JP6162479B2 - Concrete beam - Google Patents

Description

The present invention also relates to the concrete beams.

  When building column beam frames, precast prestressed concrete beams may be used. According to the precast prestressed concrete beam, since the prestressing force is introduced in advance, a long span can be realized. Moreover, shortening of a construction period is attained by using a precast member.

Precast concrete beams can be easily bolted or welded at the joints with the columns (column beam joints) by embedding steel frames for joining at both ends of the concrete beam body. (For example, refer patent document 1).
As a steel frame for joining, it is common to use H-shaped steel having high bending rigidity and bending strength and high versatility.

Japanese Patent No. 5039616

  If you try to embed H-shaped steel at the end of the beam body, the steel material in the axial direction, such as rebar and tension material, and H-shaped steel will be present in the same cross section, so the members will be complicated and will be manufactured. It takes time and effort.

  Moreover, the cross section of the beam main body may be enlarged in order to prevent the axial steel material and the H-shaped steel from buffering each other and to ensure a sufficient fixing length of the axial steel material. However, if the beam cross section is enlarged, the architectural space will be restricted.

From such a viewpoint, an object of the present invention is to propose a concrete beam that can be easily constructed and in which the degree of freedom of the building space is hardly limited.

In order to solve the above problems, a concrete beam of the present invention is a concrete beam body in which a steel material in the axial direction is disposed at the upper and lower portions of a cross section, and a base plate disposed on an end surface of the beam body, A concrete beam comprising a joining member fixed to one surface of the base plate and an embedded steel plate fixed to the other surface of the base plate and embedded in the beam main body, and an end of the axial steel material Is fixed to the base plate, the joining member is made of an H-shaped steel, the embedded steel plate is located on the extension of the H-shaped steel web, and its height dimension is that of the beam body. The shear reinforcement bars at the ends of the beam body are smaller than the interval between the steel bars in the upper and lower sections of the cross section, and are arranged closer than the shear reinforcement bars at the other parts. The padding Surrounding saw steel sheet is characterized by being reinforced intensively.
Note that the steel material in the axial direction disposed in the upper part of the beam body is a main bar, and the steel material in the axial direction disposed in the lower part of the beam body is a tension material into which tension is introduced. Good.

According to such a concrete beam , the joining member is fixed to the end surface of the beam body via the base plate, and the joining member itself is attached to the end of the beam body because the steel plate is embedded in the beam body instead of the joining member. Compared to a conventional buried concrete beam, it is possible to save time and labor when manufacturing the concrete beam.
That is, since the joining member and the steel material in the axial direction are not complicated, the arrangement of each member is easy.

Further, since the joining member and the steel in the axial direction do not interfere with each other within the same cross section, there is no need to increase the cross section at the beam end, and there is no restriction on the arrangement of the concrete beams.
Further, since the steel material in the axial direction is fixed to the base plate, it is not necessary to secure the fixing length inside the beam body. Therefore, it is difficult for the positional relationship between the members such as the axial steel material and the embedded steel plate to be restricted.

According to the concrete beam of the present invention, it can be easily constructed, and the degree of freedom of the building space is hardly limited.

It is an elevational view of a column beam frame according to an embodiment of the present invention. It is a perspective view which shows a part of beam main body of this embodiment. It is a side view which shows the junction part of a beam main body and a baseplate. (A) And (b) is a perspective view which shows a base plate, a joining member, and an embedded steel plate. (A) is the AA arrow directional view of FIG. 3, (b) is the BB sectional drawing. (A) And (b) is a side view which shows the manufacture condition of a concrete beam. (A) is a schematic diagram of the concrete beam of the present embodiment, (b) is a stress diagram of a long-term load acting on the concrete beam, and (c) is a stress diagram of a short-term load acting on the concrete beam.

  In the present embodiment, as shown in FIG. 1, a concrete beam 2 laid horizontally between a pair of columns 3 and 3 and a column beam frame 1 including the concrete beam 2 will be described.

  The concrete beam 2 of the present embodiment has a pretensioned concrete structure at the center and a steel frame at both ends. The beam main body 21, base plate 22, joining member 23, embedded steel plate 24, material Axial steel materials 25 and 26 are provided.

