JP2004270204A

JP2004270204A - Joint structure of steel pipe and joining method of steel pipe

Info

Publication number: JP2004270204A
Application number: JP2003059572A
Authority: JP
Inventors: Shinji Horikawa; 慎司堀川; Gen Mori; 玄森; Kimihisa Takano; 公寿高野; Tomohiro Ueda; 智宏上田; Akitoshi Toyohara; 陽登志豊原; Yuuichi Tatsumi; 夕一辰見
Original assignee: JFE Steel Corp
Current assignee: JFE Steel Corp
Priority date: 2003-03-06
Filing date: 2003-03-06
Publication date: 2004-09-30

Abstract

<P>PROBLEM TO BE SOLVED: To provide a joint structure of a steel pipe capable of facilitating execution by a simple structure and reducing a cost to have high reliability and to provide a joining method of the steel pipe. <P>SOLUTION: The joint structure of the steel pipe includes an outside joint pipe 1 having a locking section 5 on the inside circumferential surface and connected to one steel pipe 31 and an engaged projection 16 locking with the locking section 5 of the outside joint pipe on the outside circumferential surface, an inside joint pipe 11 connected to the other steel pipe 32, a widening diameter function is provided to the outside joint pipe 1, or a contracting diameter function is provided to the inside joint pipe 11 to press the inside joint pipe 11 into the outside joint pipe 1, the diameter of the outside joint pipe is contracted by a contracting diameter means, or the diameter of the inside joint pipe 11 is widened by a widening diameter means to lock the engaged projection 16 with the locking section 5 of the outside joint pipe 1. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、鋼管、例えば鋼管杭、既成コンクリート杭（ＰＨＣ杭、ＰＲＣ杭、ＳＣ杭）の管軸方向の継手構造及び鋼管の接合方法に関するものである。
【０００２】
【従来の技術】
ソイルセメント合成鋼管杭などの鋼管杭は、施工現場において溶接接合して継杭して施工されるのが一般的である。
しかしながら、溶接による継杭では、（１）溶接部の品質が溶接工の技量に左右されること、（２）施工が天候に左右されることなどから、溶接に代わる継杭方法の開発が望まれていた。
【０００３】
溶接によらない鋼管の接合構造の一例として、接続するそれぞれの鋼管の突き合わせ端縁部にこの鋼管の径より小さい外径の円筒状接続部を同軸上に接続、固定し、この円筒状接続部の側面上に多数のネジ孔を設け、各鋼管に接続、固定されたこれらの円筒状接続部を相互に突き合わせ、この突き合わせた二つの円筒状接続部の外周を、円弧状に適宜に分割され、各分割片に多数のボルト挿通孔を穿った分割円筒状継手で被い、この分割円筒状継手の各ボルト挿通孔と上記円筒状接続部の各ネジ孔を合わせ、これらのボルト挿通孔にボルトを通してボルト端をネジ孔に螺着して締め付けることによって上記鋼管同士を接続し、上記円筒状接続部に固定された各分割円筒状継手及び締め付けられた各ボルトの頭部は上記接続する鋼管の外径より突出しないようにしたものがある（例えば、特許文献１参照）。
【０００４】
【特許文献１】
特開平１１−８１３０４号公報（第２〜第４頁、図１）
【０００５】
【発明が解決しようとする課題】
特許文献１に記載された鋼管の接続構造は、鋼管杭とは別体の分割円筒状継手を用いており、一体化させるためには、上継ぎ手と下継ぎ手のかみ合わせばかりでなく、分割円筒状継手と上下継手のかみ合わせを配慮した精度の高い製作が要求され、製造がむずかしく製作コストも高い。また、分割円筒状継手を別途運搬し取り付ける作業が必要であり、施工性が悪い。
さらに、鋼管継手部を大径化・肉厚化した場合には、分割円筒状継手の重量が大きくなり、新たにクレーン等の運搬用重機を持ち込まなければならないなど運搬性、施工性がさらに悪くなるなど、種々問題がある。
【０００６】
本発明は、上記の課題を解決するためになされたもので、構造が簡単で施工が容易であり、コストを低減できてその上信頼性の高い鋼管の継手構造及び鋼管の接合方法を提供することを目的としたものである。
【０００７】
【課題を解決するための手段】
（１）本発明に係る鋼管の継手構造は、内周面に係止部を有し一方の鋼管に接合された外側継手管と、外周面に前記外側継手管の係止部に係止する係合突部が設けられ、他方の鋼管に接合された内側継手管とを有し、前記外側継手管に拡径機能を付与するか、又は内側継手管に縮径機能を付与して前記外側継手管内に前記内側継手管を圧入し、縮径手段により前記外側継手管を縮径し、又は拡径手段により前記内側継手管を拡径してその係合突部を前記外側継手管の係止部に係止させるようにしたものである。
【０００８】
（２）また、本発明に係る鋼管の継手構造は、内周面に係止部を有し、該係止部の下部の周方向に複数のボルト挿通孔が設けられて下端部が一方の鋼管に接合された外側継手管と、外径が前記外側継手管の内径とほぼ等しく軸方向に設けたスリットにより複数の分割片が形成され、外周面に前記外側継手管の係止部に係止する係合突部が設けられ該係合突部の下部に前記外側継手管のボルト挿通孔に対応してボルト孔が設けられた本体部を有し、上端部が他方の鋼管に接合された内側継手管とを備え、前記内側継手管の本体部を前記外側継手管内に圧入したのち前記ボルト挿通孔に挿通したボルトを前記ボルト孔に螺入して前記内側継手管を拡径し、前記係合突部を係止部に係止させるようにしたものである。
