Joint structure between concrete column and steel beam

Abstract

To provide a joint structure of a concrete column including a precast concrete member and a steel beam with improved work efficiency.SOLUTION: A joint structure 3 comprises a precast concrete column member 4 and a joint member 5. The precast concrete column member 4 includes a main reinforcement 7, a concrete portion 9 in which the main reinforcement 7 is partially embedded, and a steel plate member 10 attached to an upper surface of the concrete portion 9. The joint member 5 includes a steel frame portion 14 placed directly on the steel plate member 10. It is preferable that the precast concrete column member 4 has a hollow structure.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a joint structure between a concrete column including a precast concrete member and a steel beam. [Background technology]

[0002] A joint structure between a concrete column including a precast concrete member and a steel beam, as shown in FIG. 7, has been known (see, for example, the background art of Patent Document 1). This joint structure is a so-called beam-through type, in which a steel beam 101 penetrates a reinforced concrete column 102. At the joint with the reinforced concrete column 102, the steel beam 101 intersects in a cross shape. A plurality of cover plates 103 are welded to the steel beam 101 to form a concrete formwork for the joint in the reinforced concrete column 102. The main reinforcements 104 of the reinforced concrete column 102 are arranged at the four corners defined by the steel beams 101. A joint member 105 including the steel beams 101 and cover plates 103 arranged in a cross shape is placed on the existing portion of the reinforced concrete column 102, and concrete is poured in the area surrounded by the cover plates 103. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-059408 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the above-mentioned conventional technology, when placing the joint member 105 on the existing part of the reinforced concrete column 102, a predetermined gap is left between the joint member 105 and the reinforced concrete column 102, and then joint material is injected into this gap. This requires formwork for the joint material and scaffolding for work, which makes it difficult to sufficiently improve work efficiency.

[0005] Furthermore, when the above-mentioned conventional technology was applied to the construction of large logistics facilities, the weight of the precast concrete members used to construct the columns became heavy. As a result, when transporting the precast concrete members from the precast concrete member factory to the construction site, there were cases where only one precast concrete member could be loaded per vehicle, resulting in reduced work efficiency.

[0006] In view of the above background, an object of the present invention is to provide a joint structure between a concrete column including a precast concrete member and a steel beam, which improves work efficiency. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems, one aspect of the present invention is a joint structure (3) between a concrete column (1) and a steel beam (2), which comprises a precast concrete column member (4) including main reinforcement (7), a concrete section (9) in which the main reinforcement is at least partially embedded, and a steel plate member (10) attached to the top surface of the concrete section and having a flat top surface, and a joint member (5) including a steel section (14) that constitutes the portion of the steel beam that penetrates the concrete column and is placed directly on the steel plate member.

[0008] According to this aspect, since the steel frame section is placed directly on the steel plate members, it is not necessary to inject a joint material between the joint member and the precast concrete column member where the main section is placed below. This eliminates the need for formwork or scaffolding for injecting the joint material in this area, improving work efficiency.

[0009] In the above aspect, the precast concrete column member (4) may include a hollow portion (12) penetrating in the vertical direction, and may further include a cast-in-place concrete portion (6) filled in the hollow portion.

[0010] This method makes precast concrete columns lighter than solid structural members, which increases the number of precast concrete columns that can be loaded onto a single transport vehicle, improving work efficiency. Furthermore, the precast concrete columns can be lifted with a relatively small crane, reducing the cost of building construction.

[0011] In the above aspect, the concrete portion (9) may be configured such that the cross-sectional contour of the hollow portion (12) becomes larger from the center portion in the vertical direction toward the top and bottom.

[0012] According to this configuration, the mold for molding the hollow portion has a tapered shape, which makes it easy to remove from the mold.

[0013] In the above aspect, in a plan view, the concrete portion (9) has a rectangular frame shape, the main reinforcement (7) is arranged at the corners (11) of the frame shape, the steel plate members (10) are arranged at the sides (13) between adjacent corners, and the inner and outer edges of the steel plate members are aligned with the inner and outer edges of the sides.

[0014] Although unevenness occurs near the center of the underside of the steel frame portion due to welding, etc., this embodiment makes it possible to avoid such unevenness and abut the flat portion of the underside of the steel frame portion 14 against the steel plate member.

[0015] In the above embodiment, the concrete pillar has a resistance of 48N / mm 2 Over 100N / mm 2 It may have the following design standard strength and cross-sectional dimensions of longitudinal and lateral lengths of 0.9 m or more and 1.1 m or less.

