Beam structure

Abstract

To provide a beam structure capable of preventing the occurrence of lateral buckling in a wood-steel hybrid beam.SOLUTION: It includes a stiffening wood 31 whose both ends 31a, 31a are connected respectively to columns 2, 2, and a steel beam 32 that is provided inside the stiffening wood 31 and has both ends 32a, 32a joined respectively to the columns 2, 2, and it includes a wood-steel hybrid beam 3 that supports slabs 6 provided above the stiffening wood 31 and the upper flange 321 of the steel beam 32, headed studs 4 that are arranged in plural numbers at predetermined intervals in the extending direction of the wood-steel hybrid beam 3, protrude upward from the upper flange 321 of the steel beam 32, and are fixed to the slabs 6, stiffening fixing rods 5 which are arranged in plural numbers at predetermined intervals in the extension direction of the wood-steel hybrid beam 3, of which the upper end parts 5a are fixed to the slab 6, the parts 5b below the upper end parts 5a are fixed to the stiffening wood 31, and the lower end parts 5c of the stiffening fixed rods 5 are located below the lower flange 323 of the steel beam 32.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a beam structure. [Background technology]

[0002] In recent years, as part of measures to combat global environmental issues such as global warming, the use of wood as a building material has been promoted, and many wooden buildings have been constructed. Among these, when the building frame is long-span, wood-steel hybrid beams are often used, in which the steel frame is covered with wood, the steel frame is the main stress-bearing member, and the wood is the buckling restraint member for the steel frame. In the above configuration, it is common to install additional lateral stiffeners such as sub-beams or knee braces to prevent the wood-steel hybrid beam from buckling as a whole.

[0003] On the other hand, with regard to steel beams, which have traditionally been used as beams that make up beam structures, Patent Document 1 discloses a method for preventing overall buckling of steel beams by fixing headed studs protruding from the upper flange of a steel beam made of H-shaped steel to a concrete floor slab above the beam. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-55464 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in a beam structure using a wood-steel hybrid beam, which is a structure in which the above-mentioned steel frame is covered with wood, no method has been established that can omit the lateral stiffeners and prevent damage to the steel frame and wood due to global buckling of the wood-steel hybrid beam.

[0006] The present invention has been made in consideration of the above circumstances, and aims to provide a beam structure that can prevent the occurrence of lateral buckling in a wood-steel hybrid beam. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, the beam structure of the present invention comprises: stiffening timbers, both ends of which are joined to columns; and steel beams, which are located inside the stiffening timbers and both ends of which are joined to the columns; a wood-steel hybrid beam that supports the stiffening timbers and a floor slab located above the upper flange of the steel beam; headed studs, which are arranged at a predetermined interval in the extension direction of the wood-steel hybrid beam, protrude upward from the upper flange of the steel beam and are fixed to the floor slab; and stiffening fixing rods, which are arranged at a predetermined interval in the extension direction of the wood-steel hybrid beam, and have upper ends fixed to the floor slab and portions below the upper ends fixed to the stiffening timbers, and the lower ends of the stiffening fixing rods are located below the lower flange of the steel beam.

[0008] With the above configuration, the beam structure has multiple headed studs and multiple stiffening fixing rods fixed to the floor slab, which restrain both the stiffening wood and steel beams from being attached to the floor slab, thereby stiffening the wood-steel hybrid beam and preventing lateral buckling. Because the beam structure can prevent lateral buckling of wood-steel hybrid beams, it is not necessary to install lateral stiffeners such as sub-beams or knee braces, and it can be formed with a simple configuration, reducing the amount of steel, wood, and other materials used. In addition, because lateral stiffeners are not required, labor required for manufacturing components and assembling the beam structure can be reduced. As a result, the beam structure improves the workability of beam structure construction work and reduces construction costs. Furthermore, since lateral stiffeners are no longer necessary, the work space for construction can be expanded, which improves the workability of other work such as interior construction and equipment installation.

[0009] In addition, in the beam structure according to the present invention, the stiffening fixing rods may be provided on both sides in a width direction perpendicular to the extension direction of the steel beam in a plan view.