As shown in FIG. 2, the beam main body 21 is a concrete member and has a rectangular cross section.
Further, in the beam main body 21, material axial direction steel materials 25 and 26 and shear reinforcement bars 27 are disposed.

The axial steel materials 25 and 26 are linear members disposed along the axial direction of the beam main body 21.
The material axial direction steel material 25 arranged in the upper part of the beam main body 21 is a main bar, and the material axial direction steel material 26 arranged in the lower part of the beam main body 21 is a tension material. In addition, when distinguishing the material axial direction steel materials 25 and 26, they are called the "main reinforcement 25" and the "tensile material 26".

The main reinforcing bars 25 are made of deformed reinforcing bars, and are arranged one by one (two in total) at the upper corner of the beam main body 21.
The main reinforcing bars 25 are arranged with their end portions protruding from the end face of the beam main body 21 (see FIG. 3). The main bars 25 do not necessarily have to protrude from the end surfaces of the beam main body 21 at the ends. Further, the material, arrangement, and number of the main bars 25 are not limited.

The tension members 26 are arranged one by one (two in total) at the lower corner of the beam body 21.
The tendon material 26 is disposed in a state where the end portion protrudes from the end surface of the beam main body 21 (see FIG. 3). In addition, the structure of the tension material 26 is not limited, What is necessary is just to select suitably from PC steel rod, PC steel strand, PC steel wire, etc., and to use. Further, the arrangement and number of tendons 26 are not limited.

The shear reinforcing bars 27 are deformed reinforcing bars that are processed into a frame shape so as to surround the axial steel materials 25 and 26, and a plurality of reinforcing bars are arranged at predetermined intervals in the axial direction of the beam body 21.
In the present embodiment, as shown in FIG. 3, the shear reinforcement bars 27 at the ends of the beam main body 21 are arranged more densely than the shear reinforcement bars 27 of other parts.
It should be noted that the bar arrangement pitch and the reinforcing bar diameter of the shear reinforcement bars 27 may be set as appropriate.

As shown in FIG. 1, the base plate 22 is disposed on each end face of the beam main body 21.
As shown in FIG. 4A, the base plate 22 is a rectangular steel plate having the same shape as the cross-sectional shape of the beam main body 21, and a joining member 23 is fixed to one surface, and the other surface. An embedded steel plate 24 is fixed to the.

One through hole 22 a is formed at each corner of the base plate 22 (four in total).
The through holes 22 a are formed corresponding to the positions of the material axial direction steel materials 25 and 26 protruding from the end face of the beam main body 21.
The number and arrangement of the through holes 22a are not limited, and may be set as appropriate according to the arrangement of the material axial direction steel materials 25 and 26 protruding from the end face of the beam main body 21.

  As shown in FIG. 3 and FIG. 5A, the main bar 25 and the tension member 26 (material axial direction steel material) protruding from the end face of the beam body 21 pass through the through hole 22 a of the base plate 22, and the base plate by the nut N 22 is fixed to the surface. In addition, the fixing method of the material axial direction steel materials 25 and 26 and the base plate 22 is not limited.

As shown in FIG. 4A, the joining member 23 is a shaped steel material erected on the surface (one surface) opposite to the beam body 21 of the base plate 22, and includes a pair of upper and lower flanges 23a and 23a. The web 23b which connects both the flanges 23a and 23a is provided.
Although the joining member 23 of this embodiment is formed by fixing H-section steel to one surface of the base plate 22, the shape steel material which comprises the joining member 23 is not limited to H-section steel.

  As shown in FIG. 5A, the upper and lower flanges 23 a and 23 a are disposed at a height position close to the height position of the material axial direction steel materials 25 and 26 of the beam body 21. In addition, the joining member 23 should just be arrange | positioned so that it may not overlap with the material axial direction steel materials 25 and 26 protruded from the end surface of the beam main body 21, The shape and arrangement | positioning are not limited.

  As shown in FIG. 4, a plurality of bolt holes 23 c that are used when bolted to the column beam joint are formed at the column side end of the web 23 b of the joining member 23.

  The embedded steel plate 24 is a steel plate erected on the surface (the other surface) opposite to the joining member 23 of the base plate 22 as shown in FIG. 3 and FIG. Has been.

