Composite beam and method of constructing composite beam

Abstract

To provide a composite beam or the like which can be easily constructed.SOLUTION: A composite beam 1 has a reinforced concrete beam body 10, wood materials 21, 22 provided so as to cover both side surfaces and a bottom surface of the beam body 10 in a beam-width direction, and a stress transmission mechanism for transmitting stress between the beam body 10 and the wood materials 21 on both side surfaces of the beam body 10. The wood material 22 on the bottom surface of the beam body 10 is fixed to the wood material 21 on both side surfaces of the beam body 10, and the wood material 22 on the bottom surface of the beam body 10 contacts the wood material 21 on both side surfaces of the beam body 10.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a composite beam made of reinforced concrete and wood material. [Background technology]

[0002] Wood construction and wood-based building technologies are in wide demand internationally, as they not only contribute to global warming countermeasures, but also contribute to the well-being of users of architectural spaces. However, high-quality wood materials used in construction are costly, and the strength and rigidity of wood materials are smaller than those of conventional reinforced concrete and steel frames.

[0003] Therefore, there are examples of using composite structures that combine reinforced concrete and wood materials as a technology that can ensure the necessary strength and rigidity while suppressing cost increases and contribute to providing a good space. For example, Patent Document 1 describes a composite beam in which both sides and the bottom of a reinforced concrete beam body are covered with wood materials. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2022-15390 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the composite beam of Patent Document 1, the wooden material on the bottom of the beam body is arranged with a gap between it and the wooden material on the side of the beam body. This is to allow the wooden material on the bottom of the beam body to deform without being affected by the wooden material on the side when the composite beam is in a large deformation state, but the wooden material cannot be used as a formwork when pouring concrete for the beam body, so it is necessary to assemble a separate bottom formwork before pouring the concrete, then remove the bottom formwork and attach the wooden material to the bottom of the beam body as a finishing material. As a result, it is time-consuming and costs increase.

[0006] The present invention has been made in consideration of the above problems, and has an object to provide a composite beam or the like that can be easily constructed. [Means for solving the problem]

[0007] The first invention for solving the above-mentioned problems is a composite beam comprising a reinforced concrete beam body, wooden materials arranged to cover both sides and a bottom surface of the beam body in the beam width direction, and a stress transfer mechanism for transferring stress between the beam body and the wooden materials on both sides of the beam body, wherein the wooden material on the bottom surface of the beam body is fixed to the wooden materials on both sides of the beam body, and the wooden material on the bottom surface of the beam body is in contact with the wooden materials on both sides of the beam body.

[0008] The composite beam of the present invention covers both sides and the bottom of the reinforced concrete beam body with wooden materials, and integrates the wooden materials on both sides of the beam body with the beam body to enable stress transmission, ensuring the necessary strength and rigidity while suppressing cost increases, and contributing to the provision of a good space. Moreover, since the wooden materials on the bottom of the beam body are fixed and in contact with the wooden materials on both sides of the beam body, these wooden materials function as concave formwork, and the composite beam can be completed simply by pouring concrete inside it, so construction of the composite beam does not require much effort.

[0009] It is desirable that the stress transmission mechanism includes a separator that penetrates the beam body and has both ends fixed to wooden materials on both sides of the beam body. The separator described above serves both to prevent the wooden materials from opening when concrete is poured and to transmit stress, making construction even easier.

[0010] It is desirable that the stress transfer mechanism includes a perforated steel plate embedded across the beam body and the wooden material on the side of the beam body. The holes in the perforated steel plate are filled with the concrete of the beam body, thereby firmly integrating the wood material and the beam body.

[0011] It is desirable that no stress transmission mechanism for transmitting stress between the wooden material on the bottom surface of the beam body and the beam body is provided between the beam body and the wooden material. This makes it possible to prevent the crack width at the bottom of the beam body when the composite beam is deflected from directly affecting the wood material at the bottom of the beam body.

[0012] It is desirable that the wooden material on the bottom surface of the beam body be located higher than the lower ends of the wooden materials on both sides of the beam body. This allows a recess to be formed at the bottom of the composite beam made up of the lower ends of the wooden material on both sides of the beam body and the wooden material on the bottom of the beam body, making it possible to arrange various types of equipment such as lighting fixtures without being noticeable.

