JP2003239438A - Concrete slab with stepped section - Google Patents
Concrete slab with stepped sectionInfo
- Publication number
- JP2003239438A JP2003239438A JP2002043493A JP2002043493A JP2003239438A JP 2003239438 A JP2003239438 A JP 2003239438A JP 2002043493 A JP2002043493 A JP 2002043493A JP 2002043493 A JP2002043493 A JP 2002043493A JP 2003239438 A JP2003239438 A JP 2003239438A
- Authority
- JP
- Japan
- Prior art keywords
- board
- concrete
- boards
- concrete slab
- stepped
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Landscapes
- Panels For Use In Building Construction (AREA)
Abstract
Description
【発明の詳細な説明】
【０００１】
【発明の属する技術分野】この発明は、集合住宅の床等
に用いられる鉄筋コンクリート製のスラブにおいて、段
差を有するものに関する。
【０００２】
【従来の技術】近年、集合住宅やオフィスビル等の建築
物の床材や天井材に用いられるコンクリートスラブに
は、工場で予め鉄筋を埋め込んだＰＣ（プレキャストコ
ンクリート）基板を形成しておき、これらのＰＣ基板を
施工現場で並べて配置し、コンクリートを打設して一体
に接合するものが多い。その中でも、工場で各ＰＣ基板
の上面にボイド型枠を載せておき、これらのボイド型枠
を現場打ちコンクリート内に埋め込んで遮音性を高めた
中空タイプのものが多用されている。また、この種のコ
ンクリートスラブが集合住宅の水回り等に用いられる場
合には、配管スペース等を確保するため、段差が形成さ
れることが多い。
【０００３】図２は、上述したような中空タイプの段差
付きコンクリートスラブの一例を示す。このコンクリー
トスラブは、コンクリート薄板内に鉄筋５１が図面前後
方向に所定の間隔で平行に埋め込まれ、上面にボイド型
枠５２ａ、５２ｂが載せられた２枚のＰＣ基板５３ａ、
５３ｂを一体に接合したものである。各ＰＣ基板５３
ａ、５３ｂは、鉄筋５１が延びる方向に並べられて側端
部どうしを近接させた状態で段違いに配置されている。
そして、各ＰＣ基板５３ａ、５３ｂ上に打設された現場
打ちコンクリート５４により、ボイド型枠５２ａ、５２
ｂが覆われるとともに、下段側ＰＣ基板５３ｂ上にコン
クリート５４の段差部５５が形成され、両ＰＣ基板５３
ａ、５３ｂが一体に接合されている。なお、施工上での
み必要な配筋は、図示を省略している。
【０００４】前記段差部５５は、両ＰＣ基板５３ａ、５
３ｂに差し渡した補強筋５６、下段側ＰＣ基板５３ｂ上
に配した補強筋５７および段差部５５内に形成した梁形
補強構造５８によって補強されている。この梁形補強構
造５８は、図面前後方向に所定の間隔で配した矩形枠状
のスターラップ５８ａを４本の連結筋５８ｂで一体に連
結したもので、各補強筋５６、５７や上端筋５９ａ、５
９ｂとともに施工現場で配筋される。
【０００５】
【発明が解決しようとする課題】上述した従来の段差付
きコンクリートスラブでは、段差部を補強している補強
筋および梁形補強構造が元々ＰＣ基板とは別体であるた
め、段差部と各ＰＣ基板との一体性がやや弱くて段差部
の強度が必ずしも十分とは言えず、施工中や施工後にコ
ンクリート打継部に亀裂が生じることがある。
【０００６】そこで、この発明の課題は、段差付きコン
クリートスラブの段差部の強度を向上させることであ
る。
【０００７】
【課題を解決するための手段】上記の課題を解決するた
め、この発明は、コンクリート薄板内に鉄筋を所定の間
隔で平行に埋め込んだ複数のＰＣ基板を、鉄筋が延びる
方向に並べて側端部どうしを近接させた状態で段違いに
配置し、各ＰＣ基板上にコンクリートを打設して下段側
ＰＣ基板上にコンクリートの段差部を形成し、各ＰＣ基
板を一体に接合した段差付きコンクリートスラブにおい
て、前記各ＰＣ基板に埋め込まれた鉄筋の一端部を、そ
のＰＣ基板の側端部から突出させ、前記段差部内へ定着
させた構成を採用したのである。
【０００８】すなわち、各ＰＣ基板に埋め込まれた鉄筋
の一端部を、ＰＣ基板側端部から突出させて段差部内へ
定着させることにより、段差部と各ＰＣ基板との一体性
を改善して、段差部の強度を向上させたのである。
【０００９】
【発明の実施の形態】以下、図面に基づき、この発明の
実施形態を説明する。この段差付きコンクリートスラブ
は、図１に示すように、コンクリート薄板内に鉄筋１
ａ、１ｂが図面前後方向に所定の間隔で平行に埋め込ま
れ、上面にボイド型枠２ａ、２ｂが載せられた２枚のＰ
Ｃ基板３ａ、３ｂを一体に接合した中空タイプのもので
ある。各ＰＣ基板３ａ、３ｂは、鉄筋１ａ、１ｂが延び
る方向に並べられて側端部どうしを近接させた状態で段
違いに配置されている。そして、各ＰＣ基板３ａ、３ｂ
上に打設された現場打ちコンクリート４により、ボイド
型枠２ａ、２ｂが覆われるとともに、下段側ＰＣ基板３
ｂ上にコンクリート４の段差部５が形成され、各ＰＣ基
板３ａ、３ｂが一体に接合されている。なお、施工上で
のみ必要な配筋は、図示を省略している。
【００１０】前記段差部５は、両ＰＣ基板３ａ、３ｂに
差し渡した屈曲した補強筋６、下段側ＰＣ基板３ｂ上に
配したＬ字状の補強筋７、段差部５内に形成した梁形補
