Wooden structural member and construction method of wooden structural member

Abstract

To provide a wooden structural member and a construction method for the wooden structural member which allow the yield strength of a load support part of the wooden structural member to be maintained for a long time in the event of a fire.SOLUTION: A wooden column 10 is provided with a wooden load support part 20 in a rectangular cross section; first fireproof plates 30 each of which includes crystal water and is fixed on the outer side of the load support part 20; and metal material 70 fixed over end parts 32 of adjacent first fireproof plates 30.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a wooden structural member and a construction method of the wooden structural member.

Background Art

[0002] Patent Document 1 discloses a technique related to a wooden free-standing column used by being attached to the outside of a building. In this prior art, at each corner of the wooden free-standing column, by meshing the meshing notches of a pair of adjacent wooden decorative boards with a gap therebetween, four wooden decorative boards can be detachably attached to the structural column in any order and in a state where the restraint is relaxed, while maintaining a ventilation space between them and covering the entire circumference thereof integrally.

[0003] Patent Document 2 discloses a technique related to a wooden structural member having a load-bearing portion made of wood in a cross section and a fireproof coating portion formed of wood around the load-bearing portion. In this prior art, the fireproof coating portion is composed of a heat-insulating wood layer, a blocking air layer, and a charring allowance wood layer, and the heat-insulating wood layer, the blocking air layer, and the charring allowance wood layer are laminated in order from the load-bearing portion toward the outside.

[0004] Patent Document 3 discloses a technique related to a fireproof structure used as a building material. In this prior art, the fireproof structure includes a support wood for supporting a load and a non-combustible wood disposed outside the support wood so that the support wood is not exposed. And the non-combustible wood is formed by connecting a plurality of blocks to each other and is replaceable with respect to the support wood.

[0005] Patent Document 4 discloses a technique related to improving the fire resistance performance while ensuring the appearance and facilitating the design of structural strength in wooden building members such as columns and beams that construct the framework of wooden buildings. In this prior art, the wooden building member is composed of a long and rectangular cross-section structural part that bears a load, a covering part that covers the four sides of the cross-section of the structural part over its entire length, and a gypsum board that is interposed in layers between the structural part and the covering part to prevent the load acting on the structural part from being transmitted to the covering part.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0007] When a fire-resistant board containing crystal water is fixed outside the load-bearing part of a wooden structural member to maintain the strength of the load-bearing part during a fire, if the end of the fire-resistant board opens or the fire-resistant board falls off, there is a risk that the strength of the load-bearing part cannot be maintained for a long time.

[0008] In view of the above facts, an object of the present invention is to maintain the strength of the load-bearing part of a wooden structural member for a long time during a fire.

Means for Solving the Problems

[0009] The first aspect is a wooden structural member including a wooden load-bearing part having a rectangular cross-section, a first refractory board material containing crystal water fixed to the outside of the load-bearing part, and hardware fixed across the ends of the adjacent first refractory board materials.

[0010] In the wooden structural member of the first aspect, in the event of a fire, the temperature of the first refractory board material stagnates near 100°C due to heat absorption caused by the evaporation of crystal water. Therefore, it is possible to prevent the temperature from reaching about 260°C at which the wooden load-bearing part carbonizes until all the crystal water evaporates. In addition, the hardware fixed across the ends of the first refractory board material prevents the opening or dropping off of the ends of the first refractory board material, so that the temperature stagnation effect of the first refractory board material is maintained for a long time. Therefore, in the event of a fire, the load-bearing capacity of the load-bearing part of the wooden structural member is maintained for a long time.

[0011] The second aspect is the wooden structural member according to the first aspect, further including a second refractory board material that is disposed outside the first refractory board material and the hardware and fixed to the hardware, and having higher heat resistance than the first refractory board material, and a wooden board material fixed to the outside of the second refractory board material.

