Fire-resistant joining structure of wooden structural member using joint metal fitting

Abstract

To provide a fire-resistant joint structure capable of effectively preventing the transmission of high heat to a frame structural material via a joint metal fitting in a case of fire by a simple constitution not inhibiting stress transmission in normal times.SOLUTION: A fire-resistant joint structure using joint metal fittings 20, 30 includes base plate parts 21, 31 and insertion fixing plate parts 22, 32, wherein the insertion fixing plate parts 22, 32 are inserted into and fixed to slit parts 41, 42 formed on an end surface of a load-bearing wall 50, and the base plate parts 21, 31 are fixed to lower surfaces 51a, 52a and upper surfaces 51b, 52b of beam members 51, 52, thereby joining the load-bearing wall 50 to surfaces 51a, 52a, 51b, and 52b to be joined. The joint metal fittings 20, 30 are fixed to the slit parts 41, 42 in a state where the insertion fixing plate parts 22, 32 are covered with a thermally expandable fire-resistant sheet or a thermally expandable fire-resistant paint.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a fire-resistant joint structure for wooden structural members using metal joints, and more particularly to a fire-resistant joint structure for wooden structural members using metal joints that join wooden structural members to the joining surfaces of other structural members. [Background technology]

[0002] The need to prevent global warming and restore forest resources and forestry is gaining attention, and the active use of wood materials is also being called for from the perspective of ESG investment and SDGs. Wood materials are a material that can be reused repeatedly, and it is desirable to reuse wood materials that have been used once as a sustainable resource. Furthermore, wood materials are lightweight compared to their strength and have a high specific strength (strength / density), which makes them advantageous for use as building structures. However, in order to be used as a construction material, it is necessary to resolve the issues of anisotropy and fire resistance.

[0003] Regarding anisotropy, since the physical properties of wood materials vary depending on the fiber direction, tangential direction, radial direction, etc., it is desirable to arrange the fiber direction, which has the greatest Young's modulus and strength, in the direction in which the main stress is applied. Also, during earthquakes and typhoons, the direction of stress changes randomly, so it is preferable to use cross-laminated timber (CLT) boards as wood materials for building structures, for example, by gluing multiple boards together so that the fiber directions are perpendicular, thereby eliminating any direction that could be a weak point.

[0004] Methods for improving the fire resistance of wood materials include surrounding the wood with fire-resistant materials and pre-installing a fire-resistant capacity in the wood material to ensure the necessary strength for a specified period of time. The former prevents the structural components from burning by surrounding them with non-combustible materials such as plasterboard. The latter involves calculating in advance the thickness (fire-resistant capacity) that will burn during a specified fire-resistance period and enlarging the cross-sectional shape of the wood material so that a cross-sectional area larger than the required cross-section to maintain its structural function remains unburned. Other techniques that have been developed include impregnating wood materials with chemicals to make them fire-resistant, and applying fire-resistant paint to the surface to protect the wood material inside.

[0005] On the other hand, various structures have been developed for such wooden materials, in which wooden structural materials, such as wooden shear walls, are joined via metal connecting hardware to structural frames made of steel, reinforced concrete, or wood beams and columns that form the framework that forms the main structural part of the building (see, for example, Patent Document 1 and Patent Document 2).

[0006] In the joining structures using the joining hardware described in Patent Documents 1 and 2, the joining hardware comprises a base plate portion that is joined to the joining surface of a framework structural material made of beam members or column members, and an insert and fastening plate portion that protrudes vertically from the base plate portion, for example, having an L-shaped or T-shaped cross-sectional shape.The base plate portion is joined to the joining surface of the framework structural material, and the insert and fastening plate portion is inserted into a slit formed by cutting into the end face of the wooden structural material, and is fixed to the wooden structural material by, for example, driving multiple drift pins into the side of the wooden structural material, thereby making it possible to join a wooden structural material, such as a wooden load-bearing wall, as a single unit to a framework structural material made of beam members or column members. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 2019-119990 [Patent Document 2] Japanese Patent Publication No. 2022-144037 Summary of the Invention [Problem to be solved by the invention]

[0008] When wooden structural members are joined to framework members using metal connecting hardware, if the wooden structural members burn due to flame heating during a fire, the connecting hardware will act as a thermal bridge, and the high heat generated during combustion will be transferred to the framework members through the connecting hardware, which may have a negative impact on the structural performance of the framework members made up of beams and columns.

