JP3971679B2

JP3971679B2 - Material end fixing structure for reinforced concrete buildings

Info

Publication number: JP3971679B2
Application number: JP2002225718A
Authority: JP
Inventors: 久廣平石; 正人越路
Original assignee: Tokyo Tekko Co Ltd
Current assignee: Tokyo Tekko Co Ltd
Priority date: 2002-08-02
Filing date: 2002-08-02
Publication date: 2007-09-05
Anticipated expiration: 2022-08-02
Also published as: JP2004068304A

Description

【０００１】
【発明の属する技術分野】
本発明は、鉄筋コンクリート建造物における梁等の構成材の材端固定構造に関する。
【０００２】
【従来の技術】
従来の鉄筋コンクリート建造物における梁（構成材）の柱・梁接合部（基部）への固定構造について、柱が側柱の場合を例にとって説明する。柱・梁接合部の両側に２つの梁が一直線をなして固定される。両梁の主筋が連続した鉄筋によって形成される場合には、この連続した鉄筋が柱・梁接合部を通っている。両梁の主筋が異なる鉄筋からなる場合には、柱・梁接合部内で筒体によって連結される。
【０００３】
【発明が解決しようとする課題】
上記梁の固定構造において、梁の曲げ剛性は柱・梁接合部より小さく、梁の材端で曲げ剛性が急変する。大きな地震の際に、上記建造物が水平方向に揺れると、梁の材端近傍には大きな曲げモーメントが働く。この曲げモーメントにより、梁の主筋は引張，圧縮の交番荷重を受ける。詳述すると、建造物が一方向に傾いて、ある主筋に引張り荷重が付与されると、この主筋は材端位置に最も近い領域で降伏が開始される。この主筋の降伏すなわち伸びは、梁のコンクリートの損傷をもたらす。その後で、建造物が反対方向に傾くと、一旦伸びた主筋に圧縮荷重が付与されるが、この際、損傷したコンクリートにおいて主筋の外側にかぶっている部位（かぶりコンクリート）の剥落等の損傷が生じるため、場合によっては梁の材端近傍おいて主筋が外側にはみ出すのを阻止できず、その座屈をもたらす。このようにして梁の破損が生じる。また、主筋の降伏は接合部内にも進展し、接合部内の付着を劣化させ、場合によっては接合部内での主筋の滑りが生じる。
【０００４】
【課題を解決するための手段】
本願の第１の発明は、構成材の材端を基部に固定するために、構成材の複数の主筋を基部内へ延ばすようにした鉄筋コンクリート建造物における構成材の材端固定構造において、
上記基部内には上記主筋と同軸をなす筒体が複数配され、これら筒体に上記主筋が挿入されて連結され、これら筒体の外周のほぼ全域にはコンクリートとの付着を高めるための凹凸が形成されており、筒体における構成材寄りの一方の端は上記構成材の材端より基部の奥側に位置しており、当該一方の端から構成材の材端までの所定領域における上記主筋と基部コンクリートとの付着強度が、上記主筋と構成材コンクリートとの付着強度より低く、この所定領域の主筋が地震の際に降伏する降伏予定部として提供されることを特徴とする。
【０００５】
上記構成によれば、大きな地震の際には、筒体の端と構成材の材端との間の所定領域において主筋とコンクリートの付着強度が低いので、ここで優先的に主筋の降伏が生じる。これにより、構成材内、特に材端近傍での主筋の降伏領域の拡大を軽減でき、構成材の損傷を軽減できる。
また、主筋を挿入連結した筒体の外周には凹凸が形成されており、しかもこの筒体は鉄筋より径が大きく、外周の面積が広いので、基部コンクリートとの付着が高い。その結果、主筋が上記所定領域においてコンクリートとの付着強度が低くても、これを補なうことができ主筋の基部コンクリートへの定着性能を確保することができる。また、この筒体とコンクリートの高い付着強度により、主筋の基部内での長さを短くすることも可能である。
【０００６】
上記第１発明の一態様として、上記筒体が構成材寄りの第１領域と構成材から離れた第２領域を有し、第１領域での主筋と筒体との連結強度が、第２領域での主筋と筒体との連結強度より低く、また上記主筋と構成材コンクリートとの付着強度よりも低くなっており、この第１領域の主筋も、地震の際に降伏する降伏予定部として提供される。
上記構成によれば、大きな地震の際に筒体の第１領域における主筋でも所定領域と同様に降伏が生じる。そのため、降伏長さを十分に確保でき、構成材の損傷をより一層確実に軽減できる。また、降伏長さを確保しながら筒体を長くすることができ、筒体と基部コンクリートとの付着性を高め、ひいては主筋の基部における定着性能を確保することができる。
【０００７】
上記一態様において、構成材が基部の両側に一直線をなして固定される場合には、上記筒体の中央部が第２領域として提供され、上記筒体の両側部が上記第１領域としてそれぞれ提供され、上記筒体の両端と両構成材の材端との間がそれぞれ上記所定領域として提供される。この構成によれば、対峙する２つの構成材の破損を軽減できる。２つの構成材に対して筒体を１つで済ませることができ、構成を簡略化することができる。
【０００８】
上記第１発明の他の態様として、上記主筋は筒体の全長にわたり、構成材のコンクリートとの付着強度より高い連結強度で連結されており、実質的に上記所定領域での主筋だけが降伏予定部として提供される。この構成によれば、筒体を比較的短くしてコストを低減することができる。
【０００９】
上記他の態様において構成材が基部の両側に一直線をなして固定される場合には、上記筒体の両端と両構成材の材端との間がそれぞれ上記所定領域として提供されることを特徴とする。この構成によれば、対峙する２つの構成材の破損を軽減することができる。また、２つの構成材に対して筒体を１つで済ませることができ、構成を簡略化することができる。
【００１０】
本願の第２の発明は、構成材の材端を基部に固定するために、構成材の複数の主筋を基部内へ延ばすようにした鉄筋コンクリート建造物における構成材の材端固定構造において、
上記基部内には上記主筋と同軸をなす筒体が複数配され、これら筒体に上記主筋が挿入されて連結され、これら筒体の外周のほぼ全域にはコンクリートとの付着を高めるための凹凸が形成されており、筒体における構成材寄りの一方の端は上記構成材の材端とほぼ一致した位置にあり、
上記筒体が構成材寄りの第１領域と構成材から離れた第２領域を有し、第１領域での主筋と筒体との連結強度が、第２領域での主筋と筒体との連結強度より低く、また上記主筋と構成材コンクリートとの付着強度よりも低くなっており、この第１領域の主筋が、地震の際に降伏する降伏予定部として提供されることを特徴とする。
【００１１】
この構成によれば、大きな地震の際に筒体の第１領域における主筋で優先的に降伏が生じるので、構成材の損傷を軽減できる。また、降伏予定部を確保しながら筒体を最大限長くするので、筒体と基部コンクリートとの付着性を高め、ひいては主筋の基部における定着性能を確保することができる。
【００１２】
上記第２発明において、上記構成材が基部の両側に一直線をなして固定される場合には、上記筒体の中央部が上記第２領域として提供され、上記筒体の両側部が上記第１領域としてそれぞれ提供され、上記筒体の両端と両構成材の材端との間がそれぞれ上記所定領域として提供される。この構成によれば、対峙する２つの構成材の破損を軽減できる。２つの構成材に対して筒体を１つで済ませることができ、構成を簡略化することができる。
【００１３】
対峙する２つの構成材を固定する場合において、両構成材の主筋が異なる鉄筋で形成され、これら主筋の端部が上記筒体を介して互いに連結されている構成では、筒体が上述した役割のみならず、主筋同士を連結する役割をも果たすことができる。
【００１４】本発明は、梁固定構造に適用できる。すなわち、上記基部が柱・梁接合部であり、上記構成材が梁であり、上記主筋および筒体が水平をなしている。
【００１５】
【発明の実施の形態】
以下、本発明の第１実施形態について図１，図２を参照しながら説明する。この実施形態は、建物の外周に位置する側柱１と２本の梁２（構成材）の柱・梁接合部３（基部）に、本発明を適用したものである。柱１は、垂直に延びる複数の主筋と、これら主筋を囲む環状の剪断補強筋（いずれも図示せず）と、これら主筋および剪断補強筋を埋め込むコンクリート１ａとを有している。
【００１６】
２本の梁２は一直線をなして水平に配置されていてその材端Ｅが柱・梁接合部３に固定されている。各梁２は、上下に複数ずつ配置されて水平に延びる主筋１０と、これら主筋１０を囲む環状の剪断補強筋（図示しない）と、これら主筋１０および剪断補強筋を埋め込むコンクリート２ａとを有している。なお、柱・梁接合部３のコンクリートを符号３ａで示す。
【００１７】
上記梁２の主筋１０は、柱１の主筋と同様に異形鉄筋からなり、その外周にはフシが形成されており、コンクリート２ａとの十分な付着を確保している。図２に示すように本実施形態では、主筋１０はネジ鉄筋であり、ネジフシ１１を有している。
【００１８】
図１に戻って説明すると、両梁２の主筋１０は、異なるネジ鉄筋により形成されており、柱・梁接合部３内まで延び、その端部が柱・梁接合部３の中央に達している。柱・梁接合部３内には、上下にそれぞれ複数ずつ鋳鉄等の金属製の筒体２０が配置されている。各筒体２０は、２つの梁２の対応する主筋１０と一直線をなして水平をなしており、これら主筋１０の端部が挿入され連結されている。
【００１９】
上記筒体２０は、従来の梁主筋連結のために用いられている筒体より遥かに長く形成されており、柱せい（柱１ないしは柱・梁接合部３の幅、すなわち主筋１０の延び方向の寸法）の過半を占めている。本実施形態では柱せいより短く、その両端は梁２の材端Ｅから離れている。筒体２０の左右両側部（梁２寄りの領域）が第１領域Ｙとして提供され、筒体２０の中央部（梁２から離れた領域）が第２領域Ｎとして提供される。
【００２０】
図２に示すように、筒体２０の第２領域Ｎは雌ねじ２１ａを有する螺合部２１となっている。螺合部２１の中央は厚肉部２１ｂとなっており、この厚肉部２１ｂにモルタル注入口２１ｃが形成されている。第１領域Ｙは内周面が円滑な円筒形状をなすスリーブ部２２となっている。スリーブ部２２は螺合部２１と同軸をなし、その内径は螺合部２１の雌ねじ２１ａの谷径より大きくなっている。スリーブ部２２の周壁において螺合部２１の近傍にはモルタル注入口２２ｃが形成されている。
【００２１】
上記スリーブ部２２の外周には環状の凸部２２ａおよび軸方向に延びる凸部１２ｂが形成されている。これら凸部２２ａ，２２ｂおよび上記厚肉部２１ｂにより、筒体２０の外周のほぼ全域が凹凸形状をなしている。これにより、コンクリート３ａとの高い付着性を確保している。
【００２２】
