JPH0334532B2 - - Google Patents

Description

Detailed Description of the Invention "Field of Industrial Application" The present invention is directed to the use of small beams made of precast concrete in structures such as reinforced concrete structures, steel reinforced concrete structures, and structures made by prefabricated construction methods. Concerning construction methods for constructing beams.

"Conventional technology" This type of conventional construction method uses solid precast concrete beams with main reinforcements, stirrup reinforcements, etc. buried, and joints that protrude at predetermined positions midway through the sides of the large concrete beams. After the plates and the joint plates protruding from the end faces of the small beams are joined and welded together using joints (bolts, nuts, etc.), a formwork is constructed around the joint and concrete is poured. was.

``Problems that the invention seeks to solve'' However, according to this, there were the following problems.

(1) Solid precast concrete beams are used to complete the small beams at the same time as the construction of the main beams, so there is no need to form the small beams themselves on site, but the small beams and slabs can be assembled on site. Because it cannot be integrated with poured concrete, special construction methods are required to join the beams and slabs, which not only requires advanced technology, but also costs more materials than pouring on-site.

(2) Because the small beams are solid and heavy, transporting them,
The structure, etc. is not easy to handle.

(3) Because the small beams are molded with the main reinforcing bars buried, they cannot be cut to an appropriate length on site and many different lengths must be prepared. , the cost will be high.

(4) Since the main beam and the small beam are joined using a joining plate and a joining tool, the cost of materials is high and the work requires advanced technology.

(5) Since it is necessary to partially cover the joint with concrete, a partial formwork must be made at the intersection of the major beam and the minor beam, making the formwork work and its dismantling extremely troublesome. In addition to this, concrete pouring must be done carefully, which requires a lot of effort and time.

The present invention aims to solve these problems.

"Means for Solving the Problems" The present invention is a small beam material that has a U-shaped cross section and has a concave groove formed over its entire length, without burying the main reinforcing bars.
Using precast concrete beams with only stirrup reinforcements buried, a recess for a joint and a horizontal hole are formed in advance at a predetermined position midway on the side of the main beam, and the end face of the small beam is aligned with the recess for a joint. , Arrange the main reinforcement in the concave groove of the small beam material, and place the joint reinforcement that connects to the main reinforcement in the horizontal hole, and then insert the inside of these grooves and the horizontal hole, the joint recess, and the small beam. It is characterized by pouring concrete between the end faces of the timber.

"Example" Examples of the present invention will be described in detail below based on the drawings.

In Figures 1 and 2, the girder 1 is made of precast concrete integrally formed with the wall 2, and the H-shaped steel 3
is buried. At a predetermined midway position of this large beam 1, a rectangular joint recess 5 for joining the small beam material 4 is formed on both sides thereof, and an oblong rectangular horizontal hole penetrating both sides thereof. 6 is formed. Each recess 5 extends from the upper end of the main beam 1 to the middle of the lower end, and forms a step 7 at the lower end.
The inner surface of the recess 5 is a rough surface with unevenness. The horizontal hole 6 opens slightly above the step 7.

The small beam material 4 is also made of precast concrete and is formed into a U-shaped cross section, and has a large number of stirrup reinforcements 9 buried along the inner peripheral surface of the groove 8, but no main reinforcement. The upper frame portions of the stirrup bars 9 protrude from both upper surfaces of the small beam members 4.

The small beam material 4 is constructed between two adjacent parallel large beams 1 in the following manner.

First, a plurality of upper main reinforcements 10 were held inside the upper frame part of the arranged stirrup muscles 9 using a wire or the like, and a plurality of lower main reinforcements 11 were inserted into the grooves 8. After that, the small beam material 4 is suspended using a crane or the like using the synthetic resin belt 12 and the wire 12'.
It is placed on retractable support legs 13 that are erected on the slab on the floor immediately below, as shown in FIGS. 3 and 4. In this state, the end face of the small beam 4 is aligned with the recess 5 of the main beam 1. At this time, in order to adjust the frame of the small beam 4, the end surface of the small beam 4 is not brought into close contact with the recess 5, nor is it placed on the step 7, so that an appropriate gap is formed between it and the recess 5. It is desirable to have it in a state where it is possible.

When the main beam 1 and the small beam members 4 are in such a relationship, the concave grooves 8 of the two small beam members 4 installed in series on both sides of the main beam 1 communicate with each other via the horizontal holes 6,
Further, the upper surface of the main beam 1 and the upper surfaces of both sides of the small beam members 4 are located on substantially the same horizontal plane.

