JPH0650010B2 - Precast version - Google Patents

Description

TECHNICAL FIELD The present invention relates to a precast floor slab that forms a floor slab by placing concrete on the upper part of the floor slab.

[Prior Art] As a floor slab generally known in the past, there is a floor slab whose lower part is made of a precast plate (hereinafter abbreviated as PC version) and whose upper part is made of cast concrete. Such a floor slab is usually constructed by the following method. That is, a method of manufacturing a PC plate near a factory or a construction site, setting the manufactured PC plate in a floor slab building position, then using the set PC plate as a driving form, and placing concrete on the upper part thereof. Is.

[Problems to be Solved by the Invention] By the way, the floor slab construction method as described above has an advantage that there is no need to perform the work of retracting the formwork, labor saving, and shortening of the construction period. Since the joint strength between the PC plate and the upper concrete to be post-cast is weak, the method of reinforcing this part remains an unsolved problem. Further, by increasing the out-of-plane rigidity of the PC plate in the method of constructing the floor slab, it is possible to reduce the amount of supporting work for supporting the PC plate by that amount, and it is expected that further labor saving and shortening of the construction period can be expected. . For this reason, in the floor slab construction method, it has been desired to increase the out-of-plane rigidity of the PC plate.

The present invention has been made in view of the above circumstances, and it is possible to increase the bonding strength between a PC plate and an upper concrete to be post-cast, and to increase the out-of-plane rigidity of the PC plate without increasing the weight thereof. It is an object of the present invention to provide a PC plate which can reduce supporting work for support and can further save labor and shorten the construction period.

Further, compared to the prior art, the PC at the time of construction can be increased in rigidity and the bending of the slab can be reduced or prevented.
Versions can be provided.

[Means for Solving the Problem] The gist of the present invention is to provide a flat portion and a rib portion provided so as to project on the upper surface of the flat portion, and to provide a flat portion and an upper portion of the rib portion in an erected state. A precast plate for constructing a floor slab by placing concrete, wherein the rib portion has a grid shape in a plan view, and inside the flat portion, a tension member is parallel to the rib portion. It exists in the precast version, which is characterized by being provided as follows.

[Operation] The rib portion increases the surface area of the upper surface of the PC plate. Therefore, the bonding strength with the post-cast concrete can be increased.

Since the tension material provided in the flat portion bears tensile stress,
The out-of-plane rigidity of the PC plate can be increased. As a result, P
It is possible to reduce the support work for supporting the C plate.

Since the tension material can increase the out-of-plane rigidity of the PC plate,
It is possible to reduce or prevent the downward bending of the slab as compared with the related art.

[Embodiment] An embodiment of the present invention will be described below with reference to FIG. FIG. 1 shows a PC version according to this embodiment. However,
Unless otherwise specified, the shapes of the components described in this embodiment, their relative arrangements, and the like are not intended to limit the scope of the present invention to them, but merely illustrative examples. Absent.

In the PC plate 21 shown in this figure, a rib portion 23 projecting like a base is provided above the flat portion 22, and a sheath tube 24 into which a tension material is inserted is embedded in the flat portion 22 in the shape of a base. It has a structure.

2 and 3 show an example in which the floor slab is arranged so as to be bridged between the beams H ₂ of the S structure. In this example, the H-shaped steel 31 is arranged in advance in the portion to be the beam H _2, and the PC plate 32 is arranged above the H-shaped steel 31 so as to straddle them. At this time, since the PC plate 32 has high rigidity, it is not necessary to support the intermediate portion of the PC plate 32 with a support or the like.

4 to 6 show an example in which the floor slab is arranged so as to be bridged between the beams H ₃ of the SRC structure. In this example, the H-shaped steel 41 is arranged in advance in the portion to be the beam H ₃ , but the H-shaped steel 41 is provided with the reinforcing plate 42 at a predetermined interval in the longitudinal direction of the H-shaped steel 41, and The upper portion of the portion reinforced by the reinforcing plate 42 is wide. on the other hand,
The PC plate 43 is formed with a protruding portion 44 protruding laterally at a predetermined position on the peripheral portion, and by overlapping this protruding portion 44 with the upper portion of the wide portion of the H-shaped steel,
The PC plate 43 can be easily set in a predetermined position. Then, concrete is placed around the upper portion of the set PC plate 43 and around the H-shaped steel 41, whereby a floor slab integrated with the beam H ₃ can be obtained.

Although the post-tension method is used as a method of applying pre-stress to the PC plate in the above embodiment, the pre-tension method is not limited to this and may be used.

[Effects of the Invention] As described above, the present invention provides a PC plate having a flat portion to which prestress is introduced and a rib portion provided on one surface of the flat portion so that the rib portion is on the upper side. As described above, it is set on the floor slab construction site, the PC slab is used as a driving form, and concrete is placed on the top of the slab to construct the slab, so that the rib portion serves as a splicing key. By virtue of the fact that the bonding area between the PC plate and the post-cast concrete becomes large, the bonding strength between the PC plate and the post-cast concrete becomes large, and as a result, the rigidity of the floor slab increases.

PC by the introduction of prestress and the action of ribs
The out-of-plane rigidity of the plate itself is increased, and the support work for supporting the PC plate can be reduced or omitted, and further labor saving and shortening of the construction period can be realized.

The PC version can be made at a place other than the construction site such as a factory or an open space near the site, which facilitates production and introduction of prestress.

The PC plate is bent once when the prestress is introduced, but the bending is canceled by the load of the post-casting concrete placed on the top of the PC plate, and the PC plate becomes a flat shape.

The introduction of prestress can increase the rigidity of the floor slab itself and prevent problems such as cracks from occurring.

When the floor slab is arranged in a state of straddling between the concrete beams, the floor slab can be integrated with the concrete beam, and the floor slab excellent in strength can be constructed.

By setting the rib formation of the PC plate to a predetermined height, it is possible to omit the spacer for the upper rebar embedded in the post-cast concrete.

Rigidity at the time of construction can be enhanced as compared with the prior art, and bending of the slab can be reduced or prevented.

And so on.

[Brief description of drawings]

1 to 6 show an embodiment according to the present invention. FIG. 1 is a perspective view of a PC slab, and FIGS. 2 and 3 are constructions of floor slabs bridged between beams of S structure. FIG. 2 is a plan view, FIG. 3 is a plan view, and FIG.
Sectional views along the line XII-XII, FIGS. 4 to 6 are provided for explaining a method of constructing a floor slab that is bridged between beams of an SRC structure. FIG. 4 is a plan view, and FIG. XIV in Figure 4
FIG. 6 is a sectional view taken along line -XIV, and FIG. 6 is an enlarged view of the XV circle portion in FIG. 21 ... PC version, 22 ... flat part, 23 ... rib part, 2
4 ...... sheath tube, _{H 2} ...... Beams, 32 ...... PC version, _{H 3} ...
… Liang, 43… PC version.

Claims (1)

[Claims] 1. A floor slab comprising a flat portion and a rib portion provided so as to project from an upper surface of the flat portion, and by placing concrete on the flat portion and the upper portion of the rib portion in a erected state. A precast version to compose,
The precast plate, wherein the rib portion has a grid shape in a plan view, and a tension member is provided inside the flat portion so as to be parallel to the rib portion.