２本の主筋１０は一直線をなした状態で、その端部が上記筒２０の螺合部２１に螺合され、強固に連結される。この連結状態において、モルタル注入口２１ｃからモルタルを注入することにより、螺合部２１の内周と主筋１０の外周との間の隙間にモルタルを充填し、これにより連結強度をさらに高めている。
【００２３】
また、スリーブ部２２の注入口２２ｃからモルタル２５を注入することにより、スリーブ部２２と主筋１０との間にモルタル２５を充填する。スリーブ部２２の内周面は平滑であるので、主筋１０とスリーブ部２２とのモルタル２５を介した連結強度（主筋１０の軸方向の引張荷重に対する連結強度）は、螺合部２１と主筋１０との連結強度より遥かに低い。なお、この主筋１１とスリーブ部２２の連結強度は、主筋１０と梁２のコンクリート２ａの付着強度よりも低い。
【００２４】
上記筒体１１の両端と両梁２の材端Ｅとの間の所定領域Ｓでは、主筋１０の外周にテープが巻かれたり粘度や樹脂が塗布されているため、柱・梁接合部３のコンクリート３ａとの付着強度が非常に低く、実質的にゼロ（アンボンド状態）である。
【００２５】
上記柱・梁接合部３において、鉄筋コンクリート建造物が地震によって横揺れした時には、従来構造と同様に梁２の材端Ｅの近傍に大きな曲げモーメントが付与される。この際、コンクリート２ａ，３ａ間に割れが生じる点では従来構造と似ているが、以下に述べる点で従来構造と大きく異なる。
【００２６】
例えば柱１が図１（Ｂ）に示すように右に傾くと、右側の梁２の下側の主筋１０と左側の梁２の上側の主筋１０が引張り荷重を受ける。この際、主筋１０は、所定領域Ｓにおいてコンクリート３ａとの付着強度が実質的にゼロであり、梁２のコンクリート２ａとの付着強度より遥かに低いので、この所定領域Ｓで優先的に降伏がなされる。また、主筋１０は筒体２０の第１領域Ｙでの連結強度が梁２のコンクリート２ａとの付着強度より低いので、ここでも降伏がなされる。その結果、主筋１０は梁２内において材端Ｅの近傍での降伏の進展を軽減でき、材端Ｅの近傍でのコンクリート２ａの破損を軽減できる。
【００２７】
上記とは逆に、柱１が左に傾くと、上記の伸びた部位が圧縮荷重を受けて元の長さに戻り、右側の梁２の上側の主筋１０と左側の梁２の下側の主筋１０が引張り荷重を受けて領域Ｙ，Ｓで伸びる。このようにして、主筋１０が引張り，圧縮の交番荷重を受け持ちながら、伸びと圧縮の変形を繰り返す。その結果、地震エネルギーを吸収することができ、建造物の耐震性を向上できる。
【００２８】
次に、主筋１０の柱・梁接合部３での定着性能について説明する。筒体２０が広い外周面のほぼ全域に凹凸が形成されているので、コンクリート３ａとの付着強度が高く、引張荷重を分散して受け止めることもできる。主筋１０は筒体２０に螺合により強固に連結されているから、筒体２０とコンクリート３ａの高い付着強度により、柱・梁接合部３での定着性能を確保することができる。所定領域Ｓで主筋１０とコンクリート３ａとの付着強度が低くても、上記筒体２０がそれを補って、主筋１０の定着性能を確保しているのである。
【００２９】
次に、本発明の他の実施形態について説明する。これら実施形態において先行する実施形態に対応する構成部には同番号を付してその詳細な説明を省略する。図３を参照しながら本発明の第２実施形態を説明する。この実施形態では、筒体２０の両端が梁２の材端Ｅと一致しているかその近傍に位置しており、その長さは柱せいとほぼ一致している。第１実施形態の領域Ｓは存在しない。筒体２０を最大限に長くするので、コンクリート３ａとの付着強度を高めることができ、ひいては主筋１０の柱・梁接合部３での定着強度を高めることができる。主筋１０の降伏の殆どは筒体２０の第１領域Ｙの部分で担う。
【００３０】
図４の第３実施形態では、第１実施形態の第１領域Ｙは存在しない。例えば筒体２０の全長にわたって雌ねじが形成されており、２本の主筋１０と強固に連結されている。すなわち、筒体２０の全長が第１実施形態の第２領域Ｎと同様の連結状態となっている。筒体２０の両端と両梁２の材端Ｅとの間の領域Ｓで主筋１０は第１実施形態と同様に付着力が低くなっており、ここで地震時の降伏を担う。
【００３１】
上記第１〜第３実施形態は柱１が側柱の場合について述べたが、柱１が中柱で梁が十字形に固定される場合についてもそのまま適用できる。この場合、柱・梁接合部に一直線をなす２本の梁が２組固定されることになる。
また、上記第１〜第３実施形態において、１本の連続した鉄筋が柱・梁接合部を通り２つの梁の中間部まで延び、これら２つの梁の主筋を構成していてもよい。この場合でも、筒体は第１〜第３実施形態と同様にして梁の主筋に連結される。なお各梁では、その中間部で主筋の端部同士をカプラーで連結される。これら実施形態では、図１〜図４において、筒体内で主筋が途切れずに連続した状態となるだけであり、容易に理解できるので、図示を省略する。
【００３２】
図５に示す第４実施形態は柱１が隅柱の場合に本発明を適用したものである。この実施形態では、筒２０は梁２寄りの第１領域Ｙと梁２から離れた第２領域Ｎとを有している。筒体２０の一端と梁２の材端Ｅとの間は所定領域Ｓとなっている。これら領域Ｙ，Ｎ，Ｓでの主筋１０の連結強度，付着強度に関しては第１実施形態と殆ど同じであるので説明を省略する。なお、この隅柱での柱・梁接合部３において、第２実施形態と同様に筒２０の一端を材端Ｅと一致させて所定領域Ｓを省略して、第１領域Ｙで殆どの降伏を担ってもよいし、第３実施形態と同様に筒２０の第１領域Ｙを省略して、所定領域Ｓで殆どの降伏を担ってもよい。
【００３３】
さらに本発明は上記実施形態に拘わらず、種々の形態を採用可能である。筒体２０の外周の凹凸形状は上記実施形態に制約されず、コンクリート３ａとの付着性を高めるためのあらゆる形状の凹凸を採用することができる。例えば外周面全域に細かい凹凸を多数形成してもよい。
【００３４】
主筋１０と筒体２０の第２領域Ｎとは、螺合によらず、モルタルによる連結を採用してもよい。例えば、筒体２０の第２領域Ｎの内周には、複数の環状の突起を軸方向に間隔をおいて形成する。この環状の突起と異形鉄筋からなる主筋のフシ（ねじ鉄筋の場合にはねじフシ）とがモルタルを介して連結されることになる。
第３実施形態において、筒体２０の中央部で主筋１０と螺合し、筒体２０の左右部の内周に環状突起を形成して主筋１０とモルタル結合してもよい。この場合、この左右部の連結強度は、主筋１０と梁２内のコンクリート２ａとの付着強度より高い。
【００３５】
筒体２０の第１領域Ｙにおいて、スリーブ部２２の内周に粗く間隔をおいて環状の突起を形成し、付着強度を上記実施形態より高めてもよい。ただし、この場合の第１領域Ｙでの筒体２０と主筋１０の連結強度は、主筋１０と梁２内のコンクリート２ａとの付着強度より低い。
【００３６】
第２領域Ｙにおいて主筋１０の外周にテープを巻いたり粘度や樹脂等が塗布することにより、筒体２０との連結強度を実質的にゼロ（アンボンド状態）にしてもよい。
【００３７】
所定領域Ｓでの付着強度を低めたり、第１領域Ｙで筒体２０との連結強度を低めるために、主筋１０のフシをなくして丸棒部を形成することにより得てもよい。
【００３８】
筒体２０は、第２領域Ｎで主筋１０にかしめ等により圧着させてもよい。第１領域Ｙでのモルタル充填は省いてもよい。
上記全ての実施形態において、一部の主筋たとえば上側の主筋だけに本発明を提供してもよい。
【００３９】
本発明は、構成材が柱で基部が基礎コンクリートの場合にも適用でき、柱が構成材で基部が柱・梁接合部の場合にも適用できる。また、本発明は鉄骨鉄筋コンクリート建造物にも適用される。また、プレキャスト構造にも適用できる。さらに、構成材としてプレストレストコンクリートを用いることもできる。
【００４０】
【発明の効果】
以上説明したように本発明の固定構造によれば、地震の際の構成材の破損を著しく軽減でき、構成材主筋の基部への定着機能を著しく向上できる。
【図面の簡単な説明】
【図１】本発明の第１実施形態をなす柱・梁接合部の縦断面図であり、（Ａ）は通常時の状態、（Ｂ）は地震時の状態を示す。
【図２】同実施形態で用いられる筒体と梁主筋を示す図である。
【図３】本発明の第２実施形態をなす柱・梁接合部を示す縦断面図である。
【図４】本発明の第３実施形態をなす柱・梁接合部の縦断面図である。
【図５】本発明の第４実施形態をなす柱・梁接合部の縦断面図である。
【符号の説明】
Ｅ材端位置
Ｎ第１領域
Ｙ第２領域
Ｓ所定領域
２梁（構成材）
３柱・梁接合部（基部）
２ａ，３ａコンクリート
１０鉄筋
２０筒体[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a material end fixing structure for structural members such as beams in a reinforced concrete building.
[0002]
[Prior art]
A structure for fixing a beam (component) to a column / beam joint (base) in a conventional reinforced concrete building will be described taking a case where the column is a side column as an example. Two beams are fixed in a straight line on both sides of the column / beam joint. When the main bars of both beams are formed by continuous reinforcing bars, the continuous reinforcing bars pass through the column / beam joint. When the main bars of both beams are made of different reinforcing bars, they are connected by a cylinder in the column / beam joint.
[0003]
[Problems to be solved by the invention]