[0010] With the above configuration, the beam structure can exert the restraining effect of the floor slab on almost the entire cross section facing the extension direction of the wood-steel hybrid beam, thereby further improving the stiffening effect against lateral buckling of the wood-steel hybrid beam.

[0011] Furthermore, in the beam structure of the present invention, when the installation interval in the extension direction of the stiffening fixed rods is L1, the span (length of the beam) of the wood-steel hybrid beam is L2, and the beam depth of the wood-steel hybrid beam is D1, the following formula (1) or formula (2) may be established.

[0012]

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[0013]

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[0014] With the above configuration, the beam structure can efficiently prevent lateral buckling of the wood-steel hybrid beam by configuring it to satisfy formula (1) or formula (2).

[0015] Furthermore, in the beam structure of the present invention, when the diameter length of the stiffening fixed rod is D2 and the minimum board thickness in the width direction perpendicular to the extension direction of the stiffening wood in a planar view is T, the following equation (3) may hold.

[0016]

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[0017] With the above configuration, the beam structure can efficiently prevent lateral buckling of the wood-steel hybrid beam by configuring it to satisfy formula (3). In addition, the beam structure prevents the diameter of the stiffening fixed rod from becoming excessively large compared to the minimum thickness T of the stiffening timber, thereby achieving the desired stiffening effect against lateral buckling and preventing the stiffening timber from being easily destroyed by external forces acting in the axial direction due to a thinner minimum thickness.

[0018] Furthermore, in the beam structure according to the present invention, if the number of headed studs is A1 and the number of headed studs required when the wood-steel hybrid beam is a fully composite beam is A2, the following equation (4) may be established.

[0019]

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[0020] With the above configuration, the beam structure can be configured to satisfy formula (4) to efficiently prevent lateral buckling of the wood-steel hybrid beam. [Effects of the Invention]

[0021] According to the present invention, a beam structure can be provided that can prevent the occurrence of lateral buckling in a wood-steel hybrid beam. [Brief explanation of the drawings]

[0022] [Figure 1] 1 is a perspective view showing a frame formed by combining a plurality of beam structures according to an embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view showing an example of a beam structure according to an embodiment of the present invention, taken along line II-II in FIG. [Figure 3] FIG. 3 is a longitudinal cross-sectional view showing an example of a beam structure according to an embodiment of the present invention, taken along line III-III in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0023] A beam structure 1 according to an embodiment of the present invention will be described below with reference to FIGS. As shown in Fig. 1, the structure 10 includes a plurality of beam structures 1 and a plurality of columns 2. The beam structure 1 includes a wood-steel hybrid beam 3, a plurality of headed studs 4, and a plurality of stiffening fixing rods 5. The structure 10 may be, for example, a multi-story structure such as an apartment building.

[0024] The pillars 2 extend in the vertical direction. The structure of the pillars 2 is not limited, and examples thereof include known steel pillars, CFT pillars (concrete-filled steel pipe pillars), and RC pillars. Hereinafter, one horizontal direction relative to the pillars 2 will be referred to as the X direction, the other horizontal direction relative to the pillars 2 perpendicular to the X direction will be referred to as the Y direction, and the arrangement direction of the pillars 2 will be referred to as the Z direction. As shown in Figure 3, multiple pillars 2 are arranged at predetermined intervals in the X and Y directions.

[0025] The beam structure 1 is arranged between adjacent columns 2, 2 in the X and Y directions. Multiple beam structures 1 are formed continuously in the X and Y directions, and a frame 10a of the structure 10 is formed by combining multiple wood-steel hybrid beams 3 in a polygonal shape when viewed from above.

[0026] A floor slab 6 is formed above in the Z direction the plurality of wood-steel hybrid beams 3 that form the frame 10a. The floor slab 6 is supported by the wood-steel hybrid beams 3. The configuration of the floor slab 6 is not limited, and may be, for example, a known reinforced concrete structure or a wooden structure.

[0027] The following describes a beam structure 1 disposed between pillars 2, 2 spaced apart from each other in the X direction.