【０００９】
（３）また、本発明に係る鋼管の継手構造は、内周面に係止部を有し、該係止部の下部に複数のボルト孔が設けられて下端部が一方の鋼管に接合された外側継手管と、外径が前記外側継手管の内径とほぼ等しく軸方向に設けたスリットにより複数の分割片が形成され、外周面に前記外側継手管の係止部に係止する係合突部が設けられ該係合突部の下部に前記外側継手管のボルト孔に対応して下端部に開口する嵌合部が設けられた本体部を有し、上端部が他方の鋼管に接合された内側継手管とを備え、前記内側継手管の本体部を前記外側継手管内に圧入してその嵌合部を該外側継手管の内側からボルト孔に螺入したボルトに嵌合し、前記ボルトをさらに螺入して前記係合突部を係止部に係止させるようにしたものである。
【００１０】
（４）上記（２）又は（３）の内側継手管の本体部の大径部と係合突部との間において、内周面又は外周面に凹溝を設けた。
【００１１】
（５）また、本発明に係る鋼管の継手構造は、軸方向に設けたスリットにより複数の分割片が形成されて該分割片の内周面に係止部が設けられ、該係止部の上方の周方向に複数のボルト挿通孔が設けられた本体部を有し、一方の鋼管に接合された外側継手管と、外径が前記外側継手管の内径とほぼ等しく、外周面に前記外側継手管の係止部に係止する係合突部を有し、該係合突部の上方に前記外側継手管のボルト挿通孔に対応してボルト孔が設けられ、上端部が他方の鋼管に接合された内側継手管とを備え、前記内側継手管を前記外側継手管内に圧入したのち前記ボルト挿通孔に挿通したボルトを前記ボルト孔に螺入して前記外側継手管を縮径させ、前記係合突部を係止部に係止させるようにしたものである。
【００１２】
（６）本発明に係る鋼管の接合方法は、上記（２）の外側継手管を一方の鋼管に接合し、上記（２）又は（４）の内側継手管を他方の鋼管に接合する工程と、前記内側継手管を前記外側継手管内に圧入する工程と、前記外側継手管のボルト挿通孔に挿通したボルトを前記内側継手管のボルト孔に螺入し、前記内側継手管を拡径してその係合突部を前記外側継手管の係止部に係止させる工程とを含むものである。
【００１３】
（７）また、本発明に係る鋼管の接合方法は、上記（３）の外側継手管を一方の鋼管に接合し、上記（３）又は（４）の内側継手管を他方の鋼管に接合する工程と、前記外側継手管の内側からボルト孔にボルトを螺入する工程と、前記内側継手管を前記外側継手管内に圧入してその嵌合部を前記ボルトに嵌合する工程と、前記ボルトをさらにボルト孔に螺入して前記内側継手管を拡径し、係合突部を前記外側継手管の係止部に係止させる工程とを含むものである。
【００１４】
（８）また、本発明に係る鋼管の接合方法は、上記（５）の外側継手管を一方の鋼管に接合し、内側継手管を他方の鋼管に接合する工法と、前記内側継手管を前記外側継手管内に圧入する工程と、前記外側継手管のボルト挿通孔に挿通したボルトを前記内側継手管のボルト孔に螺入し、前記外側継手管を縮径して前記内側継手管の係合突部を前記外側継手管の係止部に係止させる工程とを含むものである。
【００１５】
（９）上記（６），（７）又は（８）の鋼管が鋼管杭であって、一方の鋼管杭に接合された外側継手管内に、他方の鋼管杭に接合された内側継手管をいずれか一方の鋼管杭の自重により圧入するようにしたものである。
【００１６】
【発明の実施の形態】
［実施の形態１］
図１は本発明の実施の形態１に係る一部を断面で示した鋼管の継手構造の模式図である。
図において、Ｊは２本の鋼管３１，３２を接合するための継手部で、下端部が接合対象である一方の鋼管３１に溶接接合された円筒状の外側継手管１と、上端部が他方の鋼管３２に溶接接合された円筒状の内側継手管１１とからなっている。
【００１７】
外側継手管１は、その外径が鋼管３１の外径とほぼ等しく形成され、上端部２の内周面は斜め上方に切除されて傾斜面３が設けられている。また、内周面の軸方向のほぼ中央部から下方には、所定の範囲で拡径された凹部４が形成されており、凹部４の上縁部には係止部５が、また凹部４の下縁には内側継手管１１の内径とほぼ等しい内径の突出段部６が形成されている。７は凹部４に設けた複数のボルト挿通孔である。
【００１８】
内側継手管１１は、上部に鋼管３２の外径とほぼ等しい外径の拡径部１２が設けられており、拡径部１２の下部には段部１３（当接部）を介して、外側継手管１の内径とほぼ等しい外径の本体部１４が設けられている。そして、本体部１４には周方向にほぼ等間隔で、段部１３から下端部に達する複数のスリット１５が設けられており、これにより、本体部１４は周方向に分割されて縮径機能を有する複数の分割片１４ａが形成されている。
【００１９】
１６は各分割片１４ａの下部外周面に突設された係合突部で、その上面が外周面と直交して下部には傾斜面１７が設けられており、係合突部１６の上面から段部１３までの高さｈ_２は、外側継手管１の係合部５から上端部２までの高さｈ_１とほぼ等しく形成されている。１８は各分割片１４ａの係合突部１６の下方に設けたボルト孔で、このボルト孔１８は外側継手管１に設けたボルト挿通穴７に対応して設けられている。
【００２０】
次に、本発明を鋼管杭の接合に実施した場合の施工手順の一例について説明する。なお、接合対象である鋼管杭３１ａ，３２ａの端部には、あらかじめ工場等において外側継手管１及び内側継手管１１が溶接により接合されており、これら鋼管杭３１ａ，３２ａが工事現場に輸送されるものとする。
【００２１】
先ず、図２（ａ）に示すように、外側継手管１が接合された鋼管杭３１ａを地中に打込む。打込みが進んで上部の鋼管杭３２ａを接続する状態になったときは、先端部に内側継手管１１が接合された鋼管杭３２ａを鋼管杭３１ａ上に位置させて位置決めし、鋼管杭３２ａの自重による圧下力により下降させ、図２（ｂ）に示すように、外側継手管１の上端部に設けた傾斜面３と、内側継手管１１の係合突部１６の下部に設けた傾斜面１７とを利用して、内側継手管１１の各分割片１４ａを撓ませて本体部１４を縮径させ、外側継手管１内に挿入する。
【００２２】
鋼管杭３２ａを引続き下降させると、内側継手管１１の各分割片１４ａがさらに撓んで縮径され、内側継手管１１はその係合突部１６の外周面が外側継手管１の内周面に沿って下降し、段部１３（当接部）が外側継手管１の上端部２に当接したときは圧下を停止する。このときの状態を図２（ｃ）に示す。
【００２３】
この状態で、外側継手管１のボルト挿通孔７に挿通した拡径手段であるボルト３５を、内側継手管１１のボルト孔１８に螺入して締付ければ、内側継手管１１の各分割片１４ａはボルト３５に引き寄せられて元の状態に戻り（拡径し）、図３に示すように、その外壁が外側継手管１の内壁に当接又は近接し、係合突部１６が外側継手管１の係止部５に係止して、上下の鋼管杭３１ａ，３２ａは、外側継手管１と内側継手管１１を介して強固に接合される。
【００２４】
このようにして接合された鋼管杭３１ａ，３２ａにおいては、鋼管杭３２ａに加わる圧縮荷重は、内側継手管１１の段部１３と外側継手管１の上端部２を介して鋼管杭３１ａに伝達され、引張荷重は、内側継手管１１の係合突部１６と外側継手管１の係止部５を介して鋼管杭３２ａに伝達される。
【００２５】
