JP4490532B2 - Precast composite beam structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an improvement in the structure of a precast composite beam of a structure.
[0002]
[Prior art and its problems]
Conventionally, in the construction of concrete buildings, for the purpose of simplifying the beam-column joint and increasing the degree of design freedom, steel columns and steel reinforced concrete structures (SRC structures) are used for the columns, and the beams are structured at the end and center. A composite structure in which different composite beams are used to construct a building by combining them is employed.
[0003]
For example, the one described in Japanese Patent No. 2629503 shown in FIGS. 16 and 17 is a concrete beam 51 and steel pipe concrete in which a PC steel material 53 and a main reinforcement 56 are arranged inside a concrete beam 51 and precasted by introducing prestress. The pillar 52 is a structure assembled by connecting the gusset plate 62 and the web of the bracket 54, and the diaphragm 55 and the bracket 54.
[0004]
In this structure, since the top end of the bracket 54 (H-shaped steel) provided at the end of the concrete beam 51 is continuously provided on the top end surface of the concrete beam 51, the flange 54 and the slab concrete adhere to each other. It is difficult to ensure strength, and studs are fused at the top of the flange to ensure unity.
[0005]
Further, in the one described in Japanese Patent Laid-Open No. 10-96294 shown in FIG. 18, a steel frame H-section steel 71 is embedded at the end of a precast concrete beam 74 and the main bar 72 is arranged inside the flange of the H-section steel 71. A hoop line 73 is wound around the outside of the flange. After joining the H-section steel 71 at the end of the beam to the concrete-filled steel pipe column 76, the gap between the beam precast concrete 74 and the concrete-filled steel pipe column 76 is placed on site at the same time as the slab is placed. Thus, an integrated column beam connection structure is obtained. In this construction method, the main bar 72 of the beam and the flange of the H-shaped steel 71 are not welded, and it is necessary to increase the required length of the H-shaped steel 71 in order to transmit stress only by adhesion of concrete inside the flange. It becomes expensive in terms of cost.
[0006]
It is an object of the present invention to provide a precast composite beam structure that solves these problems.
[0007]
[Means for Solving the Problems]
The present invention connects steel pipe concrete columns filled with concrete inside the steel pipe, and the ends of the joints with the columns are steel-concrete structures in which H-shaped steel is arranged, and the central part is a reinforced concrete structure. In the structure of the precast composite beam formed of precast concrete, the reinforcing bar of the reinforced concrete is disposed in the vicinity of the flange end of the H-shaped steel, and the first beam main reinforcing bar one-stage reinforcing bar extends in the axial direction of the precast composite beam, And a second beam main reinforcement first step extending in the axial direction of the precast composite beam, the first beam main reinforcement first step being arranged in the vicinity of the upper and lower flange ends of the H-shaped steel. It is formed on the hoop and joining the ends of the first beam main reinforcement single stage muscle, the second beam main reinforcement one stage muscle, its ends of the upper and lower Te bending piece Gerare toward the other flange portion of the H-shaped steel Hula Is formed so as to be X-shape between di-, comprising a plurality of Sturup pitch is finer disposed than the pitch of other portions of the steel skeleton concrete structure in switched portion from the reinforced concrete precast composite beam.
[0009]
Operation and effect of the invention
In the present invention, the structure is a precast composite beam formed of precast concrete that joins between steel pipe concrete columns filled with concrete inside the steel pipe, and H-shaped steel is arranged at the joint with the column. The installed steel concrete structure is adopted, and the central part is a reinforced concrete structure.
[0010]
The reinforcing bar constituting the central part is composed of the first and second beam main bars, the beam main bars and the stirrup. The first beam main reinforcement is arranged near the flange end of the H-shaped steel provided at both ends of the precast composite beam, and is arranged in the axial direction of the precast composite beam. Combining the ends of the muscles, it is configured in a hoop shape.
[0011]
In the second beam main reinforcement, the rebar located near the center of the upper flange of the H-shaped steel is directed toward the lower flange, and the rebar located near the center of the lower flange is directed toward the upper flange. Since it is bent, the second beam main reinforcement first-stage reinforcement forms an X-shape between the upper and lower flanges of the H-section steel by the upper and lower second beam main reinforcement first-stage reinforcement. Therefore, the fixing length with the H-shaped steel can be increased, and it is possible not only to resist bending by an external force but also to resist shearing.