[0013] The second invention is a construction method for a composite beam of the first invention, characterized in that it includes a step of installing the wooden materials on both sides and the bottom of the beam body at a construction location of the composite beam with the wooden material on the bottom of the beam body fixed to the wooden materials on both sides of the beam body, and a step of pouring concrete inside the wooden materials on both sides and the bottom of the beam body. A second invention is a construction method for forming the composite beam of the first invention on-site. Effect of the Invention

[0014] The present invention makes it possible to provide a composite beam or the like that can be easily constructed. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a diagram showing a frame including a composite beam 1. [Diagram 2] FIG. 1 shows a composite beam 1. [Diagram 3] FIG. 4 is a diagram showing an end portion of a separator 30. [Figure 4] 1A to 1C are diagrams illustrating a construction method for the composite beam 1. [Diagram 5] 1A to 1C are diagrams illustrating a construction method for the composite beam 1. [Figure 6] An example of a stress transfer mechanism. [Figure 7]3A to 3C are diagrams for explaining joining of wooden pieces 21 by a joining member 7. [Figure 8] 2A to 2C are diagrams for explaining joining of a steel plate 217 or a wooden board 217a to a wooden material 21 using a fastener 218. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

[0017] (1. Composite beam 1) FIG. 1 is a diagram showing a frame including a composite beam 1 according to an embodiment of the present invention. The composite beam 1 is installed, for example, between the column capitals 2a (panel zone) of columns 2, and a concrete slab 3 is provided thereon. The composite beam 1 has a composite structure made of reinforced concrete and wood materials. Meanwhile, the columns 2, including the column capitals 2a, are made of reinforced concrete, but this is not limited to this. Furthermore, the installation location of the composite beam 1 is not limited to the example shown in FIG. 1.

[0018] Fig. 2 shows a composite beam 1, and is a cross section (hereinafter simply referred to as cross section) perpendicular to the beam axis direction of the composite beam 1. The composite beam 1 is a beam body 10 having a rectangular cross section, with both side surfaces and a bottom surface in the beam width direction covered with planar wooden materials 21, 22. The beam width direction is a direction perpendicular to the beam axis direction in a plan view, and corresponds to the left-right direction in Fig. 2.

[0019] The beam body 10 is made of reinforced concrete and is constructed by embedding reinforcing bars 12, such as main bars and shear reinforcement bars, inside concrete 11.

[0020] The wooden materials 21, 22 are, for example, CLT (Cross Laminated Timber), but are not limited to this. For example, they may be laminated timber or BP material, or a combination of lumber and plywood may be used. In addition, the wooden material is omitted from the top surface of the beam body 10 because it contacts the slab 3, etc., but the top surface may be covered with a wooden material such as CLT.

[0021] In addition, in this embodiment, the wooden material 22 on the bottom surface of the beam body 10 is fixed to the wooden material 21 on both sides of the beam body 10 with fasteners 23 such as screws, and the wooden material 22 on the bottom surface of the beam body 10 contacts the wooden material 21 on both sides of the beam body 10.

[0022] Furthermore, the wooden material 22 on the bottom surface of the beam body 10 is located higher than the lower ends of the wooden materials 21 on both sides of the beam body 10, and the lower ends of the wooden materials 21 on both sides of the beam body 10 and the wooden material 22 on the bottom surface form a recess 24 that protrudes upward at the bottom of the composite beam 1. In this embodiment, a lighting fixture 25 is provided in this recess 24. Instead of the lighting fixture 25, other equipment such as a curtain rail or a sensor may be provided.

[0023] In this embodiment, a separator 30 is provided so as to penetrate the beam body 10. Both ends of the separator 30 are fixed to the wooden material 21 on both side surfaces of the beam body 10.

[0024] 3 is a diagram showing an end of separator 30. Separator 30 has a rod-shaped main body 31. The end of main body 31 passes through separator insertion hole 210 in wooden material 21 and protrudes into recess 211 provided by countersinking the outer surface (referring to the opposite side to beam main body 10; the same applies below) of wooden material 21. A screw is provided at the end of main body 31, and by tightening nut 32 onto the screw of the protruding part of main body 31 protruding into recess 211, the end of main body 31 is fixed to wooden material 21.