[0016] When applied to such a large-scale logistics facility, the hollow structure of the precast concrete column member 4 reduces its weight, resulting in a significant improvement in the efficiency of transportation work. [Effects of the Invention]

[0017] According to the above aspects, it is possible to provide a joint structure between a concrete column including a precast concrete member and a steel beam, which improves work efficiency. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a partial cross-sectional front view showing a joint structure according to an embodiment; [Figure 2] Front view showing a precast concrete column member according to an embodiment [Figure 3] 2A and 2B are diagrams showing a precast concrete column member according to an embodiment (A: plan view, B: cross-sectional view along line BB in FIG. 2, C: bottom view). [Figure 4] FIG. 1 is a plan view showing a joint structure according to an embodiment (before concrete is poured into the joint); [Figure 5] A cross-sectional view of the area surrounded by the two-dot chain line in FIG. 1, taken along line VV in FIG. 4. [Figure 6] 1 is an explanatory diagram showing a procedure for constructing a joint structure according to an embodiment; [Figure 7] FIG. 1 is a perspective view showing a joint structure according to a conventional technique (before concrete is poured into the joint); DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a joint structure 3 between a concrete column 1 and a steel beam 2 according to the embodiment. The joint structure 3 comprises a precast concrete column member 4, a joint member 5 placed on the precast concrete column member 4, and a cast-in-place concrete section 6 cast in the precast concrete column member 4 and the joint member 5. The joint structure 3 is applied to, for example, a building of a large-scale logistics facility. In a typical large-scale logistics facility, the design standard strength of the concrete column 1 is 48 N / mm 2 More than 60N / mm 2 or less than 48N / mm 2 Over 100N / mm 2The cross-sectional dimensions of the concrete pillar 1 are approximately 1 m in both vertical and horizontal lengths (for example, 0.9 m or more and 1.1 m or less).

[0020] As shown in Figures 2 and 3, the precast concrete column member 4 includes a plurality of main reinforcements 7 extending in the vertical direction, a plurality of tie bars 8 extending in the horizontal direction surrounding the main reinforcements 7, a cylindrical concrete section 9 extending in the vertical direction with the main reinforcements 7 partially buried and the tie bars 8 buried in it, and four steel plate members 10 attached to the upper surface of the concrete section 9.

[0021] The main reinforcements 7 are partially embedded in four corners 11 of the concrete portion 9 which has a rectangular frame shape in plan view. The upper ends of the main reinforcements 7 protrude from the upper surface of the concrete portion 9.

[0022] The cylindrical concrete section 9 defines a hollow section 12 that penetrates the precast concrete column member 4 from top to bottom by its inner circumferential surface. It is preferable that the cross-sectional contour of the hollow section 12 be configured so that it becomes larger from the vertical center toward the top and bottom. In the illustrated example, the inner circumferential surface defining the hollow section 12 is inclined at a predetermined angle outward from the vertical center toward the top and bottom (the "inward-outward direction" with respect to the precast concrete column member 4 refers to the direction toward the central axis extending vertically of the precast concrete column member 4 as "inward" and the direction away from the central axis as "outward"). The inclination angle of the inner circumferential surface may change midway, or the inner circumferential surface may be curved vertically.

[0023] The steel plate members 10 are attached to four side portions 13 extending between adjacent corner portions 11 on the upper surface of the concrete portion 9. The steel plate members 10 are preferably placed at predetermined positions within the formwork when the concrete of the precast concrete column member 4 is poured, and are attached to the concrete portion 9 as the concrete poured within the formwork hardens. The steel plate members 10 have a rectangular flat plate shape in a plan view and a flat upper surface. The upper surface of the steel plate member 10 is preferably flush with the portion of the upper surface of the concrete portion 9 where the steel plate member 10 is not placed. In a plan view, the inner and outer edges of the steel plate member 10 are aligned with the inner and outer edges of the side portions 13 on the upper surface of the concrete portion 9. The thickness of the steel plate member 10 is, for example, approximately 9 mm.

[0024] As shown in Figures 4 and 5, the joint member 5 includes a steel frame portion 14 arranged in a cross shape when viewed in a plane, and a cover plate 15 welded to the steel frame portion 14 so that its inner main surface is positioned on the upward extension of the outer surface of the concrete portion 9 of the precast concrete column member 4.

