Composite beam

Abstract

To provide a composite beam capable of providing a plurality of large through holes.SOLUTION: A composite beam 10 includes a wooden beam portion where the beam formation of ends 22 and 24 is higher than the beam formation of a middle portion 26, a concrete beam portion 14 provided on the upper surface of the middle portion 26 of the wooden beam portion, a shear force transmission portion 16 provided at the boundary surface between the wooden beam portion and the concrete beam portion 14, and through holes 18 and 20 formed in the concrete beam portion 14 and penetrating in the beam width direction of the concrete beam portion 14.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a composite beam having wood components. [Background technology]

[0002] 2. Description of the Related Art There are cases where a wooden beam made of a wood material such as laminated lumber is required to have a through hole for equipment (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-75458 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, since wood materials have low shear strength, it is difficult to provide large-diameter through-holes in wood beams. In addition, the inner surface of the through-hole needs to be fire-resistant coated for fire resistance, so the effective diameter of the through-hole (the diameter of the through-hole that can actually be used) is reduced by the thickness of the fire-resistant coating.

[0005] In consideration of the above, an object of the present invention is to provide a composite beam having a wood member with a plurality of large through holes. [Means for solving the problem]

[0006] The composite beam of the first embodiment has a wooden beam section whose end section has a higher beam depth than the middle section, a concrete beam section provided on the upper surface of the middle section of the wooden beam section, a shear force transmission section provided on the boundary surface between the wooden beam section and the concrete beam section, and a through hole formed in the concrete beam section that penetrates in the beam width direction of the concrete beam section.

[0007] According to the composite beam of the first aspect, a concrete beam section is provided on the upper surface of the middle section of the wooden beam section, which has a low beam ratio, and the wooden beam section and the concrete beam section are integrated by enabling shear force transmission between the wooden beam section and the concrete beam section through the shear force transmission section. This makes it possible to configure a composite beam with improved rigidity and strength. In addition, a composite effect can be obtained between the wooden beam section and the concrete beam section, and the beam ratio of the composite beam can be reduced.

[0008] In addition, during an earthquake, the wooden beam and concrete beam tend to shift horizontally, but because the end face of the concrete beam contacts the part of the wooden beam with a higher beam depth at its end, this works in cooperation with the shear force transmission section to suppress horizontal shifting between the wooden beam and the concrete beam.

[0009] Furthermore, since the through holes for passing the equipment piping and the like are formed in the concrete beam section, it is possible to form large through holes, and since there is no need to apply a fireproof coating to the inner surface of the through holes, the formed through holes do not become small. As a result, it is possible to construct a composite beam having multiple large through holes and wood members.

[0010] A composite beam according to a second aspect is the composite beam according to the first aspect, wherein a slab is provided so as to protrude from an upper end of the concrete beam portion in a beam width direction of the concrete beam portion.

[0011] According to the composite beam of the second aspect, it is possible to obtain a composite effect of the wood beam, the concrete beam, and the slab, thereby making it possible to reduce the beam width of the composite beam.

[0012] A composite beam according to a third aspect is the composite beam according to the first or second aspect, in which the concrete beam portion is made of a precast member.

[0013] According to the composite beam of the third embodiment, the composite beam can be efficiently constructed on-site. Effect of the Invention

[0014] Since the present invention has the above-mentioned configuration, it is possible to construct a composite beam having wood members with a plurality of large through holes. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 illustrates a side view of a composite beam according to an embodiment. [Diagram 2] 2 is a cross-sectional view taken along line 2-2 of FIG. 1. [Diagram 3] 3 is a cross-sectional view taken along line 3-3 in FIG. 1. [Figure 4] 4 is a cross-sectional view taken along line 4-4 of FIG. 1. [Diagram 5] FIG. 1 is a perspective view showing a column-beam joint structure according to one embodiment. [Figure 6] FIG. 11 is a diagram showing moment values ​​with respect to load point deflection obtained by a load test according to one embodiment. [Figure 7] FIG. 13 is a side view showing a test specimen B used in a load test according to one embodiment. [Figure 8] 1A-1D are cross-sectional views illustrating variations of a composite beam according to one embodiment. [Figure 9] FIG. 13 is a side view showing a variation of a composite beam according to an embodiment. [Figure 10] FIG. 11 is a side view showing a variation of a wooden beam according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, a composite beam according to one embodiment will be described with reference to the drawings.

