JP7569653B2 - Joint structure between reinforced concrete column and steel beam - Google Patents

Description

The present invention relates to a joint structure between a reinforced concrete column and a steel beam, and in particular to a joint structure between a reinforced concrete column and a steel beam that uses a diaphragm at the joint between the steel beam and the reinforced concrete column.

In order to ensure a large column span for a building or to shorten construction time, a composite structure that combines reinforced concrete columns and steel beams may be applied to the building.

At this time, the joint between the reinforced concrete column and the steel beam uses a structure in which diaphragms are provided above and below the cover plate that surrounds the column-beam joint, so that the steel beam does not penetrate the column-beam joint (non-beam penetration type: see Patent Document 1 for an example). In Patent Document 1, diaphragms 50 are provided above and below a cylindrical cover plate 40 that surrounds the column, and a connecting steel beam 21 is joined to the cover plate 40 and diaphragm 50 to construct the column-beam joint.

JP 2016-176216 A

In a non-beam-penetrating type beam-column joint structure such as that described in Patent Document 1, when designing the diaphragm, it is necessary to take into account the stress (out-of-plane bending) that occurs when the shear force of the steel beam is transmitted to the reinforced concrete column. For example, in the structure shown in Patent Document 1, it is necessary to use a diaphragm 50 with a plate thickness that is four sizes larger than the plate thickness of the flange 22 of the steel beam 20. This leads to problems such as an increase in the amount of steel material and an increase in material costs.

The object of the present invention is to provide a joint structure between a reinforced concrete column and a steel beam that can reduce the stress borne by the diaphragm and make the diaphragm thinner.

A joint structure between a reinforced concrete column and a steel beam, in which first and second steel beams are cross-joined via diaphragms joined above and below a cover plate installed on the reinforced concrete column, and filled concrete is poured at the cross-joint position including within the cover plate, wherein the cover plate is installed following the outer shape of the column so as to surround the outer periphery of the reinforced concrete column, the web ends of the first and second steel beams protrude so as to face the filled concrete in the cover plate, and overhanging webs are formed at the ends of the first and second steel beams , respectively, and headed studs are arranged in a row by stud welding on both sides of the overhanging web as a plurality of shear force transmission members at predetermined intervals along the beam height direction.

It is preferable that the upper and lower ends of the overhanging web are joined to the diaphragm.

A joint structure between a reinforced concrete column and a steel beam, in which first and second steel beams are cross-joined via diaphragms joined above and below a cover plate installed on the reinforced concrete column, and filled concrete is poured at the cross-joint position including within the cover plate, wherein the cover plate is installed following the outer shape of the column so as to surround the outer periphery of the reinforced concrete column, the web ends of the first and second steel beams protrude so as to face the filled concrete in the cover plate, and overhanging webs are formed at the ends of the first and second steel beams, respectively, and a plurality of shear force transmission members are arranged in a row at predetermined intervals along the beam height direction on both sides of the overhanging web, and the shear force transmission members are steel bars attached to the overhanging web by welding .

According to the present invention, the stress generated at the end of the steel beam is transmitted to the column via the shear force transmission section, so that the stress on the diaphragm at the column-beam joint can be reduced, and the weight of the diaphragm component can be reduced.

1 is a perspective view of a column-beam joint structure in which a cover plate and a portion of the internal concrete are omitted according to an embodiment of the present invention. FIG. 1A is a perspective view of a column-beam joint unit according to an embodiment of the present invention, and FIG. 1B is a plan view of FIG. 2(b) is a cross-sectional view taken along line IIIa-IIIa in FIG. 2(b), and FIG. 2(b) is a cross-sectional view taken along line IIIb-IIIb in FIG. 2(b). 1A is a cross-sectional perspective view of a column-beam joint unit according to another embodiment of the present invention, and FIG. 1B is a cross-sectional perspective view of a column-beam joint unit according to yet another embodiment of the present invention.

The column-beam joint structure of the present invention will be described below with reference to the attached drawings.

Figure 1 shows a column-beam joint of a column-beam joint structure 1 according to an embodiment of the present invention. The column-beam joint structure 1 mainly comprises a reinforced concrete column 10 (hereinafter simply referred to as column 10), steel beams 30 (30a, 30b), 31 (31a, 31b) that are crisscross-jointed via a diaphragm 22 at a portion that penetrates the interior of the column 10, and their joint portion (hereinafter referred to as a column-beam joint unit 20). In the column-beam joint unit 20, the end of the web 34 of the steel beam 30 protrudes a predetermined length from the column-beam cross joint position of the column 10 (inside the cover plate 21), and the ends of flanges 32 and 35 described later are joined to the end of the diaphragm 22 (see Figure 2 (a)).