[0012] In the wooden structural member of the second aspect, in the event of a fire, the second refractory board material has higher heat resistance than the first refractory board material and is less likely to crack, etc., so that the heat insulation performance can be maintained for a long time. Therefore, the temperature stagnation effect of the first refractory board material is sustained for a long time. In addition, the wooden board material forms a carbonized layer with a heat insulation effect by carbonizing due to combustion, thereby reducing the fire heat entering the interior. Therefore, in the event of a fire, the load-bearing capacity of the load-bearing part of the wooden structural member is maintained for a long time.

[0013] The third aspect is the wooden structural member according to the second aspect, wherein the first refractory board material is fixed by a first screw driven into the hardware, the first refractory board material, and the load-bearing part, the second refractory board material is fixed by a second screw driven into the second refractory board material, the hardware, and the first refractory board material, and the wooden board material is fixed by a third screw driven into the wooden board material, the second refractory board material, the hardware, and the first refractory board material.

[0014] In the wooden structural member of the third aspect, since the first fireproof board, the second fireproof board, and the wooden board are fixed with the first screw, the second screw, and the third screw, it is excellent in easy disassembling property as compared with the case of adhesive bonding.

[0015] Therefore, when the wooden board is damaged after a fire, the wooden board can be removed and replaced by removing the third screw. Similarly, when the wooden board and the second fireproof board are damaged, the third screw and the second screw can be removed to remove and replace the wooden board and the second fireproof board. When the wooden board, the second fireproof board, and the first fireproof board are damaged, the third screw, the second screw, and the first screw can be removed to remove and replace the wooden board, the second fireproof board, and the first fireproof board.

[0016] The fourth aspect is a construction method of a wooden structural member including a step of fixing a first fireproof board containing crystal water disposed outside to a wooden load support portion having a rectangular cross section, and a metal member disposed across an end portion of the adjacent first fireproof board to the load support portion; a step of building the load support portion to which the first fireproof board and the metal member are fixed; a step of disposing a second fireproof board having higher heat resistance than the first fireproof board outside the first fireproof board and the metal member, and driving a screw into the second fireproof board, the metal member, and the first fireproof board to fix the second fireproof board; and a step of disposing a wooden board outside the second fireproof board, and driving a screw into the wooden board, the second fireproof board, the metal member, and the first fireproof board to fix the wooden board.

[0017] In the construction method of the wooden structural member of the fourth aspect, a first fireproof board containing crystal water disposed outside and a metal member disposed across an end portion of the adjacent first fireproof board are fixed to a wooden load support portion having a rectangular cross section.

[0018] The steps up to this point are performed, for example, at a factory or the like other than the construction site, and the load support portion to which the first fireproof board and the metal member are fixed is transported to the construction site and built. At this time, damage to the first fireproof board during transportation from the factory or the like to the construction site or during building is prevented or suppressed by the metal member.

[0019] And by fixing and finishing the second refractory board and the wooden board with screws, the workability is improved as compared with the case where all are constructed on site.

Advantages of the Invention

[0020] According to the present invention, at the time of a fire, the bearing strength of the load supporting part of the wooden structural member can be maintained over a long period of time.

Brief Description of the Drawings

[0021]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Modes for Carrying Out the Invention

[0022] <Embodiment> A wooden column as an example of a wooden structural member according to an embodiment of the present invention will be described. Here, two orthogonal directions in the horizontal direction are defined as the X direction and the Y direction, and are indicated by arrow X and arrow Y, respectively. Further, the vertical direction orthogonal to the X direction and the Y direction is defined as the Z direction, and is indicated by arrow Z.

[0023] As shown in FIGS. 1, 2, and 3, a wooden column 10 as an example of a wooden structural member includes a load support portion 20, a first fire-resistant board 30, metal fittings 70, a second fire-resistant board 40, and a wooden board 50. Note that a portion composed of the load support portion 20, the first fire-resistant board 30, and the metal fittings 70 in the wooden column 10 is defined as a prefabricated portion 100 (see FIG. 4).

[0024] Also, the layer composed of the first fire-resistant board 30 is defined as a first fire-resistant layer 110, the layer composed of the second fire-resistant board 40 is defined as a second fire-resistant layer 120, and the layer composed of the wooden board 50 is defined as a covering layer 130. Therefore, from another perspective, the wooden column 10 is composed of a load support portion 20, a first fire-resistant layer 110, a second fire-resistant layer 120, and a covering layer 130.