図４は本実施の形態の他の例の要部の説明図である。
本例においては、図１の内側継手管１１の各分割片１４ａの係合突部１６の下方に設けたボルト孔１８に代えてボルト挿通孔１８ａを設け、このボルト挿通孔１８の内壁面にそれぞれナット１９を溶接により取付けたものである。
【００２６】
本例における施工手順は、図２、図３の場合とほぼ同様であるが、内側継手管１１が鋼管杭３２ａ（図示せず）の自重によって下降し、段部１３が外側継手管１の上端部２に当接したとき（図２（ｃ）と同じ状態）は、ボルト３５を外側継手管１と内側継手管１１のボルト挿通孔７，１８に挿通してナット１９に螺入し、ボルト３５を締付けて内側継手管１１の本体部１４を元の状態に戻し（拡径させ）、係止突部１６を係止部５に係止させることにより、上下の鋼管杭３１ａ，３２ａを外側継手管１と内側継手管１１を介して強固に接合する。
【００２７】
本実施の形態によれば、鋼管杭３２ａの端部に接合した内側継手管１１を、鋼管杭３２ａの自重により外側継手管１内に圧入してボルト３５で固定するだけで、他の部材等を使用することなく鋼管杭３１ａと３２ａを接合することができるので、構造が簡単で施工がきわめて容易であり、コストを低減できるばかりでなく、作業性を大幅に向上することができる。
【００２８】
また、外側継手管１の外径及び内側継手管１１の大径部１２の外径を、接合する鋼管杭３１ａ，３２ａの外形とほぼ等しくしたので、継手部Ｊが鋼管杭３１ａ，３２ａの外周面から出張ることがなく、このため、鋼管杭３１ａ，３２ａを地中に打込む際の貫入抵抗を小さくすることができる。
なお、外側継手管１のボルト挿通孔７にボルト３５の頭部が挿入される大径部を設ければ、接合後の外側継手管１の外周面にボルト３５の頭部が突出することがないので、地中への貫入抵抗をより低減することができる。ただし、この場合は、ボルト３５の頭部に六角レンチ等が係合する穴を設けておくことが必要である。
【００２９】
上記の説明では、本実施の形態に係る継手構造を鋼管杭３１ａ，３２ａの接合に用いた場合を示したが、本発明はこれに限定するものではなく、杭以外の鋼管を接合する場合にも本発明を実施することができる。なお、この場合は、内側継手管１１を外側継手管１内に圧入する際に、圧入機等を必要とする場合がある。
【００３０】
［実施の形態２］
図５は本発明の実施の形態２に係る鋼管の継手部の一部断面図である。なお、実施の形態１と同じ部分にはこれと同じ符号を付し、説明を省略する。
本実施の形態は、内側継手管１１の内周面の上部に、幅（高さ）Ｌ_２の凹溝２０を設けたものである（図には、凹溝２０の上縁部を段部１３と同じ位置にした場合を示してある）。
【００３１】
本実施の形態における継手部Ｊの施工手順は、実施の形態１の場合とほぼ同様であるが、内側継手管１１の内周面又は外周面に凹溝２０を設けてこの部分の肉厚を薄くして剛性を低下させたので各分割片１４ａが撓み易くなり、このため圧入力を小さくでき、大径の継手部Ｊでも内側継手管１１に接合された鋼管杭３２ａの自重により、内側継手部１１を外側継手部１内に圧入することができる。
【００３２】
図６は本実施の形態の他の例を示すもので、図４の場合は、凹溝２０の上縁部を段部１３と同じ位置に設けた場合を示したが、本例は、凹溝２０を内側継手管１１の内周面の段部１３より下方に設けたものである。
また、図７は本実施の形態のさらに他の例を示しすもので、本例は、内側継手管１１の外周面に凹溝２０を設けたもので、図にはその上縁部を段部１３と同じ位置に設けた場合を示してあるが、これに限定するものではない。
【００３３】
このように、凹溝２０は、内側継手管１１の内周面又は外周面の段部１３と係合突部１６との間の適宜位置に設けることができ、図４に示すように、凹溝２０の上縁部と分割片１４ａの下端部間の距離Ｌ_１が長いほど凹溝２０にかかる曲げモーメントが大きくなるため、各分割片１４ａの縮径方向への撓み量が大きくなり、これに伴って圧入力が小さくなる。また、凹溝２０の軸方向の長さ（幅）Ｌ_２が長くなるにしたがって、圧入力は小さくなる。
【００３４】
ときろで、継手部Ｊが大径化すると、外側継手管１及び内側継手管１１の切削加工の加工精度が悪くなるため、板厚を応力上必要な最低板厚より厚く選定することが必要であり、これにより、内側継手管１１の分割片１４ａの撓み量が小さくなって外側継手管１に圧入する際の圧入力が増大する。このため圧入力を上部の鋼管杭３２ａの自重以下に抑えるためには、内側継手管１１の分割片１４ａの軸方向の長さを長くして撓み易くする必要があるが、このようにすることにより、継手部Ｊが大形化するばかりでなく、コストの上昇は避けられない。
【００３５】
本実施の形態においては、内側継手管１１の本体部１４（分割片１４ａ）の内周面又は外周面に凹溝２０を設け、この部分の剛性を低くして撓み易くしたので、継手部Ｊの軸方向の長さを長くすることなく、外側継手管１内への圧入力を上部の鋼管杭３２ａの自重以下に抑えることができる。
これにより、継手部Ｊのコストの低減は勿論、大径化した継手部の場合でも圧入機等を使用する必要がないので、施工が容易で作業性を高めることができる。
【００３６】
［実施の形態３］
図８は本発明の実施の形態３に係る鋼管の継手部の要部の説明図及び内側継手管の分割片の内面説明図である。
本実施の形態は、図８に示すように、実施の形態１（図１）の外側継手管１に設けた複数のボルト挿通孔７に代えてボルト孔７ａを設けると共に、内側継手管１１の各分割片１４ａに設けたボルト孔１８に代えて、下端部に開口する逆Ｕ字の嵌合部２１を設けたものである。なお、ボルト３５のねじ部の先端部には、外側からボルト３５を回転しうるように、例えば六角型の如き多角形の係止穴３６が設けられている。
【００３７】
上記のように構成した本実施の形態の施工にあたっては、外側継手管１が接合された鋼管杭３１ａが地中に打込まれ、上部の鋼管杭３２ａ（図示せず）を接続する状態になったときは、図９（ａ）に示すように、外部継手管１１のボルト孔７ａに内側からボルト３５の先端部を螺入する。
そして、先端部に内側継手管が接合された鋼管杭３２ａを自重による圧下力により下降させ、図９（ｂ）に示すように、内側継手管１１の各分割片１４ａに設けた嵌合部２１を、外側継手管１に取付けたボルト３５に嵌合する。
【００３８】
ついで、外側継手管１の外側からボルト３５のねじ部の先端部に設けた係止穴３６に、例えばＬ型六角レンチを係合させてボルト３５をさらに締付ければ、内側継手管１１の各分割片１４ａはボルト３５の頭部により外側継手管１側に引き寄せられて元の状態に戻り（拡径され）、図９（ｃ）に示すように、係合突部１６が係止部５に係止し、鋼管杭３１ａ，３２ａは外側継手管１と内側継手管１１を介して強固に接合される。
本実施の形態の効果は、実施の形態１の場合とほぼ同様である。
【００３９】
［実施の形態４］
図１０は本発明の実施の形態４に係る一部を断面で示した鋼管の継手構造の模式図である。なお、実施の形態１と同じ部分にはこれと同じ符号を付し、説明を省略する。
上記の各実施の形態においては、内側継手管１１にスリット１５を設けて縮径機能をもたせ、この内側継手管１１を外側継手管１内に圧入してその係合突部１６を係止部５に係止させる場合を示したが、本実施の形態は外側継手管１にスリットを設けて拡径機能をもたせ、こ外側継手管１内に内側継手管１１を圧入して、その係合突部１６を係止部５に係止させるようにしたものである。