[0017] (composite beam) As shown in the side view of Figure 1, Figure 2, which is a cross-sectional view taken along line 2-2 of Figure 1, Figure 3, which is a cross-sectional view taken along line 3-3 of Figure 1, and Figure 4, which is a cross-sectional view taken along line 4-4 of Figure 1, the composite beam 10 is composed of a wooden beam portion 12, a concrete beam portion 14, a shear force transmission portion 16, and a number of through holes 18, 20.

[0018] The wooden beam 12 is configured to have a wooden beam lower member 34 and a wooden beam upper member 36 provided on the upper surface of the end of the wooden beam lower member 34. The wooden beam lower member 34 and the wooden beam upper member 36 are formed from laminated wood, which is a wood material.

[0019] The wooden beam portion 12 has a higher beam depth at the ends 22, 24 than at the middle portion 26. That is, the wooden beam portion 12 has a so-called inverted drop haunch shape in which the ends 22, 24 and the middle portion 26 have a variable cross section.

[0020] The concrete beam 14 is made of reinforced concrete and is provided on the upper surface of the middle section 26 of the wooden beam 12. The concrete beam 14 is formed on the upper surface of the middle section 26 of the wooden beam 12 by pouring cast-in-place concrete.

[0021] The shear force transmission section 16 is provided near the boundary surface 28 between the middle section 26 of the wooden beam section 12 and the concrete beam section 14. The shear force transmission section 16 is composed of multiple drift pins 30 as shear keys, with their lower ends embedded in the wooden beam section 12 and their upper ends embedded in the concrete beam section 14.

[0022] The drift pins 30 are arranged at predetermined intervals in the beam length direction (hereinafter referred to as "beam length direction Y1") of the composite beam 10, the wooden beam section 12, and the concrete beam section 14. This enables the transmission of shear force in the beam length direction Y1 between the wooden beam section 12 and the concrete beam section 14.

[0023] In addition, the drift pins 30 arranged at the end of the middle part 26 of the wooden beam part 12 are arranged more densely (at shorter intervals) in the beam length direction Y1 than the drift pins 30 arranged in the middle part of the middle part 26 of the wooden beam part 12. This is because the shear force generated near the end upper surface (boundary surface 28) of the middle part 26 of the wooden beam part 12 is larger than the shear force generated near the middle part upper surface (boundary surface 28) of the middle part 26 of the wooden beam part 12, and this allows the shear force in the beam length direction Y1 to be efficiently transmitted between the wooden beam part 12 and the concrete beam part 14.

[0024] The through holes 18, 20 are formed in the concrete beam section 14 located above the middle section 26 of the wooden beam section 12. The through holes 18, 20 are formed near the upper surface (boundary surface 28) of the middle section 26 of the wooden beam section 12 so as to penetrate the concrete beam section 14 in the beam width direction of the composite beam 10, the wooden beam section 12, and the concrete beam section 14 (hereinafter referred to as the "beam width direction X1").

[0025] The composite beam 10 is provided with a reinforced concrete slab 32 that protrudes in the beam width direction X1 from the upper end of the concrete beam portion 14. The slab 32 is formed by pouring cast-in-place concrete.

[0026] As shown in the perspective views of Figures 1, 2, and 5, the wooden beam lower member 34 is a rectangular prism-shaped member that spans the entire length of the wooden beam 12. At the end of the wooden beam lower member 34, a vertical slit 38 is formed that penetrates the wooden beam lower member 34 from the center in the beam width direction X1 on the upper surface of the end to the center in the beam width direction X1 on the lower surface of the end and opens on the end face side. In addition, at the end of the wooden beam lower member 34, a plurality of through holes 40 that penetrate the wooden beam lower member 34 in the beam width direction X1 are formed so as to be arranged in a circle.

