JP3685831B2 - Steel-concrete composite beam structure - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a steel-concrete composite beam structure, and more particularly, to a structure of a beam member that forms a composite beam with a steel frame and concrete.
[0002]
[Prior art]
Conventionally, there is no established technique for composing a composite beam with steel frame and concrete. Generally, the beam in the building has a reinforced concrete structure, a steel reinforced concrete structure, or a steel structure. Reinforced concrete beams are generally formed with a rectangular cross section. A reinforced concrete beam with a rigid frame structure causes a tensile force on the lower side at the center and on the upper side at the end by bending. Since concrete is weak in tensile force, reinforcing bars are always placed in the parts that generate tensile force, but the main bars are also placed on the side where compressive force is generated in the main beams.
[0003]
In other words, a reinforced concrete beam has a main bar (upper bar) along each corner on the upper side, a main bar (lower bar) along each lower corner, and the longitudinal direction of the beam. The stirrup is arranged so that the entire main muscles are rolled up at a predetermined interval in order to counter the shearing force.
[0004]
On the other hand, a steel beam, a plate beam, a truss beam, or the like is known as a steel beam. The shaped steel beam has an I-shaped cross section or an H-shaped cross section which is advantageous for bending. The plate beam is an angle steel and steel plate or a steel plate and steel plate assembled by welding or rivets. The cross-sectional shape is advantageous for bending action and convenient for joining with columns. The thing of a shape section is used, and the thing of a box shape is sometimes used.
[0005]
In addition, the truss beam is a parallel string truss with the upper chord material and the lower chord material parallel to each other. . Usually, angle steel is used for the string material and the web material.
[0006]
[Problems to be solved by the invention]
As described above, the conventional beams in the building are reinforced concrete structures or steel structures. However, the reinforced concrete beams have a problem that they are high in rigidity but very heavy, and the steel beams are lightweight. However, there was a problem that the rigidity was inferior to that of reinforced concrete beams.
[0007]
SUMMARY OF THE INVENTION An object of the present invention is to provide a structure of a steel-concrete composite beam that is made in order to solve such a conventional problem and is comparatively light and yet has the same strength as a reinforced concrete beam.
[0008]
[Means for Solving the Problems]
The present invention is a steel-concrete composite beam structure, and is configured as follows in order to solve the above technical problem. That is, the steel-concrete composite beam structure of the present invention has a steel frame body 11 having a box-shaped cross section, and the flange plate 12 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, 13, a plurality of protrusions 15 and 16 provided at predetermined intervals in the longitudinal direction, an external concrete portion 17 surrounding the outside of the steel body 11 having a box-shaped cross section, and the steel body 11 having a box-shaped cross section. An inner concrete portion 18 filled therein, and at least one opening 19 formed in the upper flange plate 12 of the steel body 11 and used for filling when the inner concrete portion 18 is formed, The protrusions 15 of the upper flange plate 12 are opposed to the protrusions 16 of the lower flange plate 13, respectively. Here, the characteristic component in the steel-concrete composite beam structure of this invention is demonstrated.
[0009]
(Steel body)
The steel body 11 has a box-shaped cross section. In other words, the upper flange plate 12, the lower flange plate 13, and the opposite side plates 14 mainly composed of iron plates are joined to each other by welding or the like. The upper and lower flange plates 12, 13 oppose the tensile force against the bending moment acting on the beam, and the both side plates 14 function as a shear reinforcing steel material. Therefore, it is preferable that the both side plates 14 for shear reinforcement are constructed using steel plates thinner than the upper and lower flange plates 12 and 13.
[0010]
(protrusion)
A large number of projections 15 and 16 provided at predetermined intervals in the longitudinal direction on the inner surfaces of the upper flange plate 12 and the lower flange plate 13, that is, the surfaces facing each other, are for forming a truss mechanism. A material, an angle material, a stat bolt or the like can be used by being fixed to the flange plates 12 and 13. These protrusions 15 and 16 are preferably formed by extending in a direction perpendicular to the longitudinal direction of the steel body 11.
[0011]
(Aperture)
An opening 19 is formed in the upper flange plate 12 of the steel frame body 11. Explaining the presence of the opening 19, the outer periphery of the steel body 11 having a box-shaped cross section is surrounded by concrete in order to resist the compressive force against the bending moment exerted on the beam, and the inside is also filled with concrete. At that time, the opening 19 described above aims to integrate the outer concrete portion 17 on the outer peripheral side of the steel body 11 and the inner concrete portion 18 on the inner side, and at the same time, fills the steel body 11 with concrete. Therefore, there may be a plurality of openings, and the shape and size can be designed as appropriate.