[0025] The load support portion 20 is a wooden rectangular columnar member with a rectangular cross-section. Also, the load support portion 20 in the present embodiment is composed of glued laminated timber, but is not limited thereto. It may be other woods, Laminated Veneer Lumber (LVL), sawn timber, solid wood, etc. Also, as tree species, larch, white pine, redwood, whitewood, hinoki, cedar, etc. can be used.

[0026] Note that glued laminated timber, LVL, and sawn timber have their structural grades indicated in JAS as building structural members, so structural calculations are easy. Also, from the viewpoints of utilization of small-diameter logs and yield, etc., the wood resources are effectively utilized for glued laminated timber and LVL.

[0027] The first fire-resistant board 30 is a board containing crystal water and is fixed to the outside of the load support portion 20. The first fire-resistant board 30 containing crystal water in the present embodiment is composed of reinforced gypsum board. In the present embodiment, since two sheets of the first fire-resistant board 30 made of reinforced gypsum board with a thickness of 21 mm are used, the thickness of the first fire-resistant layer 110 is 42 mm. Note that gypsum board is a building material made by forming a material mainly composed of gypsum into a plate shape. Also, gypsum contains a large amount of crystal water, and when exposed to fire or heat, this water is released into the air as steam while absorbing heat.

[0028] Note that the thickness of the first refractory layer 110 is not limited to 42 mm, but is preferably 20 mm or more. Also, in the first refractory layer 110, two first refractory plates 30 are stacked to form it, but it is not limited thereto. One first refractory plate 30 may be used, or three or more may be stacked.

[0029] Also, the first refractory plate 30 may be a plate containing crystal water, and may be a gypsum-based board material other than the reinforced gypsum board, or a board material other than the gypsum-based one. Note that the first refractory plate 30 preferably contains more crystal water than the second refractory plate 40 described later.

[0030] As shown in FIG. 3, in the present embodiment, the corners of the end portions 32 of the first refractory plates 30 that form the corners 112 of the first refractory layer 110 are chamfered. Note that reference numeral 34 indicates the chamfered portion. Also, the chamfering in the present embodiment is R chamfering, but it may be C chamfering.

[0031] As shown in FIGS. 1, 2, 3, and 4, the metal fitting 70 is composed of an L-shaped angle formed by bending a steel plate. As shown in FIG. 2, the metal fitting 70 has a length extending over the entire Z direction of the wooden column 10. Also, as shown in FIG. 3, since the metal fitting 70 of the present embodiment is manufactured by bending a steel plate as described above, it has a rounded corner 72.

[0032] As shown in FIGS. 1, 2, 3, and 4, the metal fitting 70 is fixed across the end portions 32 of the adjacent first refractory plates 30 at the corner 112 of the first refractory layer 110. As shown in FIGS. 1, 3, and 4, a first screw 210 is driven into the metal fitting 70, and the tip portion 212 of the first screw 210 reaches the load support portion 20.

[0033] Therefore, the metalware 70 is fixed to the load support portion 20 by the first screws 210 driven into the metalware 70, the two first refractory plates 30, and the load support portion 20, and the first refractory plates 30 are fixed to the load support portion 20 by the fixed metalware 70. In this embodiment, the two first refractory plates 30 are fastened to the load support portion 20 with screws (not shown) at a location different from the metalware 70.

[0034] In this embodiment, a heat-resistant paint is applied to the metalware 70 and the head 214 of the first screw 210, but it may not be applied.

[0035] In addition, in FIG. 2, the illustration of the first screw 210, the second screw 220, and the third screw 230, which will be described later, is omitted.

[0036] As shown in FIGS. 1, 2, 3, and 5, the second refractory plate 40 is disposed outside the first refractory plate 30 and the metalware 70. Therefore, the second refractory plate 40 covers the metalware 70 and the head 214 of the first screw 210 (see FIGS. 1, 3, and 5).

