JP7561165B2 - Joint structure and method for constructing the joint structure - Google Patents

Description

The present invention relates to a column-beam joint structure and a method for constructing the joint structure.

When joining wooden members in a wooden rigid frame structure with wooden columns and beams, it is common to insert a steel member protruding from one wooden member, such as a glued-in rod (GIR), into a hole in the other wooden member in the axial direction. By filling the hole with a filler such as an adhesive, the wooden members can be rigidly joined together (see, for example, Patent Document 1).

Patent Publication No. 2022-8273

Generally, the fiber direction of columns and beams is perpendicular to that of other components, so if the above method is applied to the joints between columns and beams, the GIR or other steel material will be inserted perpendicular to the fiber of one of the components, creating the problem that the strength of the frame will be determined by the strength in the perpendicular direction, which is weaker than the fiber direction.

Furthermore, wooden components may need to be fire-resistant, in which case the surface must be covered with a fire-resistant coating, but this does not bring out the inherent beauty of wooden construction.

In addition, when using the above-mentioned construction method to join wooden members together, it becomes necessary to move the wooden member in the axial direction in order to insert the steel material into the hole in the wooden member. In particular, when the wooden member is a beam, there is often not enough space to move it in the axial direction of the beam, making construction difficult. Also, when drilling holes in the axial direction of the wooden member, there is a limit to how far the hole can be drilled in the depth direction due to the drilling technology (for example, the length of the drilling tool), and the length to which the steel material can be fixed is limited by the drilling limit.

The present invention was made in consideration of the above-mentioned problems, and its purpose is to provide a column-beam joint structure that is excellent in terms of strength, design, and construction.

The first invention for achieving the above-mentioned object is a joint structure between a pillar and a beam, wherein the pillar is constructed by filling the inside of an outer periphery of an exterior wooden member with concrete, the beam is passed through an upwardly open slit provided in the exterior wooden member, inserted into the upper end of the pillar and embedded in the concrete , and the beam has a beam body made of wood and a steel member having one end fixed inside the beam body and the other end protruding from the beam body, and the other end of the steel member is embedded in the concrete inside the pillar .

In the present invention, the columns are made of a composite structure of concrete and wood, and the beams are placed through slits in the exterior wood and embedded in the concrete inside the columns. As a result, in the present invention, the exterior of the columns is exposed wood, making it a frame with excellent design, and the columns have excellent structural performance because they have concrete inside. In addition, since concrete is used for the columns, as described above, it is possible to avoid the strength issues that arise when steel bars are placed in the direction perpendicular to the grain, and a frame with excellent strength can be made. In addition, in the present invention, the beams can be installed by dropping them from above, making it unnecessary to move them in the beam axial direction, and construction is easy. In addition, the beams can be made of wooden members that are lightweight, high strength, and excellent in design.

The steel material may be, for example, a steel rod, and the beam body may be formed by stacking a plurality of wooden boards, and one end of the steel material may be placed in a space formed by combining grooves machined into adjacent wooden boards, and a filler material may be filled in the space.
In this case, there is no need to drill holes in the beam body in the beam axial direction, so pre-processing is simplified and the length of the groove is not limited by processing techniques.

The steel material may be an H-shaped steel, and a pair of the beams may be arranged to pass through each of the slits provided at opposing positions in the exterior timber, with the other ends of the steel material of each of the beams arranged facing each other inside the pillar and embedded in the concrete inside the pillar.
The use of H-shaped steel as the steel material is advantageous in terms of structural performance such as rigidity and strength compared to the use of steel bars such as reinforcing bars.

The second invention is a method for constructing a joint structure between a pillar and a beam, the pillar being formed by filling the inside of an exterior wooden piece located on the outer periphery with concrete, the beam having a beam body made of wooden material and a steel material having one end fixed inside the beam body and the other end protruding from the beam body, the method comprising the steps of: before filling the upper end of the pillar with concrete , passing the beam through an upwardly open slit provided at the upper end of the exterior wooden piece and dropping it from above into the upper end of the pillar; and filling the upper end of the pillar with concrete and embedding the beam in the concrete, the method being characterized in that in the embedding step, the other end of the steel material is embedded in the concrete inside the pillar .
According to the second invention, it is possible to easily join a pillar having a composite structure of concrete and wood to a beam.

