JP2017128981A - Wooden composite beam and construction method for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composite beam capable of reducing long-term deflection of a wooden beam material.SOLUTION: A composite beam 10 comprises: a wooden beam material 2; a floor material 4 that is made of Cross Laminated Timber (CLT) joined to a top surface 2a of the wooden beam material 2; a bulldog dowel joint device 6 that is arranged between the top surface 2a of the wooden beam material 2 and an undersurface 4b of the CLT floor material 4 to join the wooden beam material 2 and the CLT floor material 4 together; and a bolt 8 that passes through the wooden beam material 2 and the CLT floor material 4 to bind the wooden beam material 2 and the CLT floor material 4 together.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a wooden composite beam and a construction method thereof, and more specifically, to a wooden composite beam composed of a wooden beam material and a floor material of a cross laminated plate (CLT: Cross Laminated Timber) and a construction method thereof.

  Conventionally, when constructing floors of two or more floors of wooden buildings, a floor construction method has been adopted in which a small beam is provided for each fixed section between the beams, and the periphery of the flooring material is fastened to the beams and the small beams. . Moreover, an example of a construction method in which a structural plywood is directly laid as a floor material on a beam without providing a small beam is described in Patent Document 1 below. Further, a floor fastening structure in which a structural plywood and a beam are fastened using wood screws is described in Patent Document 2 below.

  In recent years, buildings using wooden ramen construction have been built. In the wooden ramen construction method, even a wooden structure can be designed with a large span, and a large space can be realized. In the wooden ramen construction method, the floor of the upper floor was constructed by the conventional floor construction method or the construction method in which the structural plywood is directly installed on the beam.

JP 2012-62715 A JP-A-2005-90518

  By the way, in general, even when the wooden beam material has sufficient strength in terms of the structure of a building, long-term deflection occurs over a long period of time. For this reason, in many buildings, the cross-sectional area of the wooden beam material has been increased in consideration of long-term deflection. In particular, in the case of long span beams using the wooden frame construction method, considering the long-term deflection due to secular change, high beam formation was required to secure a large cross-sectional area.

  This invention is made | formed in view of said situation, and it aims at providing the synthetic beam which can reduce the long-term deflection of a wooden beam material, and its construction method.

  The composite beam of the present invention is composed of a wooden beam material, a floor material of a cross laminated plate (CLT) joined to the upper surface of the wood beam material, and a joint for joining the wooden beam material and the floor material of the cross laminated plate. It is characterized by that.

  An orthogonal laminated board is a width direction in which the fiber direction is made substantially parallel to each other, and a board or a small angle material (including those prepared by bonding them in the length direction so that they are almost parallel to the fiber direction). These are general materials that are laminated or bonded together with their fiber directions being substantially perpendicular to each other and having a structure of three or more layers (Ministry of Agriculture, Forestry and Fisheries Notification No. 3079). In addition, the dimensional standards of the orthogonal assembled plate are a thickness of 36 mm to 500 mm, a width of 300 mm or more, and a length of 900 mm or more (same).

  In the composite beam of the present invention, the cross-sectional secondary moment I of the composite beam between the wooden beam material and the orthogonal laminated board floor is increased by joining and integrating the wooden beam material and the orthogonal laminated board floor material. Thus, the long-term deflection of the wooden beam material can be reduced.

  In addition, the structural plywood conventionally used as a flooring has a thickness of only 24 mm or 28 mm at most, and is very thin with respect to the beam formation (for example, 300 mm). For this reason, even if the structural plywood is directly installed on the beam material, there is substantially no composite effect of increasing the moment of section, and an effect of reducing the long-term deflection of the beam material could not be expected.

  On the other hand, the orthogonal laminated board is much thicker than the conventional structural plywood. For this reason, the cross-section secondary moment of the composite beam can be sufficiently increased by integrating the orthogonal laminated plate with the beam material as a floor material.

  In addition, since the secondary moment of section of the composite beam can be increased, the cross-sectional area of the beam material itself can be made smaller than before, while ensuring sufficient secondary moment of section to reduce the long-term deflection of the composite beam as a whole. can do. Particularly, the beam formation can be lowered in the beam material of the long-span ramen construction method, and the cost of the beam material can be reduced.

  In addition, the cross-assembled board is not only thicker than the structural plywood, but also a bi-directional board that has almost the same performance in the orthogonal direction. Have. For this reason, an orthogonal laminated board is suitable for using as a flooring. Further, if a beam extending in the XY direction orthogonal to each other and the orthogonal laminated plate are joined, an equivalent composite effect can be obtained in both the XY directions.

  In the present invention, it is preferable that the connector is a dowel connector disposed between the upper surface of the wooden beam member, the orthogonal laminated plate, and the lower surface.