In the beam fixing structure, the bending stiffness of the beam is smaller than that of the column / beam joint, and the bending stiffness changes suddenly at the end of the beam. If the building shakes in the horizontal direction during a large earthquake, a large bending moment acts near the end of the beam. Due to this bending moment, the main bar of the beam receives an alternating load of tension and compression. More specifically, when a building is tilted in one direction and a tensile load is applied to a certain main reinforcement, the main reinforcement starts to yield in a region closest to the material end position. This yielding or elongation of the main reinforcement causes damage to the concrete of the beam. After that, when the building is tilted in the opposite direction, a compressive load is applied to the main bars that have been stretched once. However, at this time, damage such as peeling off of the part of the damaged concrete that covers the main bars (covering concrete) Therefore, in some cases, it is impossible to prevent the main bar from protruding outside in the vicinity of the end of the beam, resulting in buckling. In this way, the beam is broken. In addition, the yield of the main reinforcement also extends into the joint, deteriorating the adhesion in the joint, and in some cases, the main bars slip in the joint.
[0004]
[Means for Solving the Problems]
The first invention of the present application is a material end fixing structure of a component material in a reinforced concrete building in which a plurality of main bars of the component material are extended into the base portion in order to fix the material end of the component material to the base portion.
A plurality of cylinders that are coaxial with the main bars are arranged in the base, and the main bars are inserted into and connected to the cylinders, and unevenness for enhancing adhesion with concrete is provided in almost the entire outer periphery of the cylinders. Is formed, and one end of the cylindrical body near the constituent material is located on the back side of the base from the material end of the constituent material, and the above in a predetermined region from the one end to the material end of the constituent material The bond strength between the main reinforcement and the base concrete is lower than the adhesion strength between the main reinforcement and the component material concrete, and the main reinforcement in this predetermined region is provided as a planned yield portion that yields in the event of an earthquake.
[0005]
According to the above configuration, in the event of a large earthquake, the bond strength between the main reinforcement and the concrete is low in a predetermined region between the end of the cylinder and the end of the constituent material. . Thereby, the expansion of the yield region of the main reinforcement in the component material, particularly in the vicinity of the material end can be reduced, and damage to the component material can be reduced.
In addition, irregularities are formed on the outer periphery of the cylindrical body in which the main bars are inserted and connected, and the cylindrical body is larger in diameter than the reinforcing bars and has a larger area on the outer periphery, and therefore, the adhesion to the base concrete is high. As a result, even if the main reinforcement has low adhesion strength with concrete in the predetermined region, this can be compensated for and the fixing performance of the main reinforcement to the base concrete can be ensured. In addition, due to the high adhesion strength between the cylindrical body and the concrete, it is possible to shorten the length of the main bar in the base portion.
[0006]
As one aspect of the first invention, the cylindrical body has a first region closer to the constituent material and a second region separated from the constituent material, and the connection strength between the main bar and the cylindrical body in the first region is second. It is lower than the connection strength between the main reinforcement and the cylinder in the area, and lower than the bond strength between the main reinforcement and the concrete material. The main reinforcement in the first area is also a planned yielding part that yields in the event of an earthquake. Provided.
According to the above configuration, yielding also occurs in the main reinforcement in the first region of the cylindrical body in the event of a large earthquake, as in the predetermined region. Therefore, the yield length can be sufficiently secured, and damage to the constituent material can be further reliably reduced. In addition, the cylinder can be lengthened while ensuring the yield length, the adhesion between the cylinder and the base concrete can be improved, and as a result, the fixing performance at the base of the main bar can be ensured.
[0007]
In the one aspect, when the constituent material is fixed in a straight line on both sides of the base portion, the central portion of the cylindrical body is provided as a second region, and both side portions of the cylindrical body are respectively provided as the first region. Provided, and the space between both ends of the cylindrical body and the material ends of both components is provided as the predetermined region. According to this configuration, it is possible to reduce damage to the two constituent members facing each other. One cylindrical body can be used for two components, and the configuration can be simplified.