[0027] The wooden beam upper member 36 is a rectangular prism-shaped member that spans the entire length of the ends 22, 24 of the wooden beam 12. The wooden beam upper member 36 is formed with a vertical slit 42 that penetrates the wooden beam upper member 36 from the center in the beam width direction X1 on the upper surface to the center in the beam width direction X1 on the lower surface and opens on the end surface side. In addition, the wooden beam upper member 36 is formed with a plurality of through holes 44 that penetrate the wooden beam upper member 36 in the beam width direction X1 and are arranged in a circle.

[0028] The end of the wooden beam lower member 34 and the wooden beam upper member 36 are joined and integrated by bonding the upper surface of the end of the wooden beam lower member 34 to the lower surface of the wooden beam upper member 36 with an adhesive. When the end of the wooden beam lower member 34 and the wooden beam upper member 36 are joined and integrated, the vertical slit 38 of the wooden beam lower member 34 and the vertical slit 42 of the wooden beam upper member 36 communicate with each other to form one vertical slit 46.

[0029] The composite beam 10 is joined to a column 50 by a column-beam joint structure 48. The column 50 is constructed by connecting an upper column 52 and a lower column 54 vertically with a joint member 58. The upper column 52 and the lower column 54 are formed from laminated lumber, which is a wood material.

[0030] The column-beam joint structure 48 is configured to include a joint member 56 and a joint member 58. The joint member 56 is configured to include an H-shaped steel 60 and a steel flat plate 62 joined to the end face of the H-shaped steel 60 with its upper end protruding.

[0031] A plurality of through holes 66, 68 are formed in a circular shape in the web 64 of the H-shaped steel 60, penetrating the web 64 in the beam width direction X1. In addition, a plurality of through holes 70 are formed in the upper end of the flat plate 62, penetrating the flat plate 62 in the beam length direction Y1.

[0032] The wooden beam 12 is moved laterally so that the web 64 of the H-shaped steel 60 is inserted into the vertical slit 46 of the wooden beam 12 until the end face of the wooden beam 12 faces the back face of the flat plate 62 (the face on the H-shaped steel 60 side) with a small gap, and is placed on the upper surface of the lower flange 72 of the H-shaped steel 60. In this state, drift pins 74 are inserted into the communicating through holes 40, 44 of the wooden beam 12 and the through holes 66, 68 of the H-shaped steel 60 to fix the end of the wooden beam 12 to the joint member 56, and the gap between the end face of the wooden beam 12 and the back face of the flat plate 62 is filled with grout.

[0033] The joint member 58 is composed of an H-shaped steel 76, a flat steel plate 80 that extends horizontally to the left and right from the upper end of the web 78 of the H-shaped steel 76 in a plan view, and a flat steel plate 82 that is provided on the flat plate 80 and joined to the web 78 of the H-shaped steel 76 so as to form a cross shape in a plan view.

[0034] A plurality of through holes 86 are formed in the upper end of the flange 84 of the H-shaped steel 76, penetrating the flange 84 in the column-formation direction of the column 50 (hereinafter referred to as the "column-formation direction Y2"). Also, a plurality of through holes 88, 90 are formed in the web 78 of the H-shaped steel 76, penetrating the web 78 in the column width direction of the column 50 (hereinafter referred to as the "column width direction X2").

[0035] A vertical slit 92 is formed at the upper end of the lower pillar 54, extending downward from the center of the lower pillar 54 in the pillar width direction X2 on the upper end surface of the lower pillar 54. In addition, a plurality of through holes 94 are formed at the upper end of the lower pillar 54, penetrating the lower pillar 54 in the pillar width direction X2.

[0036] A vertical slit 96 having a cross shape in a plan view extending upward from the lower end surface of upper column 52 is formed at the lower end of upper column 52. In addition, a plurality of through holes 98 are formed at the lower end of upper column 52, penetrating upper column 52 in the column width direction X2.

