JPH08232400A - Steel-framed concrete composite beam structure - Google Patents

Abstract

PURPOSE: To manufacture a comparatively light-weight steel-framed concrete composite beam structure, and to provide the same strength as a reinforced concrete beam. CONSTITUTION: A plurality of projecting sections 15, 16 are formed on the inwall surfaces of the upper flange plate 12 and lower flange plate 13 of a box-shaped sectional steel-framed body 11 at regular intervals in the longitudinal direction for forming truss mechanism, and the outside of the steel-framed body 11 is surrounded by an external concrete section while the inside of the steel-framed body 11 is also filled with concrete. An opening section 19 for filling the inside with concrete and for ensuring integrality with the external concrete section is made to a column side end section in the upper flange plate 12 serving also as a yield hinge. Each projecting section 15 of the upper flange plate 12 and each projecting section 16 of the lower flange plate 13 are oppositely arranged respectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steel-concrete composite beam structure, and more particularly to a structure of a beam member that constitutes a composite beam of steel and concrete.

[0002]

2. Description of the Related Art Heretofore, there has been no established technique for constructing a composite beam from steel frames and concrete. Generally, the beams in a building have a reinforced concrete structure, a steel frame reinforced concrete structure or a steel frame structure. Beams of reinforced concrete structure are generally formed with a rectangular cross section. A reinforced concrete beam with a rigid frame structure produces a tensile force downward at the center of the beam and upward at the end due to the bending action. Since concrete is vulnerable to tensile force, reinforcing bars are always placed where tensile force is generated, but main beams are also placed on the side that produces compressive force.

That is, in a reinforced concrete beam, main bars (upper bar) are arranged along each corner on the upper side, and main bars (lower bar) are arranged along each corner on the lower side. The stirrup bar (star wrap) so that the entire main bar is wound at a predetermined interval in the longitudinal direction of the
Are arranged to counter the shearing force.

On the other hand, as steel frame beams, shaped steel beams, plate beams, truss beams and the like are known. As the shaped steel beam, an I-shaped cross section or an H-shaped cross section that is advantageous for bending action is used. In addition, the plate beam is formed by welding angle steel and steel plate or steel plate and steel plate together by welding or rivets, and the cross-sectional shape is mainly because it is advantageous for bending action and convenient for joining to columns. Shaped cross-sections are used, and sometimes box-shaped cross-sections are also used.

Further, the truss beam is a chord member corresponding to the flange portion of the plate beam and a web member (oblique member
Vertical material) is assembled using gusset plates, and is a parallel chord truss that is parallel to the upper and lower chord members. Angle steel is usually used for the chord and web members.

[0006]

As described above, as the conventional beam in a building, a reinforced concrete structure or a steel frame structure is mainly used. On the other hand, in order to manufacture a composite beam made of steel and concrete, it is necessary to provide a concrete filling port for construction, and there is a problem that the filling port causes a cross-section loss in the upper flange steel material.

An object of the present invention is to solve the above-mentioned conventional problems, and to provide a structure of a steel-framed concrete composite beam which is relatively lightweight and has strength equivalent to that of a reinforced concrete beam. The purpose is to prevent the steel material, which is effective in terms of shear strength, from being damaged in the cross section by forming concrete pouring holes necessary for construction.

[0008]

The present invention is a steel-framed concrete composite beam structure, and is configured as follows in order to solve the above-mentioned technical problems. That is, the steel-concrete composite beam structure of the present invention has a box-shaped steel frame main body 11
And a plurality of protrusions 15 provided at predetermined intervals in the longitudinal direction of the flange plates 12 and 13 to form a truss mechanism on the inner wall surfaces of the upper flange plate 12 and the lower flange plate 13 of the steel frame body 11. , 16, an outer concrete portion 17 surrounding the outside of the steel frame body 11 having a box-shaped cross section, an inner concrete portion 18 filled in the steel frame body 11 having a box-shaped cross section, and an upper flange plate of the steel frame body 11. 12, and at least one opening 19 used for filling when forming the internal concrete portion 18, and the protrusions 15 of the upper flange plate 12 include the protrusions 15 of the lower flange plate 13. The projections 16 are arranged so as to face each other, and the opening 19 is formed at the end on the side of the column, and is also used as a yield hinge. Here, characteristic components of the steel-concrete composite beam structure of the present invention will be described.