[0008]
As another aspect of the first invention, the main bars are connected with a connection strength higher than the adhesion strength of the constituent material to the concrete over the entire length of the cylindrical body, and only the main bars in the predetermined region are scheduled to yield. Offered as a part. According to this structure, a cylinder can be made comparatively short and cost can be reduced.
[0009]
In the other aspect, in the case where the constituent material is fixed in a straight line on both sides of the base, the predetermined region is provided between both ends of the cylindrical body and the material end of the two constituent materials. And According to this configuration, it is possible to reduce damage to the two constituent members facing each other. In addition, one cylindrical body can be used for the two components, and the configuration can be simplified.
[0010]
According to a second invention of the present application, in order to fix the material end of the constituent material to the base, in the material end fixing structure of the constituent material in the reinforced concrete building in which a plurality of main bars of the constituent material are extended into the base,
A plurality of cylinders that are coaxial with the main bars are arranged in the base, and the main bars are inserted into and connected to the cylinders, and unevenness for enhancing adhesion with concrete is provided in almost the entire outer periphery of the cylinders. Is formed, and one end of the cylindrical body near the constituent material is in a position substantially coincident with the material end of the constituent material,
The cylinder has a first region closer to the component and a second region away from the component, and the connection strength between the main reinforcement and the cylinder in the first region is the relationship between the main reinforcement and the cylinder in the second region. It is lower than the connection strength and lower than the bond strength between the main reinforcement and the component material concrete, and the main reinforcement in the first region is provided as a planned yielding portion that yields in the event of an earthquake.
[0011]
According to this configuration, since a yield occurs preferentially in the main reinforcement in the first region of the cylindrical body in the event of a large earthquake, damage to the constituent material can be reduced. In addition, since the cylinder is lengthened as much as possible while securing the planned yield portion, adhesion between the cylinder and the base concrete can be improved, and as a result, fixing performance at the base of the main bar can be ensured.
[0012]
In the second aspect of the invention, when the component is fixed on both sides of the base in a straight line, the central portion of the cylindrical body is provided as the second region, and both side portions of the cylindrical body are the first portion. Each region is provided, and the space between both ends of the cylindrical body and the material ends of both components is provided as the predetermined region. According to this configuration, it is possible to reduce damage to the two constituent members facing each other. One cylindrical body can be used for two components, and the configuration can be simplified.
[0013]
In the case of fixing two constituent members facing each other, in the configuration in which the main reinforcing bars of both constituent members are formed of different reinforcing bars and the ends of these main reinforcing bars are connected to each other via the cylindrical member, the role of the cylindrical member is as described above. Not only can the main muscles be connected to each other.
The present invention can be applied to a beam fixing structure. That is, the base is a column / beam joint, the component is a beam, and the main bar and the cylinder are horizontal.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. In this embodiment, the present invention is applied to a column / beam joint 3 (base) of a side column 1 and two beams 2 (components) located on the outer periphery of a building. The column 1 has a plurality of main bars extending vertically, an annular shear reinforcement bar (not shown) surrounding these main bars, and a concrete 1a in which these main bars and shear reinforcement bars are embedded.
[0016]
