JP7615655B2 - Shear reinforcement method and shear reinforcement structure - Google Patents
Shear reinforcement method and shear reinforcement structure Download PDFInfo
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本発明は、梁等の横架材やフラットスラブ等の水平方向に延在する水平部材において生じるせん断ひび割れ幅の拡大を抑制するためのせん断補強方法及びせん断補強構造に関する。 The present invention relates to a shear reinforcement method and a shear reinforcement structure for suppressing the expansion of shear crack widths that occur in horizontal members that extend horizontally, such as beams and other cross members and flat slabs.
従来、フラットスラブは、押抜きせん断（パンチングシア）破壊が生じないように設計され、長期荷重や短期荷重に対しては、せん断ひび割れが発生しても、ひび割れ幅の拡大を抑えて、過度なひび割れが生じないように設計されることが多い。 Traditionally, flat slabs are designed to prevent punching shear failure, and for long-term or short-term loads, they are often designed to prevent excessive cracking by limiting the expansion of crack width even if shear cracks occur.
そこで、フラットスラブには、パンチングシアによるひび割れの幅を抑制するために、多数のせん断補強筋を設けている（例えば、特許文献１参照。）。この文献においては、フラットプレートに、第１所定長さ寸法で第１柱せん断補強領域を形成し、周辺のスラブ筋よりも高剛性のスラブ筋を配筋する。更に、かつ第１せん断補強領域の境界から第２所定長さ寸法で第２せん断補強領域を形成する。この場合、せん断補強領域においては、せん断補強筋の上部の平坦部を、高剛性のスラブ筋の上端筋に引っ掛け、せん断補強筋の下部のフック部を、高剛性のスラブ筋の下端筋に引っ掛ける。 Therefore, in order to suppress the width of cracks caused by punching shear, a large number of shear reinforcement bars are provided in flat slabs (see, for example, Patent Document 1). In this document, a first column shear reinforcement area is formed in the flat plate with a first predetermined length dimension, and slab reinforcement bars with higher rigidity than the surrounding slab reinforcement bars are arranged. Furthermore, a second shear reinforcement area is formed with a second predetermined length dimension from the boundary of the first shear reinforcement area. In this case, in the shear reinforcement area, the upper flat part of the shear reinforcement bar is hooked to the upper end bar of the high-rigidity slab reinforcement bar, and the lower hook part of the shear reinforcement bar is hooked to the lower end bar of the high-rigidity slab reinforcement bar.
図９に、従来のフラットスラブ９０に用いられるせん断補強筋の２種類の具体例を示す。図９の左側においては、上端部及び下端部を１８０°に折り曲げたせん断補強筋９５を示している。このせん断補強筋９５の上端部及び下端部を、それぞれフラットスラブ９０の上端筋９１と下端筋９２とに引っ掛ける。また、図９の右側においては、鉄筋の両側にヘッドバーが固定されたせん断補強筋９６を示している。このせん断補強筋９６の各ヘッドバーを、それぞれフラットスラブ９０の上端筋９１と下端筋９２と引っ掛ける。これにより、フラットスラブ９０にひび割れＣ９が生じた場合においても、ひび割れＣ９の拡大を抑制することができる。 Figure 9 shows two specific examples of shear reinforcement bars used in conventional flat slabs 90. The left side of Figure 9 shows a shear reinforcement bar 95 with its upper and lower ends bent at 180 degrees. The upper and lower ends of this shear reinforcement bar 95 are hooked to the upper end bars 91 and lower end bars 92 of the flat slab 90, respectively. The right side of Figure 9 shows a shear reinforcement bar 96 with head bars fixed to both sides of the reinforcing bar. Each head bar of this shear reinforcement bar 96 is hooked to the upper end bars 91 and lower end bars 92 of the flat slab 90, respectively. This makes it possible to suppress the expansion of cracks C9 even if they occur in the flat slab 90.
しかしながら、せん断補強筋を、フラットスラブの上端筋及び下端筋に引っ掛けて配置する作業には、手間や時間が掛かるため、施工性が悪かった。 However, the task of hooking the shear reinforcement bars onto the upper and lower end bars of the flat slab was time-consuming and difficult to install, making it difficult to construct.
