JPH07113261A - Construction of reinforced concrete structure by use of heat-precast beam - Google Patents

Abstract

PURPOSE:To reduce dangerous works in high positions to make the works safe and construct efficiently a structure in a short time and improve the quality thereof, in construction of a reinforced concrete structure by use of half-precast beams. CONSTITUTION:One way of a half-precast beam A is made so that beam reinforcements 6 are buried in a precast concrete 5 in the state that the upper end of stirrups 9 and the upper main reinforcements 7 of beam are exposed at the upper side. Before the half-precast beam A is hung down, the pre- assembled body 10 of beam reinforcements for the beam crossing in right angles and the hoops 16 at the joint of beam and column are assembled in advance in the state that they are supported by the beam reinforce ments 6 of the half- precast beam A. And then the half-precast beam A is hung down on a column B and the arrangement work of reinforcements at the column and beam is completed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for constructing a reinforced concrete structure using a half precast beam.

[0002]

2. Description of the Related Art In the case of constructing a reinforced concrete structure using a half precast beam, conventionally, as shown in FIG. 10, a half precast beam A in which a beam lower end main bar 8 and a stirrup 9 are embedded in a precast concrete 5.
Was manufactured at a factory or site (work site on the premises), and after hanging this half-precast beam A on the column B, the hoop reinforcement 16 of the column / beam connection part, the main reinforcement of the orthogonal direction beam were on-site. The anchor portions 11 and 12 were reinforced, and the beam upper end main reinforcement 7 of the half precast beam A was reinforced.

Therefore, although the beam material is half-precast to reduce the on-site work, a lot of dangerous work at high places remains, and the work at high places is caused by the pillar / beam joint section. Since many pillar main bars 3 are forested and the surroundings are constrained by precast concrete 5, it is a troublesome bar arrangement work, so the construction efficiency is poor and it is difficult to secure the bar arrangement accuracy. There was also a problem in terms of quality.

[0004]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above situation, and an object thereof is to construct a reinforced concrete structure using a half precast beam. An object of the present invention is to provide a construction method that can be performed safely by reducing work in place, can be efficiently constructed in a short time, and can improve construction quality.

[0005]

The technical means taken by the present invention to achieve the above object are as follows. That is, the method for constructing a reinforced concrete structure using a half precast beam of the present invention is a beam rebar having a beam top main rebar, a beam bottom main rebar and a stirrup precast concrete, and a stirrup upper end side and a beam top rebar precast. Create a unidirectional half precast beam that is buried in an exposed state on the top of concrete, and hang it around the main beam anchor part of the orthogonal direction beam and its extension part and the extension part before suspending this half precast beam. The beam reinforcement front assembly for orthogonal beams with the stirrup and the hoop reinforcement of the column / beam joint are assembled in a state of being supported by the beam reinforcement of the half-precast beam, and after that, The half precast beam is suspended on a pillar.

[0006]

According to the above configuration, in constructing a reinforced concrete structure using a half precast beam, a complex rebar group of a beam top main bar and a pillar / beam joint of the half precast beam is previously assembled. Since it is integrated with the half-precast beam, simply by hanging the half-precast beam on the column with a lifting machine, the reinforcement of the column / beam connection is completed.

[0007]

EXAMPLES FIGS. 1 to 3 show a state in which a reinforced concrete structure using a half precast beam A is being constructed.
B is a reinforced concrete pillar, which is composed of cast-in-place concrete concrete 1 and built-in pillar reinforcement 2, and pillar reinforcement 2 is composed of a large number of main pillar reinforcements 3 and hoop reinforcements 4 wound around and fixed to them. Has been done. The column bars 2 are assembled in advance at a factory or site, but may be assembled locally.

Reference numeral 5 is a precast concrete of the half precast beam A, 6 is a beam reinforcing bar embedded in the precast concrete 5, and a beam top main bar 7 having a two-step bar arrangement and a beam bottom main bar 8 having a two-step bar bar 8 , Stirrup 9 and the like. Of the beam reinforcing bars 6, the upper end side of the stirrup 9 and the upper beam upper end main bar 7 which is fixed to the stirrup 9 by being tied together with wire or the like are exposed above the precast concrete 5, and the second upper beam end bar 7 And beam bottom main bar 8
Project from the end face of the precast concrete 5 in the beam longitudinal direction.

Reference numeral 10 is a beam reinforcing bar front assembly for orthogonal beams. This beam reinforcement front assembly 10 is a half precast beam A.
Main beam anchor portions 11 and 12 and their extension portions 13 and 14 orthogonal to the beam upper end reinforcement 7 and the beam lower end reinforcement 8 and the stirrup 15 wound around and fixed to the upper and lower extension portions 13 and 14.
And abdominal muscles and width stop muscles (not shown). Reference numeral 16 denotes a hoop streak of the column / beam joint, which is arranged in a plurality of stages (five in the illustrated embodiment) at appropriate intervals in the vertical direction.

