JPH05331908A - How to join precast concrete beams - Google Patents

Abstract

(57) [Summary] [Purpose] A building with an extremely large or small amount of rebar, that is, it can accommodate both single-stage and two-stage reinforcements.
In addition, it is also possible to easily cope with the fixation of precast concrete beams of the type in which the first-stage reinforcement and the second-stage reinforcement are mixed. [Constitution] Joint end 2 of precast concrete beam 2
d is installed on the pillar head 4 and positioned so that the lower main bar 2a is arranged at an accurate position in the pillar 4a, and while maintaining this positioned state, joining of independent precast concrete beams 3 orthogonal to each other After the end portions 3b are respectively placed on the column head 4 so as to face each other, the upper main reinforcements 2g and 3e are arranged on these precast concrete beams 2 and 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for joining precast concrete beams to be erected on the heads of columns of each floor in a concrete structure such as a building.

[0002]

2. Description of the Related Art As a method of joining a precast concrete beam of this type, one having a structure shown in JP-A-3-281856 and FIG. 15 is well known as a conventional example. The precast concrete beam disclosed in JP-A-3-281856 is integrally formed so that the beams cross each other at right angles, and they are connected only by the lower main bars of the beams that cross each other. On the other hand, in the precast concrete beam 20 of FIG. 15, independent precast concrete beams 20a are separately mounted on the pillar heads 30, respectively.
b were established separately.

All of these precast concrete beams 20 are erected on a column head 30 when building a building, and after a required formwork is attached, a joint 40 between the column head 30 and the precast concrete beam 20 is cast on site. These were constructed integrally by pouring concrete.

[0004]

SUMMARY OF THE INVENTION In the above conventional example,
JP-A-3-281856, in which a precast concrete beam is joined only by the lower main bar, is particularly suitable for a two-stage bar type such as a high-rise reinforced concrete building with an extremely large amount of rebar, and a plurality of beams at the pillar head. The method of fixing the main bars separately is suitable for the one-stage bar type such as a building with a small amount of reinforcing bars, and the structural form with good adaptability is determined for each. However, in the column head of a building where the amount of rebar is not extremely large or small, the fixing method of the precast concrete beam of the conventional example cannot be adopted, and the fixing method of the precast concrete beam corresponding to the frame must be adopted. The cost of constructing a precast concrete beam or the cost of using unnecessary rebar more than necessary causes an increase in construction cost.

The present invention has been made in view of the above problems, and an object thereof is a building in which the amount of rebar is not extremely large or small, that is, a one-stage bar or a two-stage bar, or Is 1
To provide an economical precast concrete beam anchoring method capable of easily adapting to anchoring of a precast concrete beam of a type in which multi-tiered bar and two-tier bar are mixed and adapting to individual building. Is.

[0006]

Means for Solving the Problems The gist of the present invention for solving the above problems is that in a precast concrete beam that crosses in a cross shape at a column head, the concrete connected to the lower main bar is The joint end of the missing precast concrete beam is placed on the column head to arrange the lower main bar in the column, and the joint end of the independent precast concrete beam with the lower main bar protruding is formed on the column head. After placing them opposite to each other, it is due to placing another concrete bar on these precast concrete beams that intersect with each other and placing concrete at the intersections, and the facing joint ends of the independent precast concrete beams. Is made to have a U-shaped cross section, and the opposing joint ends in the defect part of the precast concrete beam having the defect part are cut off. U-shaped, and further, the opposing joint ends of the independent precast concrete beam and the opposing joint ends at the defect portion of the precast concrete beam having a defect portion are each U-shaped in cross section. Exist in.

[0007]

According to the anchoring method of the present invention, it is possible to adapt to the anchorage of a building in which the amount of reinforcing bars is extremely large or small, that is, the precast concrete beams of the single-stage type or the two-stage type, respectively. Since it is possible to perform fixing that arbitrarily corresponds to a type in which stair bars and two stair bars are mixed, it is possible to reduce the construction cost without using unnecessary reinforcing bars.

Next, the present invention will be described in more detail with reference to the illustrated embodiment. In the first embodiment shown in FIGS. 1 to 5, a precast concrete beam 1 having a cross shape is shown. The concrete beam 2 is joined by the lower main bar 2a, the concrete of the joined portion is broken, and this missing portion 2b forms the joined end portion 2d of the beam 2c.

The lower main bar 2a is, as shown in FIG.
The main bars of several rows (four in the embodiment) are arranged to join the mutual beams 2c. A lower main bar 2a is projected at a predetermined length from one end of the precast concrete beam 2, and a stir bar 2e is projectingly formed on the upper surface thereof.

