Wood-steel hybrid components

Abstract

To provide a wood-steel hybrid member securing fire resistance efficiency of a wood plugged part.SOLUTION: A wood-steel hybrid member 10 comprises: a steel frame member 12; wooden covering materials 14 provided on both outer sides of the steel frame member 12; and rod-like fixing members 16 screwed from through-holes 40 penetrating through one wooden covering material 14 to the other wooden covering material 14 through the steel frame member 12 for fixing the steel frame member 12 and the wooden covering materials 14. The through-holes 40 are buried with a refractory material 42 from end faces 32A of head parts 32 of the fixing members 16 arranged outside the steel frame member 12 to surfaces 14A of the wooden covering materials 14.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a wood-steel hybrid member made up of a wood member and a steel member. [Background technology]

[0002] Previously, the present patent applicant has developed composite members that combine steel frame members and wood members (see, for example, Patent Document 1). In particular, to ensure one-hour fire resistance, the applicant has developed a wood-steel hybrid beam, which is a structural member in which a steel beam is fire-resistantly covered with wood (hereinafter referred to as wood covering material) (see, for example, Patent Document 2). As shown in FIG. 1, after the wood covering material is fitted into an H-shaped steel beam, lag screws are driven from the web surface toward the wood covering material to integrate the steel beam and the wood covering material. The web is filled with the wood covering material. The thickness of the wood covering material is defined as the dimension from the flange surface or flange tip of the steel beam to the surface of the covering material. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-084037 [Patent Document 2] Patent Application No. 2020-148315 (currently unpublished) Summary of the Invention [Problem to be solved by the invention]

[0004] The wood covering material has holes for driving lag screws (hereinafter referred to as filler holes), and after the lag screws are installed, filler holes such as wooden plugs are driven into them to fill them. However, in the event of a fire, there is a concern that the areas where the filler has been installed may become weak points and burn, making it impossible to guarantee the specified fire resistance due to the following factors:

[0005] (1) If the length of the filler is short, the filler burns and carbonizes quickly during heating, accelerating the carbonization and red heat of the wood covering material and the rise in the temperature of the steel. (2) If the length of the filler is short, the gap between the steel and the filler acts as an insulating layer, making it difficult for heat to transfer from the filler side to the steel side, which promotes the combustion of the filler and causes it to burn out quickly. (3) At the boundary between the wood filler and the wood filler hole, heat penetrates through gaps that occur during construction or gaps that occur when the wood dries and shrinks during fire heating or cooling, causing the temperature of the steel around the wood filler to rise and the wood covering material to continue burning and remain red hot.

[0006] For this reason, there has been a demand for technology that can ensure the fire resistance of the filler wood parts in wood-steel hybrid components.

[0007] The present invention has been made in view of the above, and aims to provide a wood-steel hybrid member that ensures the fire resistance of the filler wood portion. [Means for solving the problem]

[0008] In order to solve the above-mentioned problems and achieve the object, the wood-steel hybrid member of the present invention is a wood-steel hybrid member comprising a steel frame member, wood covering materials provided on both outsides of the steel frame member, and a rod-shaped fixing member that passes through a through hole that passes through one of the wood covering materials, then passes through the steel frame member and is screwed into the other wood covering material to secure the steel frame member and the wood covering material, and is characterized in that the through hole is filled with fire-resistant material from the end face of the head of the fixing member placed on the outside of the steel frame member to the surface of the wood covering material.

[0009] Another wood-steel hybrid member according to the present invention is characterized in that, in the above-mentioned invention, the fire-resistant material is composed of one layer of filler wood or two or more layers of filler wood separated in the longitudinal direction of the through hole.

[0010] Another wood-steel hybrid member according to the present invention is characterized in that, in the above-mentioned invention, it further comprises an adhesive filled to seal gaps between the fire-resistant material and the through holes. [Effects of the Invention]

[0011] The wood-steel hybrid member of the present invention comprises a steel frame member, wood covering materials attached to both outsides of the steel frame member, and rod-shaped fixing members that pass through a through hole that penetrates one of the wood covering materials, then pass through the steel frame member and are screwed into the other wood covering material to secure the steel frame member and the wood covering material.The through hole is filled with fire-resistant material from the end face of the head of the fixing member placed on the outside of the steel frame member to the surface of the wood covering material, thereby achieving the effect of ensuring the fire resistance of the so-called buried wood portion.