[0037] The joint member 58 is moved downward so that the web 78 of the H-shaped steel 76 is inserted into the vertical slit 92 of the lower column 54 until the lower surface of the flat plate 80 faces the upper end surface of the lower column 54 with a small gap between them. In this state, a drift pin 100 is inserted into the communicating through hole 94 of the lower column 54 and the through hole 90 of the web 78 of the H-shaped steel 76 to fix the upper end of the lower column 54 to the joint member 58, and grout is filled into the gap between the lower surface of the flat plate 80 and the upper end surface of the lower column 54.

[0038] The upper column 52 is moved downward so that the web 78 of the H-shaped steel 76 and the flat plate 82 are inserted into the vertical slit 96 of the upper column 52 until the lower end surface of the upper column 52 faces the upper surface of the flat plate 80 with a small gap between them. In this state, a drift pin 100 is inserted into the communicating through hole 98 of the upper column 52 and the through hole 88 of the web 78 of the H-shaped steel 76 to fix the lower end of the upper column 52 to the joint member 58, and the gap between the lower end surface of the upper column 52 and the upper surface of the flat plate 80 is filled with grout.

[0039] The joint member 58 and the connecting member 56 are joined by aligning the flange surface of the flange 84 of the joint member 58 with the plate surface of the flat plate 62 of the connecting member 56, passing a bolt 102 through the through hole 86 of the flange 84 and the through hole 70 of the flat plate 62, and screwing it into a nut 104 and tightening it.

[0040] As shown in Fig. 1, a plurality of stud bolts 110 are provided on the upper surface of the upper flange 106 of the H-shaped steel 60 constituting the connecting member 56 so as to be embedded in a concrete beam section 108 formed on the upper surface of the upper flange 106 by reinforced concrete, enhancing the integration of the connecting member 56 and the concrete beam section 108. Note that the stud bolts 108 are omitted from the connecting member 56 shown in Fig. 5.

[0041] (effect) Next, the effects of this embodiment will be described.

[0042] According to the composite beam 10 of this embodiment, as shown in Fig. 1, the concrete beam section 14 is provided on the upper surface of the middle section 26 of the wooden beam section 12, which has a low beam depth, and the wooden beam section 12 and the concrete beam section 14 are integrated by enabling shear force transmission between the wooden beam section 12 and the concrete beam section 14 by the shear force transmission section 16. This makes it possible to configure a composite beam with improved rigidity and strength. In addition, a composite effect can be obtained between the wooden beam section 12 and the concrete beam section 14, and the beam depth of the composite beam 10 can be reduced.

[0043] 6 shows the results of a loading test performed on a specimen A (not shown) having a similar configuration to the composite beam 10 of this embodiment and a specimen B as a comparative example. Value 112 indicates the moment M with respect to the load point deflection σ at the loading point when the center of specimen A is loaded, and value 114 indicates the moment M with respect to the load point deflection σ at the loading point when the center of specimen B is loaded.

[0044] As shown in the side view of Figure 7, specimen B is a wooden beam portion 12 of the composite beam 10 of this embodiment (see Figure 1) that does not have a drop haunch shape at both ends and has a uniform cross section over the entire beam length, and the other configurations are almost the same as those of the composite beam 10.

[0045] In other words, test specimen B is composed of a wooden beam section 116 consisting only of a wooden beam lower member 34, a concrete beam section 14 formed on the upper surface of this wooden beam section 116 over the entire beam length, a shear force transmission section 16, and a number of through holes 18, 20, and a slab 32 is provided so as to protrude from the upper end of the concrete beam section 14 in the beam width direction of the concrete beam section 14.

[0046] From the values ​​112 and 114 in FIG. 6, it can be seen that the test specimen A has greater rigidity and strength than the test specimen B, and this shows that the composite beam 10 of this embodiment is a composite beam with improved rigidity and strength.

[0047] In addition, according to the composite beam 10 of this embodiment, as shown in Figure 1, during an earthquake, the wooden beam section 12 and the concrete beam section 14 tend to shift horizontally. However, since the end face of the concrete beam section 14 contacts the high beam depth part (wooden beam upper member 36) at the end of the wooden beam section 12, this cooperates with the shear force transmission section 16 to suppress the horizontal shift between the wooden beam section 12 and the concrete beam section 14.

