JP7678738B2 - Joint structure of structural materials - Google Patents

Description

The present invention relates to a joint structure for structural materials.

When wood is heated from the outside during a fire, its surface burns and a charred layer is formed. If this charred layer is formed uniformly on the surface of the wood, it prevents heat from penetrating into the wood, and inhibits structural deterioration inside the wood. Taking advantage of this characteristic, a technique is known in which the wood used for pillars, beams, etc. is made thicker, and a burned area of a predetermined thickness is provided on the surface of the wood to burn and form a charred layer, so that a sound cross section capable of supporting a long-term load is ensured inside the wood after combustion. Structural materials with such burned areas are also used in the main structural parts of wooden buildings to make them semi-fireproof.
An example of a structural material with a burn gap is a wooden building component that is characterized by comprising a structural section with a long, rectangular cross-section that receives the load, a covering section that covers at least three sides of the cross-section of the structural section over its entire length, and an insulating section that is layered between the structural section and the covering section and prevents the load acting on the structural section from being transmitted to the covering section (see Patent Document 1).

Various techniques have been proposed for joining fire-resistant materials with a burnable area on the surface of wood or on the surface of a composite material of wood and other materials. For example, Patent Document 2 proposes a joining structure for structural materials in which a recess is provided in the column to expose the burnable material that constitutes the burnable layer located inside the burnable area layer, and the beam is abutted against the recess to join the column and beam. Patent Document 3 proposes a joining structure in which a gusset plate of a bracket fixed to the side of the column is inserted into a slit that extends from the underside of the beam to the wooden core of the beam, and a plug member is inserted into the slit. Patent Document 4 proposes a joining structure in which a column member and a beam member are joined via a joint member made of a material that is harder than wood and has excellent fire resistance.

JP 2007-46286 A JP 2008-014036 A JP 2014-201984 A JP 2020-118001 A

In the wooden building components of Patent Document 1, the structural parts are covered with coating parts and insulating parts, so when attempting to join the structural parts of the wooden building components, the coating parts and insulating parts may get in the way. Therefore, when manufacturing wooden building components in a factory or the like, coating parts and insulating parts are not applied to the parts of the wooden building components that correspond to the joints, but rather, it is necessary to join the structural parts of the wooden building components at the construction site and then apply the coating parts and insulating parts to the joints. In this way, when joining the wooden building components of this document, work at the construction site is time-consuming.

In the joint structure of Patent Document 2, the fire-retardant layer of the column and the fire-retardant layer of the beam come into contact with each other at the joint between the column and the beam, but in order to bring the two into contact, it is necessary to control the positioning with high precision, which is time-consuming. For example, when joining a column and a beam, when the beam is lowered from above in the axial direction of the column, in order to bring the fire-retardant layer of the column and the fire-retardant layer of the beam into contact with each other, it is necessary to prevent the two from interfering with each other, which is time-consuming.

In Patent Document 3, it takes a lot of time to manufacture a plug member that fits the shape of the slit hole formed in the beam. Also, in order to prevent the fire resistance of the slit hole of the beam from being impaired, the plug member needs to be inserted into the slit hole without any gaps, but it takes a lot of time to insert the plug member into the slit hole without any gaps.
In Patent Document 4, it is necessary to use a material that is harder than wood and has excellent fire resistance as the joint material, and the joint structure in this document has low versatility.

The object of the present invention is to provide a joint structure for structural materials that is easy to install and has excellent fire resistance.

The present invention provides a joining structure for structural materials in which a second structural material is joined vertically to the side surface of a first structural material, and each of the first structural material and the second structural material has a load-bearing portion, a covering member that covers the side surface along the axial direction of the load-bearing portion, and a burnt layer arranged on the outside of the covering member, and at the joining portion between the first structural material and the second structural material, the axial end face of the second structural material abuts against the side surface of the load-bearing portion of the first structural material, and there is a gap between the side surface of the covering member of the first structural material facing the second structural material and the end face of the covering member of the second structural material facing the first structural material, and a flame-retardant small member is arranged to cover the gap.

The present invention also provides a joining structure for structural materials in which a second structural material is joined vertically to the side surface of a first structural material, and the first structural material and the second structural material each have a load-bearing portion, a covering member that covers the side surface along the axial direction of the load-bearing portion, and a burnt layer arranged on the outside of the covering member, and at the joining portion between the first structural material and the second structural material, the axial end face of the second structural material abuts against the side surface of the load-bearing portion of the first structural material, and there is a gap between the side surface of the covering member of the first structural material facing the second structural material and the end face of the covering member of the second structural material facing the first structural material, and a thermal expansion insulating material is arranged in the gap.

