Column-beam joint structure

Abstract

To provide a column-beam joint structure suitable for a large span frame.SOLUTION: In a column-beam joint structure of beams and reinforced concrete columns 10 installed in directions crossing each other, composite structure beams 30 composed of material end part reinforced concrete beams 33 and central part steel beams 31 are arranged at a first interval (D1) from steel beams 20 in which one end parts in a long axis direction of the steel beams 31 are installed in directions crossing the composite structure beams 30, an upper-end reinforcement 34 and a lower-end reinforcement 35 are arranged integrally with the reinforced concrete beam 33 and are joined to the steel beam 20 and the reinforced concrete column 10 through a column-beam crossing part 40 where concrete is placed.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a beam-column joint structure, and in particular to a composite structural beam consisting of a reinforced concrete beam at the end and a steel beam in the middle, and to a beam-column joint structure between a steel beam and a reinforced concrete column. [Background technology]

[0002] In order to ensure a large beam span for a building or to shorten construction time, a composite structure that combines steel beams and reinforced concrete columns may be used.

[0003] In such cases, in a composite structure of a steel beam and a reinforced concrete column, the beam-column joint may be reinforced by attaching an L-shaped shear reinforcement member to the web and flange of the steel beam, as shown in Patent Document 1, for example. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2018-172901 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the column-beam joint structure described in Patent Document 1, the intersections of the steel beams 4,4 need to be rigidly joined on-site or in a factory by welding or the like. However, this is time-consuming due to the complex cross-sectional shape, and requires the work to be done by skilled welders, which results in significant costs and time, and therefore it cannot be said that this is a column-beam joint structure suitable for large-span structures.

[0006] Therefore, an object of the present invention is to provide a column-beam joint structure suitable for large span frames. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, the present invention provides a column-beam joint structure between a beam and a reinforced concrete column erected in a direction intersecting each other, characterized in that a composite structural beam consisting of a first steel beam at the center of a reinforced concrete beam at its end is arranged with a first distance (D1) between one end of the first steel beam in the longitudinal direction and a second steel beam erected in a direction intersecting the composite structural beam, and is joined to the second steel beam and the reinforced concrete column via a column-beam intersection in which upper and lower end reinforcement are arranged integrally with the reinforced concrete beam and concrete is poured.

[0008] It is preferable that the second steel beam is covered by reinforced concrete at the column-beam intersection at the upper position of the reinforced concrete column, and that the one end of the first steel beam is arranged at a second distance (D2) from the reinforced concrete column or so as to abut against it in a plan view.

[0009] It is preferable that the second steel beam is covered by reinforced concrete at the column-beam intersection and at a predetermined range from the upper position of the reinforced concrete column by the reinforced concrete of the end reinforced concrete beam joined to the column-beam intersection.

[0010] It is preferable that the composite structural beam is supported at the one end of the first steel beam by a corbel formed on the reinforced concrete column.

[0011] It is preferable that the sub-beam is suspended between the composite structural beam and the second steel beam, whichever has a larger margin of long-term allowable strength.

[0012] It is preferable that another composite structural beam is joined via the column-beam intersection so as to face the composite structural beam across the reinforced concrete column and be arranged at the first distance (D1) from the second steel beam, and that the upper end reinforcement and the lower end reinforcement are arranged integrally from the reinforced concrete beam at one end of the longitudinal direction of the composite structural beam via the column-beam intersection to the reinforced concrete beam at one end of the longitudinal direction of the other composite structural beam, and concrete is poured.

[0013] The composite structural beam and the second steel beam are preferably precast concrete members integrated with the beam-column intersection. Effect of the Invention

[0014] According to the present invention, it is possible to provide a column-beam joint structure suitable for large span frames. [Brief description of the drawings]

