JPH0842035A - Concrete slab with offset and its placement method - Google Patents

Abstract

PURPOSE:To produce easily a floor surface with an offset by uniting an upper stage portion of an offset installed on the way of a concrete stab with a lower stage portion in parallel to the upper stage portion at the offset part and uniting the ends of tensioned PC steel materials with each other communicated with of the upper and lower stage portions with the concrete and an auxiliary member in parallel at the offset part. CONSTITUTION:An upper stage portion 1a and a lower stage portion 1b of a concrete slab 1 having an offset are united with each other at an offset part 2. The outer end of the upper stage portion 1a is placed on the upper end of a beam form M while the outer end of the lower stage portion 1b is placed on the upper end of the beam form M which is lowered When cast-in-place concrete C is placed on the concrete slab with the offset which is used as a buried form, a simple upper form is used to prepare a lower floor portion F' on the tower stage portion 1b. Both the upper and lower stage portions 1a and 1b are used as a floor PC concrete slab where an adopted cross section shape is used only when they are not corrugated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a concrete slab in which a compressive stress is generated in advance by a PC steel material, which has a step in the middle of the slab, and which is laid between the beams as an embedded formwork of the floor of the building. Regarding usage of lining up.

[0002]

2. Description of the Related Art A method of laying stepped concrete slabs between beams and pouring cast-in-place concrete to form a high and low floor surface was first proposed in Japanese Patent Laid-Open No. 3-81441. One of the applicants participated in this previous invention, "Construction method for concrete floor with steps", and a single concrete slab is composed of a corrugated sheet portion having a high wave height and a thin flat sheet portion with a step portion as a boundary. There is. Of course, the PC steel material is common from the lowermost part of the corrugated plate part to the lower part of the flat plate part. Prior to this prior invention, vertical and horizontal intermediate beams surrounding the low floor portion were specially provided, and a PC concrete plate was laid between them.

[0003]

In the above disclosed invention, since the thick portion is the corrugated sheet and only the thin portion is the flat plate, the weight of the thick portion does not become excessive, but it is still wider than the low floor portion having a small area. You will put extra concrete on the area. Therefore, the height difference of the floor could not be increased. The present invention improves on this.

[0004]

The stepped concrete slab of the present invention has a step in the middle of the concrete slab,
The upper part and the lower part parallel to this are combined at the step part, and at the step part, the ends of the tensioned PC steel material passed through each of the upper part and the lower part are parallel to the concrete. It is characterized in that it is rigidly connected by an auxiliary member. The PC steel material may be tensioned by a post-tensioning method or a pre-tensioning method. Further, there may be a plurality of steps on one concrete slab.

According to the method of using the stepped concrete slab of the present invention, when the floor PC concrete slabs are laid between the beams of a building, there is a step in the middle of the slabs, and the PC steel material of each of the upper and lower steps is the above-mentioned. Place the outer edge of the upper part of the stepped concrete slab rigidly connected at the step part on the upper part of the formwork of one beam, and place the outer end of the lower part part on the required height of the formwork of the other beam. The low floor portion is formed adjacent to the other beam by simultaneously forming the beam and the floor surface with cast concrete. Alternatively, when laying PC concrete slabs for floors between the beams of a building, the slab has a step portion that becomes lower in the middle of the slab and a step portion that returns to the original height, and the PC steel material for each of the upper and lower portions thereof. Is laid between the beams with stepped concrete slabs rigidly connected to each of the stepped portions, and cast-in-place concrete is cast to form a low floor portion between the stepped portions.

[0006]

The present invention breaks the conventional stereotype that the PC steel material to be passed through the PC concrete slab is made uniform throughout the length of the plate, and even with a single PC concrete slab, the upper step portion up to the step in the middle of the length Then, for the first time, we opened a way to put the PC steel material dedicated to each part in the stepped concrete slab that becomes the lower part. Dedicated P for upper and lower parts
If C concrete is put in and tightened, when the concrete slab is used as a beam, the boundary between them, that is, the stepped portion becomes a weak point. However, according to the present invention, since both PC steel materials are rigidly connected in the step portion, it is possible to obtain the same reinforcing effect by prestress as in the case of a single length PC steel material.

Since the upper and lower steps of the concrete slab of the present invention are vertically joined at a step in the middle of the slab, the PC steel material ends of the upper and lower steps are vertically parallel at the step. . The parallel steel ends are in concrete, so if they are fixed to concrete, they are rigidly connected with concrete. However, reinforcing bars and other auxiliary members are added to ensure the adhesion to concrete and to prevent shearing and cracking of concrete.

In the case of the pre-tensioning method, the rigid connection of the upper and lower PC steel material ends by concrete is not a problem, but in the case of the post-tensioning method, the PC steel material is usually passed through the sheath tube to apply the post-tension, so that only inside the stepped portion. The PC steel materials may be rigidly joined together without a sheath tube, and then the PC steel material may be towed by the outer edge of the plate to apply tension. The stepped concrete slab is mainly used for a stepped floor surface, but the position, number and shape of the stepped stepped concrete slab of the present invention can be appropriately changed depending on the position and step of the stepped floor. The step is not limited to one place.