The other precast concrete beams 3 orthogonal to the precast concrete 2 are independent of each other, and the lower main reinforcement 3 is provided at the joint end 3b thereof.
a is projected, and the lower main bar 3b is bent and formed in an L shape. The lower main bar 3b is also provided with several main bars (three in the embodiment) in a row to secure a predetermined fixing length. In addition, on the upper surface of the precast concrete beam 3, there are formed streaks 3c in the same manner as described above.

Then, the joint end portion 2d of the precast concrete beam 2 thus formed is erected on the column head 4 as shown in FIG. 1 so that the lower main bar 2a is arranged at an accurate position in the column 4a. Position to be streaked.

Next, this precast concrete beam 2
After the positioning is performed, the joint ends 3b of the independent precast concrete beams 3 that are orthogonal to each other are placed on the column heads 4 so as to face each other, while maintaining this state. At this time, as shown in FIG. 4, the lower main bars 3a are overlapped with each other and arranged to intersect with the upper parts of the lower main bars 2a of the precast concrete beam 2. Then, the upper end reinforcements 5 and 6 of both of these precast concrete beams 2 and 3 are respectively arranged through the lower main reinforcements 2a and 3a.

In this case, also at the free ends of the precast concrete beams installed adjacent to each other, the respective lower main reinforcements are connected to each other, and the upper reinforcements 5 and 6 are also extended and arranged in the same manner.

After assembling the required formwork, a half precast concrete floor slab (not shown) is erected on the precast concrete beams 2 and 3, and the precast concrete beams 2 and 3 on and above the pillar head 4 are installed. The precast concrete beams 2 and 3 are fixed by placing concrete at the joints. This fixing method is suitable for building a building with a relatively small amount of rebar.

The second embodiment shown in FIGS. 6 to 8 is
The lower main bar 3a of the independent precast concrete beam 3 is arranged in two steps, and the joint end 3b is formed in a U-shaped cross section.

Also in this embodiment, one of the precast concrete beams 2 is joined by the lower main bar 2a, the concrete at the joint is broken, and the missing portion 2b is formed by the beam 2
The point forming the joint end 2d of c and the other precast concrete beam 3 orthogonal to the precast concrete beam 2 are independent of each other, and the lower main bar 3a is projectingly provided at the joint end 3b, The lower main bar 3a
Is substantially the same as that of the first embodiment in that it is bent into an L shape.

Then, the U-shaped groove 3d of the joint end portion 3b of the independent precast concrete beams 3 placed facing each other.
A plurality of rows (three in the embodiment) of the upper main reinforcements 3e are arranged to form a two-stage reinforcement, and the upper end reinforcement 6 of the precast concrete beam 3 is arranged in two stages. Next, half precast concrete floor slab (not shown)
And the concrete is placed on the joint and the joint portion of the precast concrete beam 3. This fixing method is suitable for building a building in which the amount of reinforcing bars is extremely large or small.

In addition, the third embodiment shown in FIGS. 9 to 11 has a first main bar 2a in which the lower main bar 2a of the precast concrete beam 2, which is the opposite of that of the second embodiment, is two bar.
It is a mixed type of stepped bar, and the opposing joint ends 2d of the defective portion 2b are formed in a U-shaped cross section.

This embodiment also has basically the same configuration as the second embodiment, and after the independent precast concrete beams 3 which are orthogonal to each other are placed opposite to each other, the precast concrete beams 2 are A plurality of rows (four in the embodiment) of the upper main reinforcements 2g are arranged over the U-shaped groove 2f of the joining end portion 2d to form a two-stage reinforcement, and the upper end reinforcement 3e of the precast concrete beam 3 is formed in two stages. Arrange the muscles. Next, a half precast concrete floor slab (not shown) is erected, and concrete is placed on the slab and the joint portion of the precast concrete beam 2. This is also suitable for constructing a building in which the amount of reinforcing bars is extremely large or small as in the second embodiment.

Furthermore, in the fourth embodiment shown in FIGS. 12 to 14, the two precast concrete beams 2, 3 intersecting each other are crossed.
Is a type in which the lower main bars 2a, 3a of the
The opposing joint ends 2d and 3b are formed in a U-shaped cross section.

Also in this embodiment, the construction is basically the same as that of the second and third embodiments, and the joining end portion 2d of the precast concrete beam 2 having the cutout portion 2b is connected to the column head 4. Then, the joint ends 3b of the independent precast concrete beams 3 which are orthogonal to each other are placed on the column head 4 so as to face each other, and the lower main bars 2a and 3a are cross-arranged.