上記課題を解決するせん断補強方法は、上部に配置される上部鉄筋と下部に配置される下部鉄筋とを備えた鉄筋コンクリートで構成され水平方向に延在する水平部材を、せん断補強筋を用いて補強するせん断補強方法において、前記せん断補強筋は、前記上部鉄筋に掛止する掛止部と、前記掛止部が前記上部鉄筋に掛止した状態で前記掛止部から前記下部鉄筋の近傍まで延在する補強部とを備え、前記せん断補強筋の前記掛止部を前記上部鉄筋に掛止させて、前記補強部を吊り下げた後、前記補強部を前記下部鉄筋に非掛止状態で、コンクリート打設を行なう。ここで、水平部材とは、フラットスラブに限られず、梁や床等、水平方向に延在する部材であればよい。また、下部鉄筋の近傍まで延在とは、下部鉄筋まで届く長さであってもよいし、また届かない長さであっても、水平部材のひび割れの幅を抑制できる長さまで延在していればよい。 The shear reinforcement method that solves the above problem is a shear reinforcement method that uses shear reinforcement to reinforce a horizontal member that is made of reinforced concrete with an upper reinforcing bar placed at the top and a lower reinforcing bar placed at the bottom and extends horizontally, the shear reinforcement has a hook part that hooks onto the upper reinforcing bar and a reinforcing part that extends from the hook part to the vicinity of the lower reinforcing bar while the hook part hooks onto the upper reinforcing bar, and after the hook part of the shear reinforcement is hooked onto the upper reinforcing bar to hang the reinforcing part, concrete is poured with the reinforcing part not hooked onto the lower reinforcing bar. Here, the horizontal member is not limited to a flat slab, but may be any member that extends horizontally, such as a beam or floor. In addition, extending to the vicinity of the lower reinforcing bar may be a length that reaches the lower reinforcing bar, or even if it does not reach the length, it may be a length that can suppress the width of cracks in the horizontal member.
本発明によれば、ひび割れ幅の拡大を抑制するせん断補強筋を効率的に配置することができる。 According to the present invention, it is possible to efficiently place shear reinforcement bars that suppress the expansion of crack width.
以下、図１及び図２を用いて、せん断補強方法及びせん断補強構造を具体化した一実施形態を説明する。本実施形態では、フラットスラブのパンチングシアによるひび割れの幅を抑制するせん断補強方法及びせん断補強構造について説明する。 Below, an embodiment of a shear reinforcement method and a shear reinforcement structure will be described with reference to Figures 1 and 2. In this embodiment, a shear reinforcement method and a shear reinforcement structure that suppress the width of cracks caused by punching shear in flat slabs will be described.
図１に示すように、柱１５の周囲には、水平部材としてのフラットスラブ２０が設けられている。柱１５及びフラットスラブ２０は、鉄筋コンクリートで構成される。具体的には、フラットスラブ２０は、複数の上端筋２１、下端筋２２及びせん断補強筋３０を備える。複数の上端筋２１は、フラットスラブ２０の上部に格子状に配置された上部鉄筋であり、複数の下端筋２２は、フラットスラブ２０の下部に格子状に配置された下部鉄筋である。そして、これら上端筋２１、下端筋２２及びせん断補強筋３０は、コンクリート２５に埋設されて、平面状に延在するフラットスラブ２０を構成する。 As shown in FIG. 1, a flat slab 20 is provided around the column 15 as a horizontal member. The column 15 and the flat slab 20 are made of reinforced concrete. Specifically, the flat slab 20 includes a plurality of upper end bars 21, lower end bars 22, and shear reinforcement bars 30. The upper end bars 21 are upper reinforcing bars arranged in a lattice pattern on the upper part of the flat slab 20, and the lower end bars 22 are lower reinforcing bars arranged in a lattice pattern on the lower part of the flat slab 20. These upper end bars 21, lower end bars 22, and shear reinforcement bars 30 are embedded in concrete 25 to form the flat slab 20 that extends in a plane.
せん断補強筋３０は、中央の掛止部３１ａと、掛止部３１ａの両端に接続され下方に延在した２個の補強部３１ｂと、各補強部３１ｂの下端部にそれぞれ設けた定着プレート３２とを備える。本実施形態では、１本の鉄筋３１をＵ字形状に折り曲げて、掛止部３１ａ及び補強部３１ｂを構成する。掛止部３１ａは、上端筋２１の格子の間隔に対応した長さを有する。補強部３１ｂは、ひび割れＣ１が発生した際にひび割れが拡大しないように、上端筋２１から下端筋２２の近傍（下端筋２２の上面から数ミリ上の位置）まで延在させる。定着プレート３２は、金物等で構成され、せん断補強筋３０の鉄筋３１をコンクリート２５内に定着させる定着部である。 The shear reinforcement 30 comprises a central hook 31a, two reinforcing parts 31b connected to both ends of the hook 31a and extending downward, and an anchoring plate 32 provided at the lower end of each reinforcing part 31b. In this embodiment, one reinforcing bar 31 is bent into a U-shape to form the hook 31a and reinforcing part 31b. The hook 31a has a length corresponding to the spacing of the lattice of the upper end reinforcing bar 21. The reinforcing part 31b extends from the upper end reinforcing bar 21 to the vicinity of the lower end reinforcing bar 22 (a position several millimeters above the upper surface of the lower end reinforcing bar 22) so that the crack C1 does not expand when it occurs. The anchoring plate 32 is made of metal or the like and is an anchoring part that anchors the reinforcing bar 31 of the shear reinforcement 30 into the concrete 25.
