JP7711023B2 - Joint structure - Google Patents

Description

The present invention relates to a joint structure between structural members.

In GIR (glued-in rod) joints, as shown in FIG. 10, a steel rod 104 is inserted into a hole 103 formed in a wooden material 102, and the hole 103 is filled with an adhesive 105 such as epoxy resin, thereby fixing the steel rod 104 to the wooden material 102.

One effective way to increase the anchorage strength of the steel rod 104 is to increase the anchorage length of the steel rod 104. Also, Figure 9 of Patent Document 1 describes providing irregularities on the inner surface of the hole 103, which makes it possible to apply a supporting force in addition to the adhesive force of the adhesive 105 and increase the anchorage strength of the steel rod 104.

JP 2021-188326 A

When a pulling force acts on the steel rod 104, the displacement (elongation) of the steel rod 104 becomes large near the opening of the hole 103, and the adhesion stress generated in the adhesive 105 becomes larger the closer to the opening of the hole 103 and becomes smaller toward the tip. Therefore, adhesion failure of the adhesive 105 occurs on the opening side of the hole 103 where the adhesion stress is large, and this failure propagates to the tip side of the hole 103, causing the steel rod 104 to be pulled out of the wood material 102. As a result, even if the fixed length of the steel rod 104 is increased, a certain length of the tip side does not contribute to improving the strength, which is a disadvantage in terms of efficiency.

In addition, when attempting to increase the anchorage length of the steel rod 104 in a GIR joint, other issues arise, such as the length of the hole 103 being limited by the length of the drilling tool used to drill the hole 103, difficulty in ensuring the vertical accuracy of the hole 103, and deterioration of workability when inserting the steel rod 104 into the hole 103. The method described in Patent Document 1 also makes it difficult to drill the hole 103 because the hole 103 has irregularities.

The present invention was made in consideration of the above problems, and aims to provide a joint structure etc. that can efficiently fasten steel rods and reduce the fastening length.

The first invention for achieving the above-mentioned object is a joining structure between two structural members, in which a steel rod protruding from one structural member is positioned in a hole formed in the surface of the other structural member, which is a wall made of wood , facing the one structural member, and the hole is filled with a filler material, and only one of the steel rods is arranged in one of the holes, with no other steel rods present, and the hole is continuously widened in two directions, the out-of-plane direction and the in-plane direction , from the tip side of the hole toward the opening side.
The second invention is a joining structure between two structural members, in which a steel rod protruding from one structural member is positioned in a hole formed in the surface of the other structural member, which is a wall made of wood , facing the one structural member, and the hole is filled with a filler material, in which only one of the steel rods is arranged in one of the holes and no other steel rods are present, the shear rigidity of a first filler material located on the opening side of the hole is lower than the shear rigidity of a second filler material located on the tip side of the hole, the first filler material is provided only around the steel rod, and the second filler material is filled between the first filler material and the inner surface of the hole .

In the first invention, the hole widens from the tip side toward the opening side, and the thickness of the filler in the hole also increases from the tip side of the hole toward the opening side. Since the shear stiffness of the filler decreases as the filler becomes thicker, the adhesion stress (shear stress) of the filler when a pulling force acts on the steel rod can be reduced on the opening side of the hole and increased on the tip side, compared to when the cross section of the hole is constant as shown in Figure 10. As a result, the adhesion stress can be made uniform over the entire length of the steel rod, adhesion failure on the opening side of the hole can be suppressed, and adhesion stress can be generated on the tip side. Therefore, the steel rod can be fixed efficiently, the fixing length of the steel rod can be reduced, and construction is made easier. In the second invention, the same effect as above can be obtained by lowering the shear stiffness of the filler in the hole on the opening side of the hole and increasing it on the tip side.

Furthermore, in the first and second inventions, it is also desirable that the other structural member is formed by arranging a plurality of members with their faces facing each other, grooves are formed on the facing surfaces of the plurality of members, and the hole is formed by combining the grooves.
This makes it possible to easily process the grooves of each member with high precision so that the desired holes are formed.

The present invention provides a joint structure that can efficiently secure steel rods and reduce their length.

FIG. FIG. 4 is a diagram showing the three-dimensional shape of a hole 31. FIG. 4 is a diagram for explaining a groove 311. FIG. 4 is a diagram for explaining the adhesion stress of a filler 5. FIG. 13 is an example of a hole 31 that widens only in the out-of-plane direction of the wall 3. FIG. FIG. A diagram showing a joint structure 10a. FIG. 1 is a diagram explaining a GIR junction.