In this embodiment, as shown in FIG. 1, three main reinforcements 11 are arranged at a predetermined interval at the four corners of the column 10, and tie bars 12 are arranged at a predetermined interval to surround the main reinforcements 11. Note that, because the cover plate 21 has a concrete restraining effect, tie bars 12 are not arranged inside the column-beam joint unit 20.

As shown in Figs. 2(a) and (b), the column-beam joint unit 20 includes a cover plate 21, steel beams 30 and 31, and a diaphragm 22, which are preassembled at a factory. The steel beam 30 is made up of steel beams 30a and 30b that face each other across the diaphragm 22, and the steel beams 30a and 30b each form an H-shaped beam cross section consisting of a flange 32, a web 34, and a flange 35. The steel beam 31 is made up of steel beams 31a and 31b that face each other across the diaphragm 22, and the steel beams 31a and 31b each form an H-shaped beam cross section consisting of a flange 33, a web 34, and a flange 36. The steel beams 30 and 31 in this embodiment have the same beam depth and beam width.

The cover plate 21 is a steel plate member of a substantially rectangular tube shape arranged to surround the cross-joint position of the column beam of the column 10. The outer shape of the cover plate 21 in a plan view is substantially the same as the outer shape of the column cross section of the column 10, and the height of the cover plate 21 is equal to the beam width of the steel beams 30, 31. In this embodiment, the beam width of the steel beams 30, 31 is equal to the beam width of the steel beams 50 (50a, 50b), 51 (51a, 51b) joined to the column beam joint unit 20. The cover plate 21 is an assembled member of four substantially L-shaped cover plate components 21a, 21b, 21c, 21d, and the overall shape of the substantially rectangular tube is formed by joining each end of the cover plate components 21a, 21b, 21c, 21d to the diaphragm 22 and the web 34.

As shown in each of Figures 2, the diaphragm 22 is a generally cross-shaped steel plate member that constitutes the intersection of the steel beams 30, 31, and a circular arc-shaped sliding portion with a predetermined curvature is formed at the intersection. In this embodiment, the plate thickness of the diaphragm 22 is designed to be two sizes larger than the flanges 32, 33, 35, 36 (Figure 3 (b)). By fitting the ends 22a, 22b of the diaphragm 22 into the notches 23 at the upper and lower ends of the cover plate 21, the upper and lower ends of the cover plate 21 and the diaphragm 22 are aligned. The ends 22a, 22b of the diaphragms 22, 22 at the upper and lower ends of the cover plate 21 are firmly butt-welded to flanges 32, 32 and flanges 35, 35 that constitute the upper and lower flanges of the steel beam 30 (30a, 30b), and flanges 33, 33 and flanges 36, 36 that constitute the upper and lower flanges of the steel beam 31 (31a, 31b). A circular opening 24 is formed in the center of the diaphragm 22, which serves as a pouring hole or air hole when pouring concrete.

The end of the web 34 extends inside the cover plate 21 to form the overhanging web 34a. As shown in FIG. 3(a), headed studs 38 are arranged in a row at a predetermined interval along the beam height direction on both sides of the overhanging web 34a, and the overhanging web 34a and the headed studs 38 form a shear force transmission section 37 at the beam end.

The headed studs 38 arranged in a row on the overhanging web 34a cooperate with the overhanging web 34a to transmit the end stress generated at the ends of the steel beams 30, 31 to the column 10 via the filled concrete 60 (Fig. 1) poured inside the cover plate 21. As shown in Figs. 3(a) and (b), the length L and diameter of the headed studs 38 and the overhang length D of the overhanging web 34a are determined according to the end stress of the beam at the column-beam joint. If the design requires that the headed studs 38 be arranged in two rows, it is preferable to ensure a sufficient overhang length D1 of the overhanging web 34a, as shown in Fig. 3(c).

The filled concrete 60 (Figure 1) is designed to have the same strength as the concrete 13 of the column 10, and the column-beam joint unit 20 is installed at a specified position on the column 10, the hoops 12 are arranged, and the concrete is poured and filled into the space, including the inside of the cover plate 21, surrounded by a specified formwork, to form the column shape and column-beam joint.