(Steel frame body) The steel frame body 11 has a box-shaped cross section. That is, the upper flange plate 12, the lower flange plate 13, and the opposite side plates 14 that mainly consist of an iron plate.
Are joined to each other by welding or the like. The upper and lower flange plates 12 and 13 resist tensile force against the bending moment acting on the beam, and the both side plates 14 function as shear reinforcing steel materials. Therefore, it is preferable that the both side plates 14 for shearing reinforcement are made of steel plates thinner than the upper and lower flange plates 12 and 13.

(Protrusions) A large number of protrusions 15 and 16 provided on the inner surfaces of the upper flange plate 12 and the lower flange plate 13, that is, the surfaces facing each other, at predetermined intervals in the longitudinal direction form a truss mechanism. For example, a channel material, an angle material or a stud bolt is used for the flange plates 12, 13
It can be fixed and used. These protrusions 1
It is also preferable that 5 and 16 are extended and formed in the direction orthogonal to the longitudinal direction of the steel frame main body 11.

(Opening) Upper flange plate 1 of steel frame body 11
2 has an opening 19 formed therein. Explaining the existence of the opening 19, the steel frame main body 1 having a box-shaped cross section is provided to counter the compressive force against the bending moment exerted on the beam.
The outer periphery of 1 is surrounded by concrete and the inside is also filled with concrete. At that time, the above-described opening 19 serves to integrate the outer concrete portion 17 on the outer peripheral side of the steel frame body 11 and the inner concrete portion 18 on the inner side, and at the same time, functions as a filling port for concrete into the steel frame body 11. Therefore, a plurality of openings 19 may be provided, and the shape and size of the openings 19 can be designed appropriately.

However, the formation of such an opening 19 at an arbitrary position causes the upper flange plate 12, which is a steel material effective in terms of shear strength, to be broken in cross section. So, but
By forming it at the column side end of the beam and acting as a yielding hinge, it is possible to reliably yield the beam at the ultimate yield strength,
This prevents any particular cross-section loss.

<Additional Structure in the Present Invention> The steel-framed concrete composite beam structure of the present invention is composed of the above-mentioned essential components, but is also established even when the components are specifically as follows. The additional component means that a part of the external concrete part 17 surrounding the outside of the steel frame body having a box-shaped cross section is formed by a half precast concrete body 17a, and the external concrete part 17 is formed.
And the inner concrete part 18 are formed of cast-in-place concrete.

[0014]

According to the steel-concrete composite beam structure of the present invention, the upper and lower flange plates 12, 13 of the box-shaped steel frame body 11 oppose the tensile force acting on the upper and lower parts of the beam 10 and the side plates. 14 opposes the shear forces acting on this beam.

A large number of projections 15 and 16 are provided on the inner surfaces of the upper flange plate 12 and the lower flange plate 13 so as to be spaced apart from each other in the longitudinal direction and face each other. Each part forms a truss mechanism by applying a compressive force to the internal concrete part 18 interposed between them.

[0016] As a result, this steel-concrete composite beam 10 structure can reasonably transmit the force between the steel frame and the concrete, is lighter and cheaper than the reinforced concrete beam, and secures the same strength. To be done.

Further, in order to fill the inside of the steel frame main body 11 having a box-shaped cross section with concrete and to integrate it with external concrete, an opening 19 formed in the upper flange plate 12 is formed at the end on the column side to yield. By also functioning as a hinge, a predetermined strength can be obtained without causing a special cross-section loss.

[0018]

EXAMPLES The steel-framed concrete composite beam structure of the present invention will be described in more detail with reference to the examples shown in the drawings. FIG. 1 shows a steel-concrete composite beam structure according to an embodiment of the present invention.

The steel-reinforced concrete composite beam 10 of this embodiment shown in FIG. 1 includes a steel-frame main body 11 having a box-shaped cross section. The steel frame body 11 is an upper flange plate 1 mainly composed of an iron plate.
2, the lower flange plate 13, and the opposite side plates 14 are joined to each other by welding or the like.

The upper and lower flange plates 12 and 13 resist the tensile force against the bending moment acting on the beam 10, and the both side plates 14 function as shear reinforcing steel materials. Therefore, the side plates 14 for shear reinforcement are made of steel plates thinner than the upper and lower flange plates 12 and 13.

