated wood material (for example, the laminated wood material 10 described below) is a laminated wood material made by stacking and gluing together multiple boards cut from wood (for example, the sawn boards 11 described below), and is characterized in that a reinforcing material (for example, the reinforcing material 20 described below) extending vertically is provided inside the laminated wood material, and the lower end of the reinforcing material is located a predetermined distance (for example, the dimension d described below) above the lower end surface of the laminated wood material.

[0006] According to this invention, a reinforcing member extending vertically inside the laminated wood lumber is provided. This reinforcing member resists the shearing of the boards, i.e., the horizontal shear force, and therefore the shear strength of the laminated wood lumber can be increased without increasing the cross section of the laminated wood lumber. In addition, the lower end of the reinforcing material is positioned a predetermined distance above the lower end surface of the laminated wood material. This prevents the formation of a heat bridge, where heat is transferred through the reinforcing material to the upper part of the laminated wood material, even if a fire breaks out below the laminated wood material and burns the lower part of the laminated wood material, ensuring the fire resistance of the laminated wood material.

[0007] The wood laminate of the second invention is characterized in that the reinforcing material comprises a steel reinforcing material body (e.g., reinforcing material body 21 described below) and a fire-resistant material (e.g., gypsum 22, fire-resistant paint 23, mortar, cement paste, or fire-resistant adhesive described below) covering at least the lower end side of the reinforcing material body. According to this invention, the reinforcing material provided in the laminated wood lumber is composed of a steel reinforcing material body and a fire-resistant material covering at least the lower end of the reinforcing material body. Therefore, even if a fire breaks out below the laminated wood lumber, the fire-resistant material significantly suppresses heat transfer, preventing the reinforcing material from acting as a thermal bridge and transmitting heat, thereby improving the fire resistance of the laminated wood lumber.

[0008] A third aspect of the present invention is a laminated wood material in which the reinforcing material is made of steel and has a shape that tapers downward. According to this invention, the reinforcing material attached to the laminated wood lumber is tapered downwards. Therefore, even if a fire breaks out around the laminated wood lumber, the tapered tip of the reinforcing material significantly reduces heat transfer, preventing the reinforcing material from acting as a thermal bridge and thus improving the fire resistance of the laminated wood lumber.

[0009] A building according to a fourth aspect of the present invention is characterized in that the above-mentioned laminated wood lumber is used as beams and / or columns. According to this invention, by using laminated wood lumber for the beams and columns of a building, a wooden building with excellent fire resistance and shear strength can be realized. [Effects of the Invention]

[0010] According to the present invention, a laminated wood material having high shear strength while ensuring fire resistance can be provided. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a vertical cross-sectional view showing the structure of a building to which a laminated wood lumber according to one embodiment of the present invention is applied. [Figure 2] FIG. 2 is an enlarged view of the area of ​​building 1 in FIG. 1 surrounded by dashed line A. [Figure 3] 2. FIG. 3 is a cross-sectional view of the building 1 along II and a cross-sectional view along II-II in FIG. [Figure 4] This is a side view (part 1) showing the reinforcing material used inside the beam. [Figure 5] This is a side view (part 2) showing the reinforcing material used inside the beam. [Figure 6] 1A to 1C are explanatory diagrams illustrating a procedure for attaching a reinforcing material to a laminated wood material. [Figure 7] This is a diagram for calculating the number of reinforcement members to be installed in the beams of a building (Part 1, a simple beam modeled after a beam). [Figure 8] This is a diagram for calculating the number of reinforcement members to be installed in the beams of a building (part 2, longitudinal cross section of the beam). [Figure 9] FIG. 10 is a diagram for explaining the installation positions of a plurality of reinforcing members. [Figure 10] FIG. 10 is a longitudinal cross-sectional view of a modified wood laminated lumber according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] The present invention relates to a laminated wood lumber containing a reinforcement material, in which a reinforcement material having a fire-resistant material on at least one end side or a steel reinforcement material tapering toward the bottom end is provided inside the laminated wood lumber. Specifically, the reinforcement material of the present invention is covered on one end side or the entire reinforcement material with a fire-resistant paint or plaster, or the reinforcement material of the present invention is made of steel and tapered toward the bottom end. Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a vertical cross-sectional view showing the structure of a building 1 to which a laminated wood lumber 10 according to one embodiment of the present invention is applied. Fig. 2 is an enlarged view of a portion of the building 1 surrounded by a dashed line A. Fig. 3(a) is a cross-sectional view of the building 1 in Fig. 2 taken along line II, and Fig. 3(b) is a cross-sectional view of the building 1 in Fig. 2 taken along line II-II. The building 1 comprises columns 2, beams 3 made of laminated wood lumber 10 and arranged between the columns 2, and a floor slab 4 or a roof 5 arranged on the beams 3. The laminated wood lumber 10 is made by stacking and gluing together multiple sawn boards or veneers cut from wood in the vertical direction. Examples of the laminated wood lumber 10 include CLT (Cross Laminated Timber), laminated lumber, plywood, and LVL (Laminated Veneer Lumber). CLT is made by stacking and gluing together sawn boards cut from wood alternately so that the grain directions are perpendicular. Laminated lumber is made by stacking and gluing together sawn boards cut from wood so that the grain directions are parallel. Plywood is made by stacking and gluing together veneers cut from wood so that the grain directions are perpendicular. LVL is made by stacking and gluing together veneers cut from wood so that the grain directions are parallel.