Then, in the precast concrete beam 2 having the cutout portion 2b, several upper main bars 2 (4 in the embodiment) are arranged in a row over the U-shaped groove 2f of the joint end 2d.
g is reinforced to form a two-stage reinforcement, and U of the joint end 3b in the independent precast concrete beams 3 orthogonal to each other is used.
Several lines in a row across the groove 3d (three in the embodiment)
After reinforcing the upper main bar 3e of the above to form a two-stage bar, the upper end bars 2g of both precast concrete beams 2 and 3
3e is arranged in two stages. Next, a half precast concrete floor slab (not shown) is erected, and concrete is placed on the slab and the joint portion of the precast concrete beam 3. This is suitable for constructing a high-rise reinforced concrete building with an extremely large amount of rebar.

[0023]

EFFECTS OF THE INVENTION The joint end of a precast concrete beam, which is connected by a lower main bar and in which the concrete of the connecting part is missing, is placed on the head of a column to arrange the lower main bar in the column and After placing the joint ends of separate precast concrete beams with protruding main bars facing the heads of the columns, further precast concrete beams intersecting with each other are further reinforced to add concrete to the intersections. Precast concrete of the type where the amount of reinforcing bars is not extremely large or small, that is, the one-stage reinforcing bar and the two-stage reinforcing bar, and the mixture of the one-stage reinforcing bar and the two-stage reinforcing bar. It can easily support the fixing of beams and can eliminate unnecessary reinforcing bars depending on the individual building,
The construction cost can be reduced.

By making the opposing joint ends of the independent precast concrete beam U-shaped in cross section, the lower main reinforcement of this precast concrete beam can be made into a two-stage reinforcement.

By making the opposing joint ends of the defect portion of the precast concrete beam having a defect have a U-shaped cross section, the lower main reinforcement of this precast concrete beam can be a two-stage reinforcement.

The opposing joint ends of the independent precast concrete beams and the opposing joint ends at the defect portion of the precast concrete beam having a defect portion are each U-shaped in cross section, so that The lower main bar may have a two-stage bar arrangement.

[Brief description of drawings]

FIG. 1 is a plan view showing a state in which a precast concrete beam of a first embodiment is installed on a head of a column.

FIG. 2 is a perspective view of the embodiment shown in FIG. 1;

FIG. 3 is a perspective view before a precast concrete beam is installed on a pillar head.

FIG. 4 is a perspective view after a precast concrete beam is installed on a column head.

FIG. 5 is a sectional view of a joint portion of the first embodiment.

FIG. 6 is a perspective view before the precast concrete beam of the second embodiment is installed on the pillar head.

FIG. 7 is a perspective view after the precast concrete beam of the second embodiment is installed on the pillar head.

FIG. 8 is a sectional view of a joint portion of a second embodiment.

FIG. 9 is a perspective view before the precast concrete beam of the third embodiment is installed on the pillar head.

FIG. 10 is a perspective view after the precast concrete beam of the third embodiment is installed on the pillar head.

FIG. 11 is a sectional view of a joint portion of a third embodiment.

FIG. 12 is a perspective view before the precast concrete beam of the fourth embodiment is installed on the pillar head.

FIG. 13 is a perspective view after the precast concrete beam of the fourth embodiment is installed on the pillar head.

FIG. 14 is a sectional view of a joint portion of a fourth embodiment.

FIG. 15 is a cross-sectional view showing a method of fixing a conventional precast concrete beam.

[Explanation of symbols]

 1 Cross-shaped precast concrete beam 2 Precast concrete beam 2a, 3a Lower main bar 2d, 3b Joint end 3 Independent precast concrete beam 4 Column head

Claims (4)

[Claims] 1. A precast concrete beam that crosses in a cross shape at a column head, wherein the joint end portion of the precast concrete beam that is connected by a lower main bar and has the concrete of the connecting portion missing is placed on the column head and the lower part is formed. After arranging the main reinforcement in the column, after placing the joint end of the independent precast concrete beam with the lower main reinforcement projecting on the column head, another main reinforcement is added to these precast concrete beams intersecting with each other. A method for joining precast concrete beams, comprising arranging and placing concrete at the intersection. 2. The method of joining precast concrete beams according to claim 1, wherein the opposing joint ends of the independent precast concrete beams are U-shaped in cross section. 3. The method for joining precast concrete beams according to claim 1, wherein opposing joint ends of the precast concrete beams having the defect portions have U-shaped cross sections. 4. The opposing joint ends of the independent precast concrete beam and the opposing joint ends of the defect portion of the precast concrete beam having a defect portion are U-shaped in cross section, respectively. Item 2. A method for joining precast concrete beams according to Item 1.