【００４０】
図１０において、外側継手管１の本体部８の周方向には、ほぼ等間隔で上端部に開口し下部が突出段部６に達する複数のスリット９が設けられ、これにより、本体部８を周方向に分割して拡径機能を有する複数の分割片８ａを形成したものである。なお、ボルト挿通孔７は各分割片８ａの上部に設けられている。
また、内側継手管１１には、円筒状の本体部１４の上部に、外側継手管１のボルト挿通孔７に対応してボルト孔１８が設けられている。なお、このボルト孔１８をボルト挿通孔とし、その内壁面にナットを溶接により取付けてもよい。
【００４１】
次に、本実施の形態を鋼管杭の接合に実施した場合の施工手順の一例について説明する。なお、接合対象である鋼管杭３１ａ，３２ａの端部には、あらかじめ工場等において外側継手管１及び内側継手管１１が溶接によりそれぞれ接合されているものとする。
【００４２】
図１１（ａ）に示すように、外側継手管１が接合された鋼管杭３１ａが上部の鋼管杭３２ａを接合する状態まで打込まれたときは、先端部に内側継手管１１が接合された鋼管杭３２ａを鋼管杭３１ａの上方に位置させて位置決めし、鋼管杭３２ａの自重による圧下力により下降させ、図１１（ｂ）に示すように、外側継手管１の上端部に設けた傾斜面３と、内側継手管１１の係合突部１６の下部に設けた傾斜面１７とを利用して、外側継手管１の各分割片８ａを撓ませて本体部８を拡径させ、外側継手管１内に挿入する。
【００４３】
鋼管杭３２ａを引続き下降させると、内側継手管１１の係合突部１６が外側継手管１の内周面に沿って下降し、外側継手管１の各分割片８ａがさらに撓んで拡径され、段部１３（当接部）が外側継手管１の上端部２に当接したときは圧下を停止する。このときの状態を図１１（ｃ）に示す。
【００４４】
この状態で、外側継手管１のボルト挿通孔７に挿通した縮径手段であるボルト３５を、内側継手管１１のボルト孔１８に螺入して締付ければ、外側継手管１の各分割片８ａはボルト３５に引き寄せられて元の状態に戻り（縮径し）、図１２に示すように、その内壁が内側継手管１１の外壁に当接又は近接し、係合突部１６が係止部５に係止して、上下の鋼管杭３１ａ，３２ａは、外側継手管１と内側継手管１１を介して強固に接合される。
【００４５】
本実施の形態は、実施の形態１の場合とほぼ同様の効果を得ることができるが、さらに、外側継手管１の本体部８の下部内周面には凹部４が設けられているので、この部分の剛性が低くなり、実施の形態２の場合と同様に、各分割片８ａを撓み易くすることができる。
【００４６】
上記の各実施の形態においては、外側継手管１が接合された鋼管杭３１ａを地中に打設し、この鋼管杭３１ａに内側継手管１１が接合された鋼管杭３１ａを自重により下降させて接合する場合について説明したが、内側継手管１１が接合された鋼管杭３２ａを地中に打設し、外側継手管１が接合された鋼管杭３１ａを自重により下降させて外側継手管１を内側継手管１１に嵌合して接合し、鋼管杭３２ａ，３１ａを接合するようにしてもよい。
【００４７】
【発明の効果】
本発明は、内周面に係止部を有し一方の鋼管に接合された外側継手管と、外周面に外側継手管の係止部に係止する係合突部が設けられ、他方の鋼管に接合された内側継手管とを有し、外側継手管に拡径機能を付与するか、又は内側継手管に縮径機能を付与して外側継手管内に内側継手管を圧入し、縮径手段により外側継手管を縮径し、又は拡径手段により内側継手管を拡径してその係合突部を外側継手管の係止部に係止させるようにしたので、構造が簡単で施工が容易であり、コストを低減できて信頼性の高い鋼管の継手構造を得ることができる。
【図面の簡単な説明】
【図１】本発明の実施の形態１に係る一部を断面で示した鋼管の継手構造の模式図である。
【図２】実施の形態１の継手構造の施工手順の一例を示す説明図である。
【図３】実施の形態１の継手構造により２本の鋼管を接合した状態を示す一部を省略した縦断面図である。
【図４】実施の形態１の他の例の要部の説明図である。
【図５】本発明の実施の形態２に係る一部を省略した鋼管の継手構造の縦断面図である。
【図６】実施の形態２の他の例の一部を省略した縦断面図である。
【図７】実施の形態２のさらに他の例の一部を省略した縦断面図である。
【図８】本発明の実施の形態３に係る鋼管の継手構造の要部の説明図及び内側継手管の分割片の内面説明図である。
【図９】実施の形態３の施工手順の一例の説明図である。
【図１０】本発明の実施の形態４に係る一部を断面で示した鋼管の継手構造の模式図である。
【図１１】実施の形態４の施工手順の一例を示す説明図である。
【図１２】実施の形態４の継手構造により２本の鋼管を接合した状態を示す一部を省略した断面図である。
【符号の説明】
１外側継手管
２上端部
５係止部
７，１８ａボルト挿通孔
８，１４本体部
１１内側継手管
１２大径部
１３段部（当接部）
８ａ，１４ａ分割片
９，１５スリット
１６係合突部
７ａ，１８ボルト孔
１９ナット
２０凹溝
２１嵌合部
３１，３２鋼管
３１ａ，３２ａ鋼管杭
３５ボルト[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a joint structure of a steel pipe, for example, a steel pipe pile, a precast concrete pile (a PHC pile, a PRC pile, an SC pile) in a pipe axis direction, and a method of joining steel pipes.
[0002]
[Prior art]
Steel pipe piles such as soil-cement synthetic steel pipe piles are generally constructed by welding and joining piles at construction sites.
However, in the case of welded piles, (1) the quality of the welded part depends on the skill of the welder, and (2) the construction depends on the weather. Had been rare.
[0003]
