JP2810272B2 - Precast products - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a precast product used for a pillar or the like.

[0002]

2. Description of the Related Art As shown in FIGS. 4 and 5, a conventional precast product has a shaft 12 and a band 13 disposed in a precast concrete 11, and both ends of the shaft 12 are fixed to end fittings 14. As shown in FIG. Have been. The precast concrete 11 is compacted by a centrifugal force manufacturing method, and a hollow portion 15
Are formed.

[0003] Even when this centrifugal precast product is intended to be used as a column member subjected to a large shearing force, there are many cases where sufficient shear reinforcement cannot be performed due to the restriction in the production method of the concrete wall thickness. At best, the ligament
Only 13 are arranged. In addition, it is also difficult to arrange reinforcement in the hollow portion 15.

[0004]

As described above, since the shear reinforcement cannot be sufficiently performed, the centrifugal precast column or the composite precast column in which cast-in-place concrete is cast in the hollow portion thereof is subjected to a large shearing force. In this case, there are disadvantages such as insufficient shear load capacity or reduced shear toughness.

[0005] The present invention has been made in view of such a point, and an object of the present invention is to increase the shear load resistance of a precast product.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a centrifugally molded
In a precast product in which shafts and stirrups are provided in hollow precast concrete, and both ends of the shafts are fixed to end face metal fittings, the precast concrete includes, in the precast concrete, one end face metal fitting to another end face metal fitting.
On four sides along the stirrup , the shear reinforcing bars are respectively arranged in an X-shape, and these X-shaped shears are attached to one end and the other end bracket.
This is a precast product in which both ends of the shear reinforcement are fixed respectively .

[0007]

According to the present invention, a centrifugally formed hollow precast is provided.
For the shear force acting on the products, precast concrete
The four ends along the stirrup in the
The X-shaped shear reinforcing bars fixed to the surface fittings respectively function as tension bars or compression bars, and exhibit shear load-carrying capacity.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the embodiments shown in FIGS.

FIG. 1 is a perspective view of a centrifugal precast column, in which a shaft bar 12 and a band bar 13 combined with the shaft bar 12 are disposed inside a precast concrete 11 compacted to a hollow by centrifugal force. ing. Both ends of the shaft 12 are fixed to end fittings 14 provided on the upper end surface and the lower end surface of the precast concrete 11.

[0010] Further, as a shear reinforcement reinforcing member that bears a shearing force together with the stirrups 13 and the like, end fittings 14 at the upper ends of the pillars inside the respective stirrups 13 along the plane portions (four side surfaces) of the prismatic precast concrete 11. A bar-shaped shear reinforcing bar 21 or a plate-shaped shear reinforcing bar 22 is disposed in an X-shape over an end fitting 14 at the lower end of the column from above, and the upper and lower ends of the shear reinforcing bars 21 and 22 are respectively attached to the upper and lower end fittings 14. Has been established.
Although there are four sets of the X-shaped shear reinforcing bars, only two sets are shown in FIG. 1 for convenience.

To fix the rod-shaped reinforcing bars 21 to the end metal fittings 14, a screw 23 formed at the end of the rod-shaped reinforcing bars 21 is inserted into a small hole of the end metal fitting 14, as shown in FIG. Nut 25 screwed into the screw portion 23 via a sloping base 24 for
The screw is fixed by tightening.

The fixing of the plate-like reinforcing bars 22 to the end face fittings 14 is performed by directly welding to the end face fittings 14, or by welding the plate-shaped reinforcing streaks 22 into elongated holes provided in the end face fittings. The end of the plate-like reinforcing bar 22 protruding through the elongated hole 26 of the end surface fitting 14 is button-head-processed to form a projection 27 as shown in FIG.
And fix it.

As shown in FIG. 1, the rod-shaped shear reinforcement 21 or the plate-shaped shear reinforcement 22 may be used in combination with one precast product, or all four sets may be the same. Is also good.

With such a structure, when a shearing force acts on the precast concrete 11, the stirrups 13 resist the shearing force, and the shear reinforcing bars 21, 22 obliquely arranged in an X-shape form the tensile bars. Or, it resists the shearing force as a compression streak and exerts the shear load-bearing capacity. This arrangement of the X-shaped shear reinforcing bars is an effective reinforcing means particularly when used as a short pillar portion.

A large opening 28 is provided at the center of the end face metal fitting 14, and cast-in-place concrete is poured into the hollow portion of the centrifugally formed precast concrete 11 from this opening 28 at the construction site to be synthesized with the precast concrete 11. Therefore, even if the X-shaped shear reinforcing bars 21 and 22 are arranged on the side near the hollow portion of the precast concrete 11,
In some cases, the effect does not change even if it is exposed in the hollow portion.

Although a prism is illustrated in the embodiment, a similar X-shaped shear reinforcing bar may be used for a cylinder.

[0017]

According to the present invention, in the precast concrete, the shear reinforcing bars are arranged and fixed in an X-shape from one end face metal fitting to the other end face metal fitting, so that the X-shaped shear reinforcing steel is precast. It functions as a tension bar or a compression bar against the shearing force acting on the concrete, and has the effect of greatly improving the shear load bearing capacity. In particular,
X-shaped shearing on four sides along the stirrups in strike concrete
Reinforcing bars are provided, each of which has one end and
Centrifugally molded
Despite being a hollow precast product,
With sufficient shear load capacity against shear force acting from
Wear.

[Brief description of the drawings]

FIG. 1 is a perspective view showing one embodiment of a precast product of the present invention.

FIG. 2 is a front view showing an example of fixing of bar-shaped shear reinforcing bars in the precast product.

FIG. 3 is a cross-sectional view showing an example of fixing plate-shaped shear reinforcing bars in the precast product.

FIG. 4 is a perspective view showing a conventional precast product.

FIG. 5 is a sectional view of a conventional precast product.

[Explanation of symbols]

 11 Precast concrete 12 Axial bar 13 Strip bar 14 End bracket 21, 22 Shear reinforcing bar

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takehiko Maruyama 1-3-8 Shimbashi, Minato-ku, Tokyo Inside Concrete Industry Co., Ltd. (72) Inventor Teruo Matsutani 4-chome, Denho 4-chome, Konohana-ku, Osaka-shi, Osaka No. 55 Konoike Gumi Co., Ltd. (72) Inventor Yoshitaka Hosokawa 2-1-1, Komyobashi, Chuo-ku, Osaka City, Osaka Prefecture Geotop Co., Ltd. (56) References JP-A-1-105816 (JP, A) 63-94224 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) E04C 3/34 E04C 5/06

Claims (1)

(57) [Claims] 1. A precast product in which a shaft and a band are disposed in a hollow precast concrete formed by centrifugal molding, and both ends of the shaft are fixed to end fittings. X-shaped shear reinforcing bars are respectively provided on four sides along the stirrups from the metal fitting to the end face metal fitting at the other end, and one end and the other end are provided.
A precast product, characterized in that both ends of these X-shaped shear reinforcing bars are fixed to a surface fitting .