[0028] As shown in Figures 2 and 3, the wood-steel hybrid beam 3 includes a stiffening piece of wood 31 and a steel beam 32. The wood-steel hybrid beam 3 extends in the X direction. The wood-steel hybrid beam 3 is disposed between the columns 2, 2, with both ends 3a, 3a in the X direction joined to the columns 2, 2. The method of joining the wood-steel hybrid beam 3 and the columns 2, 2 is not limited, and examples include a configuration in which they are joined by welding.

[0029] The stiffening wood 31 has a rectangular parallelepiped outer shape and is arranged with its longitudinal direction facing the X direction. The stiffening wood 31 is a known type of wood, and there is no limitation on the tree species. The stiffening wood 31 has both X direction end portions 31a, 31a joined to the pillars 2, 2.

[0030] The steel beam 32 is provided inside the stiffening timber 31. The steel beam 32 is a known H-shaped steel and includes an upper flange 321, a web 322, and a lower flange 323. Similar to the stiffening timber 31, the steel beam 32 has both X-direction end portions 32a, 32a joined to the columns 2, 2. The upper end surface 321a of the upper flange 321 abuts against the floor slab 6. The steel beam 32 is not limited to an H-shaped steel and may be, for example, a known steel bar.

[0031] There is no limitation on the method for installing the steel beam 32 inside the stiffening timber 31, and for example, a groove for storing the steel beam 32 can be formed on each of the opposing surfaces of the two stiffening timbers 31, 31, and the timbers can be joined with the steel beam 32 fitted into the groove, or a hole for installing the steel beam 32 can be formed in advance in one stiffening timber 31, and the steel beam 32 can be inserted into the hole.

[0032] The headed studs 4 are arranged uniformly at a predetermined interval (pitch) in the X direction within the span of the wood-steel hybrid beam 3, and are also arranged near both ends of the upper flange 321 in the Y direction.

[0033] The headed stud 4 protrudes upward in the Z direction from the top flange 321 of the steel beam 32 and is fixed within the floor slab 6. The bottom end 4a of the headed stud 4 is welded and fixed to the top end surface 321a of the top flange 321. The headed stud 4 is a known headed stud having a shank 4b that is circular in plan view, with the bottom end 4a joined to the top flange 321, and a head 4c that is continuous with the upper end of the shank 4b and protrudes outward in a roughly circular shape in plan view from the upper edge of the shank 4b. The protruding length L3 of the headed stud 4 from the top flange 321 is preferably at least four times the shank diameter D3 of the headed stud 4.

[0034] The multiple stiffening fixing rods 5 are evenly spaced at a predetermined interval (pitch) in the X direction within the span of the wood-steel hybrid beam 3, and are also arranged outside both ends of the steel beam 32 in the Y direction and within the stiffening wood 31. The stiffening fixing rods 5 are, for example, well-known lag screw bolts or glued-in rods.

[0035] The upper end 5a of the stiffening fixing rod 5 protrudes upward in the Z direction from the upper end surface 31b of the stiffening wood 31 and is fixed in the floor slab 6, and the shaft portion 5b below the upper end 5a in the Z direction is fixed in the stiffening wood 31. The protruding length L4 of the stiffening fixing rod 5 from the upper end surface 31b is preferably at least four times the diameter length D2 of the stiffening fixing rod 5. In this embodiment, the diameter length D2 of the stiffening rod 5 is the shaft diameter of the shaft portion 5b.

[0036] The lower end 5c of the stiffening fixed rod 5 is inserted through the stiffening wood 31 in the Z direction from the upper end of the stiffening wood 31 to a position below the lower flange 323 of the steel beam 32. The lower end 5c is located below the lower flange 323 in the Z direction.

[0037] The lag screw bolt has a male thread formed around the shaft of the bolt, and is installed by screwing it into a pre-formed screw hole with dimensions approximately the same as the screw diameter at a predetermined position on the stiffening wood 31.

[0038] The glued-in rod is formed by inserting a rod-shaped connector into a hole formed in a predetermined shape in the stiffening wood 31, filling the hole with adhesive to seal the gap in the hole, and then allowing the adhesive to harden.