（フラットスラブの施工方法）
次に、上述したせん断補強構造を用いたフラットスラブ２０の施工方法について説明する。
(Flat slab construction method)
Next, a method for constructing the flat slab 20 using the above-mentioned shear reinforcement structure will be described.
図２に示すように柱１５の周囲にフラットスラブ２０の下端筋２２を格子状に配置し、交点を緊結する。そして、下端筋２２の上方に、下端筋２２と離間させて上端筋２１を格子状に配置し、交点を緊結する。 As shown in Figure 2, the bottom reinforcement bars 22 of the flat slab 20 are arranged in a lattice pattern around the columns 15, and the intersections are fastened. Then, above the bottom reinforcement bars 22, the top reinforcement bars 21 are arranged in a lattice pattern, spaced apart from the bottom reinforcement bars 22, and the intersections are fastened.
次に、フラットスラブ２０の上端筋２１に、複数のせん断補強筋３０を吊下する。
この場合、図１に示すように、せん断補強筋３０の掛止部３１ａを、隣接する２つの上端筋２１に引っ掛けるようにして、上から降ろす。そして、せん断補強筋３０の定着プレート３２は、下端筋２２よりも数ｍｍ程度、上方に配置される。
Next, multiple shear reinforcement bars 30 are suspended from the upper end bars 21 of the flat slab 20.
In this case, as shown in Fig. 1, the hooking portion 31a of the shear reinforcement 30 is lowered from above so as to hook onto two adjacent upper end reinforcements 21. The fixing plate 32 of the shear reinforcement 30 is positioned above the lower end reinforcements 22 by several mm.
図２に示すように、せん断補強筋３０は、柱１５の周囲のせん断補強領域に、適切な間隔で配置される。ここで、せん断補強領域は、例えば、ひび割れＣ１（図１）が発生する可能性がある領域である。なお、せん断補強筋３０の掛止部３１ａの延在方向は任意である。
そして、上述したように、上端筋２１、下端筋２２及びせん断補強筋３０の配置後、コンクリート打設を行なう。以上により、フラットスラブ２０が完成する。
As shown in Fig. 2, the shear reinforcement bars 30 are arranged at appropriate intervals in the shear reinforcement area around the column 15. Here, the shear reinforcement area is, for example, an area where cracks C1 (Fig. 1) may occur. The extending direction of the hook portion 31a of the shear reinforcement bars 30 is arbitrary.
Then, as described above, after the upper end reinforcement 21, the lower end reinforcement 22, and the shear reinforcement 30 are arranged, concrete is poured. With the above steps, the flat slab 20 is completed.
（作用）
フラットスラブ２０の上端筋２１にせん断補強筋３０を吊るして、せん断補強筋３０の下端部の定着プレート３２を非掛止状態にしてコンクリート打設を行なってフラットスラブ２０を構築する。この場合、せん断補強筋３０の補強部３１ｂを上端筋２１から下端筋２２の近傍まで配置する。これにより、せん断補強筋３０の下端部をフラットスラブ２０の下端筋２２に引っ掛けなくても、ひび割れの拡大を抑制できる。
(Action)
The shear reinforcement 30 is hung from the upper end reinforcement 21 of the flat slab 20, and the anchor plate 32 at the lower end of the shear reinforcement 30 is in an unhung state, and concrete is poured to construct the flat slab 20. In this case, the reinforcing portion 31b of the shear reinforcement 30 is disposed from the upper end reinforcement 21 to the vicinity of the lower end reinforcement 22. This makes it possible to suppress the expansion of cracks even if the lower end of the shear reinforcement 30 is not hooked onto the lower end reinforcement 22 of the flat slab 20.
本実施形態によれば、以下のような効果を得ることができる。
（１）本実施形態のせん断補強筋３０の掛止部３１ａを、フラットスラブ２０の上端筋２１に引っ掛けて、せん断補強筋３０を配置する。これにより、せん断補強筋３０の下部を、フラットスラブ２０の下端筋２２に固定しないので、せん断補強筋３０の配置の作業負担を軽減できる。
According to this embodiment, the following effects can be obtained.