[0012] In addition, according to another wood-steel hybrid component of the present invention, the fire-resistant material is composed of one layer of filler wood or two or more layers of filler wood separated in the longitudinal direction of the through hole, thereby achieving the effect of maintaining the design quality of the wood.

[0013] In addition, another wood-steel hybrid component according to the present invention further comprises an adhesive filled to seal the gap between the fire-resistant material and the through hole, thereby achieving the effect of preventing heat from entering through the gap. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a cross-sectional view showing an embodiment of a wood-steel hybrid member according to the present invention, where (1) is a general portion and (2) is a fastening portion. [Figure 2] Figure 2 shows a list of filler wood specifications. [Figure 3] Figure 3 shows a schematic diagram of the test specimen, where (1) is a cross-sectional view in the direction of the height, (2) is an elevation view from the non-heated side, and (3) is a cross-sectional view in the width direction. [Figure 4] Figure 4 shows the change in temperature of the unheated surface of the buried wood over time, where (1) is the top row of Figure 3, (2) is the middle row, and (3) is the bottom row. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, embodiments of the wood-steel hybrid member according to the present invention will be described in detail with reference to the drawings, although the present invention is not limited to these embodiments.

[0016] (wood-steel hybrid components) First, an embodiment of a wood-steel hybrid member according to the present invention will be described. As shown in FIG. 1(1), a wood-steel hybrid member 10 according to this embodiment includes a steel frame member 12 and wood covering materials 14 provided on both outer sides of the steel frame member 12.

[0017] As shown in FIG. 1(2), the steel frame members 12 and the wooden covering materials 14 are fixed together by a plurality of lag screws 16 (fixing members) arranged at predetermined intervals in the extension direction of the steel frame members 12 (direction perpendicular to the paper surface). The lag screws 16 are arranged so that the screwing direction of the lag screws 16 alternates in the extension direction of the steel frame members 12. This efficiently integrates the steel frame members 12 with the wooden covering materials 14 on both outer sides. In this embodiment, the wood-steel hybrid member 10 is used as a beam, and the cross-sectional dimensions of the beam are assumed to be, for example, approximately 350 to 1000 mm in height and approximately 150 to 300 mm in width, but the present invention is not limited to this.

[0018] The steel frame member 12 is an H-shaped steel beam having a web 18, an upper flange 20, and a lower flange 22. The flange width is assumed to be approximately 150 mm, the flange thickness is approximately 19 mm or more, and the web thickness is approximately 12 mm or more, but the present invention is not limited to this.

[0019] As shown in Figure 1(1), the wooden cladding material 14 is a laminated timber with a longitudinal rectangular cross section, which has a surface along the outer side of the web 18 and grooves 24 for inserting one side of the top flange 20 and one side of the bottom flange 22. The material of this laminated timber is assumed to be Japanese cypress, a species of wood-steel beam that ensures one-hour fire resistance. However, the present invention is not limited to this, and larch, for example, could also be used. The wooden cladding material 14 is in close contact with the upper surface 26 of the top flange 20 and the lower surface 28 of the bottom flange 22. Adhesive is applied to the contact surfaces 26, 28. To accommodate construction errors between the steel frame member 12 and the wooden cladding material 14, the steel frame member 12 and the wooden cladding material 14 are not in close contact with each other, but a thin layer of air 30 is provided between them. In addition, in Figure 1, the top surface of the upper flange is also covered with laminated timber, resulting in a four-sided covering, but it may also be a three-sided covering specification in which a floor plate (for example, a concrete slab or ALC plate) is placed on the top surface of the upper flange and the sides and the underside of the lower flange are covered.

