JP2853528B2 - Construction method of composite floorboard - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for constructing a composite floorboard constructed as a floor having a large span or a large load.

[0002]

2. Description of the Related Art As one of the conventional synthetic floorboards, a post-cast reinforced concrete (hereinafter abbreviated as a post-cast concrete) is provided on a precast reinforced concrete slab (hereinafter abbreviated as a precast slab), and both are integrated to form a floor slab. There are forms that perform a function. Many of these precast floorboards have a pretension type prestress introduced therein, and are used as a structural material and also as a formwork when casting post-cast concrete.

[0003]

When a composite floor slab of the type described above is used as a large span floor or a floor having a large load, it is natural to increase the thickness of the precast floor slab or the thickness of the post-cast concrete. It is necessary to take one of the measures to increase the cost, which not only increases the cost,
Occasionally, this type of composite floorboard will not be sufficient.

[0004]

SUMMARY OF THE INVENTION The present invention provides a method for constructing a composite floorboard which does not need to have a large thickness even on a floor with a large span or a large load. The purpose of the present invention is to increase the load-bearing capacity of the composite floorboard by introducing a pre-stress by a post-tension method.

That is, according to the present invention, a precast reinforced concrete slab having a large number of diagonal concave portions on its side is laid with a gap therebetween, a formwork for closing the gap is provided below the gap, and unbonded PC steel is provided in the gap. After laying wires, arrange reinforcing steel for post-cast concrete on the upper surface of the precast reinforced concrete floor plate, cast post-cast concrete on the gap and the upper surface of the precast reinforced concrete floor plate, and tension the unbonded PC steel wire after hardening of the concrete. A method of constructing a synthetic floorboard, characterized by introducing prestress.

In order to introduce prestress into the composite floorboard constructed according to the present invention by the post-tension method,
It is necessary to wire an unbonded PC steel wire to the post-cast concrete part in advance, but if this wiring site is the upper surface of the precast floorboard, the force is transmitted only to the post-cast concrete when the prestress is introduced. Therefore, it is hardly transmitted to the precast floorboard. In order to avoid this, when laying the precast floorboard, do not lay it closely but lay it with an appropriate gap, wire an unbonded PC steel wire in this gap, and place the post-cast concrete with this gap and the precast floorboard. If a pre-stress is introduced by tensioning the unbonded PC steel wire after being cast into a T-shaped section on the upper surface, the force is not only transmitted to the post-cast concrete, but also
It will also be transmitted to the precast floorboard via the side of the precast floorboard. As a result, prestress is introduced into the entire composite floorboard.

[0007] When the precast floorboard is laid, the precast floorboard in a portion where the unbonded PC steel wire is not wired is closely laid as before.

The unbonded PC steel wire is wired so as to protrude downward into the gap between the precast floorboards. When prestressing is introduced by tensioning the unbonded PC steel wire, an oblique upward force is applied to the post-cast concrete in the gap. The shear force acts on the joint surface between the post-cast concrete and the side surface of the precast floorboard. In order to resist this shearing force, it is necessary to provide recesses such as cotters and grooves on the side surfaces of the precast floorboard. Shearing is hindered by the post-cast concrete placed in the recess, and the prestress is sufficiently transmitted to the precast floorboard. Of course, it is preferable that the direction of the recess provided is a direction substantially orthogonal to the shearing force. The concave portion may be provided on the entire surface (from the upper end to the lower end) of the side surface of the precast floor plate. In order to resist the shearing force, the shape of the side surface of the precast floorboard is preferably such that the gap on the upper surface side is narrower than the gap on the lower surface side when laid, and the shape of the side surface is large. Therefore, a precast floor plate having a shape in which the outer edge of the groove is inclined inward in a normal groove type precast floor plate is preferably used.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

FIG. 1 shows an example of a composite floorboard constructed according to the present invention. FIG. 1 (a) is a plan view, FIG. 1 (b) is a view taken along the line AA in FIG. 1 (a), and FIG. FIG. 3D is a view taken in the direction of an arrow B, and FIG.

FIG. 2 shows an example of a side surface of the precast floorboard 1 used in the present invention. (A) is a longitudinal sectional view of a cotter provided, (b) is a front view of a cotter provided, (c) is a vertical cross-sectional view of a structure in which lattice-shaped grooves are provided diagonally. In each case, the concave portion is provided obliquely and has a symmetrical shape with the center in the longitudinal direction of the precast floor plate 1 as a symmetric axis. This figure shows a symmetrical shape, but it is not always necessary to be symmetrical.

Five precast floorboards 1 are placed and laid on beams 5 with a gap 2 therebetween. Formwork 9 is installed under each of the four gaps 2. The formwork 9 is an iron plate or a plastic plate. The upper end of the reinforcing bar 8 is bent and fixed to the precast floor plate 1, and the lower end thereof is bent through a hole formed in the formwork 9 to be suspended by the plurality of reinforcing bars 8 and the gap 2. It is fixed so as to cover the lower part.

Two unbonded PC steel wires 3 are wired in the four gaps 2.

Reinforcing concrete reinforcing bars 7 are arranged on the upper surface of the precast floor plate 1, and the after-cast concrete 6 is cast on the gap 2 and the upper surface of the precast floor plate 1. After the concrete 6 is hardened, the unbonded PC steel wire 3 is tensioned, and its fixed end (not shown) is fixed to the post-cast concrete 6 to introduce prestress.

In this example, two unbonded PC steel wires are shown. However, it is a matter of course that one or three unbonded PC steel wires may be used.

[0016]

According to the present invention, prestress is introduced into the entire composite floorboard composed of the precast floorboard and the post-cast concrete, so that the precast floorboard or the post-cast concrete can be used even for a large span floor or a floor having a large load. Even if the thickness is not so large, it is possible to sufficiently cope with the problem and to reduce the cost.

[Brief description of the drawings]

FIG. 1 shows an example of a composite floorboard constructed in the present invention,
(A) is a plan view, (b) is an AA view of (a),
(C) is an BB arrow view of (a), (d) is an enlarged vertical cross-sectional view of the gap.

FIG. 2 shows an example of a side portion of a precast floorboard 1 used in the present invention, in which (a) is a longitudinal sectional view of a cotter provided, (b) is a front view of a cotter provided,
(C) is a vertical cross-sectional view of a diagonally provided lattice-like groove,
(D) is a front view of the one provided with the lattice-like grooves obliquely.

[Explanation of symbols]

1: Precast floor plate, 2: gap, 3: unbonded PC
Steel wire, 4 ... pillar, 5 ... beam, 6 ... post-cast concrete,
7 ... reinforcement bar, 8 ... rebar, 9 ... formwork, 10 ... cotter, 1
1 ... groove.

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int.Cl. ⁶ , DB name) E04B 5/38 E04B 5/02 E04B 5/43 E04G 21/12

Claims (1)

(57) [Claims] 1. A precast reinforced concrete slab having a large number of diagonal recesses on its side is laid with a gap therebetween, a formwork for closing the gap is provided below the gap, and an unbonded PC steel wire is wired in the gap. At the same time, reinforcing steel for post-cast concrete is laid on the upper surface of the precast reinforced concrete floor plate, post-cast concrete is poured into the gap and the upper surface of the precast reinforced concrete floor plate, and after the concrete is hardened, the unbonded PC steel wire is tensioned to introduce prestress. A method of constructing a composite floorboard, comprising: