JPH073098B2 - Synthetic slab using precast PC version - Google Patents

Description

TECHNICAL FIELD The present invention relates to a synthetic slab in which a precast plate made of precast concrete (hereinafter referred to as a precast PC plate) is lined up and a cast-in-place concrete layer is integrated thereon. .

(Prior Art) Conventionally, in this type of synthetic slab, as shown in FIG.
Precast slabs made of concrete 2,2 ... with a plurality of ridges 1,1 integrally formed on the upper surface are arranged side by side and bridged between the beams, and reinforcing bars 3 for coupling are projected on the upper surface of the precast slab 2. There is known a synthetic slab in which a precast plate 2 and a cast-in-place concrete layer 4 are integrated by embedding a cast-in-place concrete layer 4 therein. (Japanese Patent Publication Sho 54-249
(Gazette No. 8) This type of synthetic slab uses a press-cast plate that has a convex strip integrally provided on the upper surface, so the entire pre-cast plate becomes bulky, and a high yield strength is obtained, and a long span is obtained. It has the advantage that things are easy to build.

Further, in this type of precast plate, as shown in FIG. 5, the PC steel wire 5 is inserted into the ridge 1 of the precast plate 2 to give a prestress in the longitudinal direction to reduce the thickness and increase the yield strength. It is known that it has a clear appearance. (Japanese Patent Publication No. 63-25144) (Problems to be solved by the invention) In the synthetic slab using the conventional precast plate as described above, the prestress imparted to the precast plate is the formwork of the precast plate. When placing cast-in-place concrete on the upper surface while also using
Only the prestress necessary to make a long span is applied, and in order to reduce the overall thickness and weight of the slab, another prestress is applied to the entire slab that is a combination of the precast plate and cast-in-place concrete. There was a problem that there was still a lot of field work to be done.

In view of such conventional problems, the present invention eliminates the need for prestressing work at the site, and achieves the same weight reduction and high yield strength as when prestressing was applied to the entire synthesized slab. The purpose is to provide synthetic slabs.

(Means for Achieving the Object) The feature of the present invention for achieving the above-mentioned object is that a plurality of ridges are integrally provided on the upper surface in the longitudinal direction, and a thin PC steel material is provided near the bottom surface. Is arranged in the longitudinal direction, and a large diameter is placed at a height position that divides the cross-sectional area into upper and lower parts.
A precast PC plate on which PC steel is placed is laid between the beams, and a concrete layer is cast on the PC plate integrally to form a synthetic slab. Press cast PC that gives necessary pre-stress to the entire slab composed of concrete.
It exists in a synthetic slab that uses a plate.

(Operation) This synthetic slab gives the precast PC plate the necessary prestress to the entire slab after synthesis, so it is possible to construct the slab without any support during construction.
Moreover, since the whole is a PC structure, a light and strong slab can be obtained, and a hollow portion can be provided to further reduce the weight.

In addition, since the precast PC plate has a large diameter PC steel material inserted at approximately the center height position and a small diameter PC steel material inserted near the bottom surface, the precast PC plate itself has a small central lift. PC steel with a large diameter is provided below the center height of the entire slab after cast-in-place concrete, and counteracts the vertical downward force after construction.

(Example) Next, an example of implementation of the present invention will be described with reference to Figs.

In the figure, 10 is a precast PC plate used in the present invention. In this PC plate 10, a plurality of ridges 10b are integrally projected on the upper surface of a flat plate portion 10a having a flat bottom surface, and auxiliary reinforcing bars 11 and 12 are embedded in the flat plate portion 10a and the ridges 10b. On the upper surface of the ridge 10b, a connecting reinforcing bar 13 integrated with the reinforcing reinforcing bars 11 and 12 is projected in a hoop shape.

In this PC plate 10, a large-diameter PC steel material 14 is embedded inside each of the ridges 10b at a height position that divides the cross-sectional area into upper and lower parts, and the required concrete fogging can be obtained from the bottom surface. A large number of small-diameter PC steel materials 15 are arranged and arranged in the planographic portion at the height position. Then, prestress is given by the upper and lower PC steel materials. Then, the large diameter PC steel material 14 is tensioned so as to give a prestress of a strength necessary to counter the external force applied to the entire synthetic slab after the cast-in-place concrete layer 16 to be described later is placed,
In addition, the PC steel material 15 with a small diameter gives the prestress of the strength to obtain the lift force to face the curvature due to the gravity when the PC plate itself is erected and the cast-in-place concrete layer 16 is placed on the upper surface. I'm nervous to do it.

The synthetic slab of this example is a PC version configured in this way.
10 are arranged side by side between the beams, reinforcing reinforcing bars 17 are arranged on the upper surface, and a cast-in-place concrete layer 16 is cast.

This cast-in-place concrete layer 16 is a PC as shown in FIG.
It may also be integrally formed in the groove 10c between the ridges 10b, 10b of the plate 10, and the groove 10c may be hollow as shown in FIG. Alternatively, a lightweight filler such as a synthetic resin foam material may be packed and placed. These cast-in-place concrete layers 16 are connected to the reinforcing steel bars 17 inside and the connecting steel bars 13 on the upper surface of the ridge, and by embedding them, they are integrated with the PC plate 10 to form a synthetic slab.

Further, in this embodiment, as shown in FIG. 3, a recess 18 for erection is provided on the lower surface of the end of the PC plate 10 so that the bottom surface is lower than the upper surface of the beam 19. Does not have to be according to the design.

(Effect of the invention) As described above, the synthetic slab using the precast PC plate of the present invention imparts the prestress necessary to counter the vertical downward external force applied to the entire synthetic slab at the substantially central height position of the PC plate. A large-diameter PC steel material is placed near the bottom surface, and a small-diameter PC steel material is added near the bottom surface to provide the prestress necessary to obtain the lifting force to face the deflection caused by the slab's own weight. Therefore, a long-span slab can be constructed without the need for supporting work, and a tough, lightweight synthetic slab can be constructed without prestressing after cast-in-place concrete layers. By arranging a large diameter PC steel material in the approximate center position of the PC plate, it becomes possible to give a large prestress against the downward external force required for the entire synthetic slab at the factory in advance. The field work has been significantly simplified.

[Brief description of drawings]

1 and 2 are cross-sectional views of different embodiments of the synthetic slab according to the present invention, and FIG. 3 is a precast PC used in the present invention.
FIG. 4 is a vertical sectional side view of an example of a plate, and FIGS. 4 and 5 are sectional views of different conventional examples. 10 …… PC plate, 10a …… Plate part, 10b …… Convex line, 10c …… Concave groove, 11,12,17 …… Reinforcing rebar, 13 …… Connecting rebar, 14 ……
Large-diameter PC steel material, 15 …… Narrow-diameter PC steel material, 16 …… Spot-cast concrete layer.

Claims (1)

[Claims] 1. A plurality of ridges are integrally formed on the upper surface in the longitudinal direction, a small-diameter PC steel material is arranged in the vicinity of the bottom surface in the longitudinal direction, and the cross-sectional area is divided into upper and lower parts substantially evenly. A precast PC plate with a large diameter PC steel material placed at a height position is laid between the beams, and a cast concrete layer is integrally formed on the PC plate to form a synthetic slab, and the PC plate is used. A synthetic slab that uses a precast PC plate in which the necessary prestress is given in advance to the entire slab that was synthesized with cast-in-place concrete using the large diameter PC steel material.