The present invention provides a joint structure for structural materials that is easy to install and has excellent fire resistance.

FIG. 1(a) is a cross-sectional view showing a typical joint structure of structural materials according to a preferred embodiment of the present invention, and FIG. 1(b) is an enlarged view of a main portion of FIG. 1(a). FIG. 2 is a cross-sectional view taken along line II-II in FIG. FIG. 3(a) is a cross-sectional view showing a typical joint structure of structural materials according to another preferred embodiment of the present invention, and FIG. 3(b) is an enlarged view of a main portion of FIG. 3(a). FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 5(a) to 5(e) are enlarged cross-sectional views of essential parts showing modified examples of the arrangement position of the thermal expansion insulating material in the joint structure of the embodiment shown in FIG. 3(a).

The present invention will now be described in detail based on preferred embodiments thereof.
A joint structure 1 which is a preferred embodiment of the joint structure for structural materials of the present invention is shown in Figures 1 and 2. The joint structure 1 is a joint structure for structural materials in which a second structural material 20 is joined vertically to the side surface of a first structural material 10.

The first structural member 10 is, for example, a structural timber used as a pillar of a building. The first structural member 10 includes a load-bearing portion 11, a covering member 12 that covers a side surface of the load-bearing portion 11 along the axial direction Z1, and a burnt layer 13 disposed on the outside of the covering member 12.
The cross-sectional design of the load support portion 11 is such that the load support portion 11 alone is structurally safe against long-term loads such as fixed loads, live loads, and snow loads. Such cross-sectional designs are well known. The cross-sectional shape of the load support portion 11 is rectangular, and the vertical and horizontal lengths of the load support portion 11 in the cross-section of the first structural member 10 can be appropriately changed depending on the shape or size of the beams or columns.

The covering member 12 covers four side surfaces along the axial direction Z1 of the load supporting portion 11. The covering member 12 includes a first covering member 12a covering both sides of the load supporting portion 11 in one direction X1 of the cross section of the first structural material 10, and a second covering member 12b covering both sides of the load supporting portion 11 in an orthogonal direction Y1 perpendicular to the one direction X1.
The first covering member 12a has both ends in the Y direction that coincide with both ends of the load support portion 11 in the Y direction, and covers the load support portion 11 over the entire area in the Y direction. The first covering member 12a can be fixed to the side of the load support portion 11 by known fixing means such as screws, nails, staples, or adhesives. In this embodiment, the first covering member 12a is made of a laminate in which two plate-shaped members are stacked. Each plate-shaped member constituting the laminate may be configured by connecting a plurality of members with a fastening material. As the fastening material, for example, an adhesive, a screw, a nail, a staple, or the like can be used. The first covering member 12a may also be a laminate in which three or more plate-shaped members are stacked. In the laminate, the plate-shaped members constituting the laminate may be bonded in advance with an adhesive or the like, or may not be bonded. The laminate may be fixed to a fixed member such as the load support portion 11 with or without bonding the plate-shaped members constituting the laminate. The same applies to the case where the second covering member 12b and the corner reinforcing member 15 described later are made of a laminate. The first covering member 12a may be a single plate-like member.

In this embodiment, a corner reinforcement member 15 is disposed on the outer surface of the first covering member 12a. More specifically, the corner reinforcement member 15 is disposed in a state where it is partially overlapped on the outer surface of the first covering member 12a and partially extends from one end of the load support portion 11 in the Y direction (see FIG. 1(a)). Here, the overlapped state means a state where the corner reinforcement member 15 and the first covering member 12a have an overlapping portion, and includes not only a state where the corner reinforcement member 15 and the first covering member 12a are in contact with each other, but also a state where the corner reinforcement member 15 and the first covering member 12a are separated from each other. In this embodiment, the corner reinforcement member 15 and the first covering member 12a are in contact with each other. In addition, in this embodiment, the corner reinforcement member 15 also extends from one end of the first covering member 12a.

