JPH05202574A - Precast concrete hollow column body - Google Patents

Abstract

PURPOSE:To increase connection efficiency of the later place concrete by forming the circumferential surface of each of comer sections of a precast concrete square cylindrical column body having the hollow inside obtained by a centrifugal molding machine in an uneven shape, and increasing the surface area of the circumferential surface. CONSTITUTION:A precast concrete square cylindrical column body 1 having the hollow inside is forum by a centrifugal molding machine. The surface area of the circumferential surface of each of comer sections 8 in the space 7 is increased, and a cross sectional area of the later placed concrete is increased. For that purpose, when main reinforcing bars 9 and a lateral tie 10 are set in a form of a centrifugal molding machine, fillers capable of deformation are arranged to the corner sections 8 to rotate the form, and concrete is placed to form the circumferential surface of each of the corner sections 8 in an uneven shape in accordance with the shape of each of the fillers. According to the above constitution, connection efficiency of the later placed concrete is increased, and a column construction having sufficient strength can obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hollow columnar body made of precast concrete suitable for being applied to a column in a building structure such as a building.

[0002]

2. Description of the Related Art In the construction of columns in a reinforced concrete structure, some main reinforcements (vertical reinforcements) are dispersed along the vertical direction at the construction site of the column at the conventional site, and
This is done by arranging the hoop reinforcements (bellows reinforcements) on the peripheral surface of this main reinforcement, then assembling the formwork around it, placing concrete in the formwork, and removing the formwork after hardening of the concrete. Was there. However, when this construction method is used, it takes a lot of time and labor to install and remove the formwork in the field, and it cannot be said that it is the best method in the present situation where the building tends to become higher and higher. There is.

Therefore, in a factory, a column body made of precast concrete having a hollow interior is manufactured by a centrifugal molding technique of concrete, transported to the site and set at a construction site, and the column made of the precast concrete is manufactured. A method of constructing a composite column by placing concrete in the internal space using the body as a column structural member has been considered.

[0004]

[Problems to be Solved by the Invention] When attempting to construct a column using a precast concrete hollow column body, the inside is inevitably cylindrical due to centrifugal force application. However, there is a problem that the bondability with post-cast concrete deteriorates. That is, FIG. 5 is a cross-sectional view of the hollow columnar body produced by the conventional centrifugal molding method, but the inner peripheral surface 21 of the hollow columnar body 20 is
Is formed into a cylindrical shape by centrifugal force and has an extremely small surface area. In addition, 22 in FIG. 5 is a main bar arranged in the main body of the hollow columnar body 20 made of precast concrete,
3 indicates a hoop muscle, and these main muscles 22 and hoop muscles 2
3 has a structure that partially protrudes into the internal space 24 of the hollow columnar body 20 in order to enhance the bondability with the post-cast concrete. The precast concrete hollow columnar having such a structure is disclosed in Japanese Patent Application No. 61-61
No. 278221, the inner surface of the hollow columnar body 20 is affected by centrifugal force and becomes a cylindrical shape even when it is contacted with post-cast concrete. Since the area is small, as described above, there is a problem that the jointability with the post-cast concrete is poor.

In view of this, the present invention increases the surface area of at least the inner peripheral surface of each corner portion of a prismatic cylindrical columnar body made of precast concrete having a hollow interior obtained by a centrifugal molding method, and jumps in the jointability with post-cast concrete. It is an object of the present invention to provide a hollow pillar body made of precast concrete that is improved in height.

[0006]

Means for Solving the Problems To elaborate the constitution of the present invention for achieving the above-mentioned object, a precast concrete prismatic columnar body having a hollow interior obtained by centrifugal molding is used. Of the hollow columnar body made of precast concrete, characterized in that at least the inner peripheral surface of each corner portion is formed in a concavo-convex shape to increase the surface area of the inner peripheral surface of the corner portion to improve the bondability with the post-cast concrete.

According to the precast concrete hollow columnar body of the present invention, the surface area of the inner peripheral surface of each corner portion is increased by the unevenness, and the contact area with the post-cast concrete is much more than in the case of the ordinary cylindrical shape. Therefore, it is possible to obtain a composite pillar structure made of precast concrete having sufficient strength and improved jointability with post-cast concrete. In addition, in the main body of the precast concrete rectangular cylindrical columnar body, a reinforcing bar composed of a main bar and a hoop bar was reinforced, and as shown in FIG. 5, a part of the bar was projected into the internal space of the columnar body. When the present invention is applied to a structure, a better effect can be obtained.

[0008]

EXAMPLES The concrete structure of the precast concrete hollow pillar of the present invention will be described in detail below with reference to the examples shown in the drawings. FIG. 1 is a front view showing an embodiment of the precast concrete hollow columnar body of the present invention, FIG. 2 is a sectional view taken along the line BB of FIG. 1, and FIG. 3 is a concavo-convex inner peripheral surface of the corner portion of the hollow columnar body. FIG. 4 is a partially enlarged explanatory view showing an example of a method for forming a precast concrete, and FIG. 4 is a schematic view showing an example of a method for manufacturing a precast concrete hollow columnar body by centrifugal molding.