[0039] The wood-steel hybrid beam 3 is fixed in a floor slab 6 provided above the wood-steel hybrid beam 3 by a plurality of headed studs 4 and a plurality of stiffening fixing rods 5, and supports the floor slab 6. The wood-steel hybrid beam 3 extending in the Y direction is also formed in the same configuration as above.

[0040] The design standards for Beam Structure 1 conform to Shimizu's Steel Beam Lateral Buckling Stiffening Method. This method connects the concrete floor slab and H-shaped steel beams with headed studs, and stiffens the steel beams against lateral buckling by using the floor slab to restrain the out-of-plane deformation of the upper flange and torsion around the material axis. When the installation interval (pitch) of the stiffening fixed rods 5 in the X direction is L1, the span (length of the beam) of the wood-steel hybrid beam 3 is L2, and the beam depth (height in the Z direction) of the wood-steel hybrid beam 3 is D1, it is desirable that the following equation (1) or equation (2) be established for the beam structure 1.

[0041]

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[0042]

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[0043] It is desirable that the beam structure 1 satisfies the following formula (3), where D2 is the shaft diameter of the stiffening fixed rod 5 and T is the minimum thickness in the Y direction of the stiffening timber 31. The minimum thickness T is the distance between the Y direction ends of the upper flange 321 and lower flange 323 and the Y direction end of the stiffening timber 31, and is the minimum thickness of the stiffening timber 31 at the flange height position of the steel beam 32.

[0044]

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[0045] In the beam structure 1, it is desirable that equation (4) holds true, where A1 is the number of headed studs 4 provided on the upper flange 321 and A2 is the number of headed studs 4 required when the wood-steel hybrid beam 3 is a fully composite beam.

[0046]

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[0047] Next, the functions and effects of the beam structure 1 according to the present embodiment will be described with reference to the drawings.

[0048] 2 and 3, the beam structure 1 comprises a wood-steel hybrid beam 3 that has stiffening timbers 31 and steel beams 32 and supports a floor slab 6, a plurality of headed studs 4 that protrude upward in the Z direction from an upper flange 321, and a plurality of stiffening fixing rods 5. Upper ends 5a of the headed studs 4 and stiffening fixing rods 5 are fixed in the floor slab 6, and a shaft portion 5b below the upper end 5a of the stiffening fixing rod 5 in the Z direction is fixed in the stiffening timber 31. A lower end 5c of the stiffening fixing rod 5 is located below the lower flange 323 of the steel beam 32 in the Z direction.

[0049] With the above configuration, in the beam structure 1, both the stiffening timber 31 and the steel beam 32 are restrained to the floor slab 6 by the multiple headed studs 4 and multiple stiffening fixed rods 5 fixed in the floor slab 6. Therefore, the wood-steel hybrid beam 3 is stiffened, and when an external force with a horizontal component acts on the wood-steel hybrid beam 3, lateral buckling of the wood-steel hybrid beam 3 can be prevented.

[0050] Furthermore, because the beam structure 1 can prevent lateral buckling of the wood-steel hybrid beam 3, it is possible to eliminate the need for lateral stiffeners such as sub-beams and knee braces as shown in Figure 1, and it can be formed with a simple configuration. This allows for a reduction in the amount of steel, wood, and other materials used. Furthermore, because the beam structure 1 does not require the installation of lateral stiffeners, it is possible to reduce labor required for manufacturing the components that make up the beam structure 1 and for assembling the beam structure. As a result, the beam structure 1 improves the workability of its construction work and reduces construction costs. Furthermore, the above-mentioned beam structure 1 eliminates the need for the installation of lateral stiffeners, allowing for an expansion of the work space, thereby improving the workability of work other than construction work on the beam structure 1 and the frame 10a, such as interior construction and equipment construction.