The present invention can provide a column-beam joint structure that is excellent in terms of strength, design, and construction.

FIG. A diagram showing the cross section of a column 2 and a beam 4. 4A to 4C are diagrams showing a method of constructing the joint structure 1. 4A to 4C are diagrams showing a method of constructing the joint structure 1. 4A to 4C are diagrams showing a method of constructing the joint structure 1. A diagram showing a beam 40. An example of beam 4 placement. A diagram showing a cross section of a column 2 and a beam 4a. 4A to 4C are diagrams showing a method of constructing the joint structure 1a. An example using steel beam 4b.

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

[First embodiment]
(1. Joint structure 1)
Fig. 1(a) is a diagram showing a rigid frame structure including a joint structure 1 according to a first embodiment of the present invention. This structure is a structure for the periphery of a building, and has a rigid frame structure with a single structural plane composed of columns 2 and beams 4. The columns 2 and beams 4 are provided on multiple upper and lower floors. In this example, the beams 4 on each floor are located at the top of the columns 2 on each floor, but they can also be located slightly lower than the top. In addition, a slab (not shown) is placed on the beams 4.

The joint structure 1 of this embodiment joins a column 2 and a beam 4. FIG. 1(b) is a perspective view showing the joint structure 1. In the joint structure 1, a beam 4 is joined to the side surface of the column 2. Note that in FIG. 1(b), the upper layer column 2 that is stacked on top of the column 2 in the figure is omitted.

Figure 2 shows the cross sections of the column 2 and beam 4 for the joint structure 1 in Figure 1(b). Figure 2(a) is a vertical cross section of the column 2 and beam 4, and Figure 2(b) is a horizontal cross section of the column 2 and beam 4. Figure 2(c) is a horizontal cross section of the column 2, and Figure 2(d) is a vertical cross section of the beam 4. Figures 2(b) and (c) are cross sections taken along lines a-a and b-b in Figure 2(a), respectively, and Figure 2(a) is a cross section taken along line c-c in Figure 2(b). Figure 2(d) is a cross section taken along line d-d in Figure 2(b).

The column 2 is a composite structural column made of concrete C and wood, and its horizontal cross section is rectangular. However, the cross-sectional shape of the column 2 is not limited to this, and may be other polygonal or circular shapes. The column 2 has an outer casing wooden material 21 on the outer periphery, main reinforcement bars 22 are placed on the inside, and concrete C is filled in. In this way, the inside of the column 2 is made of reinforced concrete with excellent fire resistance. In the column 2 of this embodiment, hoop reinforcement is omitted, but hoop reinforcement may be present.

The exterior timbers 21 are made of planks of wood such as LVL (Laminated Veneer Lumber) and CLT (Cross Laminated Timber). Four exterior timbers 21 are arranged corresponding to each side of the rectangular cross section of the column 2, and the ends of the exterior timbers 21 are joined together at the corners of the cross section with bolts 23 such as lag screw bolts. Note that other wood materials such as laminated timber and BP material can also be used as the exterior timbers 21. The ends of the exterior timbers 21 can also be joined together with adhesives instead of bolts 23.

The exterior timbers 21 improve the design by forming the exterior appearance of the columns 2, and also exert a shear reinforcement function due to their in-plane rigidity. The exterior timbers 21 are also expected to play a role in compensating for the fire resistance of columns 2 that do not have hoop reinforcement (the omission of hoop reinforcement may reduce the fire resistance of the concrete part) by acting as a fire repellent in the event of a fire. For this reason, it is desirable for the thickness of the exterior timbers 21 to be the minimum thickness that allows them to function as a fire repellent while still having sufficient in-plane rigidity.

In this embodiment, a slit 211 is provided at the upper end of the exterior wood 21 at a position corresponding to the beam 4 on the side of the column 2. The slit 211 is open upward and is provided only at the position corresponding to the beam 4.