In this embodiment, the column main reinforcement 3, the beam upper main reinforcement 7 of the half precast beam A, the beam lower main reinforcement 8, the main reinforcement anchor portions 11 and 12 of the beam reinforcement front assembly 10 and the extension portion 1 are used.
As 3 and 14, threaded joint reinforcing bars (deformed reinforcing bars in which ribs are spirally formed to increase the adhesive force with concrete) are used. Reference numeral 17 is a main joint metal fitting constituted by a long nut 17a and a lock nut 17b. In addition, in this embodiment, the main bar anchor portions 11 and 12 and the extension parts 13 and 14 of the beam reinforcing bar front assembly 10 are formed by bending a single threaded joint bar into a substantially U-shape at the center. The main reinforcement anchor portions 11 and 12 are configured by a substantially U-shaped bent portion and a horizontal reinforcing bar portion (upper and lower threaded bar reinforcing bars located inside the column / beam joint portion) in the vicinity thereof. ing.

A method of constructing a reinforced concrete structure reaching the states shown in FIGS. 1 to 3 will be described. First, at a factory or a site, as shown in FIGS. 4 to 6, a beam upper end main bar 7, a beam lower end main bar 8 and a star. A unidirectional half-precast beam A in which the beam reinforcing bar 6 provided with the wrap 9 is embedded in the precast concrete 5 with the upper end side of the star wrap 9 and the beam upper end main bar 7 exposed above the precast concrete 5 is produced. .

Both the upper ends of the beams 7 are stirrup 9 before the concrete is cast into the precast concrete 5.
The beam top main bar 7 located above the upper surface of the precast concrete 5 is fixed to the stirrup 9 with the binding line. Good. The lock nut 17b or both the lock nut 17b and the long nut 17a are screwed to both ends of the beam upper end main bar 7 and the beam lower end main bar 8 at appropriate times.

In this embodiment, since the beams crossing in a T-shape are targeted, the pair of precast concrete 5 and 5 are opposed to each other with a gap corresponding to the column / beam joints. The beam upper end main bar 7 and the beam lower end main bar 8 are arranged as one continuous piece over the precast concrete 5 and 5 on both sides.

After the above half precast beam A is produced, before suspending the half precast beam A, a grid-like ruler (not shown) or the like for indicating the position of the column main bar 3 is used on the ground. By the bar arrangement work, the hoop reinforcements 16 of the column / beam joints and the beam reinforcement front assembly 10 for the orthogonal beams are connected to the beam reinforcement of the half precast beam A (the beam upper end located between the precast concretes 5 and 5). Main bars 7 and beam bottom main bars 8)
Arrange the muscles so that they are supported by 6.

Specifically, the main reinforcement anchor portions 11 and 12 of the beam reinforcement front assembly 10 for the orthogonal beam are connected to the beam upper end reinforcement 7.
It is also fixed to the beam bottom main bar 8 by binding it with a wire or the like. As for the hoop reinforcement 16 of the column / beam connection, the uppermost hoop reinforcement 16 is used for the beam top main reinforcement 7 of the half precast beam A.
Reinforcing bar for vertical suspension, which is fixed to the hoop muscle 16 by bundling and fixing it to the hoop muscle 16 and fixing
In addition, the hoop muscles 16 of the second stage and below are bound and fixed with a wire or the like.

On the other hand, at the upper end of each pillar main bar 3, as shown in FIG. 7, a cylindrical shaft portion 18a and a sharpened portion 18b provided at the upper end thereof.
The guide jig 18 composed of and is fitted from above at an appropriate time.

Then, as shown in FIGS. 8 and 9, the half precast beam A is suspended on the pillar B using a lifting machine such as a crane. As described above, the half-precast beam A is pre-assembled with the hoop reinforcement 16 of the column / beam joint and the reinforcing bar preassembly 10 for the orthogonal beam, so that the half-precast beam A is placed on the pillar B. Simply hang it up, and the bar / beam connection will be completed. Therefore, dangerous high-place work is reduced, safe and efficient construction can be done in a short time, and all the complicated bar arrangements of the column / beam joints are performed on the ground, ensuring the bar arrangement accuracy. It is easy and the construction quality can be improved.