[0020] As shown in Figure 1(2), the lag screw 16 is a metal rod-shaped body having a plate-shaped head 32 and a shaft-shaped threaded portion 34. The threaded portion 34 has a pointed tip and is threaded on its outer surface. In the example of Figure 1(2), the lag screw 16 is screwed into the wood sheathing 14 through through holes 36 provided on the upper and lower sides of the web 18 within the same cross section of the wood-steel hybrid component 10. The head 32 is located on one side of the web 18, and the threaded portion 34 passes through the through hole 36 in the web 18 and is screwed into the wood sheathing 14 on the opposite side.

[0021] A washer 38 made of a plate is provided between the right side of the web 18 and the wooden cladding material 14, and the screw portion 34 is inserted into the washer 38. The steel frame member 12 and the wooden cladding material 14 are connected via the washer 38, and any installation errors between the steel frame member 12 and the wooden cladding material 14 can be absorbed by cutting the wooden cladding material 14 in the area of ​​the washer 38. This improves workability.

[0022] The left-hand wood covering material 14 has a circular plug hole 40 (through hole) for attaching the lag screw 16 to the web 18. This plug hole 40 is filled with a cylindrical plug 42 (fire-resistant material) after the lag screw 16 is tightened. The length of the plug 42 is the length from the end face 32A of the head 32 of the lag screw 16 to the surface 14A of the wood covering material 14. This ensures the fire resistance of the plug portion.

[0023] The wood filler 42 can be made of the same type of wood (hiba) or high-density wood (larch) as the wood covering material 14, or it can be made of inorganic materials (for example, reinforced gypsum board). This has been verified in a heating test, as described below, to confirm its fire resistance.

[0024] Furthermore, to prevent gaps from forming at the boundary between the plug 42 and the plug hole 40, adhesives such as vinyl acetate resin adhesives or calcium carbonate adhesives, or fire door sealants may be filled in. This prevents heat from entering through gaps that form at the boundary between the plug 42 and the plug hole 40. Other organic or inorganic adhesives may also be used.

[0025] The filler 42 may have any structure as long as it fills the filler hole 40 to the length that contacts the head 32 of the lag screw 16. For example, it may be composed of a single layer of filler 42 as shown in the example in the figure, or it may be composed of two or more separate layers along the length of the filler hole 40. The advantage of using two or more layers of filler 42 is that it allows for design consideration. That is, by providing a thin layer (e.g., approximately 15 mm) of finishing filler (finishing material) on the surface of the wood covering material 14, the presence of the filler 42 on the surface of the wood covering material 14 can be made less noticeable from a design perspective. Furthermore, a vinyl acetate resin adhesive that becomes transparent (semi-transparent) after drying and becomes less noticeable can be used as a filler to fill the gap between the filler 42 and the filler hole 40, taking design considerations into account.

[0026] According to this embodiment, after installing the lag screw 16 through the plug hole 40 in the wood covering material 14, the plug 42 is driven in long enough to contact the head 32 of the lag screw 16, ensuring sufficient thickness of the covering material around the plug and preventing the plug 42 from burning through. Also, by minimizing the gap between the steel material, such as the lag screw 16, and the plug 42, heat is transferred from the plug 42 side to the steel material side, suppressing a temperature rise in the plug 42 and preventing the plug 42 from burning through prematurely.

[0027] (Fire resistance verification) Next, an example of a test conducted to verify the fire resistance of this embodiment and the results thereof will be described.

[0028] In order to understand the appropriate specifications for filler wood to seal holes in wood covering materials that can achieve one-hour fire resistance, we placed filler wood of several specifications (specifications 1 to 6) in a small wall test specimen that replicated the side of a wood-steel hybrid beam, and conducted a heating test to verify one-hour fire resistance using a small wall furnace. The small wall test specimen was made of cypress laminated timber (height 1300mm x width 1300mm x thickness 150mm, density 0.52g / cm). 3 ) was used. A list of the specifications of the embedding wood installed in the small wall specimen is shown in Figure 2. As shown in Figure 2, embedding wood specifications 1 to 4 correspond to examples of the present invention, and embedding wood specifications 5 and 6 correspond to comparative examples. Also, a schematic diagram of the small wall specimen and the positions of the thermocouples is shown in Figure 3.