[0048] Furthermore, according to the composite beam 10 of this embodiment, as shown in Fig. 1, the through holes 18, 20 for passing equipment piping and the like are formed in the concrete beam section 14, so that large through holes can be formed, and since there is no need to apply fireproof coating to the inner surface of the through holes, the formed through holes do not become small. As a result, a composite beam having a wooden member (wooden beam section 12) with multiple large through holes can be constructed.

[0049] In addition, according to the composite beam 10 of this embodiment, as shown in Figure 1, the through holes 18, 20 for passing equipment piping, etc. are formed near the upper surface of the wooden beam portion 12, i.e., in a location near the neutral axis of the composite beam 10 where large stress is not generated, so that reinforcement of the through holes can be reduced or made unnecessary, and larger through holes can be formed.

[0050] 1 to 4, the composite beam 10 of this embodiment has a slab 32 extending from the upper end of the concrete beam section 14 in the beam width direction (beam width direction X1) of the concrete beam section 14, thereby achieving a composite effect of the wooden beam section 12, the concrete beam section 14, and the slab 32. This allows the beam width of the composite beam 10 to be reduced.

[0051] (Modification) Next, a modification of the above embodiment will be described.

[0052] In the above embodiment, as shown in Fig. 1, an example was shown in which the wooden beam 12 was formed from laminated lumber, but the wooden beam 12 may be any member made of wood. For example, as shown in the cross-sectional view of Fig. 8, the wooden beam 12 may be configured to have a wooden beam core material 118 that serves as a load support portion, a fire-retardant layer 120 provided around the beam core material 118, and a wooden substitute fire layer 122 provided around the fire-retardant layer 120. The fire-retardant layer 120 is configured by alternately arranging wooden boards 124 and mortar boards 126.

[0053] In this wooden beam section 12, when a fire breaks out, the fuel layer 122 burns and carbonizes, and this carbonized fuel layer 122 suppresses heat transfer from the outside of the fuel layer 122 to the beam core material 118. Furthermore, the fire-stopping layer 120 prevents flames and heat from penetrating the beam core material 118 from the outside of the fuel layer 122. This suppresses the temperature rise of the beam core material 118 during and after a fire, and makes it possible to stop the beam core material 118 from burning.

[0054] In the above embodiment, as shown in FIG. 1, an example was shown in which both ends (ends 22, 24) of the wooden beam portion 12 are in a drop haunch shape, but it is sufficient that at least one end of the wooden beam portion 12 is in a drop haunch shape.

[0055] For example, as in the composite beam 128 shown in the side view of Figure 9, the end 22 of the wooden beam portion 12 may be shaped as a drop haunch, and the end 24 of the wooden beam portion 12 may be shaped so that the cross-section of the middle portion 26 is equal to the cross-section of the end 24 over the entire length of the end 24 in the beam length direction Y1.

[0056] In this example, the right end of the composite beam 128 is joined to a wooden beam 130 by a joining member 132. The joining member 132 is configured to include a joining plate 136 attached to the side of the beam 130 by a screw member 134 such as a lag screw, and a gusset plate 138 provided on the plate surface of the joining plate 136 so as to protrude from this plate surface.

[0057] The right end of the composite beam 128 is joined to a beam 130 by fixing the wooden beam 12 to a gusset plate 138 of a joining member 132 inserted into a slit (not shown) formed in the end face of the wooden beam 12 with a drift pin 140. The beam 130 may be a member of other structures such as reinforced concrete, steel-reinforced concrete, and steel frame construction.

[0058] Furthermore, in the above embodiment, as shown in Figure 1, an example was shown in which the wooden beam section 12 was formed by combining the wooden beam lower member 34 and the wooden beam upper member 36, but the members that are combined to form the wooden beam section 12 may be members of any shape.

[0059] For example, as shown in the side view of Figure 10, the wooden beam section 12 may be formed by integrating a wooden beam intermediate member 142 that constitutes the middle portion 26 of the wooden beam section 12 and a wooden beam end member 144 that constitutes the ends 22, 24 of the wooden beam section 12 with a connecting member 146.