[0025] The steel frame portion 14 constitutes a part of the steel beam 2 (see FIG. 1 ). The steel frame portion 14 includes a first steel frame member 16 including an H-shaped steel extending horizontally in a direction parallel to the extension direction of a pair of parallel side portions 13; a second steel frame member 17 including an H-shaped steel that is joined at one end to the first steel frame member 16 by welding or the like and extends horizontally perpendicular to the first steel frame member 16; and a third steel frame member 18 including an H-shaped steel that is joined at one end to the first steel frame member 16 on the side opposite to the second steel frame member 17 by welding or the like and extends horizontally perpendicular to the first steel frame member 16. The third steel frame member 18 is positioned on an extension line of the second steel frame member 17, so the steel frame portion 14 forms a cross shape in a plan view. In a plan view, the intersection of the cross shape of the steel frame portion 14 is aligned with the central axis of the precast concrete column member 4. The first steel frame member 16 is placed directly on two steel plate members 10 arranged on opposing side portions 13, and each of the second and third steel frame members 17, 18 is placed directly on a corresponding one of the steel plate members 10. The widths of the first to third steel frame members 16, 17, 18 are equal to or less than the length of the corresponding steel plate member 10 (the length along the extension direction of the side portions 13), and the first to third steel frame members 16, 17, 18 do not directly abut against the upper surface of the concrete portion 9.

[0026] The multiple cover plates 15 are welded to the steel frame 14 without any gaps so that they form a rectangular frame shape in plan view as a whole, and function as a formwork. After the joint members 5 are placed so that there is no gap between the lower edges of the cover plates 15 and the upper surface of the concrete section 9, cast-in-place concrete is poured into the area surrounded by the cover plates 15 and the hollow section 12, thereby forming the cast-in-place concrete section 6.

[0027] The cast-in-place concrete section 6, together with the precast concrete column member 4, constitutes part of the concrete column 1 (see Figure 1). The area surrounded by the cover plate 15 includes the cross-shaped intersection of the steel frame section 14, so the steel frame section 14 penetrates the cast-in-place concrete section 6 in two mutually perpendicular directions. The part of the main reinforcement 7 that protrudes from the top surface of the concrete section 9 is embedded in the cast-in-place concrete section 6, except for its upper end.

[0028] As shown in Figure 5, another precast concrete column member 4 is placed on top of the precast concrete column member 4 and the joint member 5. A sleeve 19 is embedded in the lower end of the concrete portion of the precast concrete column member 4 to form a mechanical joint for the main reinforcement 7. The sleeve 19 extends vertically, and its lower end opens to the underside of the concrete portion 9. The upper part of the sleeve 19 receives the lower end of the main reinforcement 7 of the precast concrete column member 4, and the lower part of the sleeve 19 receives the upper end of the main reinforcement 7 of the precast concrete column member 4 placed below it. The sleeve 19 is filled with joint grout (not shown). The joint grout is injected through an injection hole 20 that opens on the side of the concrete portion 9 and communicates with the lower end of the sleeve 19, and is discharged through a discharge hole 21 that opens on the side of the concrete portion 9 and communicates with the upper end of the sleeve 19, thereby filling the sleeve 19.

[0029] Joint grout 22 is poured between the upper surfaces of the cast-in-place concrete portion 6 and the steel frame portion 14 in the area surrounded by the cover plate 15 and the concrete portion 9 of the precast concrete column member 4 placed above it. Part of the joint grout 22 has also penetrated into the lower end of the hollow portion 12 and hardened.

[0030] A method for constructing the joint structure 3 will be described with reference to FIGS.

[0031] Workers manufacture precast concrete column members 4 in a factory. The precast concrete column members 4 are manufactured using formwork so that their extension direction (the up-down direction after construction) is horizontal. The manufactured precast concrete column members 4 are transported to the construction site by truck or other vehicle.

[0032] As shown in Figure 6(A), workers use a crane or the like to place the precast concrete column member 4 in a predetermined position, and then place the joint member 5 on the precast concrete column member 4. As shown in Figure 5, the joint member 5 is placed so that the steel frame portion 14 directly abuts the steel plate member 10.

[0033] As shown in Figure 6(B), workers pour concrete into the area surrounded by the hollow portion 12 of the precast concrete column member 4 and the cover plate 15 (see Figure 5) of the joint member 5 to construct the cast-in-place concrete portion 6. In addition, workers place a beam member 23 that forms part of the steel beam 2 between the two joint members 5 and join the beam member 23 to the steel portion 14 using splices and high-strength bolts (not shown), etc.