As an example of a joining structure of steel pipes not based on welding, a cylindrical connecting part having an outer diameter smaller than the diameter of the steel pipe is coaxially connected and fixed to a butt end of each steel pipe to be connected, and this cylindrical connecting part is fixed. A large number of screw holes are provided on the side surface of the cylindrical connection portion, and these cylindrical connection portions connected and fixed to each steel pipe are butted against each other, and the outer periphery of the two butted cylindrical connection portions is appropriately divided into an arc shape. Covering each divided piece with a divided cylindrical joint having a large number of bolt insertion holes, aligning each bolt insertion hole of this divided cylindrical joint with each screw hole of the cylindrical connection portion, and fitting these bolt insertion holes. The steel pipes are connected to each other by screwing a bolt end into a screw hole through a bolt and tightening, and each split cylindrical joint fixed to the cylindrical connection portion and a head of each tightened bolt are connected to the steel pipe. Than the outside diameter of There are those do not appear (e.g., see Patent Document 1).
[0004]
[Patent Document 1]
JP-A-11-81304 (pages 2 to 4, FIG. 1)
[0005]
[Problems to be solved by the invention]
The steel pipe connection structure described in Patent Document 1 uses a split cylindrical joint separate from a steel pipe pile. In order to integrate the steel pipe pile, not only the upper joint and the lower joint are engaged but also the split cylindrical joint is used. High-precision manufacturing is required in consideration of the engagement between the joint and the upper and lower joints, making it difficult to manufacture and expensive. In addition, it is necessary to separately transport and attach the divided cylindrical joint, and the workability is poor.
Furthermore, when the diameter and thickness of the steel pipe joints are increased, the weight of the divided cylindrical joint increases, and the transportability and workability are further deteriorated, such as the necessity of bringing in new heavy equipment such as a crane. There are various problems.
[0006]
The present invention has been made in order to solve the above-mentioned problems, and provides a steel pipe joint structure and a method of joining steel pipes, which have a simple structure, are easy to construct, can reduce cost, and have high reliability. It is intended for that purpose.
[0007]
[Means for Solving the Problems]
(1) In the joint structure for a steel pipe according to the present invention, the outer joint pipe has a locking portion on the inner peripheral surface and is joined to one of the steel pipes, and the outer peripheral surface is locked to the locking portion of the outer joint pipe. An engagement projection is provided, and an inner joint pipe joined to the other steel pipe is provided.The outer joint pipe has a diameter increasing function, or the inner joint pipe has a diameter decreasing function, and the outer joint pipe has a diameter decreasing function. The inner joint pipe is press-fitted into the joint pipe, the outer joint pipe is reduced in diameter by a diameter reducing means, or the inner joint pipe is increased in diameter by a diameter increasing means, and the engagement projection is engaged with the outer joint pipe. It is designed to be locked to a stop.