  The gibber joint is a kind of wood joint, and is disposed between two members to be joined and has a function of preventing shear deviation between the two members by being inserted into both members. . Examples of gibber joints include split rings, core plates, and bulldog gibels.

  By the way, since the joint strength by the diver joint is generally capable of withstanding the stress at the end of the building and lower than the strength, the dibel joint is not usually used for joining structural members. On the other hand, in the composite beam, as described below, a gibber joint can be used for joining structural members.

  In designing the composite beam, it is possible to design the beam so that sufficient strength can be maintained with only the beam material without considering the composite effect. As a result, if the safety at the end is ensured in the same way as before with just the beam material, the joint itself between the beam material in the composite beam and the floor material of the orthogonal laminated plate does not require the ability to withstand ultimate stress. . Therefore, the joint need only satisfy the performance (shear performance) sufficient to withstand the shearing force due to the long-term deflection between the beam and the floor of the orthogonal laminated plate. Tools can be used.

  By joining the wooden beam member and the orthogonal laminated plate with the gibel joint tool, shear deviation between the wooden beam member and the orthogonal laminated plate can be prevented. Further, since the gibber connector is always pressed against the beam material by the load of the floor material of the orthogonal assembly plate, the bonding is maintained even when the material shrinks or creeps due to aging. Furthermore, since each individual jib connector has a certain area, the use of a jib connector can reduce the concentration of shearing force on the connector compared to the case where the members are joined with wood screws. .

  Further, the composite beam construction method of the present invention includes a preparation step of preparing a wooden beam material and a flooring material of an orthogonal laminated plate, an arrangement step of arranging a diver joint on the upper surface of the wooden beam material, and a wooden beam material The floor of the orthogonal gluing board is piled on the upper surface of the plate, and the dive joint is inserted into both the wooden beam and the floor of the orthogonal gluing board to join the wooden beam and the floor of the crossing board. And a joining step to be performed.

  Thus, according to the construction method of the composite beam of the present invention, the diver joint is arranged on the upper surface of the wooden beam material, and the floor material of the orthogonal laminated plate is stacked thereon, and the wooden beam material and the orthogonally assembled material can be easily obtained. A composite beam is constructed by joining the floor of the board. For this reason, it is not necessary to manufacture the composite beam in advance in a factory or the like, and it is possible to transport the beam material and the floor material of the orthogonal laminated plate to the construction site and to easily construct the composite beam at the construction site. In joining, it is preferable to squeeze the dowel joint into the wooden beam material and the orthogonal laminated plate by performing one or both of driving with a wooden hammer and tightening with a bolt or the like.

  According to the composite beam of the present invention, the long-term deflection of the wooden beam material can be reduced.

1 is a perspective view of a composite beam according to an embodiment of the present invention. It is sectional drawing of the composite beam shown in FIG. It is a perspective view of a dowel connector. It is a partial cross-section exploded perspective view of a composite beam according to an embodiment of the present invention. (A) is a schematic diagram showing how a composite beam bends, and (B) is a schematic diagram showing how a conventional single beam is bent.

Hereinafter, embodiments of a composite beam and its construction method according to the present invention will be described with reference to the drawings.
FIG. 1 shows a perspective view of a composite beam 10 in which a wooden beam material 2 and a CLT floor material 4 are integrated, and FIG. 2 shows a cross-sectional view of the composite beam shown in FIG.

  The composite beam 10 of the present embodiment includes a wooden beam member 2, a flooring 4 of a cross laminated plate (CLT) joined to the upper surface 2 a of the wooden beam member 2, and an upper surface 2 a of the wooden beam member 2 and a CLT flooring 4. And a bulldog dowel joint 6 that joins the wooden beam member 2 and the CLT floor member 4 to each other.

  The wooden beam material 2 of this embodiment has dimensions of a beam formation H = 360 mm, a width W = 120 mm, and a length L = 4 m, and is arranged at intervals of a beam distance D = 3 m. The wooden beam material 2 may be a solid material or a laminated material.

On the other hand, the CLT flooring 4 of the present embodiment has a thickness T = 150 mm to 180 mm, a width of 3 m, and a length of 3 m.
In addition, it is preferable that the thickness of the flooring 4 of CLT is 90 mm-270 mm, More preferably, it is good that it is 150 mm-180 mm. Moreover, a synthetic | combination effect can be heightened by making the width | variety of the flooring 4 of CLT into 3 m or more. Moreover, there is no restriction | limiting in particular in the length of the flooring 4 of CLT, For example, 10 m or more may be sufficient.