[0015] [Figure 1] 1 is a plan view showing a column-beam structure including a column-beam joint structure between a steel beam and a composite structural beam and a reinforced concrete column according to a first embodiment of the present invention. FIG. [Diagram 2] 2A is a front cross-sectional view taken along line IIa-IIa in FIG. 1, and FIG. 2B is a plan cross-sectional view taken along line IIb-IIb in FIG. [Diagram 3] FIG. 1(a) is a diagram explaining the process of arranging the steel beams and formwork for the beam-column joint structure of the first embodiment, FIG. 1(b) is a diagram explaining the process of placing reinforcement within the formwork, and FIG. 1(c) is a diagram explaining the completed state of the beam-column joint structure after the formwork has been removed after concrete has been poured into it. [Figure 4] FIG. 11 is a plan view showing a column-beam structure including a column-beam joint structure between a steel beam and a composite structural beam and a reinforced concrete column according to a second embodiment of the present invention. [Diagram 5] 5A is a front cross-sectional view taken along the line Va-Va in FIG. 4, and FIG. 5B is a front cross-sectional view taken along the line Vb-Vb in FIG. [Figure 6] 6 is a plan sectional view taken along the line VI-VI in FIG. 5(a). [Figure 7] FIG. 1(a) is a diagram explaining the process of arranging steel beams and formwork for a column-beam joint structure according to the second embodiment, FIG. 1(b) is a diagram explaining the process of placing reinforcement within the formwork, and FIG. 1(c) is a diagram explaining the completed state of the column-beam joint structure after the formwork has been removed after concrete has been poured into it. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A column-beam joint structure according to an embodiment of the present invention will now be described with reference to the accompanying drawings. In addition, the same reference numerals are used to designate the same or equivalent components.

[0017] [First embodiment] 1, 2(a) and 2(b) show a column-beam joint structure 1 according to a first embodiment of the present invention. The column-beam joint structure 1 is composed of a reinforced concrete column 10, a steel beam 20 penetrating above the reinforced concrete column 10, a composite structural beam 30 arranged in a direction intersecting the steel beam 20, and a column-beam intersection part 40 made of reinforced concrete provided at the position where the steel beam 20 penetrates above the reinforced concrete column 10 and at the longitudinal end part of the composite structural beam 30.

[0018] The reinforced concrete column 10 (hereinafter referred to as the column 10) is a reinforced concrete column constructed on-site, with a cross section of 1050 mm × 1050 mm. As shown in Figures 2(a) and (b), the column main reinforcement bars 12 protruding from the upper end of the column body 11 are arranged in a position that does not interfere with the steel beam 20.

[0019] The steel beam 20 is an H-shaped steel, and is disposed so as to penetrate above the column body 11 of the column 10. In this embodiment, the steel beam 20 has a beam depth and beam width of 900 mm×300 mm. The steel beam 20 has a greater margin of long-term allowable strength than the composite structural beam 30. For this reason, as shown in FIG. 1, sub-beams 50 are disposed at predetermined intervals between the steel beams 20, 20.

[0020] As shown in FIG. 1, FIG. 2(a) and FIG. 2(b), the composite structural beam 30 is composed of a steel beam 31 at the center and a reinforced concrete beam 33 at the end. The composite structural beam 30 is composed of an H-shaped steel beam 31 arranged in a direction intersecting with the steel beam 20, and a reinforced concrete beam 33 formed by pouring concrete so as to cover the longitudinal end 32 of the steel beam 31 integrally with the upper end of the column body 11 and the longitudinal end 32 of the other steel beam 31. The longitudinal end 32 of the steel beam 31 does not contact the column 10 in a plan view, and is joined to the steel beam 20 and the column 10 via the reinforced concrete beam 33 and the column-beam intersection 40. In this embodiment, the longitudinal end 32 of the steel beam 31 is arranged at a first distance D1 of about 500 mm from the steel beam 20 and at a second distance D2 of about 200 mm from the column 10. The steel beam 31 has a beam depth and width of 800 mm×300 mm. The reinforced concrete beam 33 has a beam depth and width of 1200 mm×600 mm, and a beam length of 2000 mm. The upper end reinforcement 34 and the lower end reinforcement 35 are arranged in the reinforced concrete beam 33. Fixing hardware 38 is attached to the ends of the upper end reinforcement 34 and the lower end reinforcement 35. Stirrup reinforcements 36 are arranged to surround the upper end reinforcement 34 and the lower end reinforcement 35 at a predetermined interval, and at the end 37, the intervals are narrowed to reinforce the reinforced concrete beam 33 near the end 37. The beam length of the reinforced concrete beam 33 is preferably 1.5 to 3 times the beam depth of the steel beam whose longitudinal end is covered with reinforced concrete.