[0008]
(2) Further, the steel pipe joint structure according to the present invention has a locking portion on the inner peripheral surface, a plurality of bolt insertion holes are provided in a circumferential direction below the locking portion, and the lower end portion has one side. A plurality of divided pieces are formed by an outer joint pipe joined to the steel pipe and a slit having an outer diameter substantially equal to the inner diameter of the outer joint pipe and provided in an axial direction, and a plurality of divided pieces are formed on an outer peripheral surface of the outer joint pipe. An engaging projection for stopping is provided, and a lower part of the engaging projection has a main body part provided with a bolt hole corresponding to a bolt insertion hole of the outer joint pipe, and an upper end part is joined to the other steel pipe. An inner joint pipe, and a main body of the inner joint pipe is press-fitted into the outer joint pipe, and then a bolt inserted into the bolt insertion hole is screwed into the bolt hole to expand the inner joint pipe. The engaging projection is locked to a locking portion.
[0009]
(3) The joint structure for a steel pipe according to the present invention has a locking portion on an inner peripheral surface, a plurality of bolt holes are provided in a lower portion of the locking portion, and a lower end portion is joined to one of the steel pipes. A plurality of divided pieces are formed by the outer joint pipe and a slit having an outer diameter substantially equal to the inner diameter of the outer joint pipe and provided in the axial direction, and the outer circumferential surface is engaged with a locking portion of the outer joint pipe. A projection is provided, and a main body is provided below the engagement projection with a fitting portion opened at the lower end corresponding to the bolt hole of the outer joint pipe, and the upper end is joined to the other steel pipe. The inner joint pipe, and press-fits the main body of the inner joint pipe into the outer joint pipe, and fits a fitting portion thereof to a bolt screwed into a bolt hole from the inside of the outer joint pipe, A bolt is further screwed in to lock the engaging projection with the locking portion.
[0010]
(4) A concave groove is provided on the inner peripheral surface or the outer peripheral surface between the large-diameter portion of the main body of the inner joint pipe of (2) or (3) and the engagement projection.
[0011]
(5) In the joint structure for a steel pipe according to the present invention, a plurality of divided pieces are formed by slits provided in the axial direction, and a locking portion is provided on an inner peripheral surface of the divided piece. An outer joint pipe joined to one of the steel pipes, the outer diameter of the outer joint pipe being substantially equal to the inner diameter of the outer joint pipe; The outer joint pipe has a bolt hole corresponding to a bolt insertion hole above the engaging protrusion, the upper end of the other steel pipe being provided above the engagement protrusion. An inner joint pipe joined to the outer joint pipe, and after the inner joint pipe is press-fitted into the outer joint pipe, a bolt inserted into the bolt insertion hole is screwed into the bolt hole to reduce the diameter of the outer joint pipe. The engaging projection is locked to a locking portion.
[0012]
(6) The method for joining steel pipes according to the present invention includes the steps of joining the outer joint pipe of (2) to one steel pipe and joining the inner joint pipe of (2) or (4) to the other steel pipe. Press-fitting the inner joint pipe into the outer joint pipe, screwing a bolt inserted into a bolt insertion hole of the outer joint pipe into a bolt hole of the inner joint pipe, and expanding the inner joint pipe. Locking the engaging projection to the locking portion of the outer joint pipe.
[0013]
(7) In the method for joining steel pipes according to the present invention, the outer joint pipe of (3) is joined to one steel pipe, and the inner joint pipe of (3) or (4) is joined to the other steel pipe. A step of screwing a bolt into a bolt hole from the inside of the outer joint pipe, a step of press-fitting the inner joint pipe into the outer joint pipe and fitting the fitting portion to the bolt, Is further screwed into a bolt hole to expand the diameter of the inner joint pipe, and the engaging projection is locked to a locking portion of the outer joint pipe.
[0014]
(8) In addition, the method for joining steel pipes according to the present invention includes a method of joining the outer joint pipe of (5) to one steel pipe and joining the inner joint pipe to the other steel pipe; Press-fitting into the outer joint pipe, screwing a bolt inserted into the bolt insertion hole of the outer joint pipe into a bolt hole of the inner joint pipe, reducing the diameter of the outer joint pipe, and engaging the inner joint pipe. Locking the projection to the locking portion of the outer joint pipe.
[0015]
(9) The steel pipe of the above (6), (7) or (8) is a steel pipe pile, and an inner joint pipe joined to another steel pipe pile is inserted into an outer joint pipe joined to one steel pipe pile. The steel pipe pile is press-fitted by its own weight.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
[Embodiment 1]
FIG. 1 is a schematic diagram of a joint structure for a steel pipe, a part of which is shown in cross section according to Embodiment 1 of the present invention.
In the figure, J is a joint part for joining two steel pipes 31 and 32, and a lower end part is a cylindrical outer joint pipe 1 welded to one steel pipe 31 to be joined, and an upper end part is the other end. And a cylindrical inner joint pipe 11 which is welded to the steel pipe 32.
[0017]
The outer joint pipe 1 has an outer diameter substantially equal to the outer diameter of the steel pipe 31, and an inner peripheral surface of the upper end portion 2 is cut obliquely upward to provide an inclined surface 3. A recess 4 whose diameter is enlarged within a predetermined range is formed below a substantially central portion in the axial direction of the inner peripheral surface. A projecting step 6 having an inner diameter substantially equal to the inner diameter of the inner joint pipe 11 is formed on a lower edge of the inner joint pipe 11. Reference numeral 7 denotes a plurality of bolt insertion holes provided in the recess 4.
[0018]
The inner joint pipe 11 is provided with an enlarged diameter part 12 having an outer diameter substantially equal to the outer diameter of the steel pipe 32 at an upper part, and a lower part of the enlarged diameter part 12 through a step part 13 (abutting part). A main body 14 having an outer diameter substantially equal to the inner diameter of the joint pipe 1 is provided. The main body 14 is provided with a plurality of slits 15 reaching the lower end from the step 13 at substantially equal intervals in the circumferential direction, whereby the main body 14 is divided in the circumferential direction and has a diameter reducing function. Having a plurality of divided pieces 14a.