[0009] To address this issue, one possible means of preventing the transfer of high heat to the frame structural members through the metal joints is to spray mortar or rock wool onto the areas where the metal joints contact the wooden structural members or the frame structural members to form a fire-resistant coating that acts as a heat sink or heat insulator. However, this spraying process is time-consuming and it is difficult to prevent the transfer of high heat through the insertion and fastening plates inserted into the slits formed in the wooden structural members. Another possible approach is to apply a fire-resistant coating of insulating boards or rock wool to the surfaces of the insertion and fastening plates of the metal joints, but this would increase the thickness of the bearing wall by the thickness of the fire-resistant coating and could hinder the transfer of stress between the wooden structural members and the frame structural members under normal conditions through the metal joints.

[0010] For these reasons, there is a need to develop a new fire-resistant joint structure that effectively blocks the transfer of high heat to the frame structural materials through the inserted and fixed plate portions of the joining metal fittings in the event of a fire, using a simple configuration that does not require much effort and does not hinder stress transfer under normal conditions, thereby preventing a deterioration in the structural performance of the frame structural materials due to heat.

[0011] The present invention aims to provide a fire-resistant joint structure for wooden structural materials using connecting hardware that has a simple configuration that does not hinder stress transmission under normal conditions, and that effectively prevents the transfer of high heat to the frame structural materials through the inserted and fixed plate portions of the connecting hardware in the event of a fire, thereby preventing a deterioration in the structural performance of the frame structural materials due to heat. [Means for solving the problem]

[0012] The present invention provides a fire-resistant joining structure for wooden structural materials using a joining hardware that includes a base plate portion and an insert / fix plate portion that protrudes vertically from the base plate portion, and that joins the wooden structural material to the joining surface of another structural material by inserting and fixing the insert / fix plate portion into a slit portion formed by cutting into the end face of the wooden structural material and fixing the base plate portion to the joining surface of the other structural material.The above-mentioned object has been achieved by providing a fire-resistant joining structure for wooden structural materials using a joining hardware in which at least the portion of the insert / fix plate portion that is inserted into the slit portion is covered with a heat-expandable fire-resistant sheet or heat-expandable fire-resistant paint, and the insert / fix plate portion is fixed to the slit portion.

[0013] Furthermore, in the fire-resistant joining structure of wooden structural materials using the joining hardware of the present invention, the wooden structural materials are installed inside a framework of column members and beam members, forming a load-bearing wall that, together with the column members and beam members, bears the stress generated during an earthquake, and it is preferable that the other structural materials to which the wooden structural materials are joined on their joining surfaces are beam members made of concrete, steel, or wood.

[0014] In addition, it is preferable that the fire-resistant joining structure of wooden structural materials using the joining metal of the present invention is made of a material in which the main material reacts at a temperature of 250 to 300°C due to the heat of a fire, expanding 20 to 30 times and forming a carbonized layer, at the heat of a fire, the heat-expandable fire-resistant sheet or heat-expandable fire-resistant paint.

[0015] Furthermore, in the fire-resistant joining structure of wooden structural materials using the joining metal fittings of the present invention, it is preferable that the main material of the heat-expandable fire-resistant sheet or heat-expandable fire-resistant paint is one that contains ammonium polyphosphate, ammonium phosphate, or melamine phosphate.

[0016] Furthermore, it is preferable that the fire-resistant joining structure of wooden structural materials using the joining hardware of the present invention has a solidifying material filled in the gap between the part of the insertion and fixing plate part covered with the heat-expandable fire-resistant sheet or heat-expandable fire-resistant paint inserted into the slit part and the slit part.

[0017] In addition, in the fire-resistant joining structure of wooden structural materials using the joining hardware of the present invention, it is preferable that the insertion and fixing plate portion of the joining hardware is fixed to the wooden structural material in a state where it is inserted into the slit portion using a drift pin.