強構造８および各ＰＣ基板３ａ、３ｂの側端部から突出
する鉄筋１ａ、１ｂの突出部Ｔａ、Ｔｂにより補強され
ている。
【００１１】前記梁形補強構造８は、図面前後方向に所
定の間隔で配した矩形枠状のスターラップ８ａを４本の
連結筋８ｂで一体に連結したもので、各補強筋６、７や
上端筋９ａ、９ｂとともに施工現場で配筋される。
【００１２】これに対して、前記鉄筋１ａ、１ｂは、予
め工場でそれぞれの一端部が突出するように各ＰＣ基板
３ａ、３ｂに埋め込まれており、そのうちの上段側の鉄
筋１ａの突出部ＴａはＰＣ基板３ａ側端面から突出して
斜め下方に折り曲げられ、下段側の鉄筋１ｂの突出部Ｔ
ｂはＰＣ基板３ｂ内部で上向きに折り曲げられてＰＣ基
板３ｂ側端面近傍の上面から上方へ突出している。そし
て、これらの各鉄筋１ａ、１ｂの突出部Ｔａ、Ｔｂが段
差部５内に定着して段差部５を補強するようになってい
る。
【００１３】すなわち、この段差付きコンクリートスラ
ブでは、段差部５が、元々各ＰＣ基板３ａ、３ｂと別体
の補強筋６、７や梁形補強構造８だけでなく、各ＰＣ基
板３ａ、３ｂに埋め込まれた鉄筋１ａ、１ｂの突出部Ｔ
ａ、Ｔｂによっても補強されており、前述した従来スラ
ブに比べて、段差部５と各ＰＣ基板３ａ、３ｂとの一体
性の改善がはかられている。
【００１４】なお、両ＰＣ基板３ａ、３ｂは側端部どう
しが上下方向で僅かにラップするように配置されてお
り、これらの側端部のラップ部分の間に現場打ちコンク
リート４が入り込んでのみ込み部１０が形成されてい
る。こののみ込み部１０は、上段側ＰＣ基板３ａの側端
に沿って垂直方向に伸びる亀裂の発生を防止するための
もので、強度面からは形成した方が好ましいが、必ずし
も形成しなくてもよい。
【００１５】この実施形態の段差付きコンクリートスラ
ブと、のみ込み部を含めた外形形状および寸法が同じ従
来スラブとについて、それぞれの両端部を支持して上面
側から負荷を徐々にかけていく実験を行ったところ、実
施形態のコンクリートスラブは、段差部の割れの発生荷
重および鉄筋の曲げ降伏荷重が、いずれも従来スラブに
比べて約１５％大きくなり、段差部とＰＣ基板との一体
性の改善による強度の向上が確認された。
【００１６】なお、この発明は、上述の実施形態のよう
に２枚のＰＣ基板を段違いに配置した段差付きコンクリ
ートスラブだけでなく、３枚以上のＰＣ基板を並べ、そ
のうちの少なくとも２枚の間に段差がつくように配置し
た段差付きスラブにも適用できる。この場合は、各ＰＣ
基板が、階段状にあるいは凹部や凸部を形成するように
配置されていてもよいし、同じ高さで配置された複数の
ＰＣ基板を含んでいてもよい。
【００１７】また、ボイド型枠を載せないＰＣ基板を接
合して形成する段差付きスラブにも、もちろん適用でき
る。
【００１８】
【発明の効果】以上のように、この発明の段差付きコン
クリートスラブは、段違いに配置されるＰＣ基板に埋め
込まれた鉄筋の一端部を、そのＰＣ基板の側端部から突
出させて、下段側ＰＣ基板上に形成されるコンクリート
の段差部内へ定着させたものであるから、従来よりも段
差部と各ＰＣ基板との一体性が改善されて段差部の強度
が向上しており、施工中や施工後にコンクリート打継部
に亀裂が生じるおそれが少ない。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reinforced concrete slab used for a floor of an apartment house or the like, which has a step. 2. Description of the Related Art In recent years, PC (precast concrete) substrates in which reinforcing steel is embedded in advance in a factory are formed on concrete slabs used as flooring materials and ceiling materials of buildings such as apartment houses and office buildings. In many cases, these PC boards are arranged side by side at a construction site, and concrete is cast and integrally joined. Among them, a hollow type in which a void form is placed on the upper surface of each PC board at a factory and these void forms are buried in cast-in-place concrete to improve sound insulation properties is often used. In addition, when this type of concrete slab is used around water in an apartment house, a step is often formed in order to secure a piping space or the like. FIG. 2 shows an example of the hollow type stepped concrete slab as described above. In this concrete slab, two PC boards 53a having reinforcing bars 51 embedded in a concrete thin plate in parallel at predetermined intervals in the front-rear direction of the drawing and having void formwork 52a, 52b mounted on the upper surface,