The flange plate 1 is provided on the inner wall surfaces of the upper flange plate 12 and the lower flange plate 13 which constitute the steel frame body 11.
A large number of channel members 15 and 16 are provided by means such as welding, which extend in the width direction of 2 and 13 and are spaced at predetermined intervals in the longitudinal direction. Then, as shown in FIG. 3, each channel member 15 of the upper flange plate 12 has a lower flange plate 1
The three channel members 16 are arranged to face each other. Each of these channel members 15 and 16 functions as a protrusion for forming a truss mechanism.

The steel frame body 11 having a box-shaped cross section is surrounded by an outer concrete portion 17. This external concrete part 1
7, the part excluding the upper part is formed of a half precast concrete body 17a. The outer concrete portion 17b at the upper portion is formed of cast-in-place concrete as described later.

Concrete is also filled in the steel frame body 11 having a box-shaped cross section. This internal concrete part 1
8 is also made of cast-in-place concrete as described later. In this connection, the upper flange plate 12 of the steel frame body 11
A plurality of openings 19 are formed in the.

These openings 19 are used as a filling port when filling the inside of the steel frame body 11 with concrete, and are also used for ensuring the integrity with the external concrete portion 17. By the way, such formation of the opening 19 causes the upper flange plate 12, which is a steel material effective in shear strength, to have a cross-section loss. However, if a yield hinge is formed at the column-side end of the beam, the beam can be surely yielded at the ultimate yield strength. Therefore, the opening 19 is formed at the column-side end of the upper flange plate 12 as shown in FIG. By using it also as a yield hinge, a special cross-section loss is prevented.

As is clear from FIG. 2, for example, a bolt or a short projection 20 having various shapes is provided on the lower surface of the lower flange portion 13 in order to improve the adhesion with the external concrete portion 17. It is also preferable that a bar member 21 such as a reinforcing bar is fixed to the tip end portions of these protrusions 20.

The steel-framed reinforced concrete composite beam 10 thus constructed can be formed as follows.
That is, after first forming the steel frame body 11 described above,
Outside the outer concrete part 17 except the upper part, U
Form in a letter shape. Up to this point, it can be formed in advance in a factory or the like.

A half beam semi-finished product in which the half precast concrete body 17a thus formed and the steel frame body 11 having a box-shaped cross section are arranged and integrated therein are transported to a construction site and installed as shown in FIG. In the gap between the precast concrete floorboards 22 which is the position, the upper surface of the half precast concrete body 17a is installed so as to contact the lower surface of the precast concrete floorboard 22, and both ends thereof are used as columns (not shown) on both sides. connect.

As a result, the upper portion of the steel frame body 11 projecting from the half precast concrete body 17a projects slightly above the surface of the precast concrete floor plate 22. After that, concrete is filled from the opening 19 formed in the upper flange plate 12 to form the internal concrete portion 18, and concrete is also placed on the precast concrete floor plate 22 to form the floor portion.

As a result, the concrete 23 cast to form the floor portion is filled in the gap between the both side plates 14 of the steel frame body 11 and the end portions of the precast concrete floor plate 22 and at the same time on the steel frame body 11. The flange plate 12 is embedded to form the upper portion 17b of the outer concrete portion 17, whereby the steel-concrete composite beam 10 is completed.

According to the structure of the steel-concrete composite beam 10 as described above, the upper and lower flange portions 12 and 13 of the steel-frame main body 11 having a box-shaped cross section resist the tensile force acting on the upper and lower portions of the beam, and Both side plates 14 oppose the shearing forces acting on this beam.

A large number of channel members 15 and 16 are provided on the inner surfaces of the upper flange plate 12 and the lower flange plate 13 so as to be spaced apart in the longitudinal direction and face each other, as shown in FIG. A pair of upper and lower channel members positioned at the above positions form a truss mechanism by applying a compressive force to the oblique region portion 24 of the internal concrete portion 18 interposed therebetween.

The channel materials 15 and 16 may be installed in a minimum number and a mutual interval required for forming the truss mechanism. Therefore, the number and the interval of the channel materials 15 and 16 are set to the beam. It is appropriately designed from the length of 10, the required strength, and the like.

As a result, the steel-concrete composite beam 10 can reasonably transmit the force between the steel frame and the concrete, is lighter and cheaper than the reinforced concrete beam, and has the same strength. It

In the steel-concrete composite beam 10 of the above-described embodiment, the channel material 1 is formed on the inner surfaces of the upper flange plate 12 and the lower flange plate 13 to form the truss mechanism.
5 and 16 are provided, the channel material may be replaced with an angle material or a stud bolt, or as shown in FIG. 4, the upper and lower flange plates may be integrally formed with the protruding portions 25 and 26. May be.