[0012]
<Additional configuration in the present invention>
Although the steel-concrete composite beam structure of the present invention is composed of the above-described essential components, it is established even when the components are specifically as follows. The additional component is formed by a half precast concrete body 17a excluding the upper part of the outer concrete part 17 surrounding the outside of the steel body 11 having a box-shaped cross section, and the upper part of the outer concrete part 17 and the upper part. The internal concrete portion 18 is formed of cast-in-place concrete.
[0013]
[Action]
According to the steel-concrete composite beam structure of the present invention, the upper and lower flange plates 12 and 13 of the box-shaped steel body 11 counteract the tensile force acting on the upper and lower portions of the beam 10, and the side plate 14 Counters shear forces acting on the beam.
[0014]
A large number of protrusions 15, 16 provided on the inner surfaces of the upper flange plate 12 and the lower flange plate 13 at intervals in the longitudinal direction and opposed to each other are a pair of upper and lower protrusions positioned in an oblique direction, respectively. A truss mechanism is formed by applying a compressive force to the internal concrete portion 18 interposed therebetween.
[0015]
As a result, this steel-concrete composite beam structure can rationally transmit force between the steel frame and concrete, and is lighter and less expensive than reinforced concrete beams, while ensuring the same strength.
[0016]
【Example】
Hereinafter, the steel-concrete composite beam structure of the present invention will be described in more detail with reference to the embodiments shown in the drawings. FIG. 1 shows a steel-concrete composite beam structure according to an embodiment of the present invention.
[0017]
A steel-concrete composite beam 10 of this embodiment shown in FIG. 1 includes a steel frame body 11 having a box-shaped cross section. The steel frame body 11 is configured by joining an upper flange plate 12, a lower flange plate 13, and opposing side plates 14 mainly composed of an iron plate to each other by welding or the like.
[0018]
The upper and lower flange plates 12 and 13 oppose the tensile force against the bending moment acting on the beam 10, and the both side plates 14 function as a shear reinforcing steel material. Accordingly, the side plates 14 for shear reinforcement are made of steel plates thinner than the upper and lower flange plates 12 and 13.
[0019]
The inner wall surfaces of the upper flange plate 12 and the lower flange plate 13 constituting the steel frame body 11 extend in the width direction of the flange plates 12 and 13 and have a number of channel members 15 at predetermined intervals in the longitudinal direction. 16 are provided by means such as welding. As shown in FIG. 3, each channel member 15 of the upper flange plate 12 is disposed opposite to each channel member 16 of the lower flange plate 13. Each of these channel members 15 and 16 functions as a projection for forming a truss mechanism.
[0020]
The steel body 11 having a box-shaped cross section is surrounded by an external concrete portion 17. The outer concrete portion 17 is formed of a half precast concrete body 17a except for its upper portion. The upper external concrete portion 17b is made of cast-in-place concrete as will be described later.
[0021]
In addition, the steel body 11 having a box-shaped cross section is filled with concrete. This internal concrete portion 18 is also formed of cast-in-place concrete as will be described later. In this regard, a plurality of openings 19 are formed in the upper flange plate 12 of the steel body 11.
[0022]
These openings 19 are used as filling ports when filling the concrete inside the steel frame body 11 and are used for ensuring the integrity with the external concrete portion 17.
[0023]
As is clear from FIG. 2, it is also preferable to provide, for example, bolts or short projections 20 having various shapes on the lower surface of the lower flange portion 13 in order to enhance adhesion to the external concrete portion 17. Furthermore, it is also preferable to stick a bar 21 such as a reinforcing bar to the tip of these protrusions 20.
[0024]
The steel-framed reinforced concrete composite beam 10 thus configured can be formed as follows. That is, after first forming the steel frame main body 11 described above, the outer concrete portion 17 is formed outside the upper portion in a U shape. Up to this point, it can be formed in advance at a factory or the like.
[0025]
The half precast concrete body 17a formed in this way and the beam semi-finished product in which the steel frame body 11 having a box-shaped cross section is arranged and integrated therein are conveyed to the construction site and are at the beam installation position as shown in FIG. In the gap between the precast concrete floor boards 22, the upper surface of the half precast concrete body 17a is installed in contact with the lower surface of the precast concrete floor board 22, and both ends thereof are connected to columns on both sides (not shown).