The corner reinforcement member 15 can be fixed to the outer surface of the first covering member 12a by known fixing means such as screws, nails, staples, or adhesives. In this embodiment, the corner reinforcement member 15 is made of a laminate of two plate-shaped members stacked together. Each plate-shaped member constituting the laminate may be made of multiple members connected together with fastening materials. The corner reinforcement member 15 may also be a laminate of three or more plate-shaped members stacked together. The plate-shaped members constituting the corner reinforcement member 15 do not necessarily need to be connected together with fastening materials, and the ends of the plate-shaped members may be butted together. The corner reinforcement member 15 may be a single plate-shaped member.

The second covering member 12b extends from both ends of the load support portion 11 in the X1 direction, and the tip surface in the extending direction faces the portion of the corner reinforcing member 15 extending from one end of the load support portion 11. The second covering member 12b can be fixed to the side of the load support portion 11 by known fixing means such as screws, nails, staples, or adhesives. In this embodiment, the second covering member 12b is made of a laminate of two overlapping plate-like members. The second covering member 12b may also be a laminate of three or more overlapping plate-like members. The second covering member 12b may also be a single plate-like member.

The burnable layer 13 includes a first burnable layer 13a arranged on the outside of each of the first covering members 12a in the X1 direction, and a second burnable layer 13b arranged on the outside of each of the second covering members 12b in the Y1 direction. The first burnable layer 13a is fixed to the outside of the first covering member 12a via a spacer 17 so as to have a ventilation layer 6 between the first covering member 12a and the first covering member 12a. As shown in FIG. 1(a), it is preferable that the ventilation layer 6 also extends between the corner reinforcing member 15 and the burnable layer 13a, and also exists between the second covering member 12b and the second burnable layer 13b. By having the ventilation layer 6 between the burnable layer 13 and the load support portion 21, it is easy to keep the load support portion 21 dry. For example, even if the load support portion 21, the first covering member 12a, the second covering member 12b, or the corner reinforcement member 15 becomes wet due to rain or the like, the moisture that evaporates from the load support portion 21 is easily diffused into the air through the ventilation layer 6.

The thickness T of the burnable layer 13 can be set based on known burnable design. Burnable design is a design method that adds a specified amount of burnable to the cross section required for long-term structural strength and short-term structural strength during earthquakes, etc., and is a design that ensures non-damage in terms of fire resistance performance (the ability to withstand the load supporting the building even when heated by a fire and not collapse) with the load-bearing part 11, and then provides a burnable layer of a thickness according to the required fire resistance performance around it. For example, a burnable design is performed that provides a 45 mm wood covering for quasi-fire resistance for one hour.

Since the general carbonization rate of wood is about 0.6 mm/min, the thickness T of the burnable layer 13 is preferably 36 mm or more, more preferably 45 mm or more, from the viewpoint of imparting a 1-hour fire resistance to the burnable layer 13. The thickness T of the burnable layer 13 is preferably 72 mm or more, more preferably 90 mm or more, from the viewpoint of imparting a 2-hour fire resistance to the burnable layer 13. The thickness T of the burnable layer 13 is preferably 108 mm or more, more preferably 120 mm or more, from the viewpoint of imparting a 3-hour fire resistance to the burnable layer 13.

In this embodiment, the spacers 17 are disposed intermittently or continuously in either or both of the axial direction Z1 and the direction Z2 perpendicular to the axial direction Z1 of the load supporting portion 11. In the embodiment shown in Fig. 1, the spacers 17 are disposed intermittently or continuously in the axial direction Z1.
In this embodiment, the spacer 17 is fixed to the load support 11 and the first covering member 12a by screws (not shown), and the first burnable layer 13a is fixed to the spacer 17 by screws or nails (not shown). It is preferable that the tip of the screw or nail (not shown) that fixes the first burnable layer 13a does not reach the load support 11 in order to prevent the screw or nail from becoming a thermal bridge. In this embodiment, it is preferable to perform countersinking on the first burnable layer 13a so that the screw does not protrude from the outer surface of the first burnable layer 13a.

In this embodiment, as described above, the second structural member 20 is joined to the side surface of the first structural member 10. The second structural member 20 is, for example, a structural square timber used as a beam in a wooden building.
Describing the second structural material 20 in further detail, the second structural material 20 comprises a load-bearing portion 21, a covering member 22 covering the side surface of the load-bearing portion 21 along the axial direction Z2, and a burnt layer 23 applied to the outside of the covering member 22.
The load-bearing portion 21 of the second structural material 20, like the load-bearing portion 11 of the first structural material 10, is designed in such a cross-sectional manner that the load-bearing portion 21 alone is structurally safe against long-term loads (long-term loads) such as fixed loads, live loads, and snow loads.