[0021] (Composition of column-beam joint structure 1) As shown in Fig. 2(a) and (b), in the beam-column joint structure 1, the longitudinal ends of the composite structural beams 30, 30 are connected to the beam width direction end of the steel beam 20 at the beam-beam intersection 40 on the column 11. Upper end reinforcement 34 and lower end reinforcement 35 are arranged at a predetermined interval from the inside of the reinforced concrete beam 33 at the longitudinal end of one composite structural beam 30 through the inside of the column-beam intersection 40 at the top of the column 11 to the inside of the reinforced concrete beam 33 at the longitudinal end of the other composite structural beam 30, via the top and bottom of the flange of the steel beam 20. After the reinforcing bars are arranged, concrete is poured at once from the longitudinal end of one composite structural beam 30 through the top of the column 11 to the longitudinal end of the other composite structural beam 30, thereby forming the beam-column joint structure 1 integrally. As shown in FIG. 1, the steel beam 20 does not protrude from end face A of the column 10 (at the column-beam intersection 40), and the composite structural beam 30 is not connected to end face B of the column 10.

[0022] (Construction method for column-beam joint structure 1) Next, a construction method for the beam-column joint structure 1 will be described. As shown in Fig. 3(a), the steel beams 20, 31 are arranged in a mutually intersecting direction using pipe supports 61. After that, the bottom plate of a formwork 60 for integrally pouring the reinforced concrete beam 33 and the concrete of the beam-column intersection 40 is set in line with the upper end of the column 10 using the pipe supports 61 in the range from the longitudinal end of the steel beam 31 to the longitudinal ends of the column 10 and the other steel beams 31.

[0023] 3(b), upper end reinforcement 34, lower end reinforcement 35, and stirrup reinforcement 36 are arranged so as to surround the steel beams 20 and 31, and hoop reinforcement 13 is arranged so as to penetrate the web 21 of the steel beam 20. After the reinforcement is arranged, the remaining (side) formwork 60 is installed.

[0024] Concrete is poured into the formwork 60, cured, and after it reaches a predetermined compressive strength, the pipe supports 61 are removed and the formwork 60 is dismantled. As shown in Fig. 3(c), the beam-column joint structure 1 is completed in which the reinforced concrete beam 33 at the longitudinal end of the composite structural beam 30 and the beam-column intersection 40 of the column 10 are integrally formed.

[0025] As described above, according to the beam-column joint structure 1 of this embodiment, since there is no steel beam at the end in the longitudinal direction of the composite structural beam 30 where the bending moment is large, the design moment is small and the cross section of the steel beam 31 can be made small, resulting in cost reduction. In addition, the steel beams 20 and 31 are all single materials, and there is no need to weld the steel beams 20 and 31 that are perpendicular to each other, and there is no need to transport cross-shaped steel materials with crossed steel beams, which is limited by the width of the truck bed. Therefore, costs can be significantly reduced, and transportation to the site is made easier, improving transportation efficiency. Since welding between steel beams is not required, steel materials can be processed even if they are not S-grade or H-grade fabs that require advanced technology, resulting in cost reduction. Furthermore, since the steel beams 31 are not embedded in (do not reach) the columns 10 in plan view, when arranging the column main reinforcements 12, it is only necessary to arrange them around the steel beams 20 without considering the arrangement of the steel beams 31, which increases the degree of freedom in arranging the column main reinforcements 12 compared to a structure in which steel beams in both directions are joined on the columns, improving workability and shortening the construction time. Also, the sub-beams 50 can be spanned across the steel beams 20 which have a margin for long-term load. Thus, the column-beam joint structure 1 is suitable for large-span frames.

[0026] [Second embodiment] 4, 5(a), 5(b), and 6 show a beam-column joint structure 2 according to a second embodiment of the present invention. The beam-column joint structure 2 differs from the first embodiment in that the steel beam 20 is covered by a reinforced concrete beam 22 at the upper periphery of the column 10. Also, it differs from the first embodiment in that the column 10 is provided with a corbel 15 that supports a composite structural beam 30.