The embedded steel plate 24 is located on the extension (vertical plane shape) of the web 23b.
In the present embodiment, one embedded steel sheet 24 is used, but a plurality of embedded steel sheets 24 may be provided.

The shape of the embedded steel plate 24 is not limited, but is set to a size that does not interfere with the material axial direction steel materials 25 and 26 embedded in the beam main body 21, the shear reinforcing bars 27, and the like.
The height dimension of the embedded steel plate 24 of the present embodiment is smaller than the height dimension of the web 23b and smaller than the interval between the material axial direction steel materials 25 and 26. Further, the protruding dimension of the embedded steel sheet 24 is ½ or less of the protruding dimension of the bonding member 23. The embedded steel plate 24 is surrounded by three shear reinforcement bars 27.

  A plurality of stud bolts 24 a are erected on both surfaces of the embedded steel plate 24. In the present embodiment, two rows of stud bolts 24 a are arranged on both surfaces of the embedded steel plate 24 in the direction of the material axis of the beam main body 21 and in the up and down direction (total of 10). The stud bolt 24 a is erected in a direction orthogonal to the material axis direction of the beam body 21.

  The number and arrangement of the stud bolts 24a are not limited. The embedded steel plate 24 may be formed with other shear force transmission means instead of the stud bolt 24a. For example, irregularities may be formed on the surface of the embedded steel sheet 24, or through holes may be formed in the embedded steel sheet 24.

The embedded steel plate 24 and the stud bolt 24 a are disposed in the region A at the center of the beam main body 21.
The area A is an area similar to the cross-sectional shape of the beam main body 21, and the area of the area A in the present embodiment is ¼ or less of the cross-sectional area of the beam main body 21. The area of the region A is not limited.

  The column 3 of the present embodiment has a concrete-filled steel pipe structure, and a column beam joint 31 is formed corresponding to the height position of the concrete beam 2 as shown in FIG. Note that the pillar 3 is not necessarily a CFT pillar, and may be a steel reinforced concrete structure, a steel structure, or the like.

  As shown in FIG. 3, in the beam-column joint portion 31, a structural steel material 32 projects from the surface of the column 3. In the present embodiment, the column beam joint portion 31 is formed by a shape steel material 32 having the same shape as the H-section steel constituting the joint member 23 of the concrete beam 2.

The concrete beam 2 is horizontally placed between the columns by fixing the joining member 23 to the column beam joint 31 of the column 3.
In the joint portion between the concrete beam 2 and the column 3, a joining plate 33 disposed across the web 23a of the joining member 23 and the web of the shaped steel member 32 is disposed with both surfaces of both webs sandwiched therebetween. Yes.

And the joining member 23 and the structural steel material 32 are connected by fastening | tightening a nut to the volt | bolt B which penetrated the joining board 33, the joining member 23, or the structural steel material 32. FIG.
Moreover, in this embodiment, the flanges of the joining member 23 and the die steel material 32 are welded together. In addition, what is necessary is just to perform joining of flanges as needed.

Next, the manufacturing method of the concrete beam 1 of this embodiment is demonstrated.
First, as shown in FIG. 6A, the base plate 22 is disposed at positions corresponding to both ends of the beam main body 21.
A joining member 23 and an embedded steel plate 24 are fixed to the base plate 22 in advance.

Next, the material axial direction steel materials 25 and 26 and the shear reinforcement bars 27 are arranged (bar arrangement). And the tension | tensile_strength T is introduce | transduced into the tension material 26, and a side surface formwork (not shown) is assembled.
The ends of the axial steel materials 25 and 26 are projected from the base plate 22.

Next, concrete is placed in the formwork.
When a predetermined strength is developed in the concrete, the mold is removed, the tension of the tension member 26 is released, and the prestressing force P is introduced into the concrete beam 1 (see FIG. 6B).

  Then, nuts N are fastened to the ends of the main reinforcement 25 and the tension material 26, and the main reinforcement 25 and the tension material 26 are fixed to the base plate 22.

  In addition, the concrete beam 2 needs to transmit mainly the shearing force reliably between the concrete structure part (beam main body 21) and the steel structure part (base plate 22, joining member 23, and embedded steel plate 24) in the long term. Yes (see (b) of FIG. 7), it is necessary to reliably transmit the shearing force and the bending moment in the short term (during an earthquake) (see (c) of FIG. 7).