[0037] The second refractory plate 40 is made of a material having higher heat resistance than the first refractory plate 30. In this embodiment, it is a calcium silicate board with a thickness of 35 mm made of zonalite-based calcium silicate as the material. Therefore, the thickness of the second refractory layer 120 is 35 mm. Note that the thickness of the second refractory layer 120 is not limited to 35 mm, but it is preferably 35 mm or more. Also, in the second refractory layer 120, the second refractory plates 40 are not stacked, but this is not limiting. The second refractory plates 40 may be stacked and configured. The calcium silicate board is a refractory cladding board produced by adding water to a siliceous raw material and a calcareous raw material to form a slurry, supplying it to an autoclave with a stirrer, performing a hydrothermal synthesis reaction at high temperature and high pressure to generate a calcium silicate hydrate slurry, mixing reinforcing fibers, and drying it after press molding. The calcium silicate board has excellent heat resistance (heat resistant temperature is 1000 ℃ or higher) and is used for refractory coating materials, refractory walls (partition walls, outer walls), etc. The calcium silicate board also contains crystal water, but the amount is less than that of gypsum board.

[0038] As shown in FIGS. 1, 3, and 5, second fireproof plates 40 are driven with second screws 220. The second screws 220 penetrate the metalware 70, and the tip portions 212 reach the first fireproof plates 30. Note that the second screws 220 do not reach the load support portion 20. Thus, in the present embodiment, the second fireproof plates 40 are fixed to the metalware 70 and the first fireproof plates 30 by the second screws 220. Note that the second screws 220 are more firmly fixed to the metalware 70 than to the first fireproof plates 30. Thus, substantially, the second fireproof plates 40 are fixed to the metalware 70.

[0039] Also, the second fireproof plates 40 may be plates having higher heat resistance than the first fireproof plates 30. For example, they may be autoclaved lightweight aerated concrete (ALC). Note that "heat resistance" is the property of maintaining physical properties. In the present embodiment, since the second fireproof plates 40 have higher heat resistance than the first fireproof plates 30, the second fireproof plates 40 can maintain their physical properties at higher temperatures. Thus, for example, even at a temperature at which the first fireproof plates 30 crack or bend, the second fireproof plates 40 do not crack or bend, or if they do, the degree is small.

[0040] As shown in FIGS. 1, 2, and 3, the wooden plates 50 are fixed to the outside of the second fireproof plates 40. In the present embodiment, since the wooden plates 50 are made of 20-mm plates, the thickness of the coating layer 130 is 20 mm. Note that the thickness of the coating layer 130 is not limited to 20 mm, but desirably is 16 mm or more, and more desirably 20 mm or more. Also, in the coating layer 130, the wooden plates 50 are not configured by being stacked, but the coating layer 130 is not limited thereto. The coating layer 130 may be configured by stacking a plurality of wooden plates 50.

[0041] Note that although the wood-based board 50 in the present embodiment is made of glued laminated wood, it is not limited thereto. It may be other types of wood such as solid wood, Laminated Veneer Lumber (LVL), sawn timber, plywood, and solid wood. Further, as tree species, larch, spruce, redwood, whitewood, cypress, and cedar are used. In the present embodiment, the surface 52 of the wood-based board 50 is the outer peripheral surface of the wooden column 10 and is a design surface.

[0042] As shown in FIGS. 1 and 3, a third screw 230 is driven into the wood-based board 50. The third screw 230 penetrates the second fireproof board 40 and the metal fitting 70, and the tip portion 232 reaches the first fireproof board 30. Note that the third screw 230 does not reach the load support portion 20. Thus, in the present embodiment, the wood-based board 50 is fixed to the second fireproof board 40, the metal fitting 70, and the first fireproof board 30 by the third screw 230. Note that the third screw 230 is more firmly fixed to the metal fitting 70 than to the second fireproof board 40 and the first fireproof board 30. Thus, substantially, the wood-based board 50 is fixed to the metal fitting 70.