[0025] A hole-filling material 212 made of wood or the like is provided in the recess 211 of the wooden material 21, thereby improving the design of the composite beam 1. On the inside surface (referring to the beam main body 10 side; the same applies below) of the wooden material 21, a plate nut 33 is fastened to the screw at the end of the main body 31. Reference numeral 34 in Fig. 3 denotes a washer used together with the nut 32, and reference numeral 35 denotes a packing used together with the plate nut 33 to prevent slag leakage from the separator insertion hole 210 when pouring the concrete 11, which will be described later.

[0026] The separator 30 is a member for preventing the wooden materials 21 from opening by resisting the lateral pressure applied to the wooden materials 21 when the concrete 11 is poured, but in this embodiment, it also functions as a stress transmission mechanism for transmitting shear stress between the beam body 10 and the wooden materials 21 on both sides of the beam body 10. Therefore, the beam body 10 and the wooden materials 21 are integrated, and the rigidity of the beam as a whole is increased, thereby reducing the deflection of the composite beam 1.

[0027] In this embodiment, as shown in Fig. 2, a separator 30' is also provided on the wooden material 21. This separator 30' has both ends of a rod-shaped main body fixed to fixing parts 36 such as angle bars provided on the upper end surface of the wooden material 21 using nuts or the like (not shown).

[0028] On the other hand, no stress transmission mechanism for transmitting stress is provided between the beam body 10 and the wooden material 22 on its bottom surface. This makes it possible to prevent the width of a crack from directly affecting the wooden material 22 when a local crack occurs at the bottom of the beam body 10 when the composite beam 1 is deflected. In other words, the width of a crack at the bottom of the beam body 10 is absorbed by the deformation of the wooden material 21 on the side surface and the deformation of the fastener 23 between the wooden materials 21 and 22, and does not directly affect the wooden material 22.

[0029] (2. Construction method of composite beam 1) When constructing the composite beam 1, first, in the factory, the wooden material 22 is fixed to the wooden material 21 as shown in Fig. 4(a) to integrate the wooden materials 21 and 22. Also in the factory, the separators 30 and 30' are installed and necessary reinforcement is arranged.

[0030] When fixing the wooden material 22 to the wooden material 21, as shown in FIG. 4(b), a sealant 221 is applied to the end face of the wooden material 22 in the beam width direction to prevent slag leakage when pouring the concrete 11, and then the wooden material 21 is fixed to the end face of the wooden material 22 by a fixture 23. This prevents slag leakage from between the wooden materials 21 and 22, and avoids the need to remove the slag in a later process. Note that instead of the sealant 221, slag-stopping tape may be applied or a gasket may be attached to stop the slag. The slag-stopping may be applied not only to the end face of the wooden material 22, but also to the corners of the wooden materials 21 and 22.

[0031] In this embodiment, the wooden pieces 21, 22 are transported from the factory to the site in the state shown in Fig. 4(a), and as shown in Fig. 5(a), the wooden pieces 21, 22 are supported from below by shoring 4 or the like and installed at the construction site of the composite beam 1. In this embodiment, a joist 41 in the beam axis direction that supports the undersides of the wooden pieces 21, 22 on its surface is used as the shoring 4, thereby preventing scratches from remaining on the undersides of the wooden pieces 21, 22 due to the support pressure from the shoring 4. However, the joist 41 that supports the wooden piece 22 is ultimately located at a position where the lighting equipment 25 will be attached, and so there is no problem even if some scratches are made on the underside of the wooden piece 22, as these will be hidden.

[0032] 5(b), the wooden members 21, 22 are used as a formwork, and concrete 11 is poured inside the formwork to form the beam body 10. The separators 30, 30' function as stoppers to resist the lateral pressure of the concrete 11 and maintain the gap between the wooden members 21 on both sides of the beam body 10, as in the conventional construction method.

[0033] The concrete 11 of the beam body 10 is poured together with the concrete of the slab 3, and at this time, a sheet material 5 such as a polyethylene film is hung on the outside of the wooden material 21 to prevent the concrete from adhering to the wooden material 21 on both sides of the beam body 10. The sheet material 5 is sandwiched between the outer surface of the wooden material 21, with a batten 6 placed on the outside of the upper end of the wooden material 21. The batten 6 is fixed to the wooden material 21 with nails 61 or the like.

[0034] Thereafter, the composite beam 1 shown in Fig. 1 is constructed by removing the shoring 4, sheet material 5, battens 6, etc. Note that the nail holes in the wooden material 21 are hidden by a heat insulating material (not shown) such as rock wool attached to the ceiling.