The covering member 22 of the second structural member 20 covers three side surfaces of the load support portion 21 along the axial direction Z2. The covering member 22 includes a first covering member 22a covering both sides of the load support portion 21 in one direction X2 of the cross section of the second structural member 20, and a second covering member 22b covering one side of the load support portion 21 in the perpendicular direction Y2 perpendicular to the one direction X2. In this embodiment, the positions of the ends of the first covering member 22a and the second covering member 22b in the axial direction Z2 do not coincide with the positions of the ends of the load support portion 21. Specifically, the ends of the first covering member 22a and the second covering member 22b do not reach the ends of the load support portion 21. In other words, the positions of the ends of the first covering member 22a and the second covering member 22b are located inward in the axial direction Z2 from the positions of the ends of the load support portion 21. The positions of the ends of the first covering member 22a and the second covering member 22b may coincide with the position of the end of the load support portion 21, and the first covering member 22a and the second covering member 22b may cover the load support portion 21 over the entire area in the axial direction Z2.

The first covering member 22a and the second covering member 22b can be fixed to the side of the load support portion 21 by known fixing means such as screws, nails, staples, or adhesives. In this embodiment, the first covering member 22a and the second covering member 22b are made of a laminate of two plate-shaped members stacked together. Each plate-shaped member constituting the laminate may be made of a plurality of members connected together by a fastening material. The first covering member 22a and the second covering member 22b may also be a laminate of three or more plate-shaped members stacked together. The plate-shaped members constituting the laminate may or may not be bonded together in advance by adhesive or the like. The first covering member 22a and the second covering member 22b may also be a single plate-shaped member having fire resistance.

The burnable layer 23 includes a first burnable layer 23a arranged on the outside of each of the first covering members 22a in the X2 direction, and a second burnable layer 23b arranged on the outside of the second covering member 22b in the Y2 direction. The first burnable layer 23a is fixed to the outside of the first covering member 22a via a spacer 27 so as to have a ventilation layer 6 between the first covering member 22a and the first covering member 22a. The thickness T of the burnable layer 23 can be set based on a known burnable design, similar to the burnable layer 13 of the first structural material 10.

The spacers 27 are disposed intermittently or continuously in either or both of the axial direction Z2 and the direction Z1 perpendicular to the axial direction Z2 of the load support portion 21. In the embodiment shown in Fig. 1, the spacers 27 are disposed intermittently or continuously in the Z1 direction.
In this embodiment, the method of fixing the spacer 27 of the second structural material 20 to the load support portion 21 and the first covering member 22a may be the same as the method of fixing the spacer 17 of the first structural material 10 to the load support portion 11 and the first covering member 12a. Also, the method of fixing the first burnable layer 23a of the second structural material 20 to the spacer 27 may be the same as the method of fixing the first burnable layer 13a of the first structural material 10 to the spacer 17.

In this embodiment, in the axial direction Z2 of the second structural material 20, the load support portion 21 and the covering member 22 extend from the burnt layer 23, and the load support portion 21 extends from the covering member 22. The end face of the second structural material 20 in the axial direction Z2 is the end face 21a of the load support portion 21 of the second structural material 20.

1 and 2, in the joint structure 1 of this embodiment, at the joint between the first structural material 10 and the second structural material 20, an end face in the axial direction Z2 of the second structural material 20 abuts against a side surface 11e of the load supporting portion 11 of the first structural material 10. In this embodiment, a portion of the load supporting portion 11 of the first structural material 10 is provided that is not covered by the covering member 12 and the burnt layer 13, and an end face 21a of the load supporting portion 21 of the second structural material 20 abuts against the side surface 11e of the load supporting portion 11 at that portion.
In this embodiment, a recess 19 is formed in the first structural material 10 to expose the side surface 11e of the load support portion 11, and an end face 21a of the load support portion 21 of the second structural material 20 is fixed to the side surface 11e of the load support portion 11 at the recess 19. The recess 19 can be formed by cutting out a part of the burnt layer 13 and the covering member 12 so as to penetrate through the burnt layer 13 and the covering member 12 of the first structural material 10. The load support portion 11 of the first structural material 10 and the load support portion 21 of the second structural material 20 can be fixed by a known method.