[0043] As shown in FIG. 3, in the present embodiment, a countersink 55 is formed on the surface 52 of the wood-based board 50, and the third screw 230 is driven into the countersink 55. After driving the third screw 230, the countersink 55 is filled with a wooden plug 56. Thus, the head 234 of the third screw 230 in the present embodiment is not exposed.

[0044] Note that when a plurality of wood-based boards 50 are stacked with the coating layer 130, the head 234 of the third screw 230 may be positioned between the wood-based boards 50 and the wood-based boards 50. Alternatively, the head 234 of the third screw 230 may be exposed. Further, in the present embodiment, as described above, the surface 52 of the wood-based board 50 is a design surface, but a decorative board, wallpaper, or the like constituting the design surface may be pasted on the surface 52 of the wood-based board 50.

[0045] In addition, the first screw 210, the second screw 220, and the third screw 230 in this embodiment are screws of the same specification, differing only in the driving location. However, the screw specifications may be changed depending on the driving location.

[0046] Also, the intervals (pitches) in the X, Y, and Z directions of the first screw 210, the second screw 220, and the third screw 230 in this embodiment are 300 mm, but it is not limited thereto. However, the intervals (pitches) in the X, Y, and Z directions of the first screw 210, the second screw 220, and the third screw 230 are desirably 300 mm or less.

[0047] (Construction method) Next, an example of the construction method of the wooden column 10 will be described.

[0048] First, a prefabricated part 100 composed of the load support part 20, the first fireproof board 30, and the metal fittings 70 in the wooden column 10 shown in FIG. 4 is fabricated. In this embodiment, the prefabricated part 100 is fabricated at a location separate from the construction site, for example, at a factory.

[0049] At a factory or the like, the first fireproof board 30 is overlapped on the peripheral surface of the wooden load support part 20 and temporarily fixed with screws (not shown). Metal fittings 70 are provided at the corners 112 of the first fireproof layer 110, and the first fireproof board 30 is fixed to the load support part 20 with the first screws 210. In this embodiment, the two first fireproof boards 30 are also fastened to the load support part 20 with screws (not shown) at a location separate from the metal fittings 70.

[0050] This prefabricated part 100 is transported to the construction site and erected at the installation position. Then, as shown in FIG. 5, after the second fireproof board 40 is fixed with the second screws 220, as shown in FIG. 1, the wooden board 50 is fixed with the third screws 230 to complete the work.

[0051] (Response after a fire) Next, the response after a fire occurs will be described.

[0052] When only the wooden board 50 is damaged by a fire, remove the third screw 230, replace the wooden board 50, and fix it with a new third screw 230.

[0053] When the wooden board 50 and the second fireproof board 40 are damaged by a fire and the first fireproof board 30 is not damaged, remove the third screw 230 and the second screw 220, replace the wooden board 50 and the second fireproof board 40, and fix them with new third screw 230 and second screw 220.

[0054] When the wooden board 50, the second fireproof board 40 and the first fireproof board 30 are damaged by a fire and the load support part 20 is not damaged, remove the third screw 230, the second screw 220 and the first screw 210, replace the wooden board 50, the second fireproof board 40 and the first fireproof board 30, and fix them with new metal fittings 70, the first screw 210, the second screw 220 and the third screw 230.

[0055] (Replacement of wooden board) Next, the replacement of the wooden board will be described.

[0056] It is possible to replace only the wooden board 50 due to aging deterioration, renovation, etc. Specifically, remove the third screw 230 as in the case after a fire and replace the wooden board 50. Since the replaced old wooden board 50 has no damage or little damage, it can be used as it is or processed for other purposes, such as materials for furniture, etc.

[0057] (Function and effect) Next, the function and effect of this embodiment will be described.

[0058] In the case of a fire, in the wooden column 10, the first fireproof board 30 has a temperature stagnation at around 100 °C due to heat absorption by the evaporation of the crystal water. Therefore, it is possible to prevent the temperature of the wooden load support part 20 from reaching about 260 °C at which carbonization occurs until all the crystal water evaporates.