[0013] The laminated wood lumber 10 of this embodiment is a laminated lumber, and as shown in Figures 2 and 3, twelve layers of planks 11 are stacked together. A plurality of rod-shaped reinforcing members 20 extending vertically are provided inside the laminated wood lumber 10. Specifically, holes 12 are provided in the laminated wood lumber 10, and reinforcing members 20 are inserted into these holes 12, extending from the underside of the floor slab 4 to the third plank 11 from the bottom. The lower end of the reinforcing member 20 is located a predetermined distance d above the underside of the laminated wood lumber 10 so as to ensure the fire resistance time required for the laminated wood lumber 10 (required fire resistance time). Meanwhile, the upper end of the reinforcing member 20 is flush with the upper surface of the laminated wood lumber 10. For example, as shown in FIG. 4(a), the reinforcing material 20 includes a reinforcing material body 21 made of steel, such as a screw, wire, or bolt, and gypsum 22 as a fire-resistant material that entirely covers the reinforcing material body 21. Alternatively, as shown in FIG. 4(b), the reinforcing material 20 may include a reinforcing material body 21 made of steel, such as a screw, wire, or bolt, and a fire-resistant paint 23 applied to one end of the reinforcing material body 21. Alternatively, as shown in FIG. 5(a), the reinforcing material 20 may be made of steel, such as a screw, wire, or bolt, and have a shape that tapers toward the tip. Alternatively, as shown in FIG. 5(b), the reinforcing material 20 may be made of steel, such as a screw, wire, or bolt, and have an overall thin shape.

[0014] The procedure for attaching the reinforcing material 20 to the laminated wood lumber 10 is as follows. First, as shown in FIG. 6, a hole 12 is drilled in the top surface of the laminated wood lumber 10 using an electric drill or the like. The height position of the bottom of the hole 12 is set to a dimension d above the bottom surface of the laminated wood lumber. Next, an adhesive is filled into the hole 12 from above, and then the reinforcing material 20 is inserted into the adhesive-filled hole 12 to fix the reinforcing material 20 inside the laminated wood lumber 10. For example, a heat-resistant adhesive or resorcinol, which has excellent fire resistance, is used as the adhesive. Furthermore, when a steel material that becomes thinner toward the bottom end (for example, a drift pin) is used as the reinforcing material 20, the reinforcing material may be driven into the hole with an electric hammer or the like.

[0015] [Calculation of the number of reinforcement materials to be installed] The number of bolts installed as reinforcing materials for beams of buildings using the laminated wood lumber of the present invention was determined below. Assume that an earthquake force acts on the above-mentioned building, causing it to deform as shown in Figure 7. At this time, the beams of the building can be modeled as simple beams with a uniformly distributed load acting on them, as shown in Figure 8. Here, if the uniformly distributed load is w (N / m) and the beam span is L (m), the bending moment M generated at the center of the beam can be expressed by the following equation (1).

number

[0016] Furthermore, if the char depth due to fire is d (mm), this char depth d can be expressed as d = 0.7t using the required fire resistance time t (min). Furthermore, if the beam depth is H (mm), the effective beam depth after a fire is (Hd), as shown in Figure 8(a). Furthermore, as shown in Figure 8(b), the distance between the center of gravity on the compression side and the center of gravity on the tension side is 2 / 3 (Hd). Therefore, if the tensile force generated in the lower half of the center of the beam is T (N), the following equation (2) is established.

number

number

[0017] The number of bolts required as reinforcement is sufficient to withstand the tensile force T that occurs in the lower half of the center of the beam. The standard strength of the bolt is F (N / mm 2 ), effective cross-sectional area of ​​the bolt (mm 2 ) is A, the required number of bolts n (pieces) is expressed by the following formula (4).