(1) In this embodiment, the hanging portion 31a of the shear reinforcement 30 is hooked onto the upper end reinforcement 21 of the flat slab 20 to place the shear reinforcement 30. As a result, the lower portion of the shear reinforcement 30 is not fixed to the lower end reinforcement 22 of the flat slab 20, so that the workload of placing the shear reinforcement 30 can be reduced.
（２）本実施形態のせん断補強筋３０の各補強部３１ｂは、上端筋２１から下端筋２２の近傍まで延在する。これにより、ひび割れＣ１が生じた場合においても、ひび割れＣ１が拡大することを抑制することができる。日本機械学会ＲＣ規準における設計方法では、フラットスラブの耐力は、フラットスラブの断面厚とコンクリート強度のみで決定されており、せん断補強筋３０の下端筋２２の固定は、フラットスラブ２０の終局設計には考慮されていない。従って、せん断補強筋３０を下端筋２２に固定しなくても、フラットスラブの断面厚とコンクリート強度を担保すれば、従来と同様に、フラットスラブの耐力を維持することができる。 (2) In this embodiment, each reinforcing portion 31b of the shear reinforcement 30 extends from the upper end reinforcement 21 to the vicinity of the lower end reinforcement 22. This makes it possible to prevent crack C1 from expanding even if it occurs. In the design method in the RC Standards of the Japan Society of Mechanical Engineers, the strength of a flat slab is determined only by the cross-sectional thickness of the flat slab and the concrete strength, and the fixing of the lower end reinforcement 22 of the shear reinforcement 30 is not taken into consideration in the ultimate design of the flat slab 20. Therefore, even if the shear reinforcement 30 is not fixed to the lower end reinforcement 22, the strength of the flat slab can be maintained as in the conventional case, as long as the cross-sectional thickness of the flat slab and the concrete strength are guaranteed.
（３）本実施形態のせん断補強筋３０は、２つの上端筋２１に引っ掛ける掛止部３１ａを備え、掛止部３１ａは、２つの上端筋２１に対応する長さを有する。これにより、フラットスラブ２０のコンクリート打設時にも、せん断補強筋３０の揺動や配置ずれを抑制できる。 (3) In this embodiment, the shear reinforcement 30 has a hook portion 31a that hooks onto the two upper end reinforcements 21, and the hook portion 31a has a length corresponding to the two upper end reinforcements 21. This makes it possible to suppress the swaying and displacement of the shear reinforcement 30 even when pouring concrete into the flat slab 20.
（４）本実施形態のせん断補強筋３０はＵ字形状を有する。これにより、１回の作業で、２つの補強部３１ｂを効率的に配置することができる。
（５）本実施形態のせん断補強筋３０は、掛止部３１ａ及び補強部３１ｂを１本の鉄筋で構成するので、簡単な構成でせん断補強筋３０を実現できる。
(4) The shear reinforcement 30 of the present embodiment has a U-shape. This allows the two reinforcement portions 31b to be efficiently arranged in one operation.
(5) In the present embodiment, the hanging portion 31a and the reinforcing portion 31b of the shear reinforcement 30 are formed from a single steel bar, so that the shear reinforcement 30 can be realized with a simple structure.
本実施形態は、以下のように変更して実施することができる。本実施形態及び以下の変更例は、技術的に矛盾しない範囲で互いに組み合わせて実施することができる。
・上記実施形態では、フラットスラブ２０の上端筋２１にせん断補強筋３０を吊下させた場合に、定着プレート３２が下端筋２２よりも数ミリ上に位置するように、せん断補強筋３０の補強部３１ｂの長さを決定した。せん断補強筋３０の補強部３１ｂの長さは、水平部材のひび割れの幅を抑制できる長さであれば、これに限定されない。
This embodiment can be modified as follows: This embodiment and the following modifications can be combined with each other to the extent that there is no technical contradiction.
In the above embodiment, the length of the reinforcing portion 31b of the shear reinforcement 30 is determined so that the anchor plate 32 is positioned several millimeters above the bottom end reinforcement 22 when the shear reinforcement 30 is suspended from the top end reinforcement 21 of the flat slab 20. The length of the reinforcing portion 31b of the shear reinforcement 30 is not limited to this as long as it is a length that can suppress the width of cracks in the horizontal member.