[0059] In addition, since the metal fittings 70 fixed across the end of the first refractory plate 30 prevent the opening or dropping off of the end 32 of the first refractory plate 30, the temperature stagnation effect of the first refractory plate 30 is maintained over a long period of time.

[0060] Further, the second refractory plate 40 has higher heat resistance than the first refractory plate 30 and is less likely to crack or bend, so that the heat insulation performance can be maintained over a long period of time. Therefore, the temperature stagnation effect of the first refractory plate 30 is sustained over a long period of time.

[0061] In addition, the wooden plate 50 forms a carbonized layer having a heat insulation effect on the coating layer 130 by carbonizing due to combustion, thereby reducing the heat of the fire that penetrates inside.

[0062] Therefore, at the time of a fire, the load-bearing capacity of the load support portion 20 of the wooden column 10 is maintained over a long period of time.

[0063] Note that the tip 232 of the third screw 230 and the tip 222 of the second screw 220 do not reach the load support portion 20. Therefore, heat transfer to the load support portion 20 via the third screw 230 and the second screw 220 is prevented.

[0064] In addition, the metal fittings 70 and the head 214 of the first screw 210 are covered with the second refractory plate 40. Therefore, heating of the metal fittings 70 and the head 214 of the first screw 210 is suppressed from being transferred to the load support portion 20 via the first screw 210. Further, since the metal fittings 70 and the head 214 of the first screw 210 of the present embodiment are coated with a heat-resistant paint, an increase in the temperature of the metal fittings 70 and the head 214 of the first screw 210 is suppressed. Therefore, heat transfer to the load support portion 20 via the first screw 210 is further suppressed. That is, the amount of heat received by the load support portion 20 due to the heat bridge via the first screw 210 is suppressed. Note that the metal fittings 70 and the head 214 of the first screw 210 may not be coated with a heat-resistant paint.

[0065] In addition, by applying a heat-resistant paint to the metalware 70, it is possible to suppress the amount of heat received from the corners of the load support portion 20 that is heated from both sides.

[0066] Further, since the wooden column 10 has the first fireproof board 30, the second fireproof board 40, and the wooden board 50 fixed by the first screw 210, the second screw 220, and the third screw 230, it is excellent in easy disassembling property compared to the case of adhesive bonding.

[0067] Therefore, when the wooden board 50 is damaged after a fire, the third screw 230 can be removed and the wooden board 50 can be replaced. Similarly, when the wooden board 50 and the second fireproof board 40 are damaged, the second screw 220 and the third screw 230 can be removed and the wooden board 50 and the second fireproof board 40 can be replaced. When the wooden board 50, the second fireproof board 40, and the first fireproof board 30 are damaged, the third screw 230, the second screw 220, and the first screw 210 can be removed and the wooden board 50, the second fireproof board 40, and the first fireproof board 30 can be replaced.

[0068] In addition, in the case of aging deterioration, renovation, etc., the third screw 230 can be removed and the wooden board 50 can be replaced. Since the replaced old wooden board 50 has no damage or little damage, it can be used as it is or after processing for other uses, such as materials for furniture. Therefore, ultimately, the period until the wooden board 50 is crushed or made into fuel is extended, that is, the period of carbon fixation is extended, and the structure is environmentally excellent.

[0069] In addition, in the present embodiment, the previously fabricated portion 100 composed of the load support portion 20, the first fireproof board 30, and the metalware 70 in the wooden column 10 is fabricated outside the construction site, for example, in a factory, transported to the construction site, and erected. Therefore, damage to the first fireproof board 30 during transportation from a factory or the like to the construction site or during erection by the metalware 70 is prevented or suppressed. And by fixing the second fireproof board 40 and the wooden board 50 with the second screw 220 and the third screw 230 at the site for finishing, the workability is improved compared to the case where all the work is done at the site.

[0070] In addition, the end 32 of the first refractory plate member 30 located at the corner 112 of the first refractory layer 110 is chamfered. Therefore, although the hardware 70 is manufactured by bending a steel plate and has a rounded corner 72, the corner 72 and the end 32 of the first refractory plate member 30 do not interfere with each other. Therefore, the generation of a gap or unevenness between the hardware 70 and the end 32 of the first refractory plate member 30 is less likely to occur, and thus the manufacturing is easy.

