JPH07109112B2 - Construction method of watful slab and lower part of watful slab - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for constructing a waffle slab and a lower structure of the waffle slab used for carrying out the method.

"Prior Art" Waffle slabs are slabs having a grid-like rib R in the lower part, as shown in FIGS. 10 (a) and 10 (b). It has the advantage that it can be made without beam.

FIG. 11 shows a waffle slab construction method that has been conventionally used.

That is, conventionally, a method of assembling a supporting structure 3 with a support 1 and a large pulling 2 and laying out a plurality of molds 4 formed in a substantially rectangular parallelepiped shape on the upper part of the supporting structure 3 and arranging and then placing concrete on the upper part. Was getting a waffle slab.

[Problems to be Solved by the Invention] The above construction method has the following drawbacks.

The number of work steps on the critical path is increased, and the support 1 must be kept over the entire slab until the cast concrete hardens to some extent, during which post-processing (equipment construction, finishing work, etc.) The construction period will be longer due to reasons such as being unable to proceed.

The support 1 must be left until the concrete cast as described above is solidified, during which the formwork 4 cannot be dismantled and a large number of formwork 4 is required.

The present invention has been made in view of the above circumstances, the construction period can be significantly shortened, and a waffle slab construction method that requires a small number of molds to be used, and waffles used directly in carrying out the construction method. It is intended to provide a lower slab structure.

"Means for Solving Problems" The method of the present invention is that a lower part of a slab including at least ribs is formed in another place in advance, and the slab lower structure made in this other place is moved to a predetermined place and laid. The feature is that concrete is placed on the top and spliced.

Further, the waffle slab lower structure has a grid-like rib, the length of which is set to a value that can be passed to both columns or column formwork arranged at intervals, and the height thereof. Is characterized by being set lower than the height of the finished slab so as to leave a concrete spliced portion that is spliced on site.

"Operation" Since the lower structure of the waffle slab is made in another place, the work of making the lower structure and the work performed in the building can be performed in parallel, and the work period can be shortened accordingly. In addition, when pouring concrete on the lower structure of the waffle slab, it is not necessary to take support over the entire slab as in the conventional example, and post-construction work is carried out immediately after the post-cast concrete is placed. Also, the construction period can be shortened.

Also, when making a waffle slab lower structure at a factory,
It is not always necessary to make one floor of the building by one-time pouring like in pouring inside the building, and it is possible to make it separately for each section surrounded by beams.

[Examples] Examples of the present invention will be described below with reference to the drawings.

The waffle slab according to the method of the present invention is made by the following procedure.

(1) Manufacture of lower waffle slab structure A lower waffle slab structure 10 (hereinafter, referred to as a half waffle) including at least a portion to be the rib R of the waffle slab is made in advance at a place different from the site, such as a factory. .

The length 1 of the half waffle 10 is set to a value that can be passed to both of the column molds 11 (or columns) arranged at intervals. That is, the size of the half waffle 10 is, as a general rule, the size surrounded by the beam 12a. However, when the part surrounded by the beam 12a is too large, it may be divided into a plurality of parts (eighth embodiment). See figure). Further, the height h ₁ of the half waffle 10 is set lower than the height h ₀ of the finished slab so as to leave a concrete splicing portion that is spliced on site (see FIG. 1 (c)). The cross-sectional shape of the rib R is not only rectangular but also tapered as shown in FIGS. 6 (a) and 6 (b), such that the lower side is narrowed or the upper side is narrowed. Further, a cotter 12 (which will be described later in detail) may be formed on the upper surface of the rib R, and if there is a portion P that becomes a cap, the cotter 12 may be provided in that portion as well ( (See FIG. 7).

Here, an example of a procedure for making the half waffle 10 will be described with reference to FIGS. 2 and 3. First, the molds 4 are lined up on the bed 13 having a flat upper surface, and the surroundings thereof are arranged. Assemble 14 side formwork to the part. Reinforcing bars 15 are assembled on the laid formwork 4. Next, concrete C is poured from the top. The half waffle 10 is obtained by the above work.

In the example shown in FIG. 2, the half waffle 10 is formed in multiple stages by repeating the above-described operations in order on the upper side of the already molded half waffle 10. According to such a molding method, the space can be effectively used, and a large number of half waffles can be obtained in a narrow space.
In the method of manufacturing the half waffle 10 described above, a partition plate (not shown) for edge cutting is interposed between the half waffle 10 already formed and the half waffle 10 formed on the upper part of the half waffle 10 in order to avoid the joining. Is preferred. Further, when the ribs R are overlapped with each other as shown in the figure, the load of the upper half waffle 10 mainly acts on the rib R of the lower half waffle 10, and the load lowers the lower half waffle 10. It is possible to prevent problems such as damage to the half waffle 10 in advance.

FIG. 3 is for explaining a half waffle 10 having a different shape from that described above, and the half waffle described above has a rib R.
In contrast to having only a portion, the half waffle 10 shown in this example includes not only the rib R portion but also a flat portion 16 connecting the rib R to the upper portion thereof. However, it goes without saying that even in the half waffle 10 shown here, a concrete splicing portion that is spliced on site is left on the upper part. The manufacturing method of this kind of half waffle is basically the same as the above. That is, the steps from 1 to 3 above are repeated to make them.

(2) Installation of lower structure of waffle slab As shown in FIG. 1 (a), the half waffle 10 obtained as described above is moved to a predetermined position, that is, between the column molds 11 arranged at intervals. It is installed in a state of being bridged over. When the pillar is cast in advance, the pillar form 11 is replaced and the pillar is directly bridged. Further, in this case, the lower side of the beam may be supported by a support or the like, if necessary.