53b are integrally joined. Each PC board 53
a and 53b are arranged stepwise in a state where the reinforcing bars 51 are arranged in the extending direction and the side ends are brought close to each other.
Then, the void form 52a, 52 is formed by the cast-in-place concrete 54 cast on each PC board 53a, 53b.
b is covered, and a step portion 55 of the concrete 54 is formed on the lower PC board 53b.
a and 53b are integrally joined. It should be noted that reinforcements necessary only for construction are not shown. [0006] The step 55 is provided with two PC boards 53 a, 5.
3b, reinforcing bars 57 provided on the lower PC board 53b, and beam-shaped reinforcing structures 58 formed in the step portions 55 are provided. This beam-shaped reinforcing structure 58 is formed by integrally connecting rectangular frame-shaped stirrups 58a arranged at predetermined intervals in the front-rear direction of the drawing by four connecting bars 58b. , 5
Bars are arranged at the construction site together with 9b. [0005] In the above-described conventional concrete slab with steps, the reinforcing bars and beam-shaped reinforcing structures for reinforcing the steps are originally separate from the PC board. And the strength of the step portion is not always sufficient, and cracks may occur in the concrete joint during and after construction. It is an object of the present invention to improve the strength of a step portion of a stepped concrete slab. [0007] In order to solve the above-mentioned problems, the present invention provides a plurality of PC boards in which reinforcing bars are embedded in parallel in a concrete thin plate at predetermined intervals in the direction in which the reinforcing bars extend. Steps are arranged with the side ends close to each other, concrete is cast on each PC board, concrete steps are formed on the lower PC board, and each PC board is joined together with a step In the concrete slab, a configuration is adopted in which one end of a reinforcing bar embedded in each PC board is projected from a side end of the PC board and fixed in the step. In other words, one end of the reinforcing bar embedded in each PC board is projected from the PC board side end and fixed in the step, thereby improving the integration between the step and each PC board. The strength of the step was improved. Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, this stepped concrete slab is provided with reinforcing bars 1 in a concrete thin plate.