number

[0018] The calculation was carried out by inputting specific values ​​into the formula for the number of reinforcement members to be installed. The beam span L was set to 6.0m, the uniformly distributed load w to 9.6kN / m, the beam depth H to 300mm, and the required fire resistance time t to 60min. The bolts were also set to M8. The standard strength F of an M8 bolt is 400N / mm. 2 , effective cross-sectional area A is 36.6 mm 2 As a result, the number of bolts, n, was set to four, as shown in Table 1 below. [Table 1]

[0019] When installing multiple bolts as reinforcement, the bolt installation positions should be determined based on the drift pin spacing specified in the wooden structure design standards. For a board such as that shown in Figure 9, the bolt installation positions can be set as shown in Table 2 below. [Table 2]

[0020] According to this embodiment, the following effects are obtained. (1) Reinforcement members 20 extending vertically are provided inside the laminated wood lumber 10. These reinforcement members 20 resist misalignment between the planks 11, i.e., horizontal shear force, and therefore the shear strength of the laminated wood lumber 10 can be increased without increasing the cross section of the laminated wood lumber 10. This prevents misalignment (lamina fracture) between the planks 11 that make up the laminated wood lumber 10. In addition, the lower end of the reinforcing material 20 is positioned a predetermined distance d above the lower end surface of the laminated wood material. Therefore, even if a fire breaks out below the laminated wood material 10 and the lower part of the laminated wood material 10 burns, a heat bridge in which the heat is transferred through the reinforcing material 20 to the upper part of the laminated wood material 10 can be prevented, and the fire resistance of the laminated wood material 10 can be ensured.

[0021] (2) The reinforcing material 20 provided in the wood laminate lumber 10 is configured to include a steel reinforcing material body 21 and gypsum 22 or fire-resistant paint 23 that covers at least the lower end of the reinforcing material body 21. Alternatively, the reinforcing material 20 provided in the wood laminate lumber 10 is shaped to taper toward the lower end. Therefore, even if a fire breaks out below the wood laminate lumber 10, the gypsum 22 or fire-resistant paint 23 significantly suppresses heat transfer, or the reinforcing material 20, which tapers toward the lower end, significantly suppresses heat transfer. Therefore, the reinforcing material 20 acts as a thermal bridge to suppress heat transfer, thereby improving the fire resistance of the wood laminate lumber 10. (3) By using the laminated wood lumber 10 for the beams 3 of a building, a wooden building with excellent fire resistance and shear strength can be realized.

[0022] The present invention is not limited to the above-described embodiment, and modifications and improvements within the scope of achieving the object of the present invention are included in the present invention. For example, in this embodiment, the beams 3 of the building 1 are formed from laminated wood lumber 10, but this is not limited to this, and the columns 2 may also be formed from laminated wood lumber 10, or both the columns 2 and the beams 3 may be formed from laminated wood lumber 10. In addition, in this embodiment, adhesive is filled into the hole 12 formed in the wood laminate 10, and then the reinforcing material 20 is inserted into this hole 12 to join the reinforcing material 20 and the wood laminate 10, but this is not limited to this, and the reinforcing material may be pressed into the hole with an electric hammer or the like without using adhesive. In addition, in this embodiment, the upper end of the reinforcing material 20 is flush with the upper surface of the wood laminate 10, but this is not limited to this. As shown in Figure 10, the upper end of the reinforcing material 20 may be lower than the upper surface of the wood laminate 10, and a filler wood 13 may be pressed into the upper end of the hole 12 to block it. In addition, in this embodiment, gypsum 22 and fire-resistant paint 23 are used as the fire-resistant material, but the fire-resistant material is not limited to these, and mortar, cement paste, and fire-resistant adhesive may also be used. [Explanation of symbols]

[0023] 1...Building 2...Column 3...Beam 4...Floor slab 5...Roof 10... Laminated wood 11... Sawn board (board) 12... Hole 13... Filler wood 20...Reinforcement material 21...Reinforcement material body 22...Gypsum (fireproof material) 23...Fireproof paint (fireproof material)

Claims

1. A laminated wood material that is joined to a pillar and forms a beam that extends approximately horizontally, The laminated wood material is formed by stacking and adhering a plurality of planks cut from wood and extending substantially horizontally, A reinforcing material is provided inside the end of the wood laminate on the column side, extending vertically and penetrating at least one of the laminated boards in the vertical direction, A laminated wood material characterized in that the upper end of the reinforcing material is flush with the upper end surface of the laminated wood material or is lower than the upper end surface of the laminated wood material, and the lower end of the reinforcing material is located a predetermined distance above the lower end surface of the laminated wood material.

2. 2. The wood laminated material according to claim 1, wherein the reinforcing material comprises a steel reinforcing material body and a fire-resistant material covering at least the lower end side of the reinforcing material body.

3. 2. The laminated wood material according to claim 1, wherein the reinforcing material is made of steel and has a shape that tapers downward.

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