The two beams 2 are arranged in a straight line and horizontally, and the material ends E are fixed to the column / beam joint 3. Each beam 2 has a plurality of main bars 10 arranged vertically and extending horizontally, an annular shear reinforcing bar (not shown) surrounding these main bars 10, and a concrete 2a in which these main bars 10 and shear reinforcing bars are embedded. ing. The concrete of the column / beam joint 3 is indicated by reference numeral 3a.
[0017]
The main reinforcing bar 10 of the beam 2 is formed of a deformed reinforcing bar like the main reinforcing bar of the column 1, and a fistula is formed on the outer periphery thereof to ensure sufficient adhesion with the concrete 2a. As shown in FIG. 2, in the present embodiment, the main reinforcement 10 is a screw rebar and has a screw flange 11.
[0018]
Referring back to FIG. 1, the main reinforcing bars 10 of both beams 2 are formed of different threaded reinforcing bars, extend into the column / beam joint 3, and their ends reach the center of the column / beam joint 3. Yes. In the column / beam joint 3, a plurality of metal cylinders 20 such as cast iron are arranged one above the other. Each cylindrical body 20 forms a straight line with the corresponding main bars 10 of the two beams 2 and is horizontal, and ends of these main bars 10 are inserted and connected.
[0019]
The cylindrical body 20 is formed to be much longer than a conventional cylindrical body used for connecting the main beam of the beam. The column 20 (the width of the column 1 or the column / beam joint 3, that is, the extending direction of the main beam 10). Occupy the majority). In this embodiment, the length is shorter than the column length, and both ends thereof are separated from the material end E of the beam 2. The left and right side portions (region close to the beam 2) of the cylindrical body 20 are provided as the first region Y, and the central portion (region away from the beam 2) of the cylindrical body 20 is provided as the second region N.
[0020]
As shown in FIG. 2, the 2nd area | region N of the cylinder 20 is the screwing part 21 which has the internal thread 21a. The center of the threaded portion 21 is a thick portion 21b, and a mortar inlet 21c is formed in the thick portion 21b. The first region Y is a sleeve portion 22 having a cylindrical shape with a smooth inner peripheral surface. The sleeve portion 22 is coaxial with the screwing portion 21, and the inner diameter thereof is larger than the valley diameter of the female screw 21 a of the screwing portion 21. A mortar inlet 22 c is formed in the vicinity of the threaded portion 21 on the peripheral wall of the sleeve portion 22.
[0021]
On the outer periphery of the sleeve portion 22, an annular convex portion 22a and a convex portion 12b extending in the axial direction are formed. Due to the convex portions 22a and 22b and the thick portion 21b, almost the entire outer periphery of the cylindrical body 20 has an uneven shape. Thereby, the high adhesiveness with the concrete 3a is ensured.
[0022]
In a state where the two main reinforcing bars 10 are in a straight line, the end portions thereof are screwed into the screwing portions 21 of the cylinder 20 and are firmly connected. In this connected state, by injecting mortar from the mortar inlet 21c, the gap between the inner periphery of the threaded portion 21 and the outer periphery of the main bar 10 is filled with mortar, thereby further increasing the connection strength.
[0023]
Further, the mortar 25 is filled between the sleeve portion 22 and the main muscle 10 by injecting the mortar 25 from the inlet 22 c of the sleeve portion 22. Since the inner peripheral surface of the sleeve portion 22 is smooth, the connection strength between the main muscle 10 and the sleeve portion 22 via the mortar 25 (connection strength against the tensile load in the axial direction of the main muscle 10) is the screwed portion 21 and the main muscle 10. It is much lower than the connection strength. The connection strength between the main reinforcement 11 and the sleeve portion 22 is lower than the adhesion strength between the main reinforcement 10 and the concrete 2 a of the beam 2.
[0024]
In a predetermined region S between both ends of the cylindrical body 11 and the material ends E of both beams 2, tape or a viscosity or resin is applied around the outer periphery of the main bar 10. The adhesion strength with the concrete 3a is very low and substantially zero (unbonded state).
[0025]
In the column / beam joint 3, when the reinforced concrete structure rolls due to an earthquake, a large bending moment is applied in the vicinity of the material end E of the beam 2 as in the conventional structure. At this time, it is similar to the conventional structure in that a crack is generated between the concrete 2a and 3a, but is significantly different from the conventional structure in the following points.
[0026]