[0035] As described above, the composite beam 1 of this embodiment has both sides and the bottom of the reinforced concrete beam body 10 covered with wooden materials 21, 22, and the wooden materials 21 on both sides of the beam body 10 are integrated with the beam body 10 to enable stress transmission, thereby ensuring the necessary strength and rigidity while suppressing cost increases, and contributing to the provision of a good space.

[0036] Furthermore, since the wooden material 22 on the bottom surface of the beam body 10 is fixed to and in contact with the wooden materials 21 on both sides of the beam body 10, these wooden materials 21, 22 function as a concave formwork, and the composite beam 1 can be completed by simply carrying it to the site after reinforcing bars have been arranged in the factory and pouring concrete inside, which saves time in constructing the composite beam 1 and makes it easier to control the accuracy of construction, thereby contributing to shortening the on-site process.

[0037] In this embodiment, the separator 30 serves both to prevent the wooden members 21 from opening when concrete is poured and to transmit stress, making construction even easier.

[0038] In this embodiment, no stress transmission mechanism is provided between the beam body 10 and the wooden material 22 on its bottom surface. This makes it possible to prevent the crack width at the bottom of the beam body 10 caused by the bending of the composite beam 1 from directly affecting the wooden material 22.

[0039] Furthermore, in this embodiment, the wooden material 22 on the bottom surface of the beam body 10 is raised higher than the lower end of the wooden material 21 on the side surface, so that a recess 24 can be formed in the bottom of the composite beam 1, and various equipment such as lighting equipment 25 can be arranged without being noticeable, resulting in a clean appearance and improved design. Also, because the wooden material 22 is not noticeable, it is possible to simplify the curing required during construction to prevent the wooden material 22 from being damaged. However, it is possible to provide the wooden material 22 at the same height as the lower end of the wooden material 21.

[0040] However, the present invention is not limited to the above embodiment. For example, in this embodiment, the separator 30 is used as a stress transfer mechanism between the beam body 10 and the wooden material 21, but as shown in FIG. 6(a), a perforated steel plate 40 that is embedded across the beam body 10 and the wooden material 21 and has a hole in the embedded part in the beam body 10 may be used as the stress transfer mechanism. The concrete 11 of the beam body 10 is filled into the hole of the perforated steel plate 40, so that the wooden material 21 and the beam body 10 can be firmly integrated. The perforated steel plate 40 in FIG. 6(a) is a perforated steel plate dowel, but a punching metal may be used instead.

[0041] As another stress transfer mechanism, as shown in Fig. 6(b), a groove or the like is cut into the inner surface of the wooden material 21 to form an uneven shape 213, thereby structurally integrating the wooden material 21 with the beam body 10. The uneven shape 213 in Fig. 6(b) is a rectangular wave shape, but it can also be a triangular wave shape as shown in Fig. 6(c).

[0042] These stress transfer mechanisms can be used in conjunction with separators 30, 30', but separators 30, 30' can be omitted by temporarily installing a separate device (not shown) on the outside of the wooden material 21 to prevent the wooden material 21 from opening when the concrete 11 is poured.

[0043] In some cases, multiple wooden pieces 21, 22 may be joined in the beam axis direction. In this case, the wooden pieces 21, 22 can be joined using a joining member such as Home Connector (registered trademark). FIG. 7(a) shows an example of joining wooden pieces 21 together in the beam axis direction using a joining member 7, and shows a cross section of the wooden pieces 21 in the thickness direction. The beam axis direction corresponds to the left-right direction in FIG. 7(a). The joining member 7 is a steel cylinder with both ends open, and is arranged so as to straddle holes 214 in the opposing end faces of both wooden pieces 21. The holes 214 are formed so as to extend from the end faces of the wooden pieces 21 through the interior of the wooden pieces 21 in the beam axis direction.

[0044] The end face of the wooden material 21 is also provided with a notch 215 extending from the hole 214 to the outer surface of the wooden material 21. An injection pipe 8 is passed through the injection hole formed by the notches 215 of both wooden materials 21, and the adhesive 9 can be injected into the inside of the joining member 7 through the opening 71 on the side of the joining member 7 using this injection pipe 8. The adhesive 9 overflows from both ends of the joining member 7 and also fills the inside of the hole 214. After that, the injection pipe 8 is removed, and the injection hole is blocked with a wooden blocking material 216 such as a wooden plug, as shown in FIG. 7(b), whereby the wooden materials 21 are joined together in the beam axis direction by the joining member 7.

