JP2022061695A - Joint structure between reinforced concrete column and steel beam - Google Patents

Abstract

To provide a joint structure between a reinforced concrete column and a steel beam, where the thickness of a diaphragm can be reduced in a column-beam joint between the reinforced concrete column and the steel beam.SOLUTION: At a beam-column joint where steel beams 32 and 33 are cross-joined via a diaphragm 22 joined above and below a plug plate 21 installed on a reinforced concrete column 10, the plug plate 21 is installed so as to surround an outer peripheral surface of the reinforced concrete column 10 so as to follow the outer shape of the column. An overhanging web 34a is formed by projecting an end of a web 34 of the steel beams 32 and 33 so as to face each other in the plug plate 21. The overhanging web 34a has a structure in which a plurality of headed studs 38 are arranged in a row at predetermined intervals along the beam height direction.SELECTED DRAWING: Figure 1

Description

The present invention relates to a joint structure between a reinforced concrete column and a steel beam, and more particularly to a joint structure between a reinforced concrete column and a steel beam $ having a structure in which a diaphragm is used for the joint between the steel beam and the reinforced concrete column.

In order to secure a large column span of a building or shorten the construction period, a synthetic structure combining reinforced concrete columns and steel beams may be applied to the building.

At this time, at the joint between the reinforced concrete column and the steel beam, a structure is provided above and below the plug plate surrounding the column-beam joint so that the steel beam does not penetrate the column-beam joint (non-beam penetration type: as an example). Patent Document 1) and the like are used. In Patent Document 1, a diaphragm 50 is provided above and below a tubular closing plate 40 surrounding a column, and a connecting steel beam 21 is joined to the closing plate 40 and the diaphragm 50 to construct a column-beam joint.

Japanese Unexamined Patent Publication No. 2016-176216

In the non-beam penetration type column-beam joint structure as described in Patent Document 1, the stress (out-of-plane bending) generated when the shearing force of the S-structured beam is transmitted to the reinforced concrete column when designing the diaphragm. Need to be considered. For example, in the structure shown in Patent Document 1, it is necessary to use a diaphragm 50 having a plate thickness that is 4 sizes larger than the plate thickness of the flange 22 of the beam 20 of the S structure. Therefore, there is a problem that the amount of steel material increases and the material cost increases.

Therefore, an object of the present invention is to provide a joint structure of a reinforced concrete column and a steel frame beam capable of reducing the stress borne by the diaphragm and reducing the plate thickness of the diaphragm.

Reinforced concrete columns in which the first and second steel beams are cross-joined via diaphragms joined above and below the plug plates installed on the reinforced concrete columns, and filled concrete is placed at the cross-joint positions including the inside of the block plates. It is a joint structure between the steel beam and the steel beam, and the closing plate is installed so as to surround the outer peripheral surface of the reinforced concrete column so as to follow the outer shape of the column, and the web material end of the first and second steel beam. A plurality of overhanging webs are formed at the ends of the first and second steel frames so as to face each other in the closing plate, and a plurality of overhanging webs are formed on the side surfaces of the overhanging webs at predetermined intervals along the beam height direction. It is characterized in that the shear force transmission members of the above are arranged in a row.

The shear force transmitting member is preferably a headed stud.

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

The shear force transmitting member is preferably a steel bar attached to the overhanging web through the through hole of the overhanging web.

According to the present invention, since the stress generated at the end of the steel frame beam is transmitted to the column via the shear force transmission portion, the stress on the diaphragm at the column-beam joint can be reduced, and the weight of the diaphragm member can be reduced. Can be planned.

It is a perspective view of the column-beam joint structure which omitted a part of the plug plate and the internal concrete which concerns on embodiment of this invention. (A) is a perspective view of a beam-column joint unit according to an embodiment of the present invention, and (b) is a plan view of (a). (A) is an internal cross-sectional view shown by the cross-sectional line IIIa-IIIa of FIG. 2 (b), and (b) is an internal cross-sectional view shown by the cross-sectional line IIIb-IIIb of FIG. 2 (b). (A) is a cross-sectional perspective view of a beam-column joint unit according to another embodiment of the present invention, and (b) is a cross-sectional perspective view of a beam-column joint unit according to still another embodiment of the present invention. ..