For example, when the column 1 is tilted to the right as shown in FIG. 1B, the lower main bar 10 of the right beam 2 and the upper main bar 10 of the left beam 2 receive a tensile load. At this time, the main bar 10 has substantially zero adhesion strength with the concrete 3a in the predetermined region S and is much lower than the adhesion strength of the beam 2 with the concrete 2a. Made. Moreover, since the connection strength in the 1st area | region Y of the cylindrical body 20 is lower than the adhesion strength with the concrete 2a of the beam 2, the main reinforcement 10 is yielded here. As a result, the main reinforcement 10 can reduce the progress of yielding in the vicinity of the material end E in the beam 2, and can reduce the breakage of the concrete 2a in the vicinity of the material end E.
[0027]
Contrary to the above, when the column 1 is tilted to the left, the stretched portion receives a compressive load and returns to its original length, and the upper main bar 10 of the right beam 2 and the lower side of the left beam 2 are restored. The main muscle 10 receives the tensile load and extends in the regions Y and S. In this manner, the main muscle 10 is repeatedly stretched and compressed while taking the alternating load of tension and compression. As a result, seismic energy can be absorbed and the earthquake resistance of the building can be improved.
[0028]
Next, fixing performance at the column / beam joint 3 of the main reinforcement 10 will be described. Since the cylindrical body 20 has irregularities formed on almost the entire outer peripheral surface, the adhesion strength with the concrete 3a is high, and the tensile load can be dispersed and received. Since the main bar 10 is firmly connected to the cylinder 20 by screwing, the fixing performance at the column / beam joint 3 can be ensured by the high adhesion strength between the cylinder 20 and the concrete 3a. Even if the adhesion strength between the main reinforcement 10 and the concrete 3a is low in the predetermined region S, the cylindrical body 20 compensates for it, and the fixing performance of the main reinforcement 10 is ensured.
[0029]
Next, another embodiment of the present invention will be described. In these embodiments, components corresponding to the preceding embodiments are assigned the same reference numerals and detailed description thereof is omitted. A second embodiment of the present invention will be described with reference to FIG. In this embodiment, both ends of the cylindrical body 20 are coincident with or located in the vicinity of the material end E of the beam 2, and the length thereof is substantially coincident with the pillar. The area S of the first embodiment does not exist. Since the cylindrical body 20 is lengthened to the maximum, the adhesion strength with the concrete 3a can be increased, and as a result, the fixing strength at the column / beam joint 3 of the main reinforcement 10 can be increased. Most of the yielding of the main muscle 10 is performed by the portion of the first region Y of the cylindrical body 20.
[0030]
In the third embodiment of FIG. 4, the first region Y of the first embodiment does not exist. For example, a female screw is formed over the entire length of the cylindrical body 20 and is firmly connected to the two main bars 10. That is, the entire length of the cylindrical body 20 is in a connected state similar to that of the second region N of the first embodiment. In the region S between both ends of the cylindrical body 20 and the material ends E of both beams 2, the main reinforcement 10 has a low adhesive force as in the first embodiment, and is responsible for yielding during an earthquake.
[0031]
Although the said 1st-3rd embodiment described the case where the pillar 1 was a side pillar, it can apply as it is also when the pillar 1 is a middle pillar and a beam is fixed to a cross shape. In this case, two sets of two beams that form a straight line at the column / beam joint are fixed.
Moreover, in the said 1st-3rd embodiment, one continuous rebar extends through the column / beam joint to the middle part of the two beams, and may constitute the main bars of these two beams. Even in this case, the cylinder is connected to the main bar of the beam in the same manner as in the first to third embodiments. In each beam, the ends of the main bars are connected by a coupler at the intermediate portion. In these embodiments, in FIG. 1 to FIG. 4, the main muscles are merely in a continuous state without interruption, and can be easily understood, so illustration is omitted.
[0032]