In addition, the joint structure 1 has a gap 7 between the side surface 2e of the covering member 12 of the first structural material 10 on the second structural material 20 side and the end surface 2a of the covering member 22 of the second structural material 20 on the first structural material 10 side at the joint between the first structural material 10 and the second structural material 20. In other words, at the joint between the first structural material 10 and the second structural material 20, the side surface 11e of the covering member 12 of the first structural material 10 and the covering member 22 of the second structural material 20 do not abut, but are separated from each other. In this embodiment, the gap 7 is formed along the three side surfaces covered by the covering members 22a and 22b of the second structural material 20. The gap 7 may be formed along any one or more of the three side surfaces covered by the covering members 22a and 22b of the second structural material 20. The gap 7 may be continuous in the circumferential direction of the second structural material 20, or may be divided into a plurality of parts in the circumferential direction.

The advantages of the joint structure 1 of this embodiment, in which the end face of the axial direction Z2 of the second structural material 20 abuts against the side surface 11e of the load-supporting portion 11 of the first structural material 10 at the joint between the first structural material 10 and the second structural material 20 and which has the gap 7, are as follows.
If the covering members 12, 22 of the first structural material 10 and the second structural material 20 are to abut against each other without any gaps at their joint, it is necessary to join the first structural material 10 and the second structural material 20 while maintaining the abutting state of the covering members 12, 22. Also, in order for the covering members 12, 22 to abut against each other without any gaps, it is necessary to precisely manufacture the first structural material 10 and the second structural material 20 according to the designed dimensions. Thus, it takes a lot of work to construct a joint structure in which the covering members 12, 22 of the first structural material 10 and the second structural material 20 are abutting against each other at their joint.

In contrast, in the joint structure 1 of this embodiment, a gap 7 is provided between the side surface 2e of the covering member 12 of the first structural material 10 and the end surface 2a of the covering member 22 of the second structural material 20 at the joint between the first structural material 10 and the second structural material 20, so that no work is required to maintain the state in which both covering members 12, 22 are in contact with each other. Furthermore, even if the length in the axial direction Z2 of the covering member 22 of the second structural material 20 is shorter than the design dimension, for example, the joint structure 1 can be constructed without work to compensate for the length of the covering member 22.
In this manner, the joint structure 1 of the present embodiment can be easily constructed.

In addition, at the joint between the first structural material 10 and the second structural material 20, the end face of the axial direction Z2 of the second structural material 20 abuts against the side face 11e of the load support portion 11 of the first structural material 10, which prevents the side face 11e of the load support portion 11 of the first structural material 10 and the end face 21a of the load support portion 21 of the second structural material 20 from being directly exposed to flames. This prevents the load support portion 11 of the first structural material 10 and the load support portion 21 of the second structural material 20 from burning, improving the fire resistance of the joint structure 1.

1 and 2, in this embodiment, a flame-retardant small member 71 is disposed so as to cover the gap 7. More specifically, the small member 71 closes an opening in the gap 7 located on the opposite side to the load support portion 21 of the second structural material 20. In this embodiment, similar to the gap 7 on both sides of the load support portion 21 of the second structural material 20 in the X2 direction, a gap 7 is also formed between the covering member 12 of the first structural material 10 and the covering member 22 of the second structural material 20 on one side of the load support portion 21 of the second structural material 20 in the Y2 direction, and the gap 7 and the small member 71 covering the gap 7 are present so as to surround three sides in the circumferential direction of the load support portion 21 of the second structural material 20. Flame retardant means having fire resistance equal to or greater than flame retardant performance, and is, for example, a material as specified in Article 1, Item 6 of the Enforcement Order of the Building Standards Act. More specifically, it means that when 50 kW/ ^m2 of radiant heat is irradiated to the surface from a radiant electric heater, the total heat generation in the five minutes after heating starts is 8 MJ/ ^m2 or less, and there are no cracks or holes that penetrate to the back surface that are harmful from a fire prevention perspective within five minutes after heating starts, and the heat generation rate within five minutes after heating starts does not exceed 200 kW/ ^m2 for 10 seconds or more.
Since the small member 71 is arranged to cover the gap 7, the penetration of flames through the gap 7 can be prevented, and therefore the joint structure 1 has excellent fire resistance.
In this manner, the joint structure 1 of the present embodiment can be easily constructed and has excellent fire resistance.