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

FIG. 1 shows a beam-column joint of a beam-column joint structure 1 according to an embodiment of the present invention. The column-beam joint structure 1 is a reinforced concrete column 10 (hereinafter, simply referred to as a column 10) and a steel beam 30 (30a, 30b) that is cross-joined via a diaphragm 22 at a portion penetrating the inside of the column 10. , 31 (31a, 31b) and their joints (hereinafter referred to as column-beam joint units 20) are the main configurations. In the column-beam joint unit 20, the end of the web 34 of the steel frame beam 30 projects by a predetermined length at the column-beam cross-joint position (inside the closing plate 21) of the column 10, and the ends of the flange 32 and the flange 35 described later are extended. Is joined to the end of the diaphragm 22 (see FIG. 2A).

In the present embodiment, as shown in FIG. 1, in the column 10, three main bars 11 are arranged at predetermined intervals at the four corners of the column 10, and band bars 12 are arranged at predetermined intervals so as to surround the main bars 11. Reinforcement is done. Since the closing plate 21 has a concrete restraining effect, the band reinforcement 12 is not arranged inside the column-beam joint unit 20.

As shown in FIGS. 2A and 2B, the column-beam joint unit 20 has a closing plate 21, steel frames 30, 31 and a diaphragm 22 pre-assembled at a factory. The steel frame beam 30 is composed of steel frame beams 30a and 30b facing each other with the diaphragm 22 interposed therebetween, and the steel frame beams 30a and 30b form an H-shaped beam cross section including a flange 32, a web 34, and a flange 35, respectively. The steel beam 31 is composed of steel beams 31a and 31b facing each other with the diaphragm 22 interposed therebetween, and the steel beams 31a and 31b form an H-shaped beam cross section including a flange 33, a web 34, and a flange 36, respectively. .. The steel frames 30 and 31 of the present embodiment have the same beam formation and beam width.

The plug plate 21 is a substantially square cylindrical steel plate member arranged so as to surround the cross-joint position of the columns and beams of the column 10. The external shape of the plug plate 21 in a plan view is substantially equal to the external shape of the column cross section of the column 10, and the height of the plug plate 21 is equal to the beam formation of the steel frame beams 30 and 31. In this embodiment, the beam formation of the steel frame beams 30 and 31 and the beam formation of the steel frame beams 50 (50a, 50b) and 51 (51a, 51b) joined to the column-beam joint unit 20 are the same. The closing plate 21 is an assembly member of four substantially L-shaped closing plate constituents 21a, 21b, 21c, 21d, and each end of the closing plate constituents 21a, 21b, 21c, 21d is attached to the diaphragm 22 and the web. By joining to 34, a substantially square tubular overall shape is formed.

As shown in each figure of FIG. 2, the diaphragm 22 is a substantially cross-shaped steel plate member constituting the intersection of the steel frame beams 30 and 31, and an arcuate sliding portion having a predetermined curvature is formed at the intersection. .. In the present embodiment, the plate thickness of the diaphragm 22 is designed to be two sizes larger than the flanges 32, 33, 35, and 36 (FIG. 3 (b)). By fitting the ends 22a and 22b of the diaphragm 22 and the notches 23 at the upper and lower ends of the closing plate 21, the upper and lower ends of the closing plate 21 and the upper and lower ends of the diaphragm 22 coincide with each other. At the ends 22a and 22b of the diaphragms 22 and 22 at the upper and lower ends of the closing plate 21, the flanges 32 and 32 and the flanges 35 and 35, which form the upper and lower flanges of the steel beam 30 (30a and 30b), respectively, The flanges 33, 33 and the flanges 36, 36 constituting the upper flange and the lower flange of the steel beam 31 (31a, 31b) are firmly joined by butt welding. At the central position of the diaphragm 22, a circular opening 24 that serves as a casting hole or an air hole at the time of placing concrete is formed.

The end of the web 34 extends inside the closing plate 21 to form the overhanging web 34a. As shown in FIG. 3A, headed studs 38 are arranged in rows on both side surfaces of the overhanging web 34a at predetermined intervals along the beam height direction, and the overhanging web 34a and the headed studs 38 form a beam. A shear force transmission portion 37 at the end is formed.

The headed studs 38 arranged in a row on the overhanging web 34a, in cooperation with the overhanging web 34a, apply the timber end stress generated at the ends of the steel beam 30 and 31 to the filled concrete 60 cast inside the closing plate 21 (FIG. It can be transmitted to the pillar 10 via 1). As shown in FIGS. 3A and 3B, the length L, the diameter, and the overhang length D of the overhanging web 34a of the headed stud 38 are determined according to the beam end stress at the column-beam joint. .. When it is necessary to arrange the headed studs 38 in two rows by design, it is preferable to sufficiently secure the overhang length D1 of the overhang web 34a as shown in FIG. 3 (c).