Next, as shown in FIGS. 5 to 7, conventionally known thin precast concrete plates 14 for slabs are installed between the parallel small beams 4, and then they are placed in series across the girders 1 as shown in FIG. The upper main reinforcements 10 of the small beams 4 are connected to each other by the upper joint reinforcements 15, and the lower main reinforcements 1
1 are connected to each other by lower joint reinforcements 16 passing through the horizontal holes 6 of the main beams 1, and upper joint reinforcements 17 of the truss plates 14 on both sides of the small beam members 4 are connected to each other by upper joint reinforcements 17, as shown in FIG. 18, and a lower joint bar 19 between the upper surfaces of the truss plates 14 on both sides.
Set up. For example, it is sufficient to temporarily connect the reinforcing bars by wrapping wire around them.

After this, inside the concave groove 8 of the small beam material 4, the horizontal hole 6 of the main beam 1
Concrete is poured between the end face of the small beam 4 and the recess 5 and on the thin precast concrete plate 14, and the upper and lower main reinforcements 10, 11 and the upper frame part of the stirrup reinforcement 9 are buried in the concrete 20. At the same time, the upper end reinforcements 17 and lattice reinforcements 21 of the thin precast concrete plate 14 are buried in the concrete 20 to construct a slab.

In the above embodiment, the girder 1 and the wall 2 are made of integral precast concrete, but they may be cast in the field as one piece as shown in Fig. 10, or they may be made of small-sized concrete as shown in Fig. 11. When using a girder 24 made of precast concrete that has the same structure as the beam 4, that is, a U-shaped cross section and a large number of stirrup bars 23 embedded along the inner peripheral surface of the groove 22, the groove 22 is formed. A recess 5 for a joint is provided on the outer surface of the side wall, and a horizontal hole 6 is formed therethrough, and a small beam material 4 is constructed in the recess 5 in the same manner as above, and the main reinforcement 11 and joint reinforcement 16 are installed. After arranging reinforcement in the same manner as described above, concrete is poured into the groove 22 to construct the girder at the same time as the girder and the slab, and the wall 2 may be cast separately on site. In addition, in the above embodiment, the case where the small beam members 4 are constructed on both sides of the large beam 1 is assumed, but when only one side is constructed, the upper and lower joint bars 15, 1
6 should be prevented from protruding to the other side of the girder 1. In this case, the joint recess 5 is formed only on one side of the girder 1.

"Effects of the Invention" As mentioned above, the present invention has the following effects.

Because the beams can be constructed simultaneously with the slab and integrally with it using cast-in-place concrete,
Slab construction work is significantly simpler than before, and material costs are also lower.

Because the beams are hollow and lightweight, they are easy to transport,
The structure is easy to handle.

The stirrup bars are buried in the small beams, but the main bars are not, so the small beams can be cut to any desired length on site.
Therefore, there is no need to prepare a large number of different lengths as in the past, which is economical.

Align the end faces of the small beams with the joint recesses of the girders, place main reinforcements in the grooves of the small beams, and place joint reinforcements that connect to the main reinforcements in the horizontal holes of the girders. Because the small beams can be constructed by pouring concrete, the material costs are lower and the work is easier compared to the conventional construction method in which the large beams and small beams are joined using joining plates and fittings. It's easy.

When concrete is filled into the concave groove of the small beam, concrete is also filled between the horizontal hole of the large beam, its joint recess, and the end face of the small beam, so that the large beam and the small beam are filled with concrete. This eliminates the need for complex form work, its dismantling work, and concrete pouring work as in the past, making it possible to significantly shorten the construction period and reduce construction costs compared to the past.

[Brief explanation of drawings]

Figures 1 to 9 show an embodiment of the present invention according to the construction procedure; Figures 1, 3, 5, and 7 are perspective views;
4 and 6 are sectional views, FIGS. 8 and 9 are enlarged sectional views, and FIGS. 10 and 11 are sectional views of main parts showing other embodiments. 1... girder, 5... recess for joint, 6... horizontal hole,
4...Small beam material, 8...Concave groove, 9...Starlap reinforcement, 10, 11...Upper and lower main reinforcement, 15, 16...Joint reinforcement.

Claims (1)

[Claims] 1 A small precast concrete beam with a U-shaped cross section and a stirrup reinforcement is formed by forming a joint recess and a horizontal hole at a predetermined position midway on the side of a large beam made of precast concrete or cast-in-place concrete. Align the end face with the concave part for the joint, arrange the main reinforcement in the concave groove of the small beam material, and arrange the joint reinforcement connected to this main reinforcement in the horizontal hole,
Thereafter, concrete is poured inside the groove and the horizontal hole and between the concave part for the joint and the end face of the beam material.