a and 1b are buried in parallel at a predetermined interval in the front-rear direction of the drawing, and two P
It is a hollow type in which C substrates 3a and 3b are integrally joined. The PC boards 3a and 3b are arranged stepwise in a state where the rebars 1a and 1b are arranged in the extending direction and their side ends are brought close to each other. And each PC board 3a, 3b
The void formwork 2a, 2b is covered with the cast-in-place concrete 4 cast on the upper side, and the lower PC board 3
The step portion 5 of the concrete 4 is formed on "b", and the PC boards 3a and 3b are integrally joined. It should be noted that reinforcements necessary only for construction are not shown. The step portion 5 includes a bent reinforcing bar 6 extending over both the PC boards 3a and 3b, an L-shaped reinforcing bar 7 disposed on the lower PC board 3b, and a beam formed in the step portion 5. It is reinforced by the reinforcing structure 8 and the protruding portions Ta and Tb of the reinforcing bars 1a and 1b protruding from the side ends of the PC boards 3a and 3b. The beam-shaped reinforcing structure 8 is formed by integrally connecting rectangular frame-shaped stirrups 8a arranged at predetermined intervals in the front-rear direction of the drawing by four connecting bars 8b. They are arranged together with the upper end bars 9a and 9b at the construction site. On the other hand, the reinforcing bars 1a and 1b are preliminarily embedded in the PC boards 3a and 3b at the factory such that one ends of the reinforcing bars 1a and 1b protrude. Protrudes from the PC board 3a side end face and is bent obliquely downward, and the protruding portion T of the lower reinforcing bar 1b
b is bent upward inside the PC board 3b and protrudes upward from the upper surface near the end face on the PC board 3b side. The projecting portions Ta and Tb of these reinforcing bars 1a and 1b are fixed in the step portions 5 to reinforce the step portions 5. That is, in the stepped concrete slab, the stepped portion 5 is formed not only on the reinforcing bars 6, 7 and the beam-shaped reinforcing structure 8 separate from the PC boards 3a, 3b, but also on the PC boards 3a, 3b. Projection T of embedded reinforcing bars 1a, 1b
a and Tb, and the integration of the step portion 5 and each of the PC boards 3a and 3b is improved as compared with the conventional slab described above. The PC boards 3a and 3b are arranged so that their side edges slightly wrap in the vertical direction, and only when the cast-in-place concrete 4 enters between the lap portions of these side edges. An insertion portion 10 is formed. This recessed portion 10 is for preventing the generation of a crack extending in the vertical direction along the side edge of the upper PC board 3a, and is preferably formed from the viewpoint of strength, but is not necessarily formed. Good. With respect to the stepped concrete slab of this embodiment and a conventional slab having the same outer shape and dimensions including a recessed portion, an experiment was conducted in which both ends were supported and a load was gradually applied from the upper surface side. However, in the concrete slab of the embodiment, the load at which the step portion cracks and the bending yield load of the reinforcing bar are all about 15% larger than those of the conventional slab, and the strength due to the improvement in the integration between the step portion and the PC board is increased. Improvement was confirmed. The present invention is not limited to the stepped concrete slab in which the two PC boards are arranged stepwise as in the above embodiment, but three or more PC boards are arranged and at least two of the PC boards are arranged. The present invention can also be applied to a stepped slab arranged so as to have a step. In this case, each PC
The substrate may be arranged stepwise or in such a manner as to form a concave portion or a convex portion, or may include a plurality of PC substrates arranged at the same height. Further, the present invention can of course be applied to a stepped slab formed by joining a PC board on which no void formwork is mounted. As described above, in the stepped concrete slab of the present invention, one end of a reinforcing bar embedded in a PC board arranged stepwise is protruded from a side end of the PC board. Since it is fixed in the step portion of the concrete formed on the lower side PC board, the integration of the step portion and each PC board is improved and the strength of the step portion is improved as compared with the related art. There is little possibility of cracks occurring in the concrete joint during and after construction.