[0051] The stiffening fixed rods 5 are arranged outside both ends of the steel beams 32 in the Y direction and within the stiffening timbers 31. With the above configuration, the beam structure 1 can exert a restraining effect of the floor slab 6 to which the upper end portion 5a of the stiffening fixing rod 5 is fixed over substantially the entire cross section 3b facing the X direction of the wood-steel hybrid beam 3. Therefore, the stiffening effect against lateral buckling of the wood-steel hybrid beam 3 can be further improved.

[0052] The beam structure 1 can efficiently prevent lateral buckling of the wood-steel hybrid beam 3 by configuring it to satisfy formula (1) or formula (2).

[0053] By configuring the beam structure 1 to satisfy formula (3), lateral buckling of the wood-steel hybrid beam 3 can be efficiently prevented. In addition, the beam structure 1 prevents the shaft diameter D2 of the stiffening fixed rod 5 from becoming excessively large relative to the minimum plate thickness T of the stiffening wood 31, and while achieving the desired stiffening effect against lateral buckling, the reduced minimum plate thickness T prevents the stiffening wood 31 from being easily destroyed by an external force having a Z component.

[0054] The beam structure 1 can efficiently prevent lateral buckling of the wood-steel hybrid beam 3 by configuring it to satisfy formula (4).

[0055] Although the embodiment of the beam structure according to the present invention has been described above, the present invention is not limited to the above embodiment and can be modified as appropriate within the scope of the invention. For example, in the above embodiment, a plurality of beam structures 1 are formed continuously in the X direction and the Y direction, but a configuration in which a plurality of beam structures 1 are formed continuously in only one of the X direction and the Y direction is also possible.

[0056] In the above embodiment, the stiffening fixing rods 5 are arranged within the stiffening timbers 31 on both sides of the steel beam 32 in the Y direction, but they may also be arranged within the stiffening timbers 31 on one side of the steel beam 32 in the Y direction.

[0057] In the above embodiment, the lower end 5c of the stiffening fixing rod 5 is located below the lower flange 323 in the Z direction and at the middle of the stiffening wood 31 in the Z direction, but the lower end 5c may also be configured to reach the lower end of the stiffening wood 31. [Explanation of symbols]

[0058] 1 beam structure 2 pillars 3 Wood-steel hybrid beams 4 headed studs 5 Stiffening fixed rod 5a Upper end 5b Shaft 5c Lower end 6 Floor slab 31 Stiffening wood 31a End 32a end 32 Steel beam 321 Upper flange 323 Lower flange

Claims

1. a wood-steel hybrid beam comprising a stiffening timber, both ends of which are joined to the columns, and a steel beam disposed inside the stiffening timber, both ends of which are joined to the columns, the wood-steel hybrid beam supporting a floor slab disposed above the stiffening timber and the upper flange of the steel beam; a plurality of headed studs arranged at predetermined intervals in the extension direction of the wood-steel hybrid beam, protruding upward from the upper flange of the steel beam, and fixed to the floor slab; a plurality of stiffening rods arranged at predetermined intervals in the extension direction of the wood-steel hybrid beam, the upper ends of which are fixed to the floor slab and the portions below the upper ends of which are fixed to the stiffening timber; Equipped with The lower end of the stiffening fixing rod is located below the lower flange of the steel beam. Beam structure.

2. The stiffening fixing rods are provided on both sides of the steel beam in a width direction perpendicular to the extension direction in a plan view. The beam structure of claim 1 .

3. The installation interval in the extension direction of the stiffening fixing rods is L １ , the span (length of the beam) of the wood-steel hybrid beam is L ２ , the beam depth of the wood-steel hybrid beam is D １ Then, the following formula (1) or (2) holds: A beam structure according to claim 1 or 2. [Equation 1] [Equation 2]

4. The diameter of the stiffening fixing rod is D ２ When the minimum board thickness in the width direction perpendicular to the extension direction of the stiffening wood in a plan view is T, the following formula (3) is established: A beam structure according to any one of claims 1 to 3. [Equation 3]

5. The number of headed studs is A １ , the number of headed studs required when the wood-steel hybrid beam is a completely composite beam is A ２ Then, the following equation (4) holds: A beam structure according to any one of claims 1 to 4. [Equation 4]

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