The usage of the stepped concrete slab of the present invention is applied to the case where the low floor portion is near the one side beam and the case where the low floor portion is at the intermediate position. In the case of the former, there is only one step on the concrete slab, the outer edge of the upper part is placed on the upper part of the beam form, and the outer end of the lower part is the required height of the beam form on the other side.
In other words, the plate is placed at a level that supports it horizontally, and the beam and floor surface are simultaneously molded. In the latter case, if you use a concrete slab with a low floor between two steps between the slabs, even after both beams have been completed, they can be laid as they are and laid on the floor concrete. .

[0010]

EXAMPLE FIG. 1 shows a concrete slab 1 with steps according to the present invention.
After being laid across the beam forms M, M indicated by the chain line,
It is a conceptual explanatory drawing of the state where the beam B and the floor surface F of the building were simultaneously molded by the cast-in-place concrete C. In the concrete slab 1 with steps, the upper part 1a and the lower part 1b have step parts 2
Are united in. The outer end of the upper part 1a is placed on the upper end of the beam form M, and the outer end of the lower part 1b is placed on the lower end of the beam form M. When using this stepped concrete slab as an embedded formwork and casting cast-in-place concrete C on it, a simple upper formwork is used to make a low floor portion F'on the lower stage portion 1b, but it is known technology. The description is omitted.

2 and 3 show an embodiment of a concrete slab with steps according to the present invention. The upper and lower step portions 1a and 1b have a sectional shape which is used when the floor PC concrete slab is not corrugated, and has a width of 500 mm and a height of 130 mm. In practice, two peaks and a width of 1 m are often used, but this example is for a strength test. The strength test has passed. The length of the lower portion 1b that forms the low floor portion F'of FIG. 1 is 2.9 m in total including the portion joined to the lower side of the step portion 2, and the upper portion 1a is 3.3 m longer than that. Of course, the practical products will be longer according to the beam spacing of the building.

FIG. 3 shows the step portion 2 in a perspective view.
In this embodiment, the rectangular cross section is matched to the width and height of the upper and lower tiers 1a and 1b without matching the sectional shape. By doing so, the partition walls of the low floor portion can be formed without any gaps simply by laying the plates 1 between the beams of the building. And two PCs, one on the upper part and one on the lower part
Since the volume of concrete enclosing the steel material 3 is large, it is advantageous for rigid connection. To further secure the rigid connection, see FIGS.
As described above, the auxiliary members (reinforcing bars) 4 and 5 are entangled in the end portions of the PC steel material 3 which are parallel to each other in the step portion 2.

The auxiliary member 4 has a short vertical streak. The upper part has a bent part 4a which is bent down and the bent part 4a is bent up, and the lower part has a bent part 4b which is bent up. It is also entangled in the auxiliary member 5, which is a muscle. FIG. 5 also shows cast-in-place concrete C and its braided rebar 4 '. In this example, the PC steel material 3 in the upper and lower stages is made by applying tension after hardening the concrete by the post tension method, and is fixed to the upper and lower outer end surfaces of the step portion 2 by the seat plate 6 and the grip 7. When the tension is applied by the pre-tensioning method before placing the concrete, the entire length of the PC steel material is fixed to the concrete, so that the grip is unnecessary. The XX cross section of FIG. 2 is shown in FIG. 6, and the upper and lower steps 1a and 1b have the welding wire mesh 8 inserted in the blades thereof. PC steel material 3 has a diameter of 10.8 mm
The vertical bar 4 has a diameter of 13 mm, and the welded wire mesh 8 has a diameter of 3.2 m.
It is made of m steel wire.

Although FIG. 1 is a conceptual diagram, an actual completed diagram is as shown in FIG. The braided rebar 9 of both beams B is covered with concrete, and 50 mm of concrete is placed on the upper and lower steps 1a and 1b. The low floor portion F'is lower than the other floor surface F by 200 mm. The lower surface of the upper portion 1a is higher than the lower surface of the lower portion 1b by 200 mm. Low floor part F
It is of course possible to use ′ for the entrance of the building, the bathroom, etc., but the lower side of the upper part 1a can also be effectively used for raising the ceiling below, and for air conditioning ducts and other piping and wiring.

FIG. 8 shows a procedure for manufacturing a concrete slab with steps by the pretensioning method. (A) The mold 10 was placed between the PC steel material edge fixing bases 11 and 12 on both sides. (B) The PC steel materials 3 and 3 passed through the upper and lower mold side plates were also passed through the fixing bases 12 and 13. (C) The upper and lower PC steel materials 3 and 3 of the step portion are hung on the auxiliary member 5'for rigid connection. (D) Fixing stand 1 while pulling PC steel materials 3 and 3 outward
It is fixed on Nos. 1 and 12, and concrete is added. (E) After the concrete is hardened, unnecessary parts of the upper and lower PC steel materials 3 and 3 are separated. (F) The stepped concrete slab 1 was removed from the mold, and the end of the PC steel material 3 was cut off. In the case of the post-tension method, concrete is put in the state shown in FIG. 8E, the concrete is hardened, and the mold is removed as shown in FIG.
Tension and fix both ends to the concrete end face.