In the figure, reference numeral 1 denotes a column body made of precast concrete having a hollow inside, and the column body 1 can be manufactured by using a centrifugal molding machine as shown in FIG. 4, for example. That is, a rotating body 6 having a mold frame 5 set therein is arranged on the upper surface of a rotating tire 3 which is rotationally driven by a prime mover 2 and a rotatable tire 4 which faces the rotating tire 3, and the rotating body 6 is arranged. When concrete is poured into the mold 5 from the open end of the rotating body 6 while rotating, the concrete is tightly adhered to the inner wall of the mold 5 by centrifugal force,
A columnar body 1 having a rectangular tube shape with a hollow interior is obtained by curing as it is. In FIG. 2, 7 indicates the internal space of the pillar 1,
In the conventional case, the internal space 7 has a cylindrical shape with the smallest surface area as shown in FIG. 5 due to the action of centrifugal force as described above.

According to the present invention, the inner peripheral surface of each corner portion 8 in the internal space 7 of the columnar body 1 obtained by such centrifugal molding is formed into a complicated uneven shape so that the surface area of the inner peripheral surface of the corner portion 8 is increased. The cross-sectional area of post-cast concrete is increased. In addition, 9 in FIG. 2 is a main bar arranged in the vertical direction in the main body of the precast concrete forming the columnar body, and 10 is a hoop bar arranged around the main bar 9. In order to form the inner peripheral surface of the corner portion 8 of the columnar body 1 in a concavo-convex shape, when the reinforcing bar composed of the main bar 9 and the hoop bar 10 is set in the mold 5 in the centrifugal molding machine, foam is formed in each corner part 8. This is performed by arranging a filling 11 that can be easily deformed by applying an external force such as polyurethane along the longitudinal direction and rotating the mold 5. That is, after setting the main reinforcement 9 and the hoop reinforcement 10 in the form 5, the elongated filler 11 is made to run along the main reinforcement 9 located in each corner 8 as shown in FIG. It is pressure-bonded by the scale-shaped pressing plate 12 and tightened by, for example, a binding thin wire 13.
Then, the filling material 11 is pressed by the restraining plate 12 and is in a state of protruding to the outside of the main bar 9 in a curved shape. In this state, while rotating the rotating body 6 on which the formwork 5 is set, when concrete is poured from the open end of the rotating body 6, the concrete is brought into close contact with the inner wall of the formwork 5 by the centrifugal force and each corner portion is In Fig. 8, since the filler 11 protrudes in a curved shape to the outside of the main bar 9 as described above, the flow of the concrete is obstructed, and this portion becomes uneven along the shape of the filler 11. is there.

The mold 5 set in the rotating body 6 of the centrifugal molding machine can be exchanged. If a hexagonal or octagonal mold other than the square shown in the drawing is used, a desired polygonal shape can be obtained. The column body 1 is obtained. As described above, according to the hollow columnar body of precast concrete of the present invention, the internal space 7 of the columnar body 1 does not become cylindrical as shown in FIG. 2 even by centrifugal molding, and each corner portion 8 is outside the main bar 9. Since the surface area of the inner circumference of the column 1 is significantly increased as compared with the case of the cylinder, the cross-sectional area of the post-cast concrete is also increased by that amount. It will grow. Further, as shown in FIG. 2, since each corner portion 8 of the column 1 is formed in an uneven shape, the main bar 9 and the hoop muscle 1 located at the corner part 8 are formed.
0 is also partially exposed at the corner portion 8 and the effect of combining with the post-cast concrete is further improved.

Next, an example of constructing a column using the precast concrete hollow column of the present invention will be described.
The pillar body 1 is lifted by a lifting means such as a crane at a construction site of the pillar on the construction site. In addition, a plurality of preliminarily main reinforcing bars are projected on the floor slab where the pillars are constructed, and the main reinforcing bars 9 projecting to the lower part of the suspended pillar 1 and the main reinforcing bars on the floor slab are wrapped. As a result, the reinforcing rods of the columns on the lower floor and the columns on the upper floor will eventually be connected. Then, when concrete is poured into the inner space 7 of the pillar 1 from above, the concrete is partially exposed in the inner space 7.
In addition to closely adhering to the circumference of the hoop and the hoop streak 10, it enters into a space having a complicated uneven shape at each corner portion 8 and joins with the main body made of precast concrete to be integrated.

[0013]

According to the present invention, as described above, the inner peripheral surface area of the rectangular cylindrical columnar body obtained by centrifugal molding, in particular, the inner peripheral surface area of each corner portion is set to be smaller than that of the conventional precast concrete hollow columnar body. Can be dramatically increased,
As the contact area with the post-cast concrete increases, the bondability with the post-cast concrete becomes better, and all of the main bars of the column are involved in the post-cast concrete, providing a column structure with sufficient strength. Is something that can be done.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of a precast concrete hollow columnar body of the present invention.

FIG. 2 is a cross-sectional view taken along the line BB of FIG.

FIG. 3 is a partially enlarged explanatory view showing an example of a method of forming the inner peripheral surface of the corner portion of the columnar body in a concavo-convex shape.

FIG. 4 is a schematic view showing an example of a method for manufacturing a precast concrete hollow columnar body by centrifugal molding.

FIG. 5 is a cross-sectional view showing an example of a conventional precast concrete hollow columnar body.

[Explanation of symbols]

 1: Pillar 2: Motor 3: Rotating tire 4: Tire 5: Formwork 6: Rotating body 7: Inner space 8: Corner part 9: Main bar 10: Hoop bar 11: Filler 12: Suppressor plate 13: Binding thin wire

Claims (1)

[Claims] 1. In a rectangular cylindrical columnar body made of precast concrete having a hollow interior obtained by centrifugal molding, the inner peripheral surface of each corner portion of the columnar body is formed in an uneven shape so that the surface area of the inner peripheral surface of the corner portion is increased. A hollow pillar made of precast concrete characterized by increasing the number.