The small member 71 is a member having a small cross section. Here, the small cross section means that the width of the small member 71 along the axial direction Z2 of the second structural member 20 is 10 cm or less.
The small member 71 is a separate member from the covering member 22 of the second structural material 20. Here, being a separate member means that the small member 71 and the covering member 22 are separate members. The small member 71 and the covering member 22 may be made of the same material or different materials. In this embodiment, the small member 71 is also a separate member from the covering member 12 of the first structural material 10.
Examples of the flame-retardant small members 71 that can be used include gypsum boards, waterproof gypsum boards, calcium silicate boards, wood chip cement boards, wood wool cement boards, ceramic siding, flame-retardant wood, non-combustible wood, glass wool, rock wool, thermally expandable insulating materials, mortar, concrete blocks, ALC boards, metal plates, aluminum tapes, etc. The board materials (plate-shaped materials) and the like are preferably formed or cut to a width of 10 cm or less along the axial direction Z2 of the second structural material 20.

From the viewpoint of further improving the fire resistance of the joint structure 1, at the joint between the first structural member 10 and the second structural member 20, the distance D between the side surface 2e of the covering member 12 of the first structural member 10 and the end surface 2a of the covering member 22 of the second structural member 20 is preferably 3 cm or less, more preferably 2 cm or less, and even more preferably 1 cm or less (see FIG. 1(b)). Also, from the viewpoint of making it easy to construct the joint structure 1, the distance D is preferably more than 0 cm, more preferably 1 cm or more, and even more preferably 2 cm or more (see FIG. 1(b)).

Next, an example of a construction method for the joint structure 1 of this embodiment will be described.
First, the first structural member 10 is erected with the axial direction Z1 aligned with the vertical direction. It is preferable that the first structural member 10 is provided in advance in a factory or the like with a portion of the load support portion 11 that is not covered with the covering member 12 and the burnt layer 13 and has an exposed side 11e of the load support portion 11. Then, the second structural member 20, lifted by a lifting machine or the like, is lowered from above the axial direction Z1 of the first structural member 10 to the exposed portion of the load support portion 11 of the first structural member 10. Then, the end face 21a of the load support portion 21 of the second structural member 20 is fixed to the side 11e of the load support portion 11 of the first structural member 10. At this time, a gap 7 is formed between the covering member 12 of the first structural member 10 and the covering member 22 of the second structural member 20 at the joint between the first structural member 10 and the second structural member 20. After the load supporting portion 21 of the second structural material 20 is fixed to the load supporting portion 11 of the first structural material 10, the gap 7 between the covering member 12 of the first structural material 10 and the covering member 22 of the second structural material 20 is covered with a small member 71. In this manner, the joint structure 1 can be constructed. The small member 71 can be fixed to the covering member 12 of the first structural material 10 or the covering member 22 of the second structural material 20 by any method.

In addition, according to the joint structure 1 of this embodiment, after a pair of first structural members 10 are erected at a fixed interval, when the second structural member 20 is placed between them as a beam member, the second structural member 20 can be lowered and placed so that a gap 7 is created between the covering member 12 of the first structural member 10 and the covering member 22 of the second structural member 20. Therefore, when the second structural member 20 is lowered, contact between the covering member 12 of the first structural member 10 and the covering member 22 of the second structural member 20 is suppressed, and it is easy to place the second structural member 20 in an appropriate position and to fix the second structural member 20 to the first structural member 10.

Next, another embodiment of the present invention will be described with reference to Figures 3 and 4. For configurations in the embodiment shown in Figures 3 and 4 that are not specifically described, the description of the embodiment shown in Figures 1 and 2 applies as appropriate.