The beam 4 has one end of a steel bar 42, such as a reinforcing bar, embedded and fixed inside a beam body 41 made of wood material such as laminated timber, and the other end of the steel bar 42 protrudes horizontally from the end of the beam body 41 on the column 2 side. Multiple steel bars 42 (two in the example of Figure 2(b)) are arranged on the upper and lower levels.

The beam body 41 is formed by stacking and gluing multiple wooden boards (lamina) 411, and at that time, grooves 412 pre-machined in adjacent wooden boards 411 are combined to form a space for placing one end of a steel bar 42. One end of the steel bar 42 is placed in this space and filled with a filler 413 such as an adhesive, thereby fixing that end of the steel bar 42 to the beam body 41.

The beam 4 is arranged so that the end of the beam body 41 on the column 2 side passes through the slit 211, and the protruding portion of the steel rod 42 protruding from the end is inserted into the upper end of the column 2. The end of the beam body 41 is placed on the bottom surface of the slit 211. The end face of the beam body 41 on the column 2 side abuts against the concrete C inside the column 2, and the protruding portion of the steel rod 42 is embedded in this concrete C.

In the joint structure 1, a pair of beams 4 are installed on the left and right so that they pass through slits 211 provided at opposing positions in the outer shell timber 21. The steel rods 42 of these beams 4 are positioned so that they are offset from one another in a plan view, as shown in FIG. 2(b).

(2. Method for constructing joint structure 1)
To construct the joint structure 1, first, as shown in FIG. 3(a), a precast column in which the outer shell timber 21, the main reinforcement 22, and the concrete C are integrated up to the height below the slits 211 is fabricated in advance in a factory or the like, and this precast column is then transported to the site and erected.

The beam 4, like the precast columns, is also fabricated in advance in a factory or the like, and then transported to the site and dropped onto the precast column as indicated by the arrow e in Figure 3(a). The end of the beam body 41 on the column 2 side is passed through the slit 211 in the exterior wood 21, and the protruding part of the steel rod 42 is inserted into the upper end of the column 2, and placed on top of the concrete C of the precast column.

Figure 3 (b) shows the state after the left and right beams 4 have been installed. The above-mentioned ends of the beam body 41 are placed on the bottom surfaces of the slits 211 and are supported from below. The beam body 41 is fixed to the exterior wood 21 with fixing means such as screws as necessary.

Then, concrete C is poured and filled at the top end of the pillar 2 up to the top end of the exterior wood 21, thereby constructing the joint structure 1 between the pillar 2 and the beam 4, as shown in FIG. 2(a) and other figures. In this embodiment, a new pillar 2 is installed on top of this pillar 2 to construct an upper layer frame. In FIG. 2(a), the main reinforcement 22 protrudes above the pillar 2, but the upper layer pillar 2 can be joined to the lower layer pillar 2 by inserting the protruding portion 221 (see FIG. 2(a)) of the main reinforcement 22 of the lower layer pillar 2 into a hole (not shown) made at the bottom of the concrete C of the precast pillar and filling it with a filler such as mortar.

In this manner, in this embodiment, the pillars 2 are made of a composite structure of concrete C and wood, and the beams 4 are placed through the slits 211 of the exterior timber 21 and embedded in the concrete C inside the pillars 2. As a result, in this embodiment, the exterior of the pillars 2 has exposed wood, making it a structure with excellent design, and the pillars 2 have excellent structural performance because they have concrete C inside. In addition, the exterior timber 21 functions as a fuel to suppress the temperature rise of the concrete C, which also has the effect of preventing the concrete C from exploding.

In addition, in this embodiment, concrete C is used for the columns 2, and as described above, the steel bars 42 are arranged in the direction perpendicular to the fibers, which avoids the strength issues that arise, resulting in a frame with excellent strength, and by stabilizing the rigidity and strength of the joints between the columns 2 and the beams 4, a rigid frame can be obtained that can ensure good performance against repeated loads during earthquakes. In addition, costs can be reduced compared to when the columns 2 are constructed of wood only.