[0012]
Further, by adopting such a configuration, the production can be dealt with only by bending the reinforcing bars, and it is safe and easy to construct since no fire for welding or the like is used on site.
[0013]
Furthermore, the first beam main reinforcement is arranged near the flange end of the H-section steel and is not fixed to the flange. Therefore, the flange width can be reduced, and the concrete on the back side of the H-section steel flange during concrete placement Fillability is improved.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
[0016]
1 to 5 show a configuration diagram of the present embodiment.
[0017]
As shown in FIG. 1, the main part of the building is connected to a pillar 2 standing in a vertical direction and a precast composite beam 1 that is spanned between the pillars 2 and serves as a base member for forming a floor. Built by that.
[0018]
The column 2 is made using a concrete-filled steel pipe structure formed by filling the concrete 2a inside the steel pipe 2b. In addition, two diaphragms 13 are attached substantially perpendicularly to the axis of the column 2 so as to sandwich the precast composite beam 1 from above and below at the coupling position of the column 2 with the precast composite beam 1.
[0019]
The steel pipes 2b are abutted and joined to each other via the diaphragm 13, and function as molds into which the filled concrete 2a is poured.
[0020]
Further, a gusset plate 9 is arranged in the vicinity of the central axis of the precast composite beam between the two diaphragms 13, and the gusset plate 9 is abutted against the surface of the column 2 along the axial direction and coupled to the column 2. Yes.
[0021]
In addition, the center part of the diaphragm 13 is provided with a placement hole 13a and an air vent hole 13b for allowing the filled concrete 2a to spread through the pillar 2 without any gap as shown in FIG.
[0022]
The gusset plate 9 has two rows of holes for bolts used for connection with the precast composite beam 1 in the vertical direction.
[0023]
The precast composite beam 1 coupled to the column 2 is manufactured in advance at a factory or a construction site.
[0024]
The configuration of the precast composite beam 1 will be described in detail. As shown in FIGS. 1 and 3, H-shaped steel 8 that is abutted against the column 2 is provided at both ends of the precast composite beam 1. The H-section steel 8 is composed of two flanges 8a that are respectively abutted and fixed to the two diaphragms 13, a gusset plate 9, and a web 8b that is bolted. The web 8b has two rows of holes for bolting the gusset plate 9 of the pillar 2 in the vertical direction. A band plate 12 that joins the ends of the upper and lower flanges 8a is provided to prevent deformation of the flange 8a due to an external force.
[0025]
In addition, as shown in FIG. 4, two hoop-shaped first beam main reinforcing bars 3 are arranged, and the first beam main reinforcing bars 1 are substantially equal to the length between the upper and lower flanges 8 a of the H-section steel 8. Have a width. The axial dimension of the first beam main reinforcing bar 1 streak 3 is such a length that it is located in the vicinity of the gusset plate 9 of the two opposite pillars 2.
[0026]
Further, as shown in FIG. 5, four first and second second beam main reinforcing bars 1 are arranged inside the first beam main reinforcing bars 1. As shown in FIG. 1, the second beam main reinforcement 1 streak 4 is bent downward while the second beam main reinforcement 1 streak 4 is arranged at the upper end, and the second beam main reinforcement 1 streak 4 is arranged at the lower part. An X-shape is formed so that the upper and lower second beam main bars are overlapped and are positioned between two flanges 8a of the H-section steel 8 (shown in FIGS. 1 and 4).
[0027]
In the hoop formed by the first beam main bar first-stage bar 3, a hoop-shaped beam main bar second-bar bar 5 is also arranged. The beam main reinforcing bar second reinforcing bar 5 is provided close to the outside of the stud 11 which is welded inside the upper and lower flanges 8 a of the H-shaped steel 8.
[0028]
A plurality of square stirrups 7 are arranged in the axial direction of the composite beam 1 so as to surround the outer peripheries of the upper and lower first beam main bars 1 and the second beam main bars 1. The scallop 7 is arranged so as to cover the joint between the gusset plate 9 and the web 8b. The pitch of the scallops 7 is arranged so that the pitch of the scallops 7 located in the vicinity of the X-shape formed by the second beam main reinforcing bar first step is finer than the pitches at other positions.