[0019]
Reference numeral 16 denotes an engagement protrusion projecting from a lower outer peripheral surface of each of the divided pieces 14a. An upper surface thereof is orthogonal to the outer peripheral surface, and an inclined surface 17 is provided at a lower portion. the height h ₂ to the step portion 13, is formed to be almost equal to the height h ₁ from the engaging portion 5 of the outer joint pipe 1 to the upper end portion 2. Reference numeral 18 denotes a bolt hole provided below the engaging projection 16 of each split piece 14a. The bolt hole 18 is provided corresponding to the bolt insertion hole 7 provided in the outer joint pipe 1.
[0020]
Next, an example of a construction procedure when the present invention is applied to joining of steel pipe piles will be described. The outer joint pipe 1 and the inner joint pipe 11 are welded to the ends of the steel pipe piles 31a and 32a to be joined in advance in a factory or the like, and these steel pipe piles 31a and 32a are transported to a construction site. Shall be.
[0021]
First, as shown in FIG. 2A, the steel pipe pile 31a to which the outer joint pipe 1 is joined is driven into the ground. When the driving is advanced and the upper steel pipe pile 32a is connected, the steel pipe pile 32a, to which the inner joint pipe 11 is joined at the tip, is positioned on the steel pipe pile 31a and positioned, and the weight of the steel pipe pile 32a is reduced. As shown in FIG. 2B, the inclined surface 3 provided at the upper end of the outer joint pipe 1 and the inclined surface 17 provided at the lower part of the engaging projection 16 of the inner joint pipe 11, as shown in FIG. By using the above, each divided piece 14a of the inner joint pipe 11 is bent to reduce the diameter of the main body portion 14 and inserted into the outer joint pipe 1.
[0022]
When the steel pipe pile 32a is continuously lowered, each of the divided pieces 14a of the inner joint pipe 11 is further bent and reduced in diameter, and the outer peripheral surface of the engagement projection 16 of the inner joint pipe 11 is formed on the inner peripheral surface of the outer joint pipe 1. When the step 13 (contact portion) comes into contact with the upper end portion 2 of the outer joint pipe 1, the rolling down is stopped. The state at this time is shown in FIG.
[0023]
In this state, if the bolt 35 which is a diameter expanding means inserted into the bolt insertion hole 7 of the outer joint pipe 1 is screwed into the bolt hole 18 of the inner joint pipe 11 and tightened, each divided piece of the inner joint pipe 11 is divided. 14a is attracted to the bolt 35 and returns to its original state (expands its diameter), as shown in FIG. 3, the outer wall of which abuts or approaches the inner wall of the outer joint pipe 1, and the engaging projection 16 is The upper and lower steel pipe piles 31a, 32a are firmly joined via the outer joint pipe 1 and the inner joint pipe 11 by being locked to the locking portion 5 of the pipe 1.
[0024]
In the steel pipe piles 31a and 32a thus joined, the compressive load applied to the steel pipe pile 32a is transmitted to the steel pipe pile 31a via the step 13 of the inner joint pipe 11 and the upper end 2 of the outer joint pipe 1. The tensile load is transmitted to the steel pipe pile 32a via the engagement protrusion 16 of the inner joint pipe 11 and the locking portion 5 of the outer joint pipe 1.
[0025]
FIG. 4 is an explanatory diagram of a main part of another example of the present embodiment.
In this example, a bolt insertion hole 18a is provided in place of the bolt hole 18 provided below the engagement projection 16 of each divided piece 14a of the inner joint pipe 11 of FIG. Each of the nuts 19 is attached by welding.
[0026]
The construction procedure in this example is almost the same as in FIGS. 2 and 3, except that the inner joint pipe 11 descends by its own weight of the steel pipe pile 32 a (not shown), and the step 13 is moved to the upper end of the outer joint pipe 1. When it comes into contact with the portion 2 (same state as in FIG. 2C), the bolt 35 is inserted into the bolt insertion holes 7 and 18 of the outer joint pipe 1 and the inner joint pipe 11 and screwed into the nut 19, and The upper and lower steel pipe piles 31a and 32a are moved outward by tightening the 35 to return the main body portion 14 of the inner joint pipe 11 to the original state (expanding the diameter) and to lock the locking projection 16 to the locking portion 5. The joint tube 1 and the inner joint tube 11 are firmly joined via the joint tube 11.
[0027]
According to the present embodiment, the inner joint pipe 11 joined to the end of the steel pipe pile 32a is simply pressed into the outer joint pipe 1 by the weight of the steel pipe pile 32a and fixed with the bolt 35, and other members and the like are used. Since the steel pipe piles 31a and 32a can be joined without using, the construction is simple and the construction is extremely easy, not only the cost can be reduced, but also the workability can be greatly improved.
[0028]
Further, since the outer diameter of the outer joint pipe 1 and the outer diameter of the large-diameter portion 12 of the inner joint pipe 11 are substantially equal to the outer diameters of the steel pipe piles 31a and 32a to be joined, the joint J becomes the outer periphery of the steel pipe piles 31a and 32a. Therefore, the steel pipe piles 31a, 32a can be driven into the ground with less penetration resistance.
If a large-diameter portion into which the head of the bolt 35 is inserted is provided in the bolt insertion hole 7 of the outer joint pipe 1, the head of the bolt 35 may protrude from the outer peripheral surface of the joined outer joint pipe 1. Therefore, the resistance to penetration into the ground can be further reduced. However, in this case, it is necessary to provide a hole for engaging a hexagon wrench or the like in the head of the bolt 35.
[0029]
In the above description, the case where the joint structure according to the present embodiment is used for joining the steel pipe piles 31a and 32a has been described. However, the present invention is not limited to this. The present invention can also be implemented. In this case, when the inner joint pipe 11 is press-fitted into the outer joint pipe 1, a press-fitting machine or the like may be required.
[0030]
[Embodiment 2]
FIG. 5 is a partial cross-sectional view of a joint portion of a steel pipe according to Embodiment 2 of the present invention. The same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.
This embodiment, the upper part of the inner peripheral surface of the inner joint tube 11, the width (height) is provided with a recessed groove 20 of the L ₂ (in the figure, a stepped portion of the edge on the groove 20 13 is shown.