例えば、図３に示すように、フラットスラブ４０の下端筋２２まで、補強部３６ｂが延在するせん断補強筋３５を用いてもよい。このせん断補強筋３５は、中央部の掛止部３６ａと、掛止部３６ａの両端部に接続された補強部３６ｂと、補強部３６ｂの下端部に設けた定着プレート３２とを備える。掛止部３６ａ及び２個の補強部３６ｂは１本の鉄筋３６で構成される。更に、せん断補強筋３５は、２つの補強部３６ｂの間隔が下になるに従って広がる形状を有してもよい。これにより、せん断補強筋３５の配置を効率的に行なうことができる。
更に、せん断補強筋の補強部は、下部鉄筋に対して非掛止状態であればよく、例えば、コンクリート打設時に他の部材に仮止めされた状態であってもよい。
For example, as shown in Fig. 3, a shear reinforcement 35 may be used in which the reinforcing portion 36b extends to the bottom end bar 22 of the flat slab 40. This shear reinforcement 35 includes a central hook portion 36a, reinforcing portions 36b connected to both ends of the hook portion 36a, and an anchor plate 32 provided at the bottom end of the reinforcing portion 36b. The hook portion 36a and the two reinforcing portions 36b are composed of one reinforcing bar 36. Furthermore, the shear reinforcement 35 may have a shape in which the distance between the two reinforcing portions 36b increases downward. This allows the shear reinforcement 35 to be arranged efficiently.
Furthermore, the reinforcing portion of the shear reinforcement bar need only be in a non-hooked state relative to the lower reinforcing bar, and may be temporarily attached to another member when the concrete is poured, for example.
・上記実施形態では、せん断補強筋３０の掛止部３１ａは、隣接する２つの上端筋２１に掛止させた。せん断補強筋の掛止部は、上端筋２１に引っ掛けることができれば、隣接する２つの上端筋に引っ掛ける構造に限られない。 - In the above embodiment, the hook portion 31a of the shear reinforcement 30 is hooked to two adjacent upper end bars 21. As long as the hook portion of the shear reinforcement can be hooked to the upper end bars 21, it is not limited to a structure in which it is hooked to two adjacent upper end bars.
例えば、図４に示すように、フラットスラブ４１に埋設されるせん断補強筋３７の掛止部３８ａの長さを、３つの上端筋２１に渡る長さとする。そして、掛止部３８ａを３個の上端筋２１に当接させた後、掛止部３８ａに接続する補強部３８ｂが下方に延在する構成のせん断補強筋３７としてもよい。ここで、掛止部３８ａとこれに接続する２個の補強部３８ｂは、１本の鉄筋３８で構成される。 For example, as shown in FIG. 4, the length of the hanging portion 38a of the shear reinforcement 37 embedded in the flat slab 41 is set to a length that spans three upper end reinforcements 21. The hanging portion 38a may be abutted against the three upper end reinforcements 21, and then the reinforcing portion 38b connected to the hanging portion 38a may extend downwardly. Here, the hanging portion 38a and the two reinforcing portions 38b connected thereto are composed of a single reinforcing bar 38.
・上記実施形態のせん断補強筋３０は、２本の補強部３１ｂを有する。せん断補強筋３０の補強部の数は２個に限定されない。
例えば、図５に示すように、１個の補強部５１ｂのみを備えるせん断補強筋５０を用いたフラットスラブ４２でもよい。このせん断補強筋５０は、略平坦な掛止部５１ａの一方の端部にのみ接続する補強部５１ｂを備える。せん断補強筋の掛止部５１ａ及び１個の補強部５１ｂを、１本の鉄筋５１で構成する。更に、せん断補強筋は、補強部５１ｂの下端部に定着プレート５２を設ける。
The shear reinforcement 30 in the above embodiment has two reinforcing portions 31b. The number of reinforcing portions of the shear reinforcement 30 is not limited to two.
For example, as shown in Fig. 5, a flat slab 42 may be used that uses a shear reinforcement 50 having only one reinforcing portion 51b. This shear reinforcement 50 has a reinforcing portion 51b that is connected only to one end of a substantially flat hanging portion 51a. The hanging portion 51a and one reinforcing portion 51b of the shear reinforcement are composed of one reinforcing bar 51. Furthermore, the shear reinforcement has an anchor plate 52 provided at the lower end of the reinforcing portion 51b.
・上記実施形態のせん断補強筋３０は、２個の補強部３１ｂの下端部のそれぞれに定着プレート３２を設けている。せん断補強筋の補強部を定着させる定着部は、補強部の下端部において設けられていれば、定着プレートに限られない。 - In the above embodiment, the shear reinforcement 30 has an anchoring plate 32 at each of the lower ends of the two reinforcing parts 31b. The anchoring parts that anchor the reinforcing parts of the shear reinforcement are not limited to anchoring plates, as long as they are provided at the lower ends of the reinforcing parts.