[0034] As shown in Figure 6(C), workers use a crane or the like to place a new precast concrete column element 4 above the installed precast concrete column element 4 in order to construct a concrete column 1 one story higher than the installed precast concrete column element 4. At this time, the workers insert the upper ends of the main reinforcement 7 of the installed precast concrete column element 4 into the sleeve 19 of the new precast concrete column element 4, as shown in Figure 5. After adjusting the position of the new precast concrete column element 4, the workers inject joint grout 22 between the underside of the new precast concrete column element 4 and the upper surfaces of the cast-in-place concrete portion 6 and steel frame portion 14 directly below it, and then inject joint grout (not shown) into the sleeve 19.

[0035] The effects of the joint structure 3 will be described.

[0036] Since the cross-sectional contour of the hollow portion 12 of the precast concrete column member 4 becomes larger from the center toward the top and bottom, the formwork (not shown) used to form the hollow portion 12 has a tapered shape and can be easily removed. In addition, because the precast concrete column member 4 is formed using a formwork, manufacturing costs can be reduced compared to centrifugal molding.

[0037] Because the precast concrete column members 4 have a hollow structure, they are lighter than solid column members. This allows more units to be transported per truck, and they can be lifted with a relatively small crane. In particular, for precast concrete column members 4 for large logistics facilities, while a truck could only carry one solid column member, two precast concrete column members 4 can be loaded per truck, improving work efficiency.

[0038] By placing the steel frame portion 14 of the joint member 5 directly on the steel plate member 10 of the precast concrete column member 4, it is no longer necessary to inject joint material between the joint member 5 and the precast concrete column member 4, the main part of which is placed below it. This eliminates the need for formwork for injecting joint material in this area or scaffolding for work, improving work efficiency.

[0039] Furthermore, due to welding of the second and third steel frame members 17, 18 to the first steel frame member 16, unevenness occurs on the underside of the steel frame portion 14. If an attempt is made to place the steel frame portion 14 directly on a solid precast concrete member, these unevenness will create a gap between the two. In this embodiment, the precast concrete column member 4 has a hollow structure, and the steel frame portion 14 is placed only on the steel plate members 10 arranged on the side portions 13. Therefore, the flat portion of the underside of the steel frame portion 14 can be abutted against the steel plate members 10, avoiding the uneven portion.

[0040] Although the specific embodiments have been described above, the present invention is not limited to these embodiments and can be widely modified and implemented. For example, the joint structure may be applied to buildings other than large-scale logistics facilities. Along exterior walls or at building corners, the steel frame sections may be T-shaped or L-shaped in plan view, and the steel plate members 10 may be provided only at positions corresponding to the T-shaped or L-shaped steel frame sections. Checkered steel plates may be used as formwork for forming the hollow sections, and cotters may be provided on the inner surface of the concrete sections to enhance adhesion between the concrete sections of the precast concrete column members and the cast-in-place concrete sections. A mechanical joint may be provided at the upper end of the concrete section of one precast concrete column member, and main reinforcement bars may protrude from the underside of the concrete section of another precast concrete column member placed above it. Precast concrete column members with mechanical joints at the upper and lower ends of the concrete section and precast concrete column members with main reinforcement bars protruding from the upper and lower ends of the concrete section may be used alternately. [Explanation of symbols]

[0041] 1: Concrete pillar 2: Steel beam 3:Joint structure 4: Precast concrete column members 5: Joint material 6: Cast-in-place concrete section 7: Main reinforcement 9: Concrete section 10: Steel plate members 11: Corner 12:Hollow part 13: Edge 14: Steel frame section

Claims

1. A joint structure between a concrete column and a steel beam, a precast concrete column member including a main reinforcement, a concrete portion in which the main reinforcement is at least partially embedded, a hollow portion penetrating in the vertical direction, and a steel plate member attached to the upper surface of the concrete portion and having a flat upper surface; a joint member including a steel portion that constitutes a portion of the steel beam that penetrates the concrete column and is placed directly on the steel plate member; A cast-in-place concrete portion filled in the hollow portion; Equipped with A joint structure in which the concrete portion is configured so that the cross-sectional contour of the hollow portion becomes larger from the center portion in the vertical direction toward the top and bottom.

2. 2. The joint structure of claim 1, wherein, in a plan view, the concrete portion has a rectangular frame shape, the main reinforcement is arranged at the corners of the frame shape, the steel plate members are arranged at the edges between adjacent corners, and the inner and outer edges of the steel plate members are aligned with the inner and outer edges of the edges.

3. The concrete pillar has a resistance of 48N / mm ２ More than 100N / mm ２ The joint structure according to claim 1 or 2, having a design standard strength of 0.9 m or more and a cross-sectional dimension of 0.9 m or more and 1.1 m or less in vertical and horizontal lengths.

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