JPS61126255A - Reverse flat slab structure - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a flat slab structure in which a normal flat slab is turned upside down (hereinafter referred to as a rising haunch).

(Conventional technology and problems) Flat slabs have been used for a long time as a structure in which the slab is supported by columns with capitals instead of using beams. Since there is no beam, the formwork for the bottom of the slab has been streamlined to some extent, but it is still large and when using formwork, the formwork work for the drop panels that protrude from the bottom of the slab is complicated, which reduces construction time and costs. It was necessary.

In addition, even if the floor height is low (because there are no beams, it has the advantage of increasing indoor space), however, it has poor earthquake resistance, causing excessive deflection, and increasing the slab's own weight, which is disadvantageous in the event of an earthquake. However, with the development of unbonded steel, these problems have been resolved.

However, because the unbonded steel is placed closest to the slab surface at the column location in a nearly inverted suspension curve, the tent rise is generally the fourth As shown in Figure A, a=t
2-(dl+d2), which is no different from the case where unbonded steel is used for a normal slab without a drop panel.

(Object of the invention) This invention was made in view of the above-mentioned conventional problems, and its main purpose is to streamline formwork construction and enable a more efficient method of arranging unbonded steel materials. It is.

(Structure of the Invention) In order to achieve the above object, this invention is based on the following invention: ``In a reinforced concrete slab, the bottom surface of the core slab is flat over the entire surface, and the top surface of the core slab is only in the required area around the columns, and in other areas. It is characterized by the fact that unbonded PC steel is continuously buried in the slab in a substantially reverse suspension curve on the tension side of the slab end of the column band.

(Embodiment) First, referring to FIG. 3, the construction order of a preferred embodiment of the present invention will be described.

When the slab formwork 6 is assembled, a lower end reinforcement 10 is placed on the M formwork 6 and placed on the unbonded PC steel material 14 so as to form a substantially reverse catenary curve at the column position.

At this time, the PC steel material 14 maintains a substantially inverted suspension curve t! uiPC steel material 14 is supported by attaching horizontal reinforcements or supporting metal fittings 13 to the appropriate height positions of the column reinforcements 12 as shown in i.
Of course you can. Next, the lower end reinforcing bars 11 are placed, reusable formwork is placed on the riser/groove 4 portions, and slab concrete is poured to complete the construction.

Reinforcement work when there is a conventional drop panel 5 is to arrange the lower end reinforcement 10 of the drop panel 5 part, and then place the lower end reinforcement 10 of the remaining slab with the lower end reinforcement 10 of the Sekki Dorofu Hanel 5 part. It is common to use reinforcing bars, and it is difficult to uniformly prefabricate reinforcing bars, which is extremely complicated and time-consuming.

Next, FIG. 2 is a comparative sectional view of the shape of the formwork on the bottom surface of a flat slab and an inverted flat slab. Second
Figure A shows a conventional flat slab. Due to the presence of the drop panel 5, the shape of the formwork 6' on the bottom of the slab is uneven, and a support member 8 for holding the formwork 6' must be separately provided on the support F. However, it required a large amount of construction time and cost. On the other hand, Fig. 2B shows an inverted fluff slab according to the present invention, in which the drop panel 5 portion is provided on the upper part 4 of the slab, and the bottom surface of the slab is flat over the entire surface, making it convenient to use a large (movable) formwork. A large amount of construction time and costs can be saved.

Next is a comparative diagram of tent rise in a flat slab (FIG. 4A) and an inverted flat slab (FIG. 4B). The slab thickness is set to t2. Set the slab thickness of the drop panel 5 part and the rising haunch part to Ll and An. The distance from the top of the 1τnd PC steel material 14 to the top of the slab is dl,
If the distance from the bottom of the unbonded PC steel material 14 to the top of the slab is d2, the tend 7 rise a in the flat slab is a = t2- (dl + d2), and the tend 7 rise b in the reverse flat slab is b = i- (dl
+d2).

Therefore, the tend/rise b of the inverted flat slab is larger than the tent rise a of the flat slab by Ll-1, and the 11 CM material can be arranged efficiently in terms of structural design.

FIG. 5 shows an embodiment of the present invention in which the leveling plate/chip 4 and the remaining slab portion are leveled.

The surface of the frame slab 3 is one step lower except for the Raiji/Guha/Chi 4 portions, and above the lowered frame slab (in the past, embedded piping, etc. were done after reinforcing reinforcement or in parallel) ( Piping 18, where there are no obstacles such as reinforcing bars, I! 19 freely, and then pour concrete 15 so that it is on the same level as the surface of the riser concrete 15, or use a lightweight block 16, hollow block 17, etc.

(Effects of the Invention) Since the present invention is configured as described in detail in the embodiments above, it is possible to rationalize the formwork work and more efficiently arrange the unbonded PC steel materials.
This method has the advantage of saving labor for work behind the ceiling such as duct piping and ceiling work.

[Brief explanation of the drawing]

Figure 1 is a perspective view using this invention, Figure 2 A is a flat slab, Figure B is a cross-sectional view showing a comparison of slab bottom formwork, and Figure 3 is a construction order according to this invention. FIG. 4A is a perspective view and a cross-sectional view showing a tendon rise according to the present invention, FIG. 4A is a conventional one, FIG.
The figure is a sectional view of an embodiment of the present invention in which the rising haunch and remaining slab body portion are leveled. 1... Column 2... Upper floor slab bottom 3
...Slab 4...Rising haunch 5.
...Drop panel a8'...Formwork 7...Shoring 8...Support member 10...Top reinforcement
11... Upper end reinforcement 12... Column reinforcement 13...
Horizontal reinforcement, support hardware 14...Anobond P (14 material 15...Singu concrete 16...Lightweight professional Vri 17...Cavity block 18...
...Piping 19...Wiring L...Suba 7 intervals

Claims (1)

[Claims] A slab made of reinforced concrete, characterized in that the bottom surface of the framework slab is flat over the entire surface, and the top surface of the framework slab is higher only in a required area around the columns than in other parts. Inverted flat slab structure. (2) The inverted flat slab structure according to item 1, wherein the unbonded PC steel material is continuously buried in the slab in a substantially inverted suspension curve on the tension side of the slab end of the column band.