(3) Installation of Beam Reinforcement Beam reinforcement 31 is installed at a place to be a beam as shown in Fig. 1 (b). Beam reinforcement 31 may be made in advance at another location,
Also, it may be assembled on-site.

(4) Installation of beam bottom formwork When the pillar on which the half waffle 10 is bridged is not formed and is cast integrally with concrete which is spliced on the upper part of the half waffle 10, FIG. 1 (c), Connect the lower ends of both half waffles 10 as shown in FIG. 9 (a).
The beam bottom formwork 41 by the anchoring means 42 such as anchor bolts,
Secure to the bottom edge of half waffle 10. If the columns have already been cast and formed, the beam bottom form 41 is not necessary. Further, as shown in FIG. 8, when a plurality of half waffles 10 are lined up in one section surrounded by the beams 12a, as shown in FIG.
The bottom plate 43 is fixed so as to connect the lower ends of the. The operations (3) and (4) may be reversed.

Further, in parallel with the above-mentioned operations (3) and (4), a lid 44 is attached to the upper portion of the rib R so as to close the opening between the ribs R of the half waffle 10 (Figs. 5 (a) to (c)). reference). This operation becomes unnecessary when the half waffle 10 already has the flat portion 16 on the upper portion of the rib R as shown in FIG.
The lid 44 may be one in which the upper portion of the mold 4 used in the half waffle molding is left as shown in FIG. 5 (a), and as shown in FIG. 5 (b), a dedicated lid 44 for it is provided. Alternatively, the half waffle 10 may be fitted and attached to the concave portion 45 on the upper portion of the rib R provided in advance when forming the half waffle 10. Further, as shown in FIG. 5 (c), the mold 4 used in the half waffle molding is hung while being driven into the lower structure of the waffle slab, and the mold 4 is used as a top concrete mold and also as a decorative ceiling board. Good.

(5) Installation of slab muscles As shown in Fig. 1 (b), slab muscles 51 are installed on the upper part of the column form 11 or the half waffle 10 spanning the columns.
This work is similar to the conventional one.

(6) Top concrete pouring As shown in FIG. 1 (c), concrete C is poured on the half waffle 10 and the upper part of the slab reinforcement 51 installed on the half waffle 10. At this time, since the side end surface of the half waffle 10 functions as a beam form, the beam form is unnecessary (FIG. 9 (a)).
reference).

Further, as shown in FIG. 6 and FIG. 7, when the cotter 12 is formed in advance on the upper surface of the rib R of the half waffle 10 or the upper surface of the portion P which is the capital portion, the concrete C that is post-cast is the cotter 12. Since it flows in, it is possible to secure a strong joint strength between the half waffle 10 and the post-cast concrete C in the shearing direction.

Also, as shown in FIGS. 9 (a) and 9 (c), half waffles are used.
If the side end surface 10a of 10 is roughened in advance, the joint strength between the half waffle 10 and the post-cast concrete portion can be increased.

The waffle slab is obtained as shown in FIG. 4 by the operations (1) to (6) described above. If the building has a plurality of floors, the above series of operations are repeated for each floor.

"Effects of the Invention" The method of the present invention has the following effects.

Since the lower structure of the waffle slab is made in another place, the work of making the lower structure and the work performed in the building can be performed in parallel, and the construction period can be shortened accordingly. In addition, when placing concrete on the lower structure of the waffle slab, it is not necessary to take support over the entire slab as in the conventional example, and post-construction work is immediately carried out after the post-casting concrete is placed. Also, the construction period can be shortened.

Also, when making a waffle slab lower structure at a factory,
It is not always necessary to make one floor for one placement like when placing in a building, and it is possible to make it separately for each lower structure, and a large number of formwork is not required.

Further, according to the waffle slab lower structure according to the present invention, since the ribs are formed in advance, a troublesome formwork for making the ribs on the site is not required, so that the work process on the site can be rationalized and the labor can be saved. Also, it can be easily set by passing it over both pillars or pillar formwork arranged at intervals, and it is not necessary to take a support from the lower side.

[Brief description of drawings]

The drawings show an embodiment of the present invention, and FIGS. 1 (a) to 1 (c) are sectional views showing a schematic procedure of the method of the present invention, and FIGS. 2 and 3 show a manufacturing procedure of a waffle slab lower structure. Sectional view, FIG. 4 is an exploded perspective view of a waffle slab manufactured by the method of the present invention, FIGS. 5 (a) to (c) are sectional views showing a lid of a waffle slab lower structure, and FIG. 6 is the same waffle. FIG. 7 is a perspective view showing a rib shape of a lower slab structure, FIG. 7 is a cross-sectional view of an essential part in the case of having a capital portion, FIG. 8 is a bottom view of a waffle slab made by the method of the present invention, and FIG.
(C) is a sectional view taken along lines A, B, and C of FIG.
Figures 10 (a) and 10 (b) are diagrams for explaining the waffle slab.
FIG. 11 is a diagram for explaining a conventional waffle slab construction method. 10 …… Waffle slab lower part structure (half waffle),
11 …… Post form, R …… Rib

Claims (2)

[Claims] 1. A method for constructing a waffle slab having grid-like ribs at the bottom, wherein a lower part of a slab including at least the ribs is previously formed at another location, and a slab lower structure made at this other location is provided. A waffle slab construction method characterized by making a waffle slab by moving to a predetermined location, laying it, and placing concrete on the top and splicing it. 2. Having a grid-like rib, the length is set to a value that can be passed to both columns or column formwork arranged at intervals, and the height is set to the upper side at the site. A lower structure of a waffle slab characterized by being set lower than the height of the finished slab so as to leave a concrete spliced part to be spliced.