[0018] Furthermore, it is preferable that the fire-resistant joining structure of wooden structural materials using the joining metal fittings of the present invention is filled with rock wool or mortar as a heat sink material, covering the base plate portion of the joining metal fittings. [Effects of the Invention]

[0019] According to the fire-resistant joining structure of wooden structural materials using the joining metal fittings of the present invention, with a simple configuration that does not hinder stress transmission under normal conditions, it is possible to effectively prevent the transfer of high heat to the frame structural materials through the inserted and fixed plate portions of the joining metal fittings in the event of a fire, thereby preventing a deterioration in the structural performance of the frame structural materials due to heat. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a schematic front view illustrating a fire-resistant joint structure for a wooden structural member according to a preferred embodiment of the present invention. [Figure 2] FIG. 2 is a schematic cross-sectional view taken along the line AA in FIG. [Figure 3] FIG. 2 is a schematic cross-sectional view taken along the line BB in FIG. [Figure 4]FIG. 4 is a schematic cross-sectional view taken along the line CC in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0021] As shown in Figure 1, a fire-resistant joint structure 10 for wooden structural materials according to a preferred embodiment of the present invention is a joint structure in which the upper and lower ends of a bearing wall 50, which is installed inside a framework consisting of a column member (not shown) as a framework structural material and an upper floor beam member 51 and a lower floor beam member 52, and which bears the stress generated during an earthquake together with the column members and beam members 51, 52, are joined together as a single unit using connecting metal fittings 20, 30 with the undersides 51a, 52a and upper surfaces 51b, 52b of the upper floor beam member 51 and the lower floor beam member 52, which are other structural materials, as the joining surfaces.Even if the bearing wall 50, which is a wooden structural material, burns due to flame heating during a fire, the connecting metal fittings act as a thermal bridge, preventing the high heat generated during combustion from being transmitted through the connecting metal fittings 20, 30 to the beam members 51, 52, which are the framework structural materials. The fire-resistant joint structure 10 of wooden structural materials in this embodiment has a simple configuration that does not hinder stress transmission between the load-bearing wall 50 and the upper floor side beam member 51 and the lower floor side beam member 52 under normal conditions, and when the load-bearing wall 50 burns in the event of a fire, it has the function of effectively preventing high heat from being transmitted from the load-bearing wall 50, which is a wooden structural material, to the beam members 51 and 52, which are frame structural materials, via the joint metal fittings 20 and 30, thereby allowing the thermal structural performance of the beam members 51 and 52 to continue to be maintained.

[0022] As shown in Figures 1 to 3, the fire-resistant joining structure 10 for wooden structural materials in this embodiment comprises base plate portions 21, 31 and insertable and fastening plate portions 22, 32 extending vertically from the base plate portions 21, 31, and the insertable and fastening plate portions 22, 32 are inserted and fastened into slit portions 41, 42 (see Figure 2) formed by cutting into the end face of a load-bearing wall 50, which is a wooden structural material, and the base plate portions 21, 31 are fastened to the lower surfaces 51a, 52a and upper surfaces 51b, 52b, which are the joining surfaces, of beam members 51, 52, which are other structural materials, thereby resulting in a joining structure using joining metal fittings 20, 30 that join the load-bearing wall 50, which is a wooden structural material, to the joining surfaces 51a, 52a, 51b, 52b. The joining hardware 20, 30 has the insertion and fixing plate portions 22, 32 fixed to the slit portions 41, 42 with at least the portions of the insertion and fixing plate portions 22, 32 that are inserted into the slit portions 41, 42 covered with a heat-expandable fire-resistant sheet or heat-expandable fire-resistant paint.