  In the concrete beam 2 of the present embodiment, the embedded steel plate 24 to which the stud is fixed is embedded in the beam main body 21, and the shear reinforcement bars 27 are densely arranged around the embedded steel plate 24. It has excellent shear force transmission at the joint between the beam main body 21) and the steel structure (base plate 22, joining member 23 and embedded steel plate 24).

  Further, since the main muscle 25 and the tension material 26 penetrate the base plate 22 and are fixed to the surface of the base plate 22, the transmission of the bending moment between the base plate 22, the main muscle 25 and the tension material 26 is also excellent. .

  That is, the tensile force generated by the bending moment is transmitted from the material axial direction steel materials 25 and 26 to the joining member 23 via the base plate 22. The compressive force generated by the bending moment is transmitted from the concrete surface to the joining member 23 via the base plate 22.

As described above, according to the concrete beam 2 and the column beam frame 1 of the present embodiment, since the embedded steel plate 24 is embedded in the end portion of the beam body 21, the beam body 21 and the base plate 22 can be fixed integrally.
Since the embedded steel plate 24 has a plurality of stud bolts 24a projecting from the surface, the fixing of the beam body 21 to the concrete is excellent.

  Since the embedded steel sheet 24 has a relatively small cross-sectional shape, there is less interference with the axial steel materials 25 and 26 and the shear reinforcement bars 27 in the cross section of the beam body 21, which can reduce labor during manufacturing. It becomes.

  Since the steel members 25 and 26 in the axial direction can be arranged on the outer edge side so that the effective shear is increased in the concrete cross section, a large bending strength can be expected, and the beam cross section needs to be made larger than necessary. There is no. Therefore, an effective architectural space can be constructed by adopting the column beam frame 1 of the present embodiment.

  Since the main bars 25 and the tension members 26 are fixed to the base plate 22, even if a desired fixing length cannot be ensured in the beam main body 21, the main bars 25 and the tension members 26 are excellent in stress transmission.

  Since the embedded steel plate 24 is embedded in the end portion of the beam body 21 and is reinforced intensively by the surrounding shear reinforcement bars 27, the concrete portion (beam body 21) and the steel portion (base plate 22, joining member 23 and embedded steel plate) 24) excellent in the transmission of shearing force.

  In addition, since the steel material in the axial direction (the main bars 25 and the tension material 26) is fixed to the base plate 22, the bending moment can be transmitted from the steel materials in the axial direction 25, 26 to the joining member 23 via the base plate 22.

The embodiment according to the present invention has been described above. However, the present invention is not limited to the above-described embodiment, and the above-described components can be appropriately changed without departing from the spirit of the present invention.
For example, in the present embodiment, all the material axial steel materials are protruded from the base plate. However, the material axial steel materials protruding from the base plate and the material axial steel materials not protruding may be mixed.

DESCRIPTION OF SYMBOLS 1 Column beam frame 2 Concrete beam 21 Beam main body 22 Base plate 23 Joining member 24 Embedded steel plate 25 Main reinforcement (steel material in the axial direction)
26 Tensile material (steel material in the axial direction)
3 Column 31 Beam-column joint

Claims (2)

A concrete beam body in which axial steel materials are arranged at the top and bottom of the cross section ;
A base plate disposed on an end surface of the beam body;
A joining member fixed to one surface of the base plate;
A concrete beam provided with an embedded steel plate fixed to the other surface of the base plate and embedded in the beam body,
The end portion of the material axial steel is fixed to the base plate ,
The joining member is made of H-section steel,
The embedded steel sheet is located on an extension of the web of the H-shaped steel, and the height dimension thereof is smaller than the interval between the steel members in the axial direction arranged at the upper part and the lower part of the cross section of the beam body,
The concrete is characterized in that the periphery of the embedded steel sheet is reinforced intensively by arranging the shear reinforcement bars at the ends of the beam main body more densely than the shear reinforcement bars of other parts. Beams. The axial steel material disposed in the upper part of the beam body is a main bar, and the axial steel material disposed in the lower part of the beam body is a tension material into which tension is introduced. The concrete beam according to claim 1.

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