[0071] (Fire resistance test) Next, the fire resistance test of the wooden column 10 will be described. The fire resistance test was carried out by heating according to the ISO834-1 standard heating curve. In addition, the head 234 of the third screw 230 was in an exposed state. Further, the head 234 of the third screw 230 and the hardware 70 were tested without applying a heat-resistant paint.

[0072] ·Fire resistance test results FIG. 7 is a graph showing the temperature change of each part in the fire resistance test.

[0073] In FIG. 7, (A) is the temperature at the boundary between the corner of the load support portion 20 and the corner of the first refractory layer 110 (first refractory plate member 30) as shown in FIG. 1. (B) is the temperature at the boundary between the side surface portion of the load support portion 20 and the side surface portion of the first refractory layer 110 (first refractory plate member 30). (C) is the temperature at the boundary between the hardware 70 provided at the corner 112 of the first refractory layer 110 (first refractory plate member 30) and the corner of the second refractory layer 120 (first refractory plate member 30). (D) is the temperature at the boundary between the side surface portion of the first refractory layer 110 (first refractory plate member 30) and the side surface portion of the second refractory layer 120 (first refractory plate member 30). (E) is the average temperature in the experimental furnace.

[0074] As can be seen from the graph of FIG. 7, the heating time is 180 minutes (3 hours). And as in (A) and (B), the load support portion 20 is maintained at a temperature of about 260 ° C or less at which the wood carbonizes, both at the corner and the side surface portion, even after 3 hours, and it can be seen that it has a fire resistance performance of 3 hours.

[0075] Note that the temperature of the corner of the load support portion 20 in (B) rises to nearly about 200 ° C after the heating is completed.

[0076] · Thickness of the coating layer 130 composed of the wood-based board 50 The relationship between the thickness of the wood-based board 50 (coating layer 130) and the fire resistance performance will be described. Note that the thicknesses of the first fire-resistant layer 110 and the second fire-resistant layer 120 and other conditions are the same as those in the aforementioned fire resistance test.

[0077] Fig. 6 is a graph showing the relationship between the thickness of the wood-based board 50 (coating layer 130) fixed by the third screw 230 in the fire resistance test of the wooden column 10 and the falling-off time of the wood-based board 50.

[0078] From the graph of Fig. 6, if the thickness of the wood-based board 50 (coating layer 130) is about 24 mm or more, the wood-based board 50 will not fall off for about 25 minutes. As described above, in the wooden column 10 of the present embodiment having the 35-mm second fire-resistant layer 120 and the 42-mm first fire-resistant layer 110, when the wood-based board 50 does not fall off for 25 minutes, it has a fire resistance performance of 3 hours. Note that when the thickness of the wood-based board 50 is less than 24 mm, it is possible to ensure the fire resistance performance of 3 hours by increasing the thickness of the first fire-resistant layer 110 or the second fire-resistant layer 120 due to the decrease in the heat insulation effect of the wood-based board 50.

[0079] · Thickness of the second fire-resistant layer 120 composed of the second fire-resistant board 40 The relationship between the thickness of the second fire-resistant board 40 (second fire-resistant layer 120) and the fire resistance performance will be described. Note that the first fire-resistant layer 110, the coating layer 130, and other conditions are the same as those in the aforementioned fire resistance test.

[0080] When the thickness of the second fire-resistant board 40 (second fire-resistant layer 120) is greater than 0 mm and 5 mm or less, it has a fire resistance performance of 1 hour. Note that even in the case of a wooden column where the thickness of the second fire-resistant board 40 (second fire-resistant layer 120) is 0 mm, that is, the second fire-resistant board 40 (second fire-resistant layer 120) is not provided, it also has a fire resistance performance of 1 hour.

[0081] When the thickness of the second fire-resistant board 40 (second fire-resistant layer 120) is 15 mm or more and 20 mm or less, it has a fire resistance performance of 2 hours.