In the fourth embodiment shown in FIG. 5, the present invention is applied when the pillar 1 is a corner pillar. In this embodiment, the cylinder 20 has a first region Y near the beam 2 and a second region N separated from the beam 2. A predetermined region S is formed between one end of the cylindrical body 20 and the material end E of the beam 2. Since the connection strength and adhesion strength of the main muscle 10 in these regions Y, N, and S are almost the same as those in the first embodiment, description thereof will be omitted. In the column / beam joint 3 at this corner column, one end of the cylinder 20 is made to coincide with the material end E and the predetermined region S is omitted as in the second embodiment, and most yields in the first region Y. As in the third embodiment, the first region Y of the cylinder 20 may be omitted and most yielding may be performed in the predetermined region S.
[0033]
Furthermore, the present invention can employ various forms regardless of the above embodiment. The uneven shape on the outer periphery of the cylindrical body 20 is not limited to the above-described embodiment, and uneven shapes having any shape for improving the adhesion to the concrete 3a can be employed. For example, you may form many fine unevenness | corrugations in the outer peripheral surface whole region.
[0034]
The main muscle 10 and the second region N of the cylindrical body 20 may employ mortar connection instead of screwing. For example, a plurality of annular protrusions are formed at intervals in the axial direction on the inner periphery of the second region N of the cylindrical body 20. This annular projection and the main reinforcing bar consisting of deformed reinforcing bars (in the case of screw reinforcing bars, screwing) are connected via a mortar.
In the third embodiment, the main body 10 may be screwed with the main muscle 10, and annular protrusions may be formed on the inner circumferences of the left and right portions of the cylinder 20 to be mortar coupled with the main muscle 10. In this case, the connection strength of the left and right parts is higher than the adhesion strength between the main reinforcement 10 and the concrete 2 a in the beam 2.
[0035]
In the first region Y of the cylindrical body 20, an annular protrusion may be formed on the inner circumference of the sleeve portion 22 at a rough interval to increase the adhesion strength compared to the above embodiment. However, the connection strength between the cylindrical body 20 and the main bar 10 in the first region Y in this case is lower than the adhesion strength between the main bar 10 and the concrete 2 a in the beam 2.
[0036]
In the second region Y, the strength of the connection with the cylindrical body 20 may be made substantially zero (unbonded state) by winding a tape around the outer periphery of the main bar 10 or applying a viscosity, resin, or the like.
[0037]
In order to reduce the adhesion strength in the predetermined region S or decrease the connection strength with the cylindrical body 20 in the first region Y, it may be obtained by forming the round bar portion without the bulge of the main muscle 10.
[0038]
The cylindrical body 20 may be crimped to the main muscle 10 by caulking or the like in the second region N. Mortar filling in the first region Y may be omitted.
In all the above embodiments, the present invention may be provided to only some of the main muscles, for example, the upper main muscles.
[0039]
The present invention can also be applied to the case where the component is a column and the base is foundation concrete, and can also be applied to the case where the column is a component and the base is a column / beam joint. Moreover, this invention is applied also to a steel frame reinforced concrete building. It can also be applied to a precast structure. Furthermore, prestressed concrete can also be used as a constituent material.
[0040]
【The invention's effect】
As described above, according to the fixing structure of the present invention, it is possible to remarkably reduce the damage to the constituent material in the event of an earthquake and to remarkably improve the fixing function to the base portion of the constituent material main bar.
[Brief description of the drawings]
FIGS. 1A and 1B are longitudinal sectional views of a column / beam joint constituting a first embodiment of the present invention, in which FIG. 1A shows a normal state and FIG. 1B shows an earthquake state.
FIG. 2 is a view showing a cylindrical body and a beam main bar used in the embodiment.
FIG. 3 is a longitudinal cross-sectional view showing a column / beam joint part according to a second embodiment of the present invention.
FIG. 4 is a longitudinal cross-sectional view of a column / beam joint forming a third embodiment of the present invention.
FIG. 5 is a vertical cross-sectional view of a column / beam joint forming a fourth embodiment of the present invention.
[Explanation of symbols]
E Material edge position N First region Y Second region S Predetermined region 2 Beam (component)
3 Column / beam joint (base)
2a, 3a Concrete 10 Reinforcement 20 Tubular body