例えば、図６に示すように、定着プレートの代わりに、折り曲げた定着長さ以上の鉄筋で定着部を構成してもよい。この場合、フラットスラブ４３に、１本の鉄筋によって構成されたせん断補強筋５５を用いることもできる。このせん断補強筋５５は、中央の掛止部５５ａ、掛止部５５ａの両側に接続される補強部５５ｂ、各補強部５５ｂに接続される定着部５５ｃを備える。補強部５５ｂは、補強部３１ｂと同様に、上端筋２１から下端筋２２までの距離に応じて、掛止部５５ａが上端筋２１に掛止した場合に、上端筋２１から下端筋２２の近傍まで延在する長さを有する。定着部５５ｃは、フラットスラブ４３の面の延在方向に、定着長さ以上の長さで延在させる。更に、補強部がコンクリートから抜けにくい構造の場合には、定着部を省略してもよい。 For example, as shown in FIG. 6, instead of the anchor plate, the anchoring part may be formed of a reinforcing bar with a length equal to or greater than the bent anchoring length. In this case, a shear reinforcement bar 55 formed of a single reinforcing bar may be used in the flat slab 43. This shear reinforcement bar 55 has a central hook 55a, reinforcing parts 55b connected to both sides of the hook 55a, and anchoring parts 55c connected to each reinforcing part 55b. Similar to the reinforcing part 31b, the reinforcing part 55b has a length that extends from the upper end reinforcing bar 21 to the vicinity of the lower end reinforcing bar 22 when the hook 55a hooks onto the upper end reinforcing bar 21, depending on the distance from the upper end reinforcing bar 21 to the lower end reinforcing bar 22. The anchoring part 55c extends in the extension direction of the surface of the flat slab 43 for a length equal to or greater than the anchoring length. Furthermore, if the reinforcing part is structured so that it is difficult for it to come out of the concrete, the anchoring part may be omitted.
・上記実施形態のせん断補強筋３０の掛止部３１ａ及び補強部３１ｂは、中央が平坦のＵ字形状とした。せん断補強筋の掛止部及び補強部は、この形状に限られず、例えば、フラットスラブ４３のコンクリート２５に埋設可能であれば、円弧形状の掛止部を備えたせん断補強筋であってもよい。また、せん断補強筋３０の掛止部３１ａ及び補強部３１ｂは、１本の鉄筋で構成したが、異なる部材で構成してもよい。 - The hanging portion 31a and reinforcing portion 31b of the shear reinforcement 30 in the above embodiment are U-shaped with a flat center. The hanging portion and reinforcing portion of the shear reinforcement are not limited to this shape, and may be, for example, a shear reinforcement with an arc-shaped hanging portion as long as it can be embedded in the concrete 25 of the flat slab 43. Also, although the hanging portion 31a and reinforcing portion 31b of the shear reinforcement 30 are made of a single reinforcing bar, they may be made of different materials.
・上記実施形態では、フラットスラブ２０にせん断補強筋３０を設けた。本願発明のせん断補強筋の構造は、フラットスラブに限らず、水平方向に延在する水平部材であればよく、例えば、通常の床や梁にも適用することができる。 - In the above embodiment, the flat slab 20 is provided with shear reinforcement bars 30. The structure of the shear reinforcement bars of the present invention is not limited to flat slabs, but can be applied to any horizontal member that extends horizontally, for example, to ordinary floors and beams.
図７は、梁７０の縦断面を示し、図８は、梁７０のコンクリート７５に埋設される鉄筋群の構造を示している。
図７に示すように、水平部材としての梁７０は、鉄筋籠７１をコンクリート７５に埋設して構成される。
FIG. 7 shows a vertical cross section of a beam 70, and FIG. 8 shows the structure of a group of reinforcing bars embedded in concrete 75 of the beam 70.
As shown in FIG. 7 , a beam 70 serving as a horizontal member is constructed by embedding a reinforcing bar cage 71 in concrete 75 .