[0045] Alternatively, as a method for joining the wooden pieces 21, a glue-in rod (GIR) joining method may be used in which a steel rod is placed across the holes 214 of both wooden pieces 21 and an adhesive is filled into the holes 214. On the other hand, a joining method using a plate-like member such as a steel plate or a wooden plate and a fastener such as a screw may also be considered.

[0046] FIG. 8(a) shows one example, in which a steel plate 217 is placed on the inner surface of both wooden pieces 21 so as to straddle both wooden pieces 21, and the steel plate 217 is fixed to both wooden pieces 21 with fasteners 218 such as screws.

[0047] 8(b), a notch 219 may be formed in the side of the wooden material 21 at the opposing ends of both wooden materials 21, and a wooden board 217a arranged so as to straddle the notch 219 of both wooden materials 21 may be fixed to both wooden materials 21 with a fastener 218 such as a screw. In this case, by arranging the wooden board 217a within the notch 219, the smoothness of the side of the wooden material 21 can be maintained. Although the wooden board 217a is provided on the outer surface of the wooden material 21, it may be provided on the inner surface.

[0048] In these methods, the steel material is not exposed on the outside of the wooden material 21, so that it is possible to make the most of the design of the wooden material 21. The above methods can also be applied to joining the wooden material 22 on the bottom surface of the beam body 10.

[0049] In this embodiment, the wooden materials 21 and 22 are assembled in a factory, but the wooden materials 21 and 22 may be assembled, the separators 30 and 30' may be arranged, and necessary reinforcement may be arranged at the construction site of the composite beam 1. In this embodiment, the concrete 11 is poured at the site to complete the composite beam 1, but the composite beam 1 may be completed by pouring the concrete 11 at a factory, and the composite beam 1 may be transported to the site as a precast product and installed. However, the wooden materials 21 and 22, which are the finishing materials, need to be appropriately cured so as not to be damaged during transportation, and if weight is an issue, it may be necessary to divide the composite beam 1 in the beam axis direction, transport it, and install it.

[0050] Although the preferred embodiment of the present invention has been described above with reference to the accompanying drawings, the present invention is not limited to the above examples. It is clear that a person skilled in the art can come up with various modified or altered examples within the scope of the technical ideas disclosed in this application, and it is understood that these also naturally belong to the technical scope of the present invention. [Explanation of symbols]

[0051] 1: Composite beam 10:Beam body 11: Concrete 12: Reinforcement 21, 22: Wood materials 23: Fixtures 24: Recess 25: Lighting equipment 30, 30': Separator 40: Perforated steel plate

Claims

1. The main body of the reinforced concrete beam, A wooden material provided to cover both side surfaces and a bottom surface of the beam body in the beam width direction; A stress transmission mechanism for transmitting stress between the beam body and the wooden materials on both sides of the beam body; having A composite beam, characterized in that the wooden material on the bottom surface of the beam body is fixed to the wooden materials on both sides of the beam body, and the wooden material on the bottom surface of the beam body contacts the wooden materials on both sides of the beam body.

2. 2. The composite beam according to claim 1, wherein the stress transfer mechanism includes a separator that penetrates the beam body and has both ends fixed to the wood material on both sides of the beam body.

3. 2. The composite beam according to claim 1, wherein the stress transfer mechanism includes a perforated steel plate embedded across the beam body and the wooden material on a side of the beam body.

4. A composite beam as claimed in claim 1, characterized in that no stress transmission mechanism for transmitting stress between the wooden material on the bottom surface of the beam body and the beam body is provided between the wooden material and the beam body.

5. 2. A composite beam according to claim 1, wherein the wooden material on the bottom surface of the beam body is located above the lower ends of the wooden materials on both sides of the beam body.

6. A method for constructing a composite beam according to any one of claims 1 to 5, A step of installing the wooden materials on both sides and the bottom of the beam body at a construction location of a composite beam with the wooden material on the bottom of the beam body fixed to the wooden materials on both sides of the beam body; Pouring concrete on both sides and the inside of the wooden material on the bottom of the beam body; A method for constructing a composite beam comprising the steps of:

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