Claims

In order to fix the material end of the component material to the base, in the material end fixing structure of the component material in the reinforced concrete building in which a plurality of main reinforcing bars of the component material are extended into the base,
A plurality of cylinders that are coaxial with the main bars are arranged in the base, and the main bars are inserted into and connected to the cylinders, and unevenness for enhancing adhesion with concrete is provided in almost the entire outer periphery of the cylinders. Is formed, and one end of the cylindrical body near the constituent material is located on the back side of the base from the material end of the constituent material, and the above in a predetermined region from the one end to the material end of the constituent material Reinforced concrete structure characterized in that the bond strength between the main reinforcement and the base concrete is lower than the adhesion strength between the main reinforcement and the component concrete, and that the main reinforcement in this predetermined area is provided as a planned yielding section in the event of an earthquake. The material end fixing structure of the component material in

The cylinder has a first region closer to the component and a second region away from the component, and the connection strength between the main reinforcement and the cylinder in the first region is the relationship between the main reinforcement and the cylinder in the second region. It is lower than the connection strength and lower than the bond strength between the main reinforcement and the component material concrete, and the main reinforcement in the first region is also provided as a planned yield section that yields in the event of an earthquake. Item structure for fixing a material end of a reinforced concrete building according to Item 1.

The component is fixed in a straight line on both sides of the base, the central part of the cylinder is provided as a second area, both sides of the cylinder are provided as the first area, and both ends of the cylinder The material end fixing structure for a component material in a reinforced concrete building according to claim 2, wherein the predetermined region is provided between each of the component materials and the material ends of both component materials.

The main bars are connected to each other with a connection strength higher than the adhesion strength of the constituent material to the concrete over the entire length of the cylindrical body, and substantially only the main bars in the predetermined region are provided as the planned yield portion. The material end fixing structure of the constituent material in the reinforced concrete building according to claim 1.

5. The component according to claim 4, wherein the constituent material is fixed in a straight line on both sides of a base portion, and a portion between both ends of the cylindrical body and a material end of both constituent materials is provided as the predetermined region. Material end fixing structure for reinforced concrete buildings.

In order to fix the material end of the component material to the base, in the material end fixing structure of the component material in the reinforced concrete building in which a plurality of main reinforcing bars of the component material are extended into the base,
A plurality of cylinders that are coaxial with the main bars are arranged in the base, and the main bars are inserted into and connected to the cylinders, and unevenness for enhancing adhesion to concrete is provided in almost the entire outer periphery of the cylinders. Is formed, and one end of the cylindrical body near the constituent material is in a position substantially coincident with the material end of the constituent material,
The cylinder has a first region closer to the component and a second region away from the component, and the connection strength between the main reinforcement and the cylinder in the first region is the relationship between the main reinforcement and the cylinder in the second region. Reinforced concrete that is lower than the connection strength and lower than the bond strength between the main reinforcement and the component concrete, and that the main reinforcement in the first region is provided as a planned yield section that yields in the event of an earthquake. Material end fixing structure for building components.

The component is fixed in a straight line on both sides of the base, the central part of the cylinder is provided as the second area, both sides of the cylinder are provided as the first area, The material end fixing structure for a component material in a reinforced concrete building according to claim 6, wherein the predetermined region is provided between both ends and the material ends of both component materials.

The reinforced concrete building according to any one of claims 3, 5, and 7, wherein the main reinforcing bars of both constituent members are formed of different reinforcing bars, and ends of the main reinforcing bars are connected to each other through the cylindrical body. The material end fixing structure of the component material in.

In the reinforced concrete building according to any one of claims 1 to 8, wherein the base is a column / beam joint, the constituent material is a beam, and the main reinforcement and the cylinder are horizontal. Material end fixing structure of component.