[0029]
Note that a splice bar 6 for supporting the scallop 7 for arranging the scallop 7 so as to cover the periphery of the gusset plate 9 extends from the inner side of the first beam main reinforcing bar 3 to the column 2 side at the end of the composite beam 1. Yes.
[0030]
In this way, the precast composite beam 1 is arranged, and then the mold is installed, and concrete is placed in the mold to complete the precast composite beam 1. At this time, the concrete is placed so as to leave the upper portion of the stirrup 7 and the first beam main reinforcement 1 streak 3 and in the axial direction to the entire first beam main reinforcement 1 streak 3 (the web 8b and the gusset plate 9 The mold is formed so that the stirrup 7 near the end of the composite beam 1 remains without touching the concrete so that there is no hindrance to the bolt fastening.
[0031]
Next, a method for connecting the precast composite beam 1 and the column 2 will be described with reference to FIGS.
[0032]
In FIG. 6, another steel pipe 2b is installed at the upper end of the steel pipe 2b 'already provided as the pillar 2 and fixed with a joint bolt or the like. At this time, the gusset plate 9 and the diaphragm 13 are already assembled to the newly installed steel pipe 2b.
[0033]
7 and 8, the precast composite beam 1 manufactured in advance in a factory or the like is connected to a newly installed steel pipe 2b. At this time, the web 8b and the gusset plate 9 are fastened by the bolt 10 which penetrates the hole provided in the web 8b of the precast composite beam 1 and the gusset plate 9 of the column 2. Further, the flange 8a is abutted against and joined to the diaphragm 13.
[0034]
9 to 11, a formwork is assembled to both ends of the precast composite beam 1 and the column 2, and the precast floor slab 16 is installed over the entire precast composite beam 1. A floor slab formwork may be assembled instead of the precast floor slab 16.
[0035]
12 to 14, post-cast concrete 13 is placed on the end of the precast composite beam 1 and the floor slab. At this time, the floor slab and the upper part of the slap 7 exposed from the precast composite beam 1 are simultaneously placed in the concrete without being placed in the concrete during the production of the precast composite beam.
[0036]
In FIG. 15, the concrete 2a is filled into the steel pipe 2b to form the pillar 2, and the series of operations is completed.
[0037]
By repeatedly performing the above operations, a floor with a desired number of floors can be formed on the building.
[0038]
As described above, in the precast composite beam 1 of the present invention, the first hoop-shaped first beam main reinforcement 3 is arranged outside the H-section steel 8, and the second beam main reinforcement first-stage reinforcement is arranged above and below the H-section steel 8. It is combined with the pillar 2 by bending so as to form an X shape between the flanges 8b and placing concrete.
[0039]
With such a configuration, the shearing force acting on the joint between the precast composite beam 1 and the column 2 is mainly supported by the joint between the gusset plate 9 and the web 8b, while the bending load acting on the joint is mainly the first. It is supported by the beam main reinforcement first stage reinforcement 3, the second beam main reinforcement first stage reinforcement 4, the beam main reinforcement second stage reinforcement 5, and the flange 8a of the H-section steel 8, but the second beam main reinforcement first stage reinforcement 4 has an X-shape, Since the fixing length with the H-shaped steel 8 can be increased, the performance against bending load can be improved. Furthermore, the performance improvement with respect to the shearing force by the X-shaped second beam main reinforcement 1 step reinforcement 4 can be expected.
[0040]
Further, at the construction site of the precast composite beam 1, it can be manufactured only by bending due to its structure, and it is not necessary to use fire such as welding, and the construction is safe and easy.
[0041]
At the time of concrete placement, the first beam main reinforcing bar 1 streak 3 is not fixed to the flange 8a of the H-section steel 8, so that the flange width can be narrowed and the concrete such as the back of the flange 8a can be filled. Therefore, the filling property of concrete can be improved.