In addition, in this embodiment, a slit 211 that opens upward is provided at the position corresponding to the beam 4 at the upper end of the exterior wood 21, and the beam 4 can be dropped in from above. This eliminates the need to move the beam 4 in the beam axial direction, making construction easier. Furthermore, in this embodiment, the pillar 2 and beam 4 are precast, and construction is fast because it is only necessary to fill the upper end of the pillar 2 with concrete C at the site. In addition, the end face of the beam body 41 abuts against the concrete C inside the pillar 2, making it easier to increase the rigidity and strength of the joint structure 1.

In addition, in this embodiment, the beam body 41 is formed by stacking multiple wooden boards 411 with grooves 412, and one end of the steel rod 42 is placed in the space formed by combining the grooves 412 and filled with filler material 413. Therefore, there is no need to drill holes in the beam body 41 in the beam axis direction, making pre-processing easier, and the length of the grooves 412 is not limited by processing techniques.

However, the present invention is not limited to the above embodiment. For example, in this embodiment, the precast columns are erected when the columns 2 are constructed, but after the main reinforcement 22 of the columns 2 are erected on-site as shown in FIG. 4(a), the outer shell timber 21, which has been pre-assembled into a cylindrical shape and made into a unit, can be dropped in from above as shown by the arrow f.

Figure 4 (b) shows the state after the exterior timbers 21 have been erected. When unitizing the exterior timbers 21, if necessary, opposing exterior timbers 21 are connected with separators (not shown) to resist the lateral pressure when filling the interior of the column 2 with concrete C. Since the column 2 does not have hoop reinforcement, there is no problem with the separators interfering with the hoop reinforcement and preventing the exterior timber 21 from being lowered, and the separators also function as shear reinforcement members in place of the hoop reinforcement.

After that, as shown in Figure 4 (c), the exterior wooden timber 21 is used as a formwork, and concrete C is poured and filled up to the height below the slits 211. After this, the joint structure 1 is constructed by carrying out the steps from Figure 3 (b) onwards. The main reinforcement 22 of the upper layer column 2 can be connected to the protruding portion 221 of the main reinforcement 22 of the lower layer column 2 (see Figure 2 (a)) using a mechanical joint or the like, and raised up.

The main reinforcement 22 and the exterior timber 21 units can also be dropped in at the same time. In this case, dropping in is performed with the lower end of the main reinforcement 22 protruding downward from the exterior timber 21, thereby securing working space for connecting the main reinforcement 22 to the main reinforcement 22 of the column 2 on the lower level. Alternatively, instead of dropping in the exterior timber 21 units, the exterior timber 21 can be installed from the side after the main reinforcement 22 is in place, and then assembled.

The precast columns are not limited to those described above. For example, as shown in FIG. 5(a), the main reinforcement 22, the outer shell timber 21 up to the height below the beam 4, and concrete C may be integrated into a precast column manufactured in a factory or the like, and then transported to the site and installed.

After this, the beam 4 is installed as shown in FIG. 5(b), and hoop reinforcement (not shown) is installed on the concrete C of the precast column as necessary. Then, the exterior timber 21 at the upper end of the column 2 is placed above the exterior timber 21, and the exterior timber 21 is fixed to the exterior timber 21 below and to the beam body 41 with fixing means such as screws, and concrete C is poured inside. This also allows the joint structure 1 to be constructed.

In this embodiment, the beam 4 is made of wood, but it may be made of reinforced concrete, or it may be a composite structure of concrete and wood, like the column 2. Figure 6 shows an example of a beam 40 having a composite structure, with a cross section similar to that of Figure 2(d), and is formed by placing one end of a steel rod 42 inside a concavely arranged wooden member 43 and filling it with concrete C.

The joint structure 1 of this embodiment is intended to be applied to a single-panel rigid frame structure as shown in FIG. 1(a) on the periphery of a building, but it may also be applied inside a building to the joints of rigid frame structures in two directions, the plane shown in FIG. 1(a) and a plane perpendicular to that plane in a plan view. In this case, beams 4 are also provided before and after the column 2. The steel bars 42 of these front and rear beams 4 are positioned at different heights from the steel bars 42 of the left and right beams 4 shown in FIG. 2(a) etc.