図８に示すように、鉄筋籠７１は、離間して平行に配置された複数の主筋７２と複数の帯筋７３とを備える。帯筋７３は、主筋７２の外周を環状に囲む。そして、鉄筋籠７１において上部に配置される主筋７２に、複数のせん断補強筋８０を配置する。せん断補強筋８０は、掛止部８１ａと、掛止部８１ａの両側に設けられた補強部８１ｂと、各補強部８１ｂの下端部にそれぞれ設けられた定着プレート８２とを備える。掛止部８１ａ及び２つの補強部８１ｂは、１本の鉄筋８１で略Ｕ字形状に構成される。補強部８１ｂは、上下方向の主筋７２の間隔に応じて、上部の主筋７２に掛止部８１ａが掛止した場合に、上部に配置された主筋７２から下部に配置された主筋７２の近傍まで延在する長さを有する。そして、鉄筋籠７１を配置する際に、鉄筋籠７１の上部の主筋７２に、上からせん断補強筋８０を降ろして、せん断補強筋８０の掛止部８１ａを、隣接する２本の主筋７２に引っ掛けて、吊下させる。その後、鉄筋籠７１にせん断補強筋８０を配置した鉄筋群をコンクリート打設して梁７０を構築する。
この場合、せん断補強筋８０を、鉄筋籠７１の上部に配置される主筋７２に引っ掛けたが、梁７０のコンクリート７５のかぶり厚を増加させる必要がない場合には、鉄筋籠７１の帯筋７３に引っ掛けてせん断補強筋８０を配置してもよい。
As shown in FIG. 8, the reinforcing bar cage 71 includes a plurality of main reinforcements 72 and a plurality of tie bars 73 arranged in parallel with a space therebetween. The tie bars 73 surround the outer periphery of the main reinforcements 72 in an annular shape. A plurality of shear reinforcements 80 are arranged on the main reinforcements 72 arranged at the upper part of the reinforcing bar cage 71. The shear reinforcements 80 include a hook portion 81a, reinforcing portions 81b provided on both sides of the hook portion 81a, and fixing plates 82 provided at the lower ends of the reinforcing portions 81b. The hook portion 81a and the two reinforcing portions 81b are configured in a substantially U-shape with one reinforcing bar 81. The reinforcing portions 81b have a length that extends from the main reinforcements 72 arranged at the upper part to the vicinity of the main reinforcements 72 arranged at the lower part when the hook portion 81a is hooked on the upper main reinforcements 72 according to the spacing between the main reinforcements 72 in the vertical direction. When placing the reinforcing bar cage 71, the shear reinforcement bars 80 are lowered from above onto the main reinforcements 72 at the top of the reinforcing bar cage 71, and the hanging portions 81a of the shear reinforcement bars 80 are hooked onto and suspended by two adjacent main reinforcements 72. Thereafter, concrete is poured into the reinforcing bar group in which the shear reinforcement bars 80 are placed in the reinforcing bar cage 71 to construct the beam 70.
In this case, the shear reinforcement 80 is hooked to the main reinforcement 72 placed on the upper part of the steel cage 71, but if there is no need to increase the cover thickness of the concrete 75 of the beam 70, the shear reinforcement 80 may also be arranged by hooking it to the tie bars 73 of the steel cage 71.
次に、上記実施形態及び別例から把握できる技術的思想について、以下に追記する。
（ａ）前記せん断補強筋の前記掛止部は、２つの前記上部鉄筋に掛止したことを特徴とする請求項２に記載のせん断補強構造。
（ｂ）前記せん断補強筋は、前記掛止部の両側に連結された２つの補強部を備え、
１本の鉄筋を曲げて、前記２つの補強部及び掛止部を構成したことを特徴とする前記（ａ）に記載のせん断補強構造。
（ｃ）前記水平部材は、フラットスラブであり、
前記掛止部は、前記フラットスラブの上端筋の格子の間隔に対応した長さを有することを特徴とする請求項２、前記（ａ）又は前記（ｂ）に記載のせん断補強構造。
Next, the technical ideas that can be understood from the above embodiment and other examples will be described below.
(a) The shear reinforcement structure according to claim 2, characterized in that the hanging portion of the shear reinforcement bar is hung on two of the upper reinforcing bars.
(b) the shear reinforcement includes two reinforcement parts connected to both sides of the hanging part;
The shear reinforcement structure described in (a) above, characterized in that the two reinforcing portions and the hanging portion are formed by bending a single reinforcing bar.
(c) the horizontal member is a flat slab;
A shear reinforcement structure as described in claim 2, (a) or (b), characterized in that the hanging portion has a length corresponding to the spacing of the lattice of the upper end reinforcement of the flat slab.
