JP2682929B2 - Precast products - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates to precast products suitable for synthesis with cast-in-place concrete.

[0002]

2. Description of the Related Art When a precast concrete product is used for a structure, it may be a hollow member in order to reduce the weight or to combine it with cast-in-place concrete.

For example, as shown in FIGS. 4 and 5, in the case of a building column member, a hollow precast concrete 1 and a reinforcing bar 2 are formed by centrifugal force or a vibration driving method.
A column member consisting of and is built and used as a formwork at the site, and a cast-in-place concrete 4 is placed in the hollow part 3 of the precast concrete 1 to form a composite column made of the precast concrete 1 and the cast-in-place concrete 4. can do.

[0004]

[Problems to be Solved by the Invention]
It depends on whether the integrity of the precast concrete 1 and the cast-in-place concrete 4 cast in the hollow portion 3 can be secured.

For example, when the column member is subjected to a combined action of shearing force and bending moment as axial force, due to the adhesion breakage between the precast concrete 1 and the cast-in-place concrete 4 and the difference in the physical properties, the joint surfaces of both concretes are If the integration is insufficient, vertical cracks 5 may occur in the precast concrete 1 not only in the lateral direction but also in the axial direction, and the progress may cause loss of the synthetic effect.

The present invention has been made in view of the above points, and an object thereof is to prevent the adherence between the cast-in-place concrete and the precast concrete and the deterioration of the integrity due to the difference in the physical properties of both concretes. is there.

[0007]

DISCLOSURE OF THE INVENTION The present invention is a precast product having precast concrete in which a hollow portion for forming cast-in-place concrete is formed. The shape is free, such as a circular shape or a rectangular shape, the outer peripheral side of which is embedded in the precast concrete, and the inner peripheral side of the perforated iron plate projects into the hollow portion.

[0008]

According to the present invention, the perforated iron plate acts as a rib for connecting the precast concrete and the cast-in-place concrete cast in the hollow portion over the entire circumference, whereby shearing force can be transmitted, and Prevents vertical cracking of members.

[0009]

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

In FIG. 1 and FIG. 2, a precast concrete 11 is centrifugally molded using a formwork having a rectangular cross section to form a hollow portion 12 for casting concrete in the center of the precast concrete 11. Rectangular precast columns are shown.

In the precast concrete 11, an outer peripheral side of a perforated iron plate 13 formed in a rectangular shape is embedded in advance,
The inner peripheral side of the perforated iron plate 13 has a hollow portion 12 in order to join the cast-in-place concrete that is placed in the hollow portion 12.
It is projected to.

Although not shown, the perforated iron plate 13 is arranged in the axial direction at a predetermined embedding pitch. The embedded pitch of the iron plate in the axial direction depends on the design, but the standard is about 20 cm to 100 cm. The thickness of the iron plate 13 is about 2 mm to 15 mm, though it depends on the design.

The perforated iron plate 13 is entirely covered with an insertion hole 15 for inserting a shaft bar 14 such as a reinforcing bar or a high-strength steel material (PC steel material) and a concrete through hole 16 for connecting concrete on both sides of the iron plate. A large number of holes 17 are provided in the central portion, and a large hole 17 that functions as a through hole for driving the concrete pouring pipe during the production of the precast member and driving the cast-in-place concrete to the bottom is provided.
However, when the outer dimension of the perforated iron plate 13 is designed to be inside the axial reinforcement 14, the insertion hole 15 may not always be necessary.

The through hole 15 of the axial reinforcement 14 is formed with a diameter of about 5 mm to 30 mm, and the concrete through hole 16 is formed with a diameter of about 20 mm to 50 mm. Although these holes are formed in a circular shape, holes such as an oval shape and a square shape may be punched out.

As an example of the dimensions related to the iron plate 13, the thickness of the iron plate 13 is 6 mm, the diameter of the shaft insertion hole 15 is 13 mm, the diameter of the concrete through hole 16 is 30 mm to 40 mm, and the concrete of the outer peripheral portion of the iron plate is Fog is 10 mm, the axial iron plate burying pitch is 70
cm.

Then, the axial muscle inserted into the insertion hole 15
The concrete connected through the holes 14 and the holes 16 secures the axial integrity of the precast member, and the axial reinforcement 14 and the concrete connected in the holes also resist the shearing force. Further, since the perforated iron plate 13 connects the precast concrete 11 and the cast-in-place concrete cast in the hollow portion 12 over the entire circumference, the rib action of the perforated iron plate 13 can prevent the above-mentioned vertical cracking.

FIG. 3 shows a modified example of the perforated iron plate, which is a disk-shaped perforated iron plate 13a corresponding to the case where the precast concrete column is cylindrical. In addition, the same reference numerals are given to the portions corresponding to the square perforated iron plate 13, and the description thereof will be omitted.

The shape of the holes 16 and 17 is not limited to a circular shape, but may be a square shape.

[0019]

According to the present invention, the perforated iron plate can ensure the integrity of the joint surface between the precast concrete and the cast-in-place concrete, and the rib action of the entire iron plate can prevent longitudinal cracks in the axial direction, and its progress. It is possible to prevent a decrease in shear strength by preventing the above.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of a perforated iron plate obtained by breaking the precast product of the present invention.

FIG. 2 is a horizontal sectional view of the above precast product.

FIG. 3 is a perspective view showing a modified example of a perforated iron plate according to the present invention.

FIG. 4 is a front view of a precast and cast-in-place concrete composite column.

5 is a cross-sectional view taken along the line VV of FIG. 4 for explaining the problems of the conventional composite column.

[Explanation of symbols]

 11 Precast concrete 12 Hollow part 13 Perforated iron plate 16, 17 holes

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takehiko Maruyama 1-8-3 Shimbashi, Minato-ku, Tokyo Within Nippon Concrete Industry Co., Ltd. No. 55 Konoike Gumi Co., Ltd. (72) Inventor Yoshitaka Hosokawa No. 1-10 Koraibashi, Chuo-ku, Osaka City, Osaka Prefecture Geotop Co., Ltd.

Claims (1)

(57) [Claims] 1. In a precast product in which a hollow portion for precast concrete is formed in precast concrete, the outer peripheral side of a perforated iron plate having a large number of holes for passing concrete is embedded in the precast concrete, A precast product, wherein an inner peripheral side of a perforated iron plate is projected into the hollow portion.