Further, an opening 19 also serving as a yield hinge is formed in the upper flange plate 12 in order to fill the inside of the steel frame body 11 with concrete and to integrate with the external concrete portion. Although it is configured by one circular opening located on the central axis, the present invention is not limited to this and partially cuts out both side edges of the upper flange plate 12 as shown in FIG. Even if the opening is substantially formed, the same effect as that of the above-described embodiment can be obtained.

[0036]

As described above, according to the present invention,
Concrete is placed inside and outside the box-shaped steel frame body consisting of the upper flange plate and the lower flange plate to counter the tensile force, and the side plate to counter the shearing force, and the protrusions formed on the upper and lower flange plates. Since the truss mechanism is configured by the concrete portion in the meantime, it is possible to provide a structure of a steel-framed concrete composite beam that is relatively lightweight and has the same strength as a reinforced concrete beam.

Moreover, according to the steel-concrete composite beam structure of the present invention, the opening formed in the upper flange plate is filled with the concrete in the steel-frame main body having a box-shaped cross section and is integrated with the external concrete. Since it is formed on the end portion on the side of the column and also serves as a yield hinge, the above-mentioned strength can be obtained without causing a special cross-section loss.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view of a steel-framed concrete composite beam according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing the steel-concrete composite beam of the present invention installed in a structure.

FIG. 3 is a cross-sectional view showing the steel-framed concrete composite beam shown in FIG. 2 cut along the longitudinal direction thereof.

FIG. 4 is a sectional view similar to FIG. 3, showing a steel-framed concrete composite beam according to another embodiment of the present invention.

FIG. 5 is a perspective view similar to FIG. 1, showing a steel-framed concrete composite beam according to another embodiment of the present invention partially broken away.

[Explanation of symbols]

 10 Steel-Concrete Composite Beam 11 Steel Frame Main Body 12 Upper Flange Plate 13 Lower Flange Plate 14 Side Plate 15 Channel Material 16 Channel Material 17 External Concrete Part 17a Half Precast Concrete Body 17b Upper Part of External Concrete Part 18 Internal Concrete Part 19 Opening Part 20 Projection Part 21 Bars 22 Precast concrete floorboards 23 Concrete floors 24 Compression load parts for internal concrete parts 25 Projections 26 Projections

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Katsura Kobayashi Keiji Kobayashi 2-10-10 Fujimi, Chiyoda-ku, Tokyo Maeda Construction Industry Co., Ltd. (72) Yufumi Hirota 2--10-10 Fujimi, Chiyoda-ku, Tokyo Maeda Construction Co., Ltd. (72) Inventor Yasuji Maeda 2-10-10 Fujimi, Chiyoda-ku, Tokyo Maeda Construction Co., Ltd. (72) Yuzo Ichijo 2-1026 Fujimi, Chiyoda-ku, Tokyo Maeda Construction Co., Ltd. (72) Inventor Yoji Hosokawa 2-10-10 Fujimi, Chiyoda-ku, Tokyo Maeda Construction Co., Ltd. (72) Shinji Kato 2--10-10 Fujimi, Chiyoda-ku, Tokyo Maeda Construction Industry Co., Ltd.

Claims (2)

[Claims] 1. A steel frame main body having a box-shaped cross section, and a predetermined interval in the longitudinal direction of the flange plate to form a truss mechanism on the inner wall surfaces of the upper flange plate and the lower flange plate of the steel frame main body. A plurality of protrusions, an external concrete portion surrounding the outside of the steel frame body having a box-shaped cross section, an internal concrete portion filled in the steel frame body having a box-shaped cross section, and an upper flange plate of the steel frame body. And at least one opening used for filling when forming the internal concrete portion, and the protrusions of the upper flange plate are arranged to face the protrusions of the lower flange plate, respectively. Furthermore, the steel-concrete composite beam structure in which the opening is formed at the end on the side of the column and also serves as a yield hinge. 2. A box-shaped cross section is formed of a half precast concrete body except for an upper portion of an outer concrete portion surrounding the outside of the steel frame body, and the upper portion of the outer concrete portion and the inner concrete portion are cast in situ. The steel-reinforced concrete composite beam structure according to claim 1, wherein