The following describes in detail an embodiment of the present invention with reference to the drawings.

[First embodiment]
(1. Joint structure)
Fig. 1 is a diagram showing a joint structure 1 according to a first embodiment of the present invention. The joint structure 1 joins a beam 2 and a wall 3, and Fig. 1(a) is a cross-sectional view in the thickness direction of the wall 3, and Fig. 1(b) is a cross-sectional view in the horizontal direction of the wall 3. Fig. 1(a) shows a cross-section along line B-B in Fig. 1(b), and Fig. 1(b) shows a cross-section along line A-A in Fig. 1(a).

The beam 2 is a structural member, for example, made of wood or reinforced concrete (RC).

The wall 3 is a structural member made of wood, and is formed by arranging two wood boards 30 so that their board surfaces face each other. The wood boards 30 are planar members made of wood materials such as CLT (Cross Laminated Timber) and LVL (Laminated Veneer Lumber), but the wood materials are not limited to these.

In the joint structure 1, a steel bar 4, such as a reinforcing bar, embedded in a beam 2 protrudes toward the wall 3, and the protruding portion is disposed in a hole 31 formed in the wall 3. The hole 31 extends from the surface of the wall 3 facing the beam 2 toward the inside of the wall 3, and an opening of the hole 31 is formed on that surface. The cross section of the hole 31 (referring to a cross section perpendicular to the extension direction of the hole 31; the same applies below) is circular, and the steel bar 4 is located at the center of the cross section of the hole 31. The diameter of the steel bar 4 is approximately constant throughout the entire length of the hole 31.

The holes 31 are filled with a filler material 5. The filler material 5 may be, but is not limited to, an adhesive such as epoxy resin or a grout material such as mortar. An injection hole for the filler material 5 and an air vent hole (not shown) are provided in advance in the wooden boards 30 that form the wall 3, and the filler material 5 is injected into the holes 31 through the injection hole. Mortar 6 is provided in the gap between the beam 2 and the wall 3.

Figure 2 is a perspective view showing the three-dimensional shape of hole 31 in wall 3. As shown in Figure 2, hole 31 continuously widens from the tip side of hole 31 toward the opening side in two directions, the out-of-plane direction and the in-plane direction of wall 3. The out-of-plane direction corresponds to the left-right direction in Figure 2, and the in-plane direction corresponds to the depth direction in Figure 2. The out-of-plane direction and the in-plane direction are perpendicular to each other on a plane.

Figure 3(a) shows a cross section in the thickness direction of two wooden boards 30 that form the wall 3. Grooves 311 are formed on the opposing surfaces of these wooden boards 30. The holes 31 are formed when the grooves 311 on both opposing surfaces combine when the opposing surfaces of the two wooden boards 30 are placed together as indicated by the arrows in Figure 3(a).

The groove 311 can be formed by cutting the wood board 30 with a cutting tool 8 as shown in FIG. 3(b). By moving the cutting tool 8 in the in-plane direction and thickness direction of the wood board 30, the widened shape of the groove 311 can be precisely processed, thereby realizing the widened shape of the hole 31 described above.

In this embodiment, due to the widened shape of the hole 31, when a pulling force acts on the steel rod 4, the adhesion stress of the filler 5 is made uniform over the entire length of the steel rod 4 in the hole 31, and the steel rod 4 is efficiently fixed, thereby reducing the fixed length of the steel rod 4.

In other words, the adhesive or grout material used as the filler 5 generally has a property that the greater the layer thickness, the lower the shear stiffness. In the joint structure 1, the diameter of the steel rod 4 is constant and the hole 31 widens from the tip side to the opening side, so the filler 5 becomes thicker from the tip side of the hole 31 to the opening side, and the shear stiffness gradually decreases.

When a pull-out force acts on the steel rod 4, the displacement of the steel rod 4 is large on the opening side of the hole 31, but because the filler 5 is thick on the opening side of the hole 31 and has a relatively low shear stiffness, the adhesion stress (shear stress) of the filler 5 is small. On the other hand, the displacement of the steel rod 4 is small on the tip side of the hole 31, but because the filler 5 is thin and has a relatively high shear stiffness, the adhesion stress of the filler 5 is large.

As a result, the adhesion stress generated in the filler 5 when the steel rod 4 is pulled out is uniform over the entire length of the steel rod 4 in the hole 31, as shown in the right graph of Figure 4, and the adhesion failure described above does not occur at the opening side of the hole 31, and the pull-out force is also borne at the tip side of the hole 31. In a conventional GIR joint, the adhesion force and the pull-out force calculated by the area of the triangle in the right graph of Figure 10(a) are balanced, whereas in the joint structure 1 of this embodiment, the adhesion force and the pull-out force calculated by the area of the rectangle in the right graph of Figure 4 are balanced, improving the anchorage strength of the steel rod 4.