[0023] In this embodiment, the wooden structural members are installed inside a framework of columns (not shown) and beams 51, 52, as described above, to form a shear wall 50 that, together with the columns and beams 51, 52, bears the stress generated during an earthquake. The beams 51, 52, which are other structural members to which the shear wall 50 is joined at their bottom surfaces 51a, 52a and top surfaces 51b, 52b, are preferably formed as composite beams by a wooden beam 53 and a beam-equivalent portion (RC beam portion) 54 of a reinforced concrete slab (RC slab) supported by and formed above the wooden beam 53. The wooden beam 53 is integrally fixed to the underside of the RC beam 54, which is the beam-equivalent portion of the RC slab, using fasteners such as bolts (not shown). A wooden surface layer 53b is attached to cover the outer surface of the wooden beam 53, with, for example, two layers of fire-resistant covering material 53a, such as reinforced gypsum board, interposed between them (see FIG. 3).

[0024] In this embodiment, the thermally expandable fire-resistant sheet or the thermally expandable fire-resistant paint is preferably made of a material whose main material reacts with heat during a fire at a temperature of 250 to 300°C, expands 20 to 30 times, and forms a carbonized layer. The main material of the thermally expandable fire-resistant sheet or the thermally expandable fire-resistant paint is a compound containing ammonium polyphosphate, ammonium phosphate, or melamine phosphate.

[0025] A preferred example of a thermally expandable fireproof sheet is the product name "SK Taica Sheet" (registered trademark, manufactured by SK Kaken Co., Ltd.), which is a thermally foamable fireproof sheet described in JP 2020-143495 A. A preferred example of a thermally expandable fireproof paint is the product name "SK Taica Coat" (registered trademark, manufactured by SK Kaken Co., Ltd.), which is a fireproof paint described in JP 2022-187729 A. The "SK Taica Sheet" can be applied to the surface of steel materials with a thickness of, for example, about 1.5 to 3 mm. In the event of a fire, the main material expands 20 to 30 times, forming a carbonized layer, thereby protecting the steel material from fire. The "SK Taica Coat" can be applied to the surface of steel materials as a coating film with a thickness of, for example, about 1.0 to 2.5 mm. In the event of a fire, the main material expands 20 to 30 times, forming a carbonized layer, thereby protecting the steel material from fire.

[0026] In this embodiment, the bearing wall 50, which is a wooden structural material, is preferably formed from cross-laminated timber (CLT) boards with a thickness of about 150 mm, so as to have a vertically long rectangular front shape with a height of about 2800 mm and a width of about 1400 mm, as shown in Fig. 1. The bearing wall 50 is not limited to being made from CLT boards, but may also be made from parallel laminated timber, laminated veneer lumber (LVL), plywood, or the like.

[0027] When viewed from the front, both upper and lower ends of the bearing wall 50 are joined to a wooden beam 53 and an RC beam 54 via metal joints 20, 30. The metal joints 20, 30 consist of a central metal joint 20 located in the center of the width direction, and a pair of side metal joints 30 located on either side of the central metal joint 20 in the width direction.

[0028] When viewed from the front, the central joint metal 20 joins the center of the upper end of the bearing wall 50 to the wooden beam 53 located above it. When viewed from the front, the central joint metal 20 also joins the center of the lower end of the bearing wall 50 to the RC beam 54 located below it.

[0029] The central metal joint 20 comprises a base plate portion 21 fixed to a wooden beam 53 or a reinforced concrete beam portion 54, a flat central insertion fixing plate portion 22 extending from the base plate portion 21 in the wall surface direction (vertical direction) of the bearing wall 50, and protruding plate portions 23 (see FIG. 2) protruding from the sides of the insertion fixing plate portion 22 in both thickness directions (front and back directions) of the bearing wall 50. As described above, a heat-expandable fire-resistant sheet or heat-expandable fire-resistant paint is attached or painted to a thickness of, for example, about 1.0 to 3 mm on the surfaces of the insertion fixing plate portion 22 and the protruding plate portion 23, preferably so as to cover the entire surfaces.

[0030] The base plate portion 21 is made of a rectangular steel plate with multiple through holes formed therein. The insertion and fixing plate portion 22 is a rectangular steel plate extending upward or downward toward the bearing wall 50 to be joined, and is joined integrally to the base plate portion 21 by fixing one end face in the vertical direction to the center of the base plate portion 21 by welding or the like.