Although one embodiment has been described above, it is needless to say that the present invention can be variously changed and applied according to the implementation conditions without changing the gist thereof. It is easy to think that the width of the concrete slab is the same as the width of the floor and the floor is made of one concrete slab, or the floor surface is used as it is without cast concrete. The rigid connection between the upper and lower PC steel material ends, which is an important requirement of the present invention, theoretically suffices if it is mediated by concrete. However, in practice, it is still necessary to combine concrete with various auxiliary members to ensure rigid connection. Auxiliary members are not only rebar,
The fixing grip may be fixed to the end of the PC steel material before the concrete is placed, or alternatively, the end portions of the PC steel material may be directly connected rigidly with each other by a shape steel, a steel plate, a bolt, a nut or the like. If a relatively short step can be rigidly connected, a large space can be used for the low floor and the back side.

[0017]

EFFECTS OF THE INVENTION This invention is mainly used for building floors.
As a C concrete slab, it was possible to provide a concrete slab with steps having both upper and lower surfaces and no embrittlement for the first time. Since the dedicated PC steel material is passed through each of the upper and lower stages, the cross-sectional shape of the plate could be optimized. Moreover, both PCs
By rigidly joining and integrating the steel materials in the concrete in the step portion, it is possible to obtain the same bending prevention effect as that obtained with the conventional PC steel material over the entire length. The prestressing method can be post-tensioning method or pre-tensioning method,
It was also shown that multiple steps can be provided to make various designs. Moreover, as the usage of the concrete slab with steps, concrete measures are shown for making a low floor part near one beam and for making a low floor part in the middle position of both beams. According to the present invention, a stepped floor surface can be easily formed, and a space usable below the floor surface can be provided, which has great technical and economic effects.

[Brief description of drawings]

FIG. 1 is a conceptual elevational explanatory view of the present invention.

FIG. 2 is an elevation view of an embodiment of the concrete slab of the present invention.

FIG. 3 is a perspective view of a step portion of FIG.

FIG. 4 is a plan view of a PC steel material and a reinforcing bar inside FIG.

FIG. 5 is a sectional view of a completed step portion.

6 is a cross-sectional view taken along line XX of FIG.

FIG. 7 is a sectional view of the completed floor.

FIG. 8 is an explanatory view of a procedure for manufacturing a concrete slab with steps by a pretensioning method.

[Explanation of symbols]

 1 Concrete plate with steps 2 Steps 3 PC steel 4 Auxiliary member

Front page continuation (72) Inventor Akio Tomita 1-2-7 Moto-Akasaka, Minato-ku, Tokyo Kashima Construction Co., Ltd. (72) Inventor Sai Hatamoto 1-2-7 Moto-Akasaka, Minato-ku, Tokyo Kashima Incorporated (72) Inventor Yoshima Ogami 4-24-8 Shimbashi, Minato-ku, Tokyo (2nd Toyo Kaiji Building) Inside Fuji PS Tokyo Branch (72) Inventor Hiroki Sonoda Tokyo Metropolitan Port 4-24-8 Shimbashi, Tokyo (2nd Toyo Kaiji Building) Within Fuji P.S. Tokyo Branch (72) Inventor, Kyoya Tanaka 4-24-8 Shimbashi, Minato-ku, Tokyo (2nd Toyo Kaiji Building) Shares Company Fuji PS Tokyo Branch

Claims (6)

[Claims] 1. There is a step in the middle of the concrete slab,
The upper part and the lower part parallel to this are combined at the step part, and at the step part, the ends of the tensioned PC steel material passed through each of the upper part and the lower part are parallel to the concrete. A concrete slab with steps, which is rigidly connected by an auxiliary member. 2. The concrete slab according to claim 1, wherein the PC steel material is post-tensioned by a post-tensioning method. 3. The concrete slab with steps according to claim 1, wherein the PC steel material is pretensioned by a pretensioning method. 4. The concrete slab according to claim 1, wherein there are a plurality of stepped portions at an intermediate position of the stencil. 5. When laying PC concrete slabs for floors between the beams of a building, there is a step in the middle of the slabs, and the PC steel material of each of the upper and lower steps is rigidly connected by the step. Place the outer edge of the upper part of the attached concrete slab on the upper part of the formwork of one beam, and place the outer end of the lower part at the required height of the formwork of the other beam, and place them side by side. A method for using a concrete slab with steps, characterized by forming a low floor portion adjacent to the other beam by molding. 6. When laying PC concrete slabs for floors between the beams of a building, the slab has a stepped portion that becomes lower in the middle of the slab and a stepped portion that returns to the original height. Characterized in that a low floor portion is formed between the step portions by placing step concrete concrete plates, in which PC steel materials are rigidly connected at the step portions, between the beams and casting cast-in-place concrete. How to use a concrete slab with steps.