The filled concrete 60 (FIG. 1) is designed to have the same strength as the concrete 13 of the column 10, the beam-column joint unit 20 is installed at a predetermined position on the column 10, and the reinforcing bars 12 are arranged and predetermined. The space including the inside of the plug plate 21 surrounded by the formwork is filled by casting to form a column shape and a beam-column joint.

(Structure of joint structure)
As shown in FIG. 1, in the column-beam joint structure 1, the column-beam joint portion is provided with a predetermined distance h from the upper end of the column 10 while surrounding the main bar 11 protruding from the upper end of the column 10 with the blocking plate 21. The unit 20 is installed. A band bar 12 is arranged on the main bar 11 protruding from the upper part of the column-beam joint unit 20, and the filled concrete 60 is densely placed inside the block plate 21 of the column-beam joint unit 20 as a part of the formwork. By doing so, the column-beam joint structure 1 is integrally formed. After that, the steel beam 50 (50a, 50b) and 51 (51a, 51b) are joined to the column-beam joint structure 1 (see FIG. 2B). In the beam-column joint structure 1, a predetermined number of headed studs 38 are arranged in a row on both side surfaces of the overhanging web 34a overhanging by a predetermined length inside the closing plate 21, and a shear force transmitting portion 37 is formed. The shear force and bending moment generated at the timber ends of the steel beams 30 and 31 are transmitted to the filled concrete 60 via the shear force transmission portion 37, that is, from the web 34 via the overhanging web 34a and the headed stud 38. As described above, in the column-beam joint structure 1, the stress generated at the end of the steel frames 30 and 31 can be transmitted to the filled concrete 60 without going through the diaphragm 22, so that the diaphragm is compared with the diaphragm used for the conventional beam-column joint. Therefore, the plate thickness of the diaphragm 22 can be reduced.

(Modification example)
In the above embodiment, a predetermined number of headed studs 38 are stud welded to the overhanging web 34a in the shear force transmitting portion 37, but a deformed reinforcing bar or a round steel rod processed into a predetermined shape is attached to the overhanging web 34a. It is also possible to form a shear transmission unit 37 that performs the same function. As shown in FIG. 4A, for example, the shear force transmission portion is provided with a through hole in the overhanging web 34a, and the through hole is provided with a straight rod-shaped deformed reinforcing bar having a length of 2 L (twice the length of the stud with a head L). By inserting and fixing round steel, it can be used as an alternative structure for headed studs. Alternatively, as shown in FIG. 4B, a deformed reinforcing bar or round steel bent into a substantially U shape may be attached to the overhanging web 34a.

Further, in the above-described embodiment and modification, the height of the closing plate 21 is equal to the beam formation of the steel frame beams 30 and 31 and the beam formation of the steel frame beams 50 and 51 joined to the column-beam joint unit 20. there were. When the beam formation of the intersecting steel beam is different, the height of the closing plate should be adjusted to the beam formation of the steel beam with high beam formation.

In the above embodiment, the pillar 10 is cast with concrete at a site other than the joint portion, but it can also be used for a pillar of precast concrete. When the joints and columns are integrally precast concrete, it is not necessary to secure the predetermined distance h shown in FIG.

The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of each claim. That is, an embodiment obtained by combining technical means appropriately modified within the scope of the claims also belongs to the technical scope of the present invention.

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

Claims (4)

Reinforced concrete columns in which the first and second steel beams are cross-joined via diaphragms joined above and below the plug plates installed on the reinforced concrete columns, and filled concrete is placed at the cross-joint positions including the inside of the block plates. It is a joint structure between a steel beam and a steel beam.
The closing plate is installed so as to surround the outer peripheral surface of the reinforced concrete column so as to follow the outer shape of the column.
The web material ends of the first and second steel frames project so as to face each other in the closing plate, and the projecting webs are formed at the material ends of the first and second steel frames, respectively.
A joint structure of a reinforced concrete column and a steel beam, characterized in that a plurality of shear force transmitting members are arranged in a row at predetermined intervals along the beam height direction on the side surface of the overhanging web. The joint structure between a reinforced concrete column and a steel beam according to claim 1, wherein the shear force transmitting member is a stud with a head. The joint structure between a reinforced concrete column and a steel beam according to claim 1 or 2, wherein the overhanging web has upper and lower ends joined to the diaphragm. The joint structure between a reinforced concrete column and a steel beam according to claim 1, wherein the shear force transmitting member is a steel bar attached to the overhanging web through a through hole of the overhanging web.

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