As described above, in the joint structure 1 of this embodiment, the hole 31 widens from the tip side toward the opening side, and the thickness of the filler 5 in the hole 31 also increases from the tip side of the hole 31 toward the opening side. Since the shear stiffness of the filler 5 decreases as the filler 5 becomes thicker, the adhesion stress (shear stress) of the filler 5 when a pulling force acts on the steel rod 4 can be reduced on the opening side of the hole 31 and increased on the tip side, compared to the case where the cross section of the hole 103 is constant as shown in FIG. 10. As a result, the adhesion stress can be made uniform over the entire length of the steel rod 4, adhesion failure on the opening side of the hole 31 can be suppressed, and adhesion stress can be generated on the tip side. Therefore, the steel rod 4 can be efficiently fixed, the fixing length of the steel rod 4 can be reduced, and construction is made easier.

In this embodiment, the wall 3 is formed using multiple wooden boards 30, and the holes 31 are formed by combining the grooves 311 formed in each wooden board 30, so that the grooves 311 of each wooden board 30 can be easily processed with high precision to form the specified holes 31. In this embodiment, the steel rod 4 can be efficiently fixed in place in the GIR joint for the wooden wall 3, and the fixing length of the steel rod 4 can be shortened.

However, the present invention is not limited to the above embodiment. For example, as shown in FIG. 5, an adhesion removal portion 9 may be provided around the steel rod 4 near the opening of the hole 31 to prevent adhesion with the filler 5. The adhesion removal portion 9 can be formed, for example, by wrapping a thick strip of material such as tape around the steel rod 4 in advance, or by applying clay. By providing the adhesion removal portion 9, when the steel rod 4 yields, a section can be secured in which the steel rod 4 extends in response to the deformation of the wall 3, etc., and the steel rod 4 can be prevented from fracturing due to brittleness.

In addition, by appropriately setting the shape and movement direction of the cutting tool 8, it is possible to form the cross section of the hole 31 in a shape other than circular, and it is also possible to form a hole 31 in which only one of the out-of-plane direction and in-plane direction of the wall 3 widens, without the other widening. Figure 6 shows an example of a hole 31 that widens only in the out-of-plane direction of the wall 3, similar to Figure 2. In this case, there is an advantage that it is easier to ensure the spacing of the steel rods 4 in the in-plane direction, and it is easier to arrange the steel rods 4 densely in the in-plane direction. It also becomes easier to process the holes 31 (grooves 311).

In this embodiment, the wall 3 is formed by stacking multiple wooden boards 30, but the wall 3 may also be formed by stacking multiple concrete precast boards. The wall 3 may also be formed from a single piece of wooden material or a concrete precast member, and the hole 31 can be formed by drilling the wooden material or precast member. In this case, too, the hole 31 that widens toward the opening side can be processed relatively easily.

As shown in the joint structure 1a of FIG. 7, the hole 31 may be made to widen in a stepped manner toward the opening side. This allows the hole 31 to be easily machined using common tools. For example, when stacking multiple wooden boards 30 to form a wall 3, the grooves 311 can be cut in a stepped manner by changing the cutting width and cutting depth using the cutting tool 8, and the grooves 311 of the wooden boards 30 can be overlapped to form the hole 31. When drilling holes in wood material or precast components, the hole 31 can be easily made to widen in a stepped manner by drilling multiple times using drilling tools with different drilling diameters.

In this embodiment, the wall 3 is located above the beam 2, but even if the wall 3 is located below the beam 2, the joining can be performed using a joining structure similar to the joining structure 1 in FIG. 1 (joining structure 1 is inverted upside down). In this embodiment, the two structural members joined by the joining structure 1 are the beam 2 and the wall 3, but the combination of the structural members to be joined is not limited to this, and it is possible to apply it to a general configuration in which the steel rod 4 protruding from one structural member is inserted into the hole 31 formed in the other structural member. Examples include columns, beams, columns and beams, beams and slabs, slabs, walls, columns and walls, etc. In any case, a structural member having a hole 31 can be formed by combining multiple members, and the hole 31 can be formed by combining the grooves 311 formed in each member.

Next, another example of the present invention will be described as the second embodiment. The second embodiment will be described by focusing on the differences from the first embodiment, and similar configurations will be given the same reference numerals in the figures and the like, and the description will be omitted. Furthermore, the configuration described in the second embodiment can be combined with the configuration described in the first embodiment as necessary.