[0060] Furthermore, in the above embodiment, as shown in Fig. 1, an example was shown in which the concrete beam portion 14 was made of reinforced concrete, but the concrete beam portion 14 may be made of fire-resistant concrete. For example, the concrete beam portion 14 may be a steel-reinforced concrete member using CT steel, or a precast concrete member of reinforced concrete or steel-reinforced concrete. If the concrete beam portion 14 is a precast member, the composite beam 10 can be efficiently constructed on-site.

[0061] In the above embodiment, as shown in Fig. 1, the shear force transmission part 16 is configured by the drift pin 30, but the shear force transmission part 16 may be configured by any part that enables the transmission of shear force in the beam length direction Y1 between the wooden beam part 12 and the concrete beam part 14. For example, the shear force transmission part 16 may be configured by a lag screw, a headed stud bolt, a cotter, or the like.

[0062] Furthermore, in the above embodiment, as shown in FIG. 1, an example was shown in which the slab 32 was a reinforced concrete slab formed from cast-in-place concrete, but the slab 32 may be of other structure, such as a precast concrete slab or a deck slab.

[0063] In the above embodiment, as shown in FIG. 1, an example is shown in which the pillar 50 (upper pillar 52 and lower pillar 54) is a wooden component formed from laminated timber, but the pillar 50 may be a component of other structure such as reinforced concrete structure or steel-reinforced concrete structure.

[0064] Furthermore, in the above embodiment, as shown in Fig. 1, an example in which the composite beam 10 is joined to the column 50 is shown, but the composite beam 10 may be joined to a beam. In this case, the beam may be a member of various structures such as reinforced concrete structure, steel reinforced concrete structure, and steel structure.

[0065] Although one embodiment of the present invention has been described above, the present invention is not limited to such an embodiment, and one embodiment and various modified examples may be used in appropriate combination, and it is of course possible to implement the present invention in various forms without departing from the gist of the present invention. [Explanation of symbols]

[0066] 10, 128 composite beam 12 Wooden beam part 14 Concrete beam section 16 Shear force transmission section 18, 20 Through holes 22, 24 End 26 Middle Section 28 Boundary 30 Drift pin (shear force transmission part) 32 Slab X1 Beam width direction (beam width direction of concrete beam section)

Claims

1. A wooden beam section having an end portion and a middle portion, the end portion having a higher beam depth than the middle portion, and the end portion having an inverted drop haunch shape; A concrete beam section provided on the upper surface of the middle section of the wooden beam section; A shear force transmission portion provided on the boundary surface between the wooden beam portion and the concrete beam portion; a through hole formed in the concrete beam portion and penetrating the concrete beam portion in a beam width direction, A cross section of the intermediate portion in the beam length direction is the same from one end portion to the other end portion, A composite beam in which the shear force transmission portion is composed of a plurality of drift pins arranged at intervals in the beam length direction, and the drift pins arranged at the ends of the intermediate portion are arranged more densely in the beam length direction than the drift pins arranged in the intermediate portion of the intermediate portion.

2. 2. The composite beam according to claim 1, wherein a slab is provided so as to extend from an upper end of the concrete beam section in a beam width direction of the concrete beam section.

3. 3. The composite beam according to claim 1, wherein the concrete beam section is made of precast members.

4. A wooden beam section having both end portions in the beam length direction and an intermediate portion formed between the both end portions and adjacent to the both end portions, the beam depth of at least one of the end portions being higher than the beam depth of the intermediate portion, and the upper surface of at least one of the end portions being located higher than the upper surface of the intermediate portion; A concrete beam section provided on the upper surface of the middle section of the wooden beam section; A shear force transmission portion provided on the boundary surface between the wooden beam portion and the concrete beam portion; a through hole formed in the concrete beam portion and penetrating the concrete beam portion in a beam width direction, A cross section of the intermediate portion in the beam length direction is the same from one end portion to the other end portion, A composite beam in which the shear force transmission portion is composed of a plurality of drift pins arranged at intervals in the beam length direction, and the drift pins arranged at the ends of the intermediate portion are arranged more densely in the beam length direction than the drift pins arranged in the intermediate portion of the intermediate portion.

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