In this embodiment, the end of the beam body 41 on the side of the column 2 is placed on the bottom surface of the slit 211, but this end may be placed on a temporary support (not shown) installed on the side of the exterior wood 21, so that the end face of the beam body 41 on the side of the column 2 is positioned on the surface of the exterior wood 21, as shown in Figure 7. In this case, concrete C is also filled into the slit 211, and this concrete C comes into contact with the end face of the beam body 41.

The steel rods 42 are not limited to those fixed to the ends of the beams 4, but may be embedded over the entire length of the beam body 41 in the beam axis direction, with both ends of the steel rods 42 protruding from both ends of the beam body 41 in the beam axis direction. Placing the steel rods 42 over the entire length of the beam body 41 is expected to improve the rigidity and strength of the beams 4, and can accommodate long-span beams. If the beams 4 are made of reinforced concrete, the main reinforcement can be used as steel rods 42.

The end of the steel rod 42 in the concrete C may be bent into a hook shape, and if the anchoring length of the steel rod 42 is insufficient within the width of the concrete C, the anchoring length can be ensured by providing a hook.

In addition, in this embodiment, the steel rod 42 is embedded in the beam body 41, but the steel material embedded in the beam body 41 is not limited to this. Below, an example in which a different steel material is used will be described as the second embodiment. In the second embodiment, a configuration different from the first embodiment will be described, and similar configurations will be given the same reference numerals in the figures, etc., and description thereof will be omitted.

Second Embodiment
Fig. 8(a) shows a vertical cross section of a column 2 and a beam 4a in the joint structure 1a of the second embodiment, similar to Fig. 2(a), while Fig. 8(b) shows a vertical cross section of the beam 4a taken along line g-g in Fig. 8(a).

The joint structure 1a differs from the joint structure 1 of the first embodiment in that the steel material fixed to the beam body 41 is an H-shaped steel 42a. One end of the H-shaped steel 42a is embedded and fixed inside the beam body 41, and the other end protrudes horizontally from the end of the beam body 41 on the column 2 side.

The beam body 41 is formed by combining divisions 41a, 41b, which are formed by stacking and gluing multiple wooden boards 411. These divisions 41a, 41b are formed by dividing the beam body 41 in a vertical plane parallel to the beam axis direction, and grooves 412a, 412b are formed on the opposing surfaces. The divisions 41a, 41b are combined so that one end of the H-shaped steel 42a is sandwiched between these grooves 412a, 412b, and one end of the H-shaped steel 42a is fixed to the beam body 41 by filling the space formed by the grooves 412a, 412b with a filler 413 such as an adhesive.

To construct the joint structure 1a, as described above, for example as shown in Figure 9(a), a precast column is erected on-site, in which the outer timber 21, main reinforcement 22, and concrete C are integrated up to the height below the slit 211. Then, as shown by arrow h, the beam 4a is dropped from above the precast column, the end of the beam body 41 on the column 2 side is passed through the slit 211 of the outer timber 21, and the protruding part of the H-shaped steel 42a is inserted into the upper end of the column 2.

Figure 9(b) shows the state after a pair of left and right beams 4a have been installed by passing each of them through slits 211 provided at opposing positions in the exterior wood 21. The other ends of the H-shaped steel 42a of the left and right beams 4a are positioned facing each other, and the webs of these H-shaped steel 42a are integrated inside the column 2 by bolt joints (high-strength bolt joints). In the figure, symbol P denotes a splice plate used for the bolt joint, and symbol F denotes a fastener such as a bolt used for the bolt joint.

The ends of the two H-shaped steels 42a do not need to abut each other, and by assuming a certain amount of gap as a design value, on-site construction errors can be absorbed. Also, if it is not necessary from a structural performance perspective, the bolt connection of the H-shaped steel 42a may be omitted.