[0031] The protruding plate portions 23 are steel plates that protrude in both the front and rear directions from the side edges of the insertion and fixing plate portion 22, and are fixed by welding or the like to the left and right side edges of the insertion and fixing plate portion 22. As a result, the insertion and fixing plate portion 22 and the protruding plate portion 23 form an H-shape or an I-shape as a whole when viewed from above.

[0032] The insert fastening plate portion 22 and the protruding plate portion 23 may be integrated in advance to form an H-beam or an I-beam. The protruding plate portion 23 may be fixed by welding or the like to the center portion in the width direction on both the front and rear surfaces of the insert fastening plate portion 22, so that the insert fastening plate portion 22 and the protruding plate portion 23 form a cross shape as a whole when viewed from above. Furthermore, the protruding plate portions 23 may be provided on both the left and right side edges and the front and rear surfaces of the center of the insert fastening plate portion 22, so that the insert fastening plate portion 22 and the protruding plate portion 23 form a U shape as a whole when viewed from above.

[0033] The side joint metal 30 comprises a base plate portion 31 fixed to a wooden beam 53 or a reinforced concrete beam portion 54, and a flat insert fixing plate portion 32 extending from the base plate portion 31 in the wall surface direction (vertical direction) of the bearing wall 50. As described above, a heat-expandable fire-resistant sheet or heat-expandable fire-resistant paint is attached or painted on the surface of the insert fixing plate portion 32, preferably in a thin thickness of about 1.0 to 3 mm, so as to cover the entire surface.

[0034] The base plate portion 31 is made of a rectangular steel plate with multiple through holes formed therein. The insertion and fixing plate portion 32 is a rectangular steel plate extending upward or downward toward the bearing wall 50 to be joined, and is joined integrally to the base plate portion 21 by fixing one end face in the vertical direction to the center of the base plate portion 31 by welding or the like. The insertion and fixing plate portion 32 has multiple through holes formed therein for driving in multiple drift pins 60 (see FIG. 3).

[0035] As shown in Figure 4, a recess 55b is formed in the underside of the wooden beam 53 of the beam member 51, and the base plate portion 21 is pressed against the upper surface of this recess 55b, and fasteners 56 such as fixing screws are driven into the wooden beam 53 through through holes formed in the base plate portion 21, thereby fixing the central joint metal 20 to the underside of the wooden beam 53. The remaining space in the recess 55b is filled with, for example, mortar or rock wool as a heat sink material 58 (see Figure 3), so as to cover the base plate portion 21 of the central joint metal 20.

[0036] A recess 55a is also formed in the upper surface of the RC beam section 54, and the protruding portions of anchor bolts 57 embedded in the RC beam section 54 are inserted into through-holes formed in the base plate section 21 so as to press the base plate section 21 against the bottom surface of this recess 55a, and the central joint metal 20 is fixed to the upper surface of the RC beam section 54 by tightening, for example, a nut member. The remaining space in the recess 55a is similarly filled with, for example, mortar or rock wool as a heat sink material 58 (see Figure 3).

[0037] In addition, in this embodiment, the side joint metal fittings 30 are fixed at two locations on the upper surface of the RC beam portion 54 and the lower surface of the wooden beam 53 by inserting fastening bolts 59 into through holes formed to pass vertically between two recesses 55c formed on the upper surface of the RC beam portion 54 and two recesses 55d formed on the lower surface of the wooden beam 53, and through holes formed in the base plate portion 31.

[0038] The remaining spaces of the two recesses 55c formed on the upper surface of the RC beam 54 are similarly filled with, for example, mortar or rock wool as heat sink material 58 (see FIG. 3) so as to cover the base plate portions 31 of the side joint metal fittings 30. Similarly, the remaining spaces of the two recesses 55d formed on the lower surface of the wooden beam 53 are similarly filled with, for example, mortar or rock wool as heat sink material 58 (see FIG. 3) so as to cover the base plate portions 31 of the side joint metal fittings 30.

[0039] In this way, the remaining space of recesses 55c and 55d is filled with heat sink material 58 so as to cover the base plate portion 31 of the side joint metal fittings 30, and the remaining space of recesses 55a and 55b is filled with heat sink material 58 so as to cover the base plate portion 21 of the central joint metal fittings 20. This makes it possible to effectively prevent high heat from being transmitted to the wooden beams 53 and RC beam portions 54 when the load-bearing wall 50 burns due to a fire.