[0029] The small wall specimens were heated for one hour according to the standard heating curve specified in ISO 834, and then allowed to cool in the fireproof furnace after heating. During the test, the temperature of the unheated surface of each filler wood specification was measured with a thermocouple, and the fire resistance performance was compared and verified.

[0030] The unheated surface temperature for each plug specification is shown in Figure 4. The numbers following the "T-" in the legend indicate the thermocouple position code (see Figure 3). Codes 1, 2, 7, and 8 correspond to plug specification 3. Codes 3, 4, 9, 10, 15, and 16 correspond to plug specification 1. Codes 5 and 6 correspond to plug specification 2. Codes 11 and 12 correspond to plug specification 4. Codes 13 and 14 correspond to plug specification 6. Codes 17 and 18 correspond to plug specification 5. Figure 4(3) shows that when the plug length was the same as the coating thickness (80 mm in this test), the unheated surface temperature of the plug reached 450°C or higher within 12 hours of heating. However, when the plug length was set to the length up to the lag screw head (135 mm in this test), the unheated surface temperature of the plug remained below 100°C. Furthermore, if the filler length was sufficient (135 mm or more), the temperature trends were similar whether the filler was wood (cypress or larch) or gypsum board.

[0031] It was thought that heat might leak in through the gap between the wood filler and the wood filler hole, but if the wood filler is long enough (135mm or more) and the gap between the wood filler and the wood filler hole is filled with a sealant designated for fire doors, a vinyl acetate resin adhesive, or a calcium carbonate adhesive, it will not burn out even if it is left to cool for more than 11 hours after heating for one hour.

[0032] As explained above, the wood-steel hybrid member of the present invention is a wood-steel hybrid member comprising a steel frame member, wood covering materials provided on both outsides of the steel frame member, and rod-shaped fixing members which pass through a through hole that passes through one of the wood covering materials, then pass through the steel frame member and are screwed into the other wood covering material in order to secure the steel frame member and the wood covering material together; the through hole is filled with fire-resistant material from the end face of the head of the fixing member placed on the outside of the steel frame member to the surface of the wood covering material, so that the fire resistance of the so-called wood-filled portion can be ensured.

[0033] In addition, according to another wood-steel hybrid component of the present invention, the fire-resistant material is composed of one layer of filler wood or two or more layers of filler wood separated in the length direction of the through hole, so that the design of the wood can be maintained.

[0034] In addition, another wood-steel hybrid component according to the present invention further includes an adhesive filled to seal the gap between the fire-resistant material and the through hole, thereby preventing heat from entering through the gap. [Industrial Applicability]

[0035] As described above, the wood-steel hybrid member according to the present invention is useful as a structural member such as a pillar or beam in a building, and is particularly suitable for ensuring the fire resistance of the wood filler portion. [Explanation of symbols]

[0036] 10 Wood-steel hybrid components 12 Steel members 14 Wood cladding 14A surface 16 Lag screw (fixation component) 18 Web 20 Upper flange 22 Lower flange 24 groove 26,28 Adhesive surface 30 layers 32 Head 32A end face 34 Threaded section 36 through holes 38 Washer 40 Buried hole (through hole) 42 Buried wood (fireproof material)

Claims

[Claim 1] A wood-steel hybrid member comprising a steel frame member, wood covering materials provided on both outsides of the steel frame member, and a rod-shaped fixing member that penetrates one of the wood covering materials through a through hole that penetrates the steel frame member and is screwed into the other wood covering material to fix the steel frame member and the wood covering material, The through-hole is filled with a fire-resistant material from the end face of the head of the fixing member arranged on the outside of the steel frame member to the surface of the wood covering material, The fireproof material further includes an adhesive filled to fill a gap between the fireproof material and the through hole, The fire-resistant material is composed of two layers of material separated in the length direction of the through hole, A wood-steel hybrid member characterized in that the material is a finishing wood piece placed on the surface side of the wood covering material and a reinforced gypsum board placed between this wood piece and the end face of the head of the fixing member.

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