[0042]
In addition, the slap 7 provided on the outer circumference of the first and second beam main bars 1 and 4 has different pitches in the central part of the reinforced concrete structure and in the region where the reinforced concrete structure changes to the steel-concrete structure. Since the pitch of the region to be processed is finer than that of the central portion, even when a large shearing force acts on the composite beam 1, the force can be smoothly transmitted in the structural change region.
[0043]
Further, since the beam main reinforcing bar second reinforcing bar 5 is provided in the vicinity of the stud 11 provided on the flange portion 8a of the H-section steel 8, when an external force is applied to the composite beam 1, the hoop-shaped beam main reinforcing bar second reinforcing bar 5 is provided. The acting stress can be transmitted to the flange portion 8a of the H-section steel 8 through the concrete.
[0044]
With the above configuration, the force can be smoothly transmitted from the precast composite beam 1 to the column 2 to effectively increase the proof stress and rigidity in the structural change region, and the composite beam can be lightened by reducing the beam size. A large indoor space can be secured.
[0045]
In addition, by placing the upper slap of the precast composite beam at the same time as the floor slab when the floor slab is concreted, it is possible to ensure the integrity of the floor slab and the precast composite beam.
[Brief description of the drawings]
FIG. 1 shows an embodiment of the present invention and is a cross-sectional view taken along line AA in FIG.
2 is a cross-sectional view taken along the line BB in FIG.
3 is a cross-sectional view taken along the line CC of FIG.
4 is a cross-sectional view taken along line DD in FIG.
5 is a cross-sectional view taken along line EE in FIG.
FIG. 6 is a sectional view showing the construction process (before the precast composite beam is installed).
FIG. 7 is a cross-sectional view showing the construction process (precast composite beam installation state).
FIG. 8 is a cross-sectional view showing the construction process (precast composite beam joining completed state).
FIG. 9 is a cross-sectional view showing the construction process (precast composite beam end formwork installation state).
10 is a cross-sectional view taken along line FF in FIG.
11 is a cross-sectional view taken along line GG in FIG.
FIG. 12 is a cross-sectional view showing the construction process (precast composite beam post-cast concrete placement state).
13 is a cross-sectional view taken along line HH in FIG.
14 is a cross-sectional view taken along the line II of FIG.
FIG. 15 is a cross-sectional view showing the construction process (filled concrete in a column).
FIG. 16 is a view showing a joint portion between a concrete beam and a column in a conventional example.
FIG. 17 is a view similarly showing a manufacturing example of a concrete beam.
FIG. 18 is a diagram similarly showing a conventional example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Precast composite beam 2 Column 2a Filling concrete 2b Steel pipe 3 1st beam main reinforcement 1 step reinforcement 4 2nd beam main reinforcement 1 step reinforcement 6 Beam main reinforcement 2 step reinforcement 6 Stirrup 8 Stirrup 8 H-section steel 8a Flange 8b Web 9 Gusset plate 10 Bolt 11 Stud 12 Band plate 13 Diaphragm 13a Placing hole 13b Air vent hole 14 Post-cast concrete 15 Precast concrete 16 Precast floor slab

Claims (1)

Steel pipe concrete columns filled with concrete inside the steel pipe are joined together, and the end of the joint with the pillar is steel-framed concrete with H-shaped steel, and the central part is made of reinforced concrete precast concrete In the structure of the precast composite beam,
The reinforced concrete rebar is
The first beam main reinforcement is arranged near the flange end of the H-shaped steel and extends in the axial direction of the precast composite beam;
It is arranged near the center of the flange of the H-shaped steel, and comprises a second beam main reinforcing bar and a first reinforcing bar extending in the axial direction of the precast composite beam,
The first beam main reinforcement first stage reinforcement is formed in a hoop shape by joining the ends of the first beam main reinforcement first stage reinforcement arranged near the upper and lower flange ends of the H-section steel,
Said second beam main reinforcement one stage muscle, its ends are formed to be X-shaped Te folded piece Gerare between said upper and lower flanges toward the other flange portion of the H-shaped steel,
A structure of a precast composite beam comprising a plurality of stirrups in which a pitch of a portion of the precast composite beam switching from a reinforced concrete structure to a steel concrete structure is arranged more finely than a pitch of other portions.

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