[0026]
Thereby, the upper part of the steel frame main body 11 protruded from the half precast concrete body 17a slightly protrudes above the surface of the precast concrete floor board 22. Thereafter, concrete is filled from an opening 19 formed in the upper flange plate 12 to form an internal concrete portion 18, and concrete is placed on the precast concrete floor plate 22 in order to form a floor portion.
[0027]
As a result, the concrete 23 placed for forming the floor portion is filled in a gap between the side plates 14 of the steel body 11 and the end portions of the precast concrete floor plate 22 and the upper flange plate 12 of the steel body 11. Is embedded to form an upper portion 17b of the external concrete portion 17, and thereby the steel-concrete composite beam 10 is completed.
[0028]
According to the structure of the steel-concrete composite beam 10 as described above, the upper and lower flange portions 12 and 13 in the steel 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 Counteracts the shear forces acting on this beam.
[0029]
A large number of channel members 15 and 16 provided on the inner surfaces of the upper flange plate 12 and the lower flange plate 13 at intervals in the longitudinal direction and opposed to each other are positioned obliquely as shown in FIG. A truss mechanism is formed by applying a compressive force to the oblique region portion 24 of the internal concrete portion 18 between which a pair of upper and lower channel materials are interposed.
[0030]
The channel members 15 and 16 may be installed at the minimum number necessary for forming the truss mechanism and at a distance from each other. In addition, it is appropriately designed from the required strength.
[0031]
As a result, the steel-concrete composite beam 10 can rationally transmit force between the steel frame and the concrete, and is light and inexpensive compared to the reinforced concrete beam, while ensuring the same strength.
[0032]
In the steel-concrete composite beam 10 of the above-described embodiment, the channel members 15 and 16 are provided on the inner surfaces of the upper flange plate 12 and the lower flange plate 13 in order to form a truss mechanism. Instead of the material, an angle material or a stat bolt may be used, or as shown in FIG. 4, the projecting portions 25 and 26 may be formed integrally with the upper and lower flange plates.
[0033]
【The invention's effect】
As described above, according to the present invention, concrete is applied to the inside and outside of a steel frame main body having a box-shaped cross section composed of an upper flange plate and a lower flange plate for opposing a tensile force, and a side plate for resisting a shearing force. Because the truss mechanism is composed of the protrusions formed on the upper and lower flange plates and the concrete part between them, the structure of the steel-concrete composite beam is relatively lightweight and has the same strength as the reinforced concrete beam. Can be provided.
[Brief description of the drawings]
FIG. 1 is a perspective view of a steel-concrete composite beam according to the present invention, partially broken away.
FIG. 2 is a cross-sectional view showing a steel-concrete composite beam according to the present invention installed in a structure.
FIG. 3 is a cross-sectional view showing the steel-concrete composite beam shown in FIG. 2 cut along its longitudinal direction.
4 is a cross-sectional view similar to FIG. 3, showing a steel-concrete composite beam according to another embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Steel-concrete composite beam 11 Steel frame 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 Protrusion part 21 Bar material 22 Precast concrete floor board 23 Concrete floor part 24 Compression load part 25 of internal concrete part Protrusion part 26 Protrusion part

Claims (2)

Steel box with a box-shaped cross section having upper and lower flange plates positioned at the upper and lower portions to counter tensile force, and both side plates positioned between the upper and lower flange plates and against shearing force The body,
A plurality of projections provided at predetermined intervals on said flange plate and their longitudinal on the inner wall surface of the lower flange plate of the steel body,
An external concrete portion surrounding the outside of the steel body having a box-shaped cross section;
An internal concrete portion filled in the steel body having a box-shaped cross section;
Including at least one opening formed on the upper flange plate of the steel frame body and used for filling when forming the internal concrete portion;
The protrusions of the upper flange plate are opposed to the protrusions of the lower flange plate, respectively .
The upper and lower flange plates facing each other are interposed between a pair of upper and lower protrusions having an oblique positional relationship and a pair of upper and lower protrusions having an oblique positional relationship, and A steel-concrete composite beam structure in which a truss mechanism is formed with an oblique region portion which is a part of the internal concrete portion .   The part of the box-shaped section excluding the upper part of the outer concrete part surrounding the outside of the steel body is formed of a half precast concrete body, and the upper part of the outer concrete part and the inner concrete part are formed of cast-in-place concrete. The steel-concrete composite beam structure according to claim 1.

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