  Moreover, it is preferable that the thickness of the flooring 4 of CLT is 1/3 to 1/2 of the beam formation of the wooden beam 2. Thereby, the synthetic | combination effect of a composite beam can be heightened.

Further, as shown in FIG. 1, in the present embodiment, a plurality of CLT floor materials 4 are provided in the length direction of the wooden beam material 2. Adjacent CLT flooring 4 may be brought into contact with each other or may be separated from each other. In the example shown in FIG. 1, the CLT flooring 4 is provided such that the wooden beam 2 is positioned along the center line of the CLT flooring 4. You may be located in the peripheral part of the flooring 4.
In addition, it is thought that the part of the effective width E = about 1 m which sandwiches the wooden beam material 2 among the floor materials 4 of CLT contributes substantially to the improvement of the cross-sectional secondary moment of the composite beam 10.

  In addition, the CLT flooring 4 is not only thicker than the structural plywood, but also a bi-directional plate having almost the same performance in the orthogonal direction. Has characteristics. Therefore, if the wooden beams 2 and 3 extending in the XY direction orthogonal to each other and the floor material 4 of the CLT are joined, an equivalent composite effect can be obtained in both the XY directions.

  In FIG. 3, the perspective view of the bulldog dowel joint tool 6 is shown. The bulldog dowel 6 includes a flat portion 60 having an opening 60 a formed at the center, and teeth 61 that rise up and down alternately with respect to the flat portion 60 around the flat portion 60. The bulldog gibber 6 has a shear resistance preventing the shear deviation between the wooden beam member 2 and the CLT flooring 4 by causing these teeth 61 to be embedded in the wooden beam member 2 and the CLT flooring 4. Demonstrate. The bulldog dowel joint 6 is also constantly pressed against the wooden beam material 2 by the load of the CLT floor material 4, so that the joining is maintained even when the material shrinks or creeps over time.

  In designing the composite beam 10 of the present embodiment, the wooden beam material 2 alone is designed to ensure sufficient strength so that the safety at the end time can be ensured in the same manner as in the past. The As a result, the joint itself between the wooden beam member 2 and the CLT floor member 4 in the composite beam 10 is sufficient to withstand a shearing force due to long-term deflection between the wooden beam member 2 and the CLT floor member 4. Only performance (shearing performance) is required, and performance to withstand ultimate stress is not required. For this reason, the bulldog dowel joint 6 that is not normally used for joining structural members can be used for joining the wooden beams 2 and the CLT flooring 4.

Further, the wooden beam member 2 and the CLT floor plate 4 are fastened together by bolts 8 penetrating the wooden beam member 2 and the CLT floor plate 4. Tightness ensures the integrity of the wooden beam material 2 and the CLT floor plate 4. Also, the teeth 61 of the bulldog dowel joint 6 can be embedded into the upper surface 2a of the wooden beam material 2 and the lower surface 4b of the CLT floor material 4 by tightening.
In addition, the diameter of the volt | bolt 8 can select arbitrary suitable things, such as 10 mm, 12 mm, or 16 mm, for example.

With reference to FIG. 4, the construction method of the composite beam of this embodiment is demonstrated. In the construction of the composite beam, a wooden beam material 2 and a flooring 4 of a cross laminated board (CLT) are prepared.
In the wooden beam material 2, leading holes 20 penetrating from the upper surface 2 a to the lower surface 2 b are formed at regular intervals along the length direction. Further, on the upper surface 2 a of the wooden beam member 2, a pocket portion 21 centering on the leading hole 20 is formed in order to arrange the bulldog dowel joint 6. The depth of the pocket portion 21 is preferably equal to the wall thickness of the flat portion of the bulldog gibber 6. It should be noted that the formation of the borehole 21 can be omitted.
On the other hand, the CLT flooring 4 is also formed with a leading hole 40 penetrating from the upper surface 4a to the lower surface 4b.

Next, the bulldog dowel joint 6 is disposed in each pocket portion 21 on the upper surface 2a of the wooden beam material 2 assembled at the construction site.
In the example shown in FIG. 4, the bulldog dowel joints 6 are arranged in a line along the length direction of the wooden beam member 2, but the arrangement of the dowel joints is not limited to this. For example, a plurality of dowel joints may be arranged, or may be arranged in a staggered manner.

  Subsequently, the CLT flooring 4 is overlaid on the upper surface 2a of the wooden beam material 2 on which the bulldog dowel joint 6 is disposed. At this time, the positions of the leading hole 20 of the wooden beam material 2 and the leading hole 40 of the floor material 4 of the CLT are matched. By driving the CLT flooring 4 with a wooden mallet, the teeth 61 of the bulldog dowel joint 6 are sunk into both the wooden beam 2 and the CLT flooring 4 so that the wooden beam 2 and the CLT flooring 4 And join. Further, the wood beam member 2 and the CLT floor plate 4 are fastened with the bolts 8 and nuts 9 as the fastening members through the tip hole 20 of the wood beam member 2 and the tip hole 40 of the floor member 4 of the CLT. The integrity of the wood beam material 2 and the CLT floor material 4 is ensured. In this way, the composite beam 10 in which the wooden beam material 2 and the CLT floor material 4 are joined is constructed.