１５…柱、２０，４０，４１，４２，４３…水平部材としてのフラットスラブ、２１…上部鉄筋としての上端筋、２２…下部鉄筋としての下端筋、２５，７５…コンクリート、３０，３５，３７，５０，５５，８０…せん断補強筋、３１，３６，３８，５１，８１…鉄筋、３１ａ，３６ａ，３８ａ，５１ａ，５５ａ，８１ａ…掛止部、３１ｂ，３６ｂ，３８ｂ，５１ｂ，５５ｂ，８１ｂ…補強部、３２，５２，８２…定着部としての定着プレート、５５ｃ…定着部、７０…梁、７１…鉄筋籠、７２…主筋、７３…帯筋。 15...column, 20, 40, 41, 42, 43...flat slab as horizontal member, 21...upper end bar as upper reinforcing bar, 22...lower end bar as lower reinforcing bar, 25, 75...concrete, 30, 35, 37, 50, 55, 80...shear reinforcement bar, 31, 36, 38, 51, 81...reinforcing bar, 31a, 36a, 38a, 51a, 55a, 81a...hanging part, 31b, 36b, 38b, 51b, 55b, 81b...reinforcement part, 32, 52, 82...anchoring plate as anchoring part, 55c...anchoring part, 70...beam, 71...reinforcing bar cage, 72...main bar, 73...hoop.
Claims (2)
前記せん断補強筋は、
前記上部鉄筋に掛止する掛止部と、
前記掛止部が前記上部鉄筋に掛止した状態で前記掛止部から前記下部鉄筋の近傍であって前記下部鉄筋の上方となる位置まで延在する補強部と、を備え、
前記せん断補強筋の前記掛止部を前記上部鉄筋に掛止させて、前記補強部を吊り下げた後、
前記補強部を前記下部鉄筋に閉合しない非掛止状態で、コンクリート打設を行なうことを特徴とするせん断補強方法。 A shear reinforcement method for reinforcing a horizontally extending flat slab made of reinforced concrete with an upper reinforcing bar placed at the top and a lower reinforcing bar placed at the bottom, using a shear reinforcement bar,
The shear reinforcement is
A hook portion that hooks onto the upper reinforcing bar ;
A reinforcing portion extending from the hanging portion to a position near the lower reinforcing bar and above the lower reinforcing bar when the hanging portion is hung on the upper reinforcing bar ,
After the hanging portion of the shear reinforcement is hung on the upper reinforcing bar, the reinforcing portion is suspended,
A shear reinforcement method characterized in that concrete is poured in an unhung state in which the reinforcing portion is not closed to the lower reinforcing bar.
前記せん断補強筋は、
前記上部鉄筋に掛止する掛止部と、
前記掛止部が前記上部鉄筋に掛止した状態で前記掛止部から前記下部鉄筋の近傍であって前記下部鉄筋の上方となる位置まで延在する補強部と、を備え、
前記せん断補強筋の前記掛止部を前記上部鉄筋に掛止させることにより前記補強部を吊り下げた状態で、かつ前記補強部を前記下部鉄筋に閉合しない非掛止状態で、前記せん断補強筋をコンクリートに埋設させたことを特徴とするせん断補強構造。 In a shear reinforcement structure, a flat slab extending horizontally and made of reinforced concrete with an upper reinforcing bar placed at the top and a lower reinforcing bar placed at the bottom is reinforced with shear reinforcement.
The shear reinforcement is
A hook portion that hooks onto the upper reinforcing bar ;
A reinforcing portion extending from the hanging portion to a position near the lower reinforcing bar and above the lower reinforcing bar when the hanging portion is hung on the upper reinforcing bar ,
A shear reinforcement structure characterized in that the shear reinforcement is embedded in concrete in a suspended state by hanging the hanging portion of the shear reinforcement on the upper reinforcing bar, and in an unhanging state in which the reinforcing portion is not closed to the lower reinforcing bar.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
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| JP2001262759A (en) | 2000-03-15 | 2001-09-26 | Kajima Corp | Shear reinforcement, shear reinforcement and shear reinforcement structure of flat slab |
| JP2005139650A (en) | 2003-11-05 | 2005-06-02 | Japan Life Kk | Shearing reinforcing structure, reinforcing structure, anchoring structure and joining structure using reinforcement having dished head part |
| JP2007056453A (en) | 2005-08-22 | 2007-03-08 | Yokogawa Bridge Corp | Shear reinforcement bar structure of floor slab |
| JP2007327188A (en) | 2006-06-06 | 2007-12-20 | Shimizu Corp | Reinforced concrete body |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JP2001262759A (en) | 2000-03-15 | 2001-09-26 | Kajima Corp | Shear reinforcement, shear reinforcement and shear reinforcement structure of flat slab |
| JP2005139650A (en) | 2003-11-05 | 2005-06-02 | Japan Life Kk | Shearing reinforcing structure, reinforcing structure, anchoring structure and joining structure using reinforcement having dished head part |
| JP2007056453A (en) | 2005-08-22 | 2007-03-08 | Yokogawa Bridge Corp | Shear reinforcement bar structure of floor slab |
| JP2007327188A (en) | 2006-06-06 | 2007-12-20 | Shimizu Corp | Reinforced concrete body |
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