After this, concrete C is poured and filled into the upper end of the pillar 2 up to the top end of the exterior timber 21, and the end of the H-shaped steel 42a is embedded in the concrete C, thereby constructing the joint structure 1a between the pillar 2 and the beam 4a, as shown in Figure 8(a) etc.

In the second embodiment, the pillars 2 are made of a composite structure of concrete C and wood, and the beams 4a are placed through the slits 211 of the exterior wood 21 and embedded in the concrete C inside the pillars 2, thereby achieving the same effect as in the first embodiment. In addition, the second embodiment uses H-shaped steel 42a as the steel material, which is more advantageous than the joint structure 1 of the first embodiment in terms of structural performance such as rigidity and strength, and the web of the H-shaped steel 42a can also serve as shear reinforcement for the ends of the beams 4a. On the other hand, the first embodiment uses steel bars 42 such as reinforcing bars, which has the advantage that the beams 4 can be easily manufactured, and it is not necessary to join the steel bars 42 together.

It is also possible to use the H-shaped steel as the beam itself, rather than as a steel material fixed to the beam body 41. In this case, too, a steel beam made of H-shaped steel is dropped from above the precast column, and the ends of the left and right steel beams 4b on the column 2 side are inserted into the upper end of the column 2 through the slits 211 in the exterior timber 21, as shown in Figure 10 (a). The ends of the left and right steel beams 4b are then butted together, and their webs are bolted together. After this, concrete C is poured and filled into the upper end of the column 2 up to the top of the exterior timber 21.

In cases where a long steel beam 4b is to be laid across multiple spans, as shown in FIG. 10(b), it is also possible to use an H-shaped steel beam 4b as a through beam, drop it from above the precast column, and insert it into the upper end of the column 2. After this, just as above, pour and fill the concrete C at the upper end of the column 2 up to the top of the exterior timber 21.

In this way, the beams can be steel beams 4b, which have excellent structural performance. On the other hand, in the examples of Figures 2 and 8, the beams 4, 4a can be wooden members that are lightweight, high-strength, and have excellent design aspects, and in either case, the joint structure of the present invention can reliably fix the beams to the columns.

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: Joint structure 2: Column 4, 4a, 40: Beam 4b: Steel beam 21: Outer timber 41: Beam body 42: Steel bar 42a: H-shaped steel 211: Slit 411: Wood board 412, 412a, 412b: Groove 413: Filler C: Concrete

Claims (4)

A column-beam joint structure,
The pillars are constructed by filling the inside of the outer timber shell located on the outer periphery with concrete,
The beam is passed through an upwardly open slit provided in the outer shell timber, inserted into the upper end of the column, and embedded in the concrete ;
The beam is
The beam body is made of wood,
A steel material having one end fixed inside the beam body and the other end protruding from the beam body;
having
A joint structure characterized in that the other end of the steel material is embedded in the concrete inside the pillar . The steel material is a steel bar,
The beam body is formed by laminating a plurality of wooden boards,
The joint structure according to claim 1 , characterized in that one end of the steel material is placed in a space formed by combining grooves machined into adjacent wooden boards and filled with a filler material. The steel material is an H-shaped steel,
A pair of the beams are arranged to pass through the slits provided at opposing positions of the outer shell wood,
The joint structure according to claim 1 , characterized in that the other ends of the steel members of each of the beams are arranged facing each other inside the column and embedded in the concrete inside the column. A method for constructing a column-beam joint structure, comprising the steps of:
The pillars are constructed by filling the inside of the outer timber shell located on the outer periphery with concrete,
The beam is
The beam body is made of wood,
A steel material having one end fixed inside the beam body and the other end protruding from the beam body;
having
Before filling the upper end of the column with the concrete, the beam is passed through an upwardly open slit provided at the upper end of the outer shell timber, and dropped from above to be inserted into the upper end of the column;
filling the upper end of the column with concrete and embedding the beam in the concrete;
Equipped with
A method for constructing a joint structure, characterized in that in the embedding step, the other end of the steel material is embedded in the concrete inside the pillar .

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