JPS6118623B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a precast concrete slab equipped with a three-dimensional truss, which is used to form a composite slab, a composite exterior wall, etc. by strongly bonding and integrating with cast-in-place concrete.

In recent years, in construction work, with the aim of saving labor and shortening the construction period, the so-called Omnia version construction method is used, in which Omnia version is used as a formwork and concrete is poured on-site to construct composite slabs, synthetic external walls, etc. that have the necessary strength as a structure. is being carried out.

This Omnia version is the first three-dimensional truss that is buried on one side of the precast concrete version in order to ensure the cross-sectional performance of the version in a semi-finished state and to connect it with cast-in-place concrete when constructing composite slabs. It uses the Omnia muscle shown in the figure and the Kaiser muscle shown in Figure 2, and has excellent strength characteristics.

However, Omnia bars and Kaiser bars both have one upper chord member a and two lower chord members b made of reinforcing bars.
The diagonal members c are made by connecting the gaps with reinforcing bars bent into an approximately inverted V shape or zigzag shape, and are joined using welding methods such as spot welding and flashback welding, and are very expensive. This is the key to adopting the Omnia version construction method.

Therefore, the present invention has developed an economically efficient three-dimensional truss that does not use Omnia bars or Kaiser bars, saves material costs by combining steel plates and reinforcing bars, and has the same advantages as the Omnia version. The purpose is to provide a precast concrete slab, which is made by bending a truss-shaped expanded metal so that the cross-sectional shape in the longitudinal direction is approximately an inverted V shape, and reinforcing bars placed at the bent part and inside it. The three-dimensional truss is characterized by being buried with the lower chord located in the middle of the precast concrete slab in the thickness direction, and the upper chord protruding from one side.

Embodiments of the present invention will be described below based on the drawings.

FIG. 3 shows a three-dimensional truss A, FIG. 4 shows its cross-sectional shape, and FIG. 5 shows a precast concrete version B equipped with this three-dimensional truss A.

The space truss A described above is manufactured as follows.

In other words, as shown in FIG.
... are inserted in a staggered manner, and the strip-shaped iron plate 1 is stretched in a direction orthogonal to the slits 2, as shown in FIG. 6B, to produce a planar expanded metal 3 exhibiting a truss shape.

Next, this expanded metal 3 is rolled or pressed to correct the distortion caused by stretching, and the straight plate part a' in the center, which becomes the upper chord material a, and the straight lines on both sides, which become the lower chord material b... plate part
A substantially U-shaped groove 4 is formed over the entire length of each of the diagonal members c, and a substantially U-shaped groove 5 is also formed in the plate portion c' which becomes the diagonal member c.

Next, the expanded metal 3 is bent from the center into a substantially inverted V-shape, and the deformed reinforcing bar 6 is placed inside this bent part, that is, in the groove 4 of the central straight plate part a', and is inserted from the outside. They are held together with a suitable jig, and both a' and 6 are crimped and integrated.

Then, a plurality of three-dimensional trusses A manufactured in this way are arranged parallel to each other, and the lower chord members b... are located at the middle part in the thickness direction of the precast concrete version B, and the upper chord members a are located in the middle part of the precast concrete version B. It is constructed as a precast concrete slab B with a three-dimensional truss A, which is buried so as to protrude from one side of the slab B. In the figure, 7 is the meshwork muscle.

FIG. 7 shows another embodiment, in which a plate portion is formed by discontinuing the bent portion of the expanded metal 3 in the longitudinal direction.
a'' and are connected via deformed reinforcing bars 6.Other configurations are the same as in the previous embodiment.

Figures 8A and 8B show another embodiment, in which a strip iron plate 1
It is characterized by the use of a truss-shaped expanded metal 3 made by inserting four slits 2 in a staggered manner and stretching them in a direction perpendicular to the slits 2.

In each of these examples, distortion caused by stretching is corrected by roll processing, press processing, etc., and grooves are formed to increase rigidity, but these steps are omitted. It is also possible.

The present invention has the above-mentioned configuration, uses expanded metal that has a truss shape instead of expensive Omnia bars and Kaiser bars as a three-dimensional truss, and also uses a large tensile force when hoisting it with a lifting machine. The upper chord of a three-dimensional truss, which is sometimes subject to a large compressive force due to its own weight or the weight of cast-in-place concrete, has a composite structure in which reinforcing bars and expanded metal are integrated, so the steel plate used for the expanded metal is made as thin as possible. However, while reducing material costs, sufficient strength can be obtained, and it is possible to manufacture lightweight and inexpensively.

In addition, since expanded metal is used, the contact area with concrete is large, and high adhesion strength can be expected.

In particular, when deformed reinforcing bars are used as reinforcing bars and are integrated with expanded metal by crimping, no welding work is required, which facilitates factory processing and further reduces costs.

[Brief explanation of the drawing]

1 and 2 show a conventional example, FIG. 1 is a perspective view of Omnia muscle, FIG. 2 is a perspective view of Kaiser muscle, and FIGS. 3 to 5 show an embodiment of the present invention, Fig. 3 is a perspective view of the three-dimensional truss, Fig. 4 is a vertical sectional view thereof, Fig. 5 is a sectional view of a precast concrete plate equipped with the above-mentioned three-dimensional truss, Fig. 6 A and B are process diagrams of the manufacturing method, FIG. 7 is a perspective view of a space truss showing another embodiment, and FIGS. 8A and 8B are process diagrams of a manufacturing method showing another embodiment. a... Upper chord member, b... Lower chord member, c... Diagonal member, 3
...expanded metal, 6...(unshaped) reinforcing bar,
A... Three-dimensional truss, B... Precast concrete version.

Claims (1)

[Scope of Claims] 1. A three-dimensional object formed by bending an expanded metal exhibiting a truss shape so that its cross-sectional shape in the longitudinal direction becomes approximately an inverted V-shape, and integrating the bent portion with reinforcing bars placed inside the bent portion. A precast concrete slab equipped with a three-dimensional truss in which a truss is buried with its lower chord located in the middle in the thickness direction of the precast concrete slab and its upper chord protruding from one side. 2. A precast concrete slab equipped with a three-dimensional truss according to claim 1, wherein the reinforcing bars are deformed reinforcing bars, and are integrated with the bent portions by crimping.