Second Embodiment
8 is a diagram showing a joint structure 10 according to a second embodiment of the present invention. The joint structure 10 differs from the first embodiment in that the cross section of the hole 31a does not change from the tip side to the opening side, and different fillers 5a, 5b are provided on the opening side and the tip side of the hole 31a.

The fillers 5a and 5b differ in particular in their shear rigidity, with the filler 5a (first filler) on the opening side of the hole 31a having a relatively lower shear rigidity than the filler 5b (second filler) on the tip side. The filler 5a is, for example, mortar or urethane, and the filler 5b is, for example, an adhesive such as epoxy resin. However, the fillers 5a and 5b are not limited to this, and it is sufficient that the shear rigidity of the filler 5a is lower than the shear rigidity of the filler 5b.

The hole 31a is first filled with the filler material 5a, and then the filler material 5b is filled above the filler material 5a. The wall 3 is provided with an injection hole and an air vent hole (not shown) for each of the fillers 5a and 5b, and the fillers 5a and 5b are injected into the hole 31a through the respective injection holes.

In the joint structure 10 of the second embodiment, by filling the opening side of the hole 31a with a filler 5a having a low shear stiffness and the tip side of the hole 31a with a filler 5b having a high shear stiffness, the same effect as in the first embodiment can be obtained, and the adhesion stress generated in the fillers 5a and 5b when a pull-out force acts on the steel rod 4 can be reduced on the opening side of the hole 31a and increased on the tip side. As a result, the adhesion stress can be made uniform over the entire length of the steel rod 4, and the steel rod 4 can be efficiently fixed, thereby reducing the fixing length of the steel rod 4.

In this embodiment, the wall 3 is located above the beam 2, but even if the wall 3 is located below the beam 2, the joining can be performed using a joining structure similar to the joining structure 10 in FIG. 8 (joining structure 10 is inverted upside down). In this case, the hole 31a is first filled with the filler 5b, and then the filler 5a is filled above the filler 5b. The widening shape of the hole 31 described in the first embodiment can also be applied to the second embodiment.

In addition, in this embodiment, the filler 5a is filled in the entire cross section of the hole 31a, but as shown in the joint structure 10a in FIG. 9, the filler 5a may be provided only around the steel rod 4, rather than the entire cross section of the hole 31a, and the filler 5b may be filled in the remaining portion, including the area between the filler 5a and the inner surface of the hole 31a. In this case, for example, the steel rod 4 may be inserted into the hole 31a with the filler 5a, such as urethane, provided around the steel rod 4 in advance, and then the filler 5b may be filled into the hole 31a.

In this case, the presence of the filler 5a with low shear stiffness on the opening side of the hole 31a provides the same effect as above. Also, the injection hole and the air vent hole (not shown) only need to be provided for the filler 5b, and the filling work only needs to be done once, making construction easier.

The above describes preferred embodiments of the present invention with reference to the attached drawings, but the present invention is not limited to these examples. It is clear that a person skilled in the art can come up with various modified or revised examples within the scope of the technical ideas disclosed in this application, and it is understood that these also naturally fall within the technical scope of the present invention.

1, 1a, 10, 10a: Joint structure 2: Beam 3: Wall 4: Steel rod 5, 5a, 5b: Filler 30: Wooden board 31, 31a: Hole 311: Groove

Claims (3)

A joining structure between two structural members,
The steel rod protruding from one structural member is positioned in a hole formed in a surface of the other structural member , which is a wall made of wood , on the side of the one structural member, and the hole is filled with a filler material;
Only one of the steel rods is disposed in one of the holes, and no other steel rods are present;
A joining structure characterized in that the hole continuously widens in two directions, an out-of-plane direction and an in-plane direction, from the tip side of the hole toward the opening side. A joining structure between two structural members,
The steel rod protruding from one structural member is positioned in a hole formed in a surface of the other structural member , which is a wall made of wood , on the side of the one structural member, and the hole is filled with a filler material;
Only one of the steel rods is disposed in one of the holes, and no other steel rods are present;
Among the fillers, a first filler located on an opening side of the hole has a lower shear rigidity than a second filler located on a tip side of the hole;
The first filler is provided only around the steel rod, and the second filler is filled between the first filler and the inner surface of the hole.
A joining structure characterized by: the other structural member is formed by arranging a plurality of members so that their surfaces face each other,
Grooves are formed on the opposing surfaces of the plurality of members,
The joint structure according to claim 1 or 2, wherein the hole is formed by combining the grooves.