[0027] As shown in Figures 4, 5(a), 5(b) and 6, a corbel 15 that supports a composite structural beam 30 is formed at the upper end of the column 10. In this embodiment, the corbel 15 is formed in a trapezoidal shape when viewed from the front, with an upper base (tip side of the corbel 15 (a in Figure 5(a))) of 150 mm, a lower base (column 10 side (b in Figure 5(a))) of 250 mm, and a height (projection length of the corbel 15 (c in Figure 5(a))) of 150 mm.

[0028] The steel beam 20 is covered by an end reinforced concrete beam 22 at the top of the column 10 and its surrounding area (about 1.5 to 2 times the beam depth of the steel beam 20), and the strength and rigidity of the end of the steel beam 20 are increased compared to the first embodiment. In the end reinforced concrete beam 22, upper end bars 23 and lower end bars 24 are arranged above and below the steel beam 20. Stirrup bars 25 are also arranged to surround the upper end bars 23 and lower end bars 24.

[0029] (Composition of column-beam joint structure 2) As shown in Figs. 5(a), (b) and 6, in the beam-column joint structure 2, the composite structural beams 30, 30 are connected at their longitudinal ends to the beam width direction end of the steel beam 20 on the corbel 15 of the column 11, while the steel beam 20 is covered with the end reinforced concrete beam 22 at the top of the column 10 and its periphery. Upper end reinforcements 23 and lower end reinforcements 24 are arranged at predetermined intervals near the column 10 and at the top of the column 11 of the steel beam 20. The composite structural beam 30 is arranged in the same manner as in the first embodiment. After the reinforcing bars are arranged, concrete is poured at once from the longitudinal end of one composite structural beam 30 through the top of the column 11 to the longitudinal end of the other composite structural beam 30 and in the range near the column 10 of the steel beam 20, and the beam-column joint structure 2 is integrally formed.

[0030] (Construction method for column-beam joint structure 2) Next, a construction method of the beam-column joint structure 2 will be described. As shown in FIG. 7(a), the steel beams 20 and 31 are arranged in a mutually intersecting direction using pipe supports 61. In addition, a support material 70 is arranged to support the steel beam 20 on the top surface of the column 10 and the steel beam 31 on the corbel 15. After that, a formwork 60 for integrally pouring concrete for the end reinforced concrete beam 22, the column-beam intersection 40, and the reinforced concrete beam 33 is installed using the pipe supports 61 in a range from the longitudinal end of the steel beam 31 to the longitudinal end of the column 10 and the other steel beams 31, in accordance with the upper end of the column 10. In addition, the bottom plate of the formwork 60 is installed using the pipe supports 61 in a range from the longitudinal end of the steel beam 20 to the longitudinal end of the column 10 and the other steel beams 20. At this time, the bottom plate may be suspended from the steel beams 20 and 31.

[0031] After the formwork 60 and pipe supports 61 are installed, as shown in Fig. 7(b), the upper end reinforcements 23, 34, the lower end reinforcements 24, 35, and the stirrup reinforcements 25, 36 are arranged so as to surround the steel beams 20, 31 inside the formwork 60, and the hoop reinforcement 13 is arranged so as to penetrate the web 21 of the steel beam 20. After the reinforcement is arranged, the remaining (side) formwork 60 is installed.

[0032] Concrete is poured into the formwork 60, cured, and after it reaches a predetermined compressive strength, the pipe supports 61 are removed and the formwork 60 is dismantled. As shown in Figure 7(c), the column-beam joint structure 2 is completed in which the end reinforced concrete beam 22 around the top of the column 10 of the steel beam 20, the reinforced concrete beam 33 at the longitudinal end of the composite structural beam 30, and the column-beam intersection 40 of the column 10 are integrally formed.

[0033] According to the beam-column joint structure 2 of this embodiment, the steel beam 20 is firmly fixed to the column 10 and its surroundings at the end reinforced concrete beam 22 and the column-beam intersection 40, so that the strength and rigidity of the end of the steel beam 20 can be increased, similarly to the composite structural beam 30. Therefore, the beam-column joint structure 2 is suitable for large span frames.

[0034] [Variations] In the above first and second embodiments, the longitudinal end 32 of the steel beam 31 was separated from the column 10 by a distance D2, but the steel beam 31 may be separated from the column 10 by a distance D2 so that the end abuts the column 10 in a plan view but does not contact the steel beam 20.