  FIG. 5A schematically shows the long-term deflection of the composite beam in which the wooden beam material 2 and the CLT floor material 4 are integrated, and FIG. 5B schematically shows the long-term deflection of the conventional beam. Show. FIG. 5A schematically shows only the portion of the effective width E centered on the wooden beam 2 out of the CLT floor material 4 joined to the wooden beam material 2. The composite beam 10 shown in FIG. 5 (A) has a cross-sectional secondary moment larger than that of the wooden beam material 2 due to the composite effect. Therefore, the long-term deflection of the composite beam 10 is long-term only of the wooden beam material 2 shown in FIG. Smaller than deflection.

  In addition, since the secondary moment of section of the composite beam 10 can be increased by the composite effect, the cross section moment of the wooden beam 2 itself can be secured while ensuring a sufficient secondary moment of section to reduce the long-term deflection of the composite beam 10 as a whole. The cross-sectional area can be made smaller than before. In particular, the beam formation can be lowered in the beam material of the laminated material of the long span ramen construction method, and the cost of the beam material can be reduced. In addition, a composite beam made by joining a solid beam and a CLT floor material ensures a high moment of inertia and a long-term deflection without using an expensive large cross-section laminated beam. Reduction can be achieved.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the present invention. In the embodiment described above, an example in which a bulldog dowel joint is used as the joint has been described. However, the joint in the present invention is not limited to this, and shear shear between the wooden beam material and the CLT flooring is not limited thereto. For example, a split ring and a core plate may be used as an example of a dowel joint. Moreover, a screw and a volt | bolt are mentioned as an example of connectors other than a dowel connector.

  The composite beam and its construction method of the present invention can be applied to various wooden buildings. In particular, it is suitable for use in wooden construction of public buildings that require large span beams. Moreover, since this composite beam can suppress a vibration effectively, a building use can be extended also to the use which is concerned about giving a vibration to a lower floor, such as a dance classroom use. Moreover, since the composite beam of the present invention uses CLT that can use a large amount of wood, it is expected to contribute to effective utilization of domestic wood.

2 Wood beam material 2a Upper surface 2b Lower surface 3 Wood beam material 4 Orthogonal correction plate (CLT) floor material 4a Upper surface 4b Lower surface 6 Bulldog dowel joint 8 Bolt 9 Nut 10 Composite beam 20, 40 Pre-hole 60 Flat surface 60a Opening 61 tooth

Claims (8)

With wooden beams,
A flooring of orthogonal laminated plates joined to the upper surface of the wooden beam material;
A composite beam comprising the wood beam material and a joint for joining the floor material of the orthogonal laminated plate.   2. The composite beam according to claim 1, wherein the connector is a gibber connector disposed between an upper surface of the wooden beam member and a lower surface of a floor material of the orthogonal laminated plate.   The composite beam according to claim 1 or 2, further comprising a fastening member that penetrates the wooden beam material and the floor material and is tightly coupled to the wooden beam material and the floor material of the orthogonal laminated plate. The composite beam according to any one of claims 1 to 3, wherein the wooden beam members extend in directions orthogonal to each other. The composite beam according to any one of claims 1 to 4, wherein the wooden beam material is a laminated material constituting a beam of a wooden ramen construction method. The composite beam according to any one of claims 1 to 5, wherein a floor material of the orthogonal laminated plate has a thickness of 90 mm to 270 mm. A preparatory process for preparing a wooden beam material and a flooring of orthogonal laminated boards;
An arranging step of arranging a dowel joint on the top surface of the wooden beam material;
Overlaying the floor material of the orthogonal laminated plate on the top surface of the wooden beam material on which the dowel joint is arranged, and allowing the diver joint to be embedded in both the wooden beam material and the floor material of the orthogonal laminated plate, A method for constructing a composite beam, comprising a joining step of joining the wood beam material and the floor material of the orthogonal laminated plate. In the preparation step, a tip hole is formed in each of the wooden beam material and the floor material of the orthogonal laminated plate,
The joining step includes a step of passing a fastening member through the tip hole of the wooden beam member and the floor plate of the orthogonal laminated plate, and binding the wooden beam member and the floor plate of the orthogonal laminated plate by the fastening member. The construction method of the composite beam of Claim 7 characterized by these.

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