(Configuration of joint structure)
As shown in Fig. 1, in the beam-column joint structure 1, the main reinforcement 11 protruding from the upper end of the column 10 is surrounded by a cover plate 21, and the beam-column joint unit 20 is installed at a predetermined distance h from the upper end of the column 10. The main reinforcement 11 protruding from the upper part of the beam-column joint unit 20 is reinforced with hoops 12, and the fill concrete 60 is densely poured inside the cover plate 21 of the beam-column joint unit 20 as part of the formwork, thereby integrally forming the beam-column joint structure 1. Then, the steel beams 50 (50a, 50b), 51 (51a, 51b) are joined to the beam-column joint structure 1 (see Fig. 2(b)). In the beam-column joint structure 1, a predetermined number of headed studs 38 are lined up on both sides of the overhanging web 34a that overhangs a predetermined length inside the cover plate 21 to form a shear force transmission section 37, so that the shear force and bending moment generated at the ends of the steel beams 30, 31 are transmitted to the filled concrete 60 via the shear force transmission section 37, i.e., from the web 34 to the overhanging web 34a and the headed studs 38. In this way, in the beam-column joint structure 1, the stress generated at the ends of the steel beams 30, 31 can be transmitted to the filled concrete 60 without passing through the diaphragm 22, so the thickness of the diaphragm 22 can be made thinner than that of diaphragms used in conventional beam-column joints.

(Modification)
In the above embodiment, the shear force transmission section 37 has a predetermined number of headed studs 38 stud-welded to the overhanging web 34a, but the shear force transmission section 37 that performs the same function can also be configured by attaching a deformed steel bar or a round steel bar processed into a predetermined shape to the overhanging web 34a. For example, as shown in Fig. 4(a), the shear force transmission section can be an alternative structure to the headed studs by providing a through hole in the overhanging web 34a and inserting and fixing a straight rod-shaped deformed steel bar or round steel bar with a length of 2L (twice the headed stud length L) through the through hole. Alternatively, as shown in Fig. 4(b), a deformed steel bar or round steel bar bent into an approximately U-shape can be attached to the overhanging web 34a.

In the above embodiment and modified example, the height of the cover plate 21 was equal to the beam depth of the steel beams 30, 31 and the beam depth of the steel beams 50, 51 joined to the beam-column joint unit 20. If the beam depths of the intersecting steel beams are different, the height of the cover plate should be adjusted to the beam depth of the steel beam with the higher beam depth.

In the above embodiment, the pillar 10 has concrete poured on-site in areas other than the joints, but it can also be used for precast concrete pillars. Note that if the joints and the pillar are made of precast concrete as a single unit, there is no need to ensure the specified distance h shown in Figure 1.

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, embodiments obtained by combining technical means that are appropriately modified within the scope of the claims also belong to the technical scope of the present invention.

1 Beam-column joint structure 10 Column 11 Main reinforcement 12 Hoop 20, 20A, 20B Beam-column joint unit 21 Cover plate 22 Diaphragm 22a, 22b End 23 Notch 24 Casting hole 30 (30a, 30b), 31 (31a, 31b) Steel beam 32, 33, 35, 36 Flange 34 Web 34a Overhang web 37 Shear force transfer part 38 Headed stud 60 Filled concrete

Claims (3)

A joint structure between a reinforced concrete column and a steel beam, in which a first and a second steel beam are cross-joined via diaphragms joined above and below a cover plate installed on a reinforced concrete column, and filled concrete is poured into the cross-joint position including the inside of the cover plate,
The cover plate is installed following the outer shape of the column so as to surround the outer circumferential surface of the reinforced concrete column,
The web ends of the first and second steel beams are extended so as to face the filled concrete in the closing plate, and an extended web is formed at the ends of the first and second steel beams , respectively;
A joint structure between a reinforced concrete column and a steel beam, characterized in that a plurality of headed studs are arranged at predetermined intervals along the height direction of the beam on both sides of the overhanging web by stud welding as shear force transmission members. 2. The joint structure between a reinforced concrete column and a steel beam according to claim 1 , wherein the upper and lower ends of the overhanging web are joined to the diaphragm. A joint structure between a reinforced concrete column and a steel beam, in which a first and a second steel beam are cross-joined via diaphragms joined above and below a cover plate installed on a reinforced concrete column, and filled concrete is poured into the cross-joint position including the inside of the cover plate,
The cover plate is installed following the outer shape of the column so as to surround the outer circumferential surface of the reinforced concrete column,
The web ends of the first and second steel beams are extended so as to face the filled concrete in the closing plate, and an extended web is formed at the ends of the first and second steel beams, respectively;
A plurality of shear force transmission members are arranged at predetermined intervals along the beam height direction on both side surfaces of the overhanging web,
A joint structure between a reinforced concrete column and a steel beam, characterized in that the shear force transmission member is a steel bar attached to the overhanging web by welding .

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