In particular, in this embodiment, since the sharp guide jigs 18 are fitted on the upper ends of the respective column main bars 3, the intervals between the upper ends of the column main bars 3 and the upper ends of the column main bars 3 are orthogonal to each other. Even if the positional relationship between the reinforced beam front assembly 10 for the directional beam and the hoop reinforcement 16 of the column / beam joint is slightly different, when the half precast beam A descends, the hoop reinforcement 16 and the main reinforcement anchor portion 11,
12 is guided by the sharpened portion 18b of the guide jig 18, and the rebar group of the column / beam joint can be smoothly inserted onto the main group 3 of the column.

After that, as shown in FIG. 9, the guide jig 18 is pulled out upward. After that, as before, construct a reinforced concrete structure through the steps of assembling the form around the column / beam joints, erection of the half precast floor boards for the half precast beam A, and in-situ casting of concrete. become.

In the above embodiments, the present invention has been described for a beam that intersects in a T shape, but the present invention is also applied to a beam that intersects in a cross shape and a beam that intersects in an L shape. It is possible. When a beam crossing in a cross shape is targeted, the main bar anchor portion 1 in the reinforcing bar front assembly 10 for the orthogonal beam
1 and 12 are composed of upper and lower horizontal reinforcing bars located in the column / beam joints. When targeting a beam intersecting in an L-shape, the portions of the beam upper end reinforcement 7 and the beam lower end reinforcement 8 of the half precast beam A protruding from the end surface of the precast concrete 5 are the reinforcing bar front assembly for orthogonal beams. Similar to the shape of the main bar anchor portions 11 and 12 in 10, the structure is formed by bending into a substantially U shape.

[0021]

According to the present invention, which has the above-described structure, since the beam upper main reinforcement of the half precast beam and the complicated reinforcing bar group of the column / beam joint are preassembled to the half precast beam, the lifting machine is used. By simply suspending the half-precast beam on the column, the bar / column connection will be completed. Therefore, when constructing a reinforced concrete structure using half-precast beams, dangerous high-place work can be reduced, and it can be constructed safely and efficiently in a short time, and complicated bar arrangement of columns and beams Since it is performed on the ground, it is easy to ensure the accuracy of the bar arrangement, and the construction quality is improved.

[Brief description of drawings]

FIG. 1 is a front view showing a state where a reinforced concrete structure using a half precast beam is being constructed.

FIG. 2 is a vertical sectional side view of a main part.

FIG. 3 is a plan view of a main part.

FIG. 4 is a perspective view showing a state in which a beam pre-assembly of a beam for orthogonal beams and a hoop bar of a column / beam joint are assembled in advance on a half precast beam.

FIG. 5 is a plan view showing a state in which a beam pre-assembly of a beam for orthogonal beams and a hoop bar of a column / beam joint are assembled in advance on a half precast beam.

FIG. 6 is a vertical cross-sectional side view of a main part showing a state in which a beam rebar preassembly for orthogonal beams and a hoop reinforcement of a column / beam joint are preassembled to a half precast beam.

FIG. 7 is a partially cutaway perspective view of a guide jig.

FIG. 8 is a front view illustrating a construction method.

FIG. 9 is a front view illustrating a construction method.

FIG. 10 is an explanatory diagram of a conventional example.

[Explanation of symbols]

A ... Half precast beam, B ... Column, 5 ... Precast concrete, 6 ... Beam rebar, 7 ... Beam top main bar, 8 ... Beam bottom main bar, 9 ... Star wrap, 10 ... Beam rebar tip assembly for orthogonal beam, 11,12 ... Main anchors, 13,14 ...
Extensions, 15 ... Star wrap, 16 ... Hoop streaks for column / beam connections.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akira Kaku 4-1-1, Honmachi, Chuo-ku, Osaka City Takenaka Corporation Osaka Main Store (72) Inventor Tetsuo Watanabe 4-1-1, Honmachi, Chuo-ku, Osaka No. 13 Stock Company Takenaka Corporation Osaka Main Store (72) Inventor Ryuta Murakami 4-1-1 Hommachi, Chuo-ku, Osaka City Stock Company Takenaka Corporation Osaka Main Store

Claims (1)

[Claims] 1. A unidirectional embedding method in which a beam reinforcing bar having a beam upper end bar, a beam lower end bar and a stirrup is embedded in precast concrete, and the upper end side of the stirrup and the beam upper end bar are exposed above the precast concrete. A half precast beam for a cross beam is provided with a main bar anchor part of the cross beam and its extension and a stirrup wrapped around the extension before suspending the half precast beam. The front assembly and the hoop reinforcement of the column / beam joint are assembled in a state of being supported by the beam reinforcement of the half precast beam, and then the half precast beam is suspended on the column. Construction method of reinforced concrete structure using half precast beams.