In the joint structure 1B shown in Figures 3 and 4, like the joint structure 1 shown in Figures 1 and 2, a gap 7 is formed between the covering member 12 of the first structural material 10 and the covering member 22 of the second structural material 20 at the joint between the first structural material 10 and the second structural material 20, but in the joint structure 1B, a small member 71 is not arranged.
In the joint structure 1B, as shown in Figures 3 and 4, a thermal expansion insulating material 72 is disposed in the gap 7. When heat is applied to the thermal expansion insulating material 72 during a fire or the like, the thermal expansion insulating material 72 fills all or part of the gap 7, thereby exerting a heat blocking effect and suppressing ignition due to exposure of the load supporting portion to external heat.
Before expansion, the thermal expansion insulating material 72 may be disposed so as to completely fill the gap 7, or may be disposed so as to leave a space in part of the gap 7 as shown in Fig. 3(b). It is preferable that at least a part of the thermal expansion insulating material 72 is present inside the gap 7. The thermal expansion insulating material 72 may be disposed entirely outside the gap 7 in the vicinity of the gap 7. The vicinity of the gap 7 here means that the thermal expansion insulating material 72 is disposed so close to the gap 7 that a part of it fills part or all of the gap 7 when it expands due to heat.
In this embodiment, the thermal expansion insulating material 72 is fixed to the end face 2a of the covering member 22 of the second structural material 20 so as not to reach the side surface 2e of the covering member 12 of the first structural material 10, and the thermal expansion insulating material 72 reaches the side surface 2e due to thermal expansion.
In this way, the joint structure 1B also has the gap 7, and in the event of a fire, the inflow of heat through the gap 7 is prevented by the thermally expanded thermal expansion insulation material 72, so that, like the joint structure 1, it can be easily constructed and has excellent fire resistance.

Examples of the thermal expansion insulating material 72 that can be used include foamable fireproof tape, foamable fireproof sheet, foamable caulking material, and foamable fireproof paint. Among these, it is preferable to use foamable fireproof tape because it can be easily applied in a short time.
The foamable fire-resistant tape and the foamable fire-resistant sheet each foam when heated to form a heat insulating layer. The foamable fire-resistant tape and the foamable fire-resistant sheet each contain a resin as a main constituent material. Examples of the resin that is the main constituent material of the foamable fire-resistant tape and the foamable fire-resistant sheet include butyl rubber, epoxy resin, and polyvinyl chloride resin. The foamable fire-resistant sheet can be fixed to the end surface 2a of the covering member 22 or the side surface 2e of the covering member 12 using, for example, an adhesive, a staple, or the like.
Since the foamable caulking material and the foamable fireproof paint can be applied by coating or spraying them on the application area, they can be easily applied even to areas where it is difficult to apply foamable fireproof tape or foamable fireproof sheet. Examples of resins that are the main constituent materials of the foamable caulking material and the foamable fireproof paint include silicone resins, acrylic resins, vinyl acetate resins, epoxy resins, and urethane resins.
The thermal expansion insulating material 72 is generally an organic insulating material, which is an insulating material whose main component is an organic compound.

In the joint structure 1B, as shown in Figures 5(a) to 5(e), the thermal expansion insulating material 72 may be fixed to the side surface 2e of the covering member 12 of the first structural material 10. Below, modified examples of the arrangement of the thermal expansion insulating material 72 will be described with reference to Figures 5(a) to 5(e).
5(a), the thermal expansion insulating material 72 is disposed from the bottom surface 7b to the opening 7a of the gap 7. More specifically, one end 72b in the X1 direction of the thermal expansion insulating material 72 is in contact with the bottom surface 7b of the gap 7, and the other end 72a in the X1 direction of the thermal expansion insulating material 72 is aligned with the opening surface of the opening 7a of the gap 7. The bottom surface 7b of the gap 7 is formed by the side surface of the load supporting portion 21 of the second structural member 20.
5B, the thermal expansion insulating material 72 extends beyond the opening 7a of the gap 7. More specifically, the other end 72a of the thermal expansion insulating material 72 is located on the opposite side of the opening 7a of the gap 7 from the bottom surface 7b.
5(c), the thermal expansion insulating material 72 does not reach the opening 7a of the gap 7. More specifically, the other end 72a of the thermal expansion insulating material 72 is located closer to the bottom surface 7b than the opening 7a of the gap 7.
5(d), the thermal expansion insulating material 72 does not reach the bottom surface 7b of the gap 7. More specifically, one end 72b of the thermal expansion insulating material 72 is not in contact with the bottom surface 7b of the gap 7, and the two are spaced apart.
In the example shown in FIG. 5( e ), the thermal expansion insulating material 72 is disposed outside the gap 7 .

In all of the modified examples shown in Figures 5(a) to 5(e), the gap 7 is filled by the thermal expansion insulation material 72 that expands during a fire, preventing heat from entering through the gap 7, and therefore has excellent fire resistance. In addition, all of the modified examples shown in Figures 5(a) to 5(e) have gaps 7, making them easy to install.