[0082] When the thickness of the second refractory board 40 (second refractory layer 120) is 35 mm or more and 40 mm or less, it has a fire resistance performance of 3 hours.

[0083] <Others> In addition, the present invention is not limited to the above embodiments.

[0084] For example, in the above embodiment, an example of the wooden structural member to which the present invention is applied was the wooden column 10, but it is not limited thereto. The wooden structural member to which the present invention is applied can also be applied to braces, wooden beams, etc. Note that FIG. 8 is an example in which the present invention is applied to a wooden beam 11. The wooden beam 11 does not have the first refractory layer 110, the second refractory layer 120, and the coating layer 130 on the upper surface side, and a slab 90 supported by the wooden beam 11 is provided.

[0085] Also, for example, in the above embodiment, the first refractory board 30, the metal fittings 70, the second refractory board 40, and the wooden board 50 were fixed with the first screw 210, the second screw 220, and the third screw 230, but it is not limited thereto. The first refractory board 30, the metal fittings 70, the second refractory board 40, and the wooden board 50 may be fixed by any method.

[0086] However, a method excellent in easy disassembly is preferable. Examples of methods excellent in easy disassembly include bolts, disassembly adhesives such as microcapsule-mixed adhesives and electrically conductive peelable adhesives, disassembly adhesives such as shear peel tapes and ultraviolet peel tapes, and biomimetic joining members such as hook-and-loop fasteners.

[0087] Also, the previously fabricated part 100 composed of the load support part 20, the first refractory board 30, and the metal fittings 70 is an adhesive joint that does not consider easy disassembly in consideration of transportation, and the first refractory board 30 and the wooden board 50 may be fixed by a method excellent in easy disassembly.

[0088] The wooden column 10 as an example of the wooden structural member was configured to have the load support part 20, the first refractory board 30, the metal fittings 70, the second refractory board 40, and the wooden board 50, but it is not limited thereto. At least, it may be configured to have the load support part 20, the first refractory board 30, and the metal fittings 70.

[0089] Furthermore, it can be implemented in various modes without departing from the gist of the present invention.

Explanation of Signs

[0090] 10 Wooden column (an example of a wooden structural member) 11 Wooden beam (an example of a wooden structural member) 20 Load support part 30 First fireproof board 32 End part 40 Second fireproof board 50 Wooden board 70 Hardware 210 First screw 220 Second screw 230 Third screw

Claims

1. a wooden load-bearing part having a rectangular cross-section; a first refractory board containing crystal water fixed to the outside of the load-bearing part; hardware fixed across the ends of the adjacent first refractory boards; a second refractory board disposed outside the first refractory board and the hardware and fixed to the hardware, the second refractory board having higher heat resistance than the first refractory board; a wooden board fixed to the outside of the second refractory board; comprising; the first refractory board is fixed by a first screw driven into the hardware, the first refractory board, and the load-bearing part; the second refractory board is fixed by a second screw driven into the second refractory board, the hardware, and the first refractory board and not reaching the load-bearing part; a wooden structural member.

2. The wooden board is fixed by a third screw driven into the wooden board, the second refractory board, the hardware, and the first refractory board. The wooden structural member according to Claim 1.

3. The first refractory board is composed of a gypsum board, The second refractory board is composed of a calcium silicate board. The wooden structural member according to Claim 1 or Claim 2.

4. A step of fixing a first refractory board containing crystal water disposed outside a wooden load-bearing part having a rectangular cross-section and hardware disposed across the ends of the adjacent first refractory boards to the load-bearing part; a step of building in the load-bearing part to which the first refractory board and the hardware are fixed; a step of disposing a second refractory board having higher heat resistance than the first refractory board outside the first refractory board and the hardware, and driving screws into the second refractory board, the hardware, and the first refractory board to fix the second refractory board; a step of disposing a wooden board outside the second refractory board, and driving screws into the wooden board, the second refractory board, the hardware, and the first refractory board to fix the wooden board; A construction method of a wooden structural member comprising.

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