[0035] In the above first and second embodiments, the pillar 10 is a cast-in-place reinforced concrete pillar, but it may be a reinforced concrete pillar such as a precast concrete pillar or a half-precast concrete pillar.

[0036] In addition, in the above first and second embodiments, the reinforced concrete beam 33, the column-beam intersection 40 or the end reinforced concrete beam 22, the column-beam intersection 40 and the reinforced concrete beam 33 were cast in place with concrete, but the beam-column joint including the steel beam 20 and part of the steel beam 31 may also be an integrated precast concrete member.

[0037] In the second embodiment, the corbel 15 has a trapezoidal shape in front view, but it may have a rectangular or square shape, or may have another shape. Also, it may be in contact with the lower part of the steel beam 31 and protrude downward from the lower end of the reinforced concrete beam 33, or may be flush with the lower end of the reinforced concrete beam 33. Also, the corbel may be used in the first embodiment.

[0038] In addition, in each of the above embodiments, the minor beams 50 are disposed between the steel beams 20, 20, but if the composite structural beam 30 has a greater margin in long-term allowable strength, it is preferable to dispose the minor beams between the composite structural beams 30, 30. If both have the same margin in long-term allowable strength, the minor beams may be disposed either between the steel beams 20, 20 or between the composite structural beams 30, 30, and the disposition direction of the minor beams may be determined depending on the convenience of the construction method, etc.

[0039] The present invention is not limited to the above-described embodiment, and various modifications are possible within the scope of the claims. In other words, the technical scope of the present invention also includes embodiments obtained by combining technical means that are appropriately modified within the scope of the claims. [Explanation of symbols]

[0040] 1,2 Column beam joint structure 10 Reinforced concrete pillar (column) 11 Column 12 Column main reinforcement 13 Stirrup 15. Corbel 20,31 Steel beam 21 Web 22 End of reinforced concrete beam 23,34 Upper end muscle 24,35 Bottom reinforcement 25,36 Stirrup muscle 30 Composite structural beam 33 Reinforced concrete beam 40 Column-beam intersection 50 Small beam 60 Formwork 61 Pipe Support 70 Support material

Claims

1. A column-beam joint structure between a beam and a reinforced concrete column erected in mutually intersecting directions, A composite structural beam consisting of a first steel beam at the center of a reinforced concrete beam at the end of the material is arranged at a first interval (D1) from a second steel beam erected in a direction in which one end of the longitudinal direction of the first steel beam intersects with the composite structural beam, and is joined to the second steel beam and the reinforced concrete column through a column-beam intersection in which upper and lower end reinforcements are arranged integrally with the reinforced concrete beam and concrete is poured. A column-beam joint structure characterized by:

2. The second steel beam is covered by the reinforced concrete of the column-beam intersection at an upper position of the reinforced concrete column, The one end of the first steel beam is arranged so as to be spaced apart from or in contact with the reinforced concrete column by a second distance (D2) in a plan view. The column-beam joint structure according to claim 1 .

3. The second steel beam is covered with reinforced concrete of the column-beam intersection and the end reinforced concrete beam joined to the column-beam intersection at the upper position of the reinforced concrete column and a predetermined range from the upper position of the reinforced concrete column. The column-beam joint structure according to claim 1 .

4. The composite structural beam is supported by a corbel formed on the reinforced concrete column at one end of the first steel beam. The column-beam joint structure according to claim 1 or 3.

5. The small beam is spanned between the composite structural beam and the second steel beam, whichever has a larger margin of long-term allowable strength. The column-beam joint structure according to claim 1 or 3.

6. Another composite structural beam is joined via the column-beam intersection so as to be disposed at the first interval (D1) between the second steel beam and the composite structural beam while facing the composite structural beam across the reinforced concrete column, The upper end reinforcement and the lower end reinforcement are integrally arranged from the reinforced concrete beam at one end of the longitudinal axis of the composite structural beam through the column-beam intersection to the reinforced concrete beam at one end of the longitudinal axis of the other composite structural beam, and concrete is poured. The column-beam joint structure according to claim 1 or 3.

7. The composite structural beam and the second steel beam are precast concrete members integrated with the column-beam intersection. The column-beam joint structure according to claim 1 or 3.

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