[0040] In this embodiment, a central slit portion 41 is formed in the central portion of each of the upper and lower end surfaces of the load-bearing wall 50, following the cross-sectional shape of the insertion and fixing plate portion 22 and the protruding plate portion 23 of the central connecting metal fitting 20, as shown in Figure 2.

[0041] In addition, side slits 42 are formed on both the left and right sides of the upper and lower ends of the bearing wall 50, following the cross-sectional shape of the insert and fastening plate portions 32 of the side connecting metal fittings 30. In addition, a number of through holes are formed in the upper and lower ends of the bearing wall 50, penetrating through the thickness direction, according to the positions of the through holes formed in the insert and fastening plate portions 32.

[0042] The insert and fastening plate portion 22 and protruding plate portion 23 of the central joint metal 20, which are covered with a heat-expandable fire-resistant sheet or heat-expandable fire-resistant paint, are inserted into the central slit portion 41 of the bearing wall 50. The gap between the inserted and fastening plate portion 32 and the central slit portion 41 is preferably filled with a hardening material and hardened. When filling the central slit portion 41 with a filler material, the inner surface of the central slit portion 41 can be waterproofed to prevent the bearing wall 50 from absorbing the moisture from the filler material.

[0043] The insert and fixation plate portion 32 of the side connecting hardware 30 covered with a heat-expandable fire-resistant sheet or heat-expandable fire-resistant paint is inserted into the side slit portion 42 of the bearing wall 50, and the multiple through holes formed in the insert and fixation plate portion 32 are aligned with the multiple through holes formed in the bearing wall 50, and multiple drift pins 60 are inserted and driven into these aligned through holes.This makes it possible, using the fire-resistant connecting structure 10 for wooden structural materials in this embodiment, to integrally join the upper and lower ends of the bearing wall 50 to the undersides 51a, 52a and upper surfaces 51b, 52b of other structural materials, such as the upper floor beams 51 and the lower floor beams 52, using the connecting hardware 20, 30.

[0044] Furthermore, according to the fire-resistant joint structure 10 for wooden structural materials of this embodiment, which has the above-mentioned configuration, the simple configuration does not hinder stress transmission under normal conditions, and in the event of a fire, it is possible to effectively prevent the transfer of high heat from the earthquake-resistant wall 50 to the upper floor beams 51 and lower floor beams 52 through the insertion and fixing plate portions 22, 32 of the joint metal fittings 20, 30, thereby maintaining the structural performance of the frame structural materials 51, 52 and preventing their functionality from deteriorating.

[0045] In other words, according to this embodiment, the fire-resistant joining structure 10 for wooden structural materials has a simple configuration in which the insertion and fixing plate portions 22, 32 of the joining metal members 20, 30 covered with a heat-expandable fire-resistant sheet or heat-expandable fire-resistant paint are inserted and fixed into the slit portions 41, 42, and the heat-expandable fire-resistant sheet or heat-expandable fire-resistant paint is attached or applied with a thin thickness of, for example, about 1 to 3 mm, so that under normal circumstances, it is possible to not hinder the stress transmission through the joining metal members 20, 30, and in the event of a fire, the main material of the heat-expandable fire-resistant sheet or heat-expandable fire-resistant paint expands 20 to 30 times and forms a carbonized layer that functions as an insulating layer, so that it is possible to effectively prevent the transmission of high heat from the load-bearing wall 50 to the upper floor beams 51 and the lower floor beams 52 through the insertion and fixing plate portions 22, 32.

[0046] In particular, in the event of a fire, the parts of the bearing wall 50 that come into contact with the metal joints 20, 30 will burn, and when these parts have burned off or are almost completely carbonized, the surfaces of the heat-expandable fire-resistant sheet and heat-expandable fire-resistant paint will heat up, and when they reach a predetermined heating temperature, they will begin to foam, forming an insulating layer between them and the metal joints 20, 30, thereby suppressing the temperature rise of the metal joints 20, 30.When the heat-expandable fire-resistant sheet and heat-expandable fire-resistant paint expand, the parts that come into contact with the metal joints 20, 30 will be almost completely burned off, so it is possible for the heat-expandable fire-resistant sheet and heat-expandable fire-resistant paint to expand without interfering with their function of increasing volume through foaming.