【図面の簡単な説明】 【図１】実施形態のコンクリートスラブの要部縦断面図 【図２】従来のコンクリートスラブの要部縦断面図 【符号の説明】 １ａ、１ｂ 鉄筋 ２ａ、２ｂ ボイド型枠 ３ａ、３ｂ ＰＣ基板 ４ 現場打ちコンクリート ５ 段差部 ６、７ 補強筋 ８ 梁形補強構造 ８ａ スターラップ ８ｂ 連結筋 ９ａ、９ｂ 上端筋 １０ のみ込み部[Brief description of the drawings] FIG. 1 is a longitudinal sectional view of a main part of a concrete slab according to an embodiment. FIG. 2 is a longitudinal sectional view of a main part of a conventional concrete slab. [Explanation of symbols] 1a, 1b rebar 2a, 2b void formwork 3a, 3b PC board 4 Cast-in-place concrete 5 steps 6,7 reinforcement 8 Beam-shaped reinforcement structure 8a Stirrup 8b Connecting bar 9a, 9b Upper muscle 10 Enclosed part
───────────────────────────────────────────────────── フロントページの続き (72)発明者 笹本 啓吾 神奈川県海老名市中新田780番地の１ (72)発明者 中村 敬一 大阪府東大阪市西堤本通西２丁目１番35号 ────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Keigo Sasamoto 1 of 780 Nakashinden, Ebina-shi, Kanagawa (72) Inventor Keiichi Nakamura 2-35, Nishitsutsumoto-dori Nishi 2-chome, Higashiosaka City, Osaka Prefecture
Claims (1)
で平行に埋め込んだ複数のＰＣ基板を、鉄筋が延びる方
向に並べて側端部どうしを近接させた状態で段違いに配
置し、各ＰＣ基板上にコンクリートを打設して下段側Ｐ
Ｃ基板上にコンクリートの段差部を形成し、各ＰＣ基板
を一体に接合した段差付きコンクリートスラブにおい
て、前記各ＰＣ基板に埋め込まれた鉄筋の一端部を、そ
のＰＣ基板の側端部から突出させ、前記段差部内へ定着
させたことを特徴とする段差付きコンクリートスラブ。Claims: 1. A plurality of PC boards in which reinforcing bars are embedded in parallel in a concrete thin plate at predetermined intervals in a concrete thin plate, and are arranged stepwise in a state where the side ends are brought close to each other in a direction in which the reinforcing bars extend. Then, concrete is cast on each PC board and the lower side P
A stepped portion of concrete is formed on a C board, and in a stepped concrete slab in which each PC board is integrally joined, one end of a reinforcing bar embedded in each PC board is projected from a side end of the PC board. A stepped concrete slab fixed in the stepped portion.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2002043493A JP2003239438A (en) | 2002-02-20 | 2002-02-20 | Concrete slab with stepped section |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2002043493A JP2003239438A (en) | 2002-02-20 | 2002-02-20 | Concrete slab with stepped section |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2003239438A true JP2003239438A (en) | 2003-08-27 |
Family
ID=27783269
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2002043493A Pending JP2003239438A (en) | 2002-02-20 | 2002-02-20 | Concrete slab with stepped section |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2003239438A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006307435A (en) * | 2005-04-26 | 2006-11-09 | Shimizu Corp | Slab with level difference and method of constructing the same |
| JP2007146479A (en) * | 2005-11-28 | 2007-06-14 | Kumagai Gumi Co Ltd | Stepped floor slab structure |
| JP2009102918A (en) * | 2007-10-24 | 2009-05-14 | Kumagai Gumi Co Ltd | Floor slab with level difference and its construction method |
-
2002
- 2002-02-20 JP JP2002043493A patent/JP2003239438A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006307435A (en) * | 2005-04-26 | 2006-11-09 | Shimizu Corp | Slab with level difference and method of constructing the same |
| JP4565332B2 (en) * | 2005-04-26 | 2010-10-20 | 清水建設株式会社 | Stepped slab and its construction method |
| JP2007146479A (en) * | 2005-11-28 | 2007-06-14 | Kumagai Gumi Co Ltd | Stepped floor slab structure |
| JP2009102918A (en) * | 2007-10-24 | 2009-05-14 | Kumagai Gumi Co Ltd | Floor slab with level difference and its construction method |
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