Next, matters common to the above-mentioned embodiments will be described.
The burnt layers 13, 23 can be made of a material selected from the group consisting of cross-laminated timber (CLT), laminated timber, laminated veneer lumber (LVL), plywood, lumber, particleboard (PB), and medium density fiberboard (MDF). Among these, it is preferable to make the layers from a material selected from the group consisting of cross-laminated timber (CLT), laminated timber, laminated veneer lumber (LVL), plywood, or lumber, from the viewpoints of ease of manufacturing wide and long-span materials and ease of ensuring aesthetics in large-scale wooden buildings. The CLT and laminated timber may be made by stacking a plurality of laminas having a rectangular cross section in the Y1 direction or the Y2 direction so that the vertices of the rectangles overlap each other.

The first covering member 12a, 22a may be made of gypsum board, waterproof gypsum board, calcium silicate board, ALC board, wood chip cement board, wood wool cement board, ceramic siding, mortar, flame-retardant wood, etc., and from the standpoint of fire resistance, it is preferable to use gypsum board, waterproof gypsum board, or calcium silicate board.

The spacers 17, 27 can be made of wood, steel, stainless steel, etc., and it is preferable to use wood because it is less susceptible to deformation due to heat.

Corner reinforcement members 15 can be made of gypsum board, waterproof gypsum board, calcium silicate board, ALC board, wood chip cement board, wood wool cement board, ceramic siding, mortar, flame-retardant wood, etc., and from the viewpoint of fire resistance, it is preferable to use gypsum board, waterproof gypsum board, or calcium silicate board. The material constituting corner reinforcement member 15 and the material constituting covering members 12 and 22 may be the same or different.

The second covering member 12b, 22b may be made of calcium silicate board, gypsum board, waterproof gypsum board, ALC board, wood chip cement board, wood wool cement board, ceramic siding, mortar, flame-retardant wood, etc., and it is preferable to use calcium silicate board from the viewpoint of suppressing thermal shrinkage.

Although the present invention has been described based on the preferred embodiments, the present invention is not limited to the above-described embodiments.
For example, in each of the above-described embodiments, the first burnable layers 13a, 23a are fixed to the first covering members 12a, 22a via the spacers 17, 27, but the first burnable layers 13a, 23a may be fixed to the first covering members 12a, 22a without the spacers 17, 27. Also, the second burnable layers 13b, 23b may be fixed to the second covering members 12b, 22b via the spacers 17, 27 so as to have a gap between them.

In addition, in each of the above-described embodiments, the second structural material 20 is joined to one side of the first structural material 10 in the Y1 direction, but the second structural material 20 may be joined to both sides of the first structural material 10 in the Y1 direction. Also, the second structural material 20 may be joined to one or both sides of the first structural material 10 in the X1 direction.

Reference Signs List 1, 1B Joint structure 10 First structural material 11 Load-bearing portion 12 Covering member 13 Burning margin layer 20 Second structural material 21 Load-bearing portion 22 Covering member 23 Burning margin layer 7 Gap 71 Small member 72 Thermal expansion type heat insulating material

Claims (4)

A joining structure of structural materials in which a second structural material is joined vertically to a side surface of a first structural material,
Each of the first structural member and the second structural member includes a load support portion, a covering member that covers a side surface of the load support portion along an axial direction, and a burnt layer disposed on the outside of the covering member,
at a joint between the first structural material and the second structural material, an axial end face of the second structural material abuts against a side face of the load supporting portion of the first structural material, and a gap is provided between a side face of the covering member of the first structural material facing the second structural material and an end face of the covering member of the second structural material facing the first structural material,
A joint structure for structural materials, in which a small flame-retardant member is arranged to cover the gap. A joining structure of structural materials in which a second structural material is joined vertically to a side surface of a first structural material,
Each of the first structural member and the second structural member includes a load support portion, a covering member that covers a side surface of the load support portion along an axial direction, and a burnt layer disposed on the outside of the covering member,
at a joint between the first structural material and the second structural material, an axial end face of the second structural material abuts against a side face of the load supporting portion of the first structural material, and a gap is provided between a side face of the covering member of the first structural material facing the second structural material and an end face of the covering member of the second structural material facing the first structural material,
A joining structure for structural materials , in which a thermal expansion insulating material is disposed in the gap or in the vicinity of the gap. The joining structure of structural materials according to claim 2, wherein the thermal expansion insulating material is an organic insulating material. The joining structure of structural materials according to claim 2 or 3, wherein the thermal expansion insulating material is a foamed fireproof tape, a foamed fireproof sheet, a foamed caulking material, or a foamed fireproof paint.

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