[0047] The present invention is not limited to the above-described embodiments and various modifications are possible. For example, the fire-resistant joint structure for wooden structural members of the present invention is not limited to the structure of a joint for joining the upper and lower ends of a bearing wall to upper and lower beam members via metal joints. It can also be used, for example, when joining the side end of a bearing wall to a column member via metal joints. For example, it can also be used when joining a wooden beam member as a wooden structural member to the joining surface of another structural member, such as a column member or another beam member, via metal joints. The upper floor side beam member and the lower floor side beam member may be steel beams or may be reinforced concrete beams formed integrally with the reinforced concrete beam portion. [Explanation of symbols]

[0048] 10 Fire-resistant joint structure of wooden structural materials 20 Central joint metal 21 Substrate plate section 22 Insertion and fixing plate part 23 Protruding plate part 30 Side joint metal fittings 31 Substrate plate section 32 Insertion and fixing plate part 41 Central slit 42 Side slit 50 Load-bearing wall (wooden structural material) 51 Upper floor side beam members (other structural materials) 51a Bottom surface (joint surface) 51b Top surface (joint surface) 52 Upper floor side beam members (other structural materials) 52a Bottom surface (joint surface) 52b Top surface (joint surface) 53 wooden beam 53a Fireproof cladding 53b Surface material 54 RC beam section 55a, 55b, 55c, 55d recesses 56 Fasteners 57 Anchor bolt 58 Heat sink material 59 Fastening bolt 60 Drift Pin

Claims

1. A fire-resistant joining structure for wooden structural materials, which uses a joining hardware that includes a base plate portion and an insert-and-fix plate portion that protrudes vertically from the base plate portion, and which joins the wooden structural material to the joining surface of another structural material by inserting and fixing the insert-and-fix plate portion into a slit portion formed by cutting into an end face of the wooden structural material and fixing the base plate portion to the joining surface of another structural material, A fire-resistant joining structure for wooden structural materials using joining hardware in which at least the portion of the insertion and fixing plate portion that is inserted into the slit portion is covered with a heat-expandable fire-resistant sheet or heat-expandable fire-resistant paint, and the insertion and fixing plate portion is fixed to the slit portion.

2. The wooden structural material is installed inside a framework of column members and beam members, forming a shear wall that, together with the column members and beam members, bears the stress generated during an earthquake, and the other structural material to which the wooden structural material is joined on the joining surface is a beam member made of concrete, steel, or wood.A fire-resistant joining structure for wooden structural materials using joining metal fittings as described in claim 1.

3. The fire-resistant joining structure for wooden structural materials using metal joints as described in claim 1 or 2, wherein the heat-expandable fire-resistant sheet or heat-expandable fire-resistant paint is made of a material whose main material reacts at a temperature of 250 to 300°C due to the heat of a fire, expanding 20 to 30 times and forming a carbonized layer.

4. A fire-resistant joining structure for wooden structural materials using joining hardware as described in claim 3, wherein the main material of the heat-expandable fire-resistant sheet or heat-expandable fire-resistant paint is a compound containing ammonium polyphosphate, ammonium phosphate, or melamine phosphate.

5. A fire-resistant joining structure for wooden structural materials using joining hardware as described in claim 1 or 2, wherein a solidifying material is filled in the gap between the part of the insertion and fixing plate part covered with the heat-expandable fire-resistant sheet or heat-expandable fire-resistant paint inserted into the slit part and the slit part.

6. A fire-resistant joining structure for wooden structural materials using joining hardware as described in claim 1 or 2, wherein the insertion and fixing plate portion of the joining hardware is fixed to the wooden structural material while being inserted into the slit portion using a drift pin.

7. 3. A fire-resistant joint structure for wooden structural members using metal joints according to claim 1 or 2, wherein rock wool or mortar is filled as a heat sink material so as to cover the base plate portion of the metal joints.

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