[0031]
The construction procedure of the joint portion J in the present embodiment is almost the same as that in the first embodiment, but a concave groove 20 is provided on the inner or outer peripheral surface of the inner joint pipe 11 to reduce the thickness of this portion. Since the rigidity is reduced by reducing the thickness, each divided piece 14a is easily bent, so that the press-in force can be reduced, and even in the large-diameter joint portion J, the inner weight of the steel pipe pile 32a joined to the inner joint pipe 11 causes The part 11 can be pressed into the outer joint part 1.
[0032]
FIG. 6 shows another example of the present embodiment. In the case of FIG. 4, the case where the upper edge portion of the concave groove 20 is provided at the same position as the step portion 13 is shown. The groove 20 is provided below the step 13 on the inner peripheral surface of the inner joint pipe 11.
FIG. 7 shows still another example of the present embodiment. In this example, a concave groove 20 is provided on the outer peripheral surface of the inner joint pipe 11, and the upper edge thereof is stepped. Although the case where it is provided at the same position as the part 13 is shown, the present invention is not limited to this.
[0033]
As described above, the concave groove 20 can be provided at an appropriate position between the step 13 and the engaging projection 16 on the inner peripheral surface or the outer peripheral surface of the inner joint pipe 11, and as shown in FIG. since the bending moment increases according to the upper flange and the split pieces 14a distance L ₁ is longer groove 20 between the lower end portion of the groove 20, the deflection amount is increased in the diameter direction of the divided pieces 14a, which Accordingly, the press-in force becomes smaller. Further, according to the axial length of the groove 20 (width) L ₂ is longer, the force-insertion force is reduced.
[0034]
If the diameter of the joint portion J becomes too large, the machining accuracy of the cutting process of the outer joint tube 1 and the inner joint tube 11 deteriorates. Therefore, it is necessary to select the plate thickness to be larger than the minimum plate thickness required for stress. Accordingly, the amount of bending of the divided piece 14a of the inner joint pipe 11 decreases, and the press-fitting force when press-fitting the outer joint pipe 1 increases. For this reason, in order to suppress the pressing force to be equal to or less than the own weight of the upper steel pipe pile 32a, it is necessary to increase the axial length of the divided piece 14a of the inner joint pipe 11 so as to be easily bent. This not only increases the size of the joint J, but also increases the cost.
[0035]
In the present embodiment, a concave groove 20 is provided in the inner peripheral surface or the outer peripheral surface of the main body portion 14 (divided piece 14a) of the inner joint pipe 11, and the rigidity of this portion is reduced to facilitate bending. Can be suppressed to be equal to or less than the weight of the upper steel pipe pile 32a without increasing the axial length of the steel pipe pile 32a.
This not only reduces the cost of the joint portion J, but also eliminates the need to use a press-fitting machine or the like even in the case of a joint portion having a large diameter, thereby facilitating construction and improving workability.
[0036]
[Embodiment 3]
FIG. 8 is an explanatory view of a main part of a joint portion of a steel pipe according to Embodiment 3 of the present invention and an inner surface explanatory view of a split piece of an inner joint pipe.
In this embodiment, as shown in FIG. 8, bolt holes 7 a are provided instead of the plurality of bolt insertion holes 7 provided in outer joint pipe 1 of Embodiment 1 (FIG. 1), and inner joint pipe 11 is In place of the bolt hole 18 provided in each of the divided pieces 14a, an inverted U-shaped fitting portion 21 opened at the lower end is provided. At the tip of the threaded portion of the bolt 35, a polygonal locking hole 36 such as a hexagon is provided so that the bolt 35 can be rotated from the outside.
[0037]
In the construction of the present embodiment configured as described above, the steel pipe pile 31a to which the outer joint pipe 1 is joined is driven into the ground to connect the upper steel pipe pile 32a (not shown). 9A, the distal end of the bolt 35 is screwed into the bolt hole 7a of the external joint pipe 11 from the inside, as shown in FIG. 9A.
Then, the steel pipe pile 32a, to which the inner joint pipe is joined at the distal end, is lowered by the rolling force due to its own weight, and as shown in FIG. 9 (b), the fitting part 21 provided on each divided piece 14a of the inner joint pipe 11 is formed. Is fitted to a bolt 35 attached to the outer joint pipe 1.
[0038]
Next, the bolt 35 is further tightened by engaging, for example, an L-shaped hexagon wrench with a locking hole 36 provided at the tip of the screw portion of the bolt 35 from the outside of the outer joint pipe 1. The split piece 14a is drawn toward the outer joint pipe 1 by the head of the bolt 35 and returns to its original state (expanded in diameter), and as shown in FIG. And the steel pipe piles 31a, 32a are firmly joined via the outer joint pipe 1 and the inner joint pipe 11.
The effect of this embodiment is almost the same as that of the first embodiment.
[0039]
[Embodiment 4]
FIG. 10 is a schematic diagram of a joint structure of a steel pipe showing a part according to a fourth embodiment of the present invention in cross section. The same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.
In each of the above embodiments, the inner joint pipe 11 is provided with the slit 15 so as to have a diameter reducing function, and the inner joint pipe 11 is press-fitted into the outer joint pipe 1 so that the engaging projection 16 is engaged with the engaging portion. In this embodiment, the outer joint pipe 1 is provided with a slit so as to have a diameter increasing function, and the inner joint pipe 11 is press-fitted into the outer joint pipe 1 and engaged therewith. The projection 16 is locked to the locking portion 5.
[0040]
In FIG. 10, a plurality of slits 9 are provided in the circumferential direction of the main body 8 of the outer joint pipe 1 at substantially equal intervals and open to the upper end and reach the lower step 6. A plurality of divided pieces 8a having a diameter expanding function are formed by being divided in the circumferential direction. Note that the bolt insertion holes 7 are provided above the respective divided pieces 8a.
Further, a bolt hole 18 is provided in the upper part of the cylindrical main body 14 in the inner joint pipe 11 so as to correspond to the bolt insertion hole 7 of the outer joint pipe 1. The bolt hole 18 may be a bolt insertion hole, and a nut may be attached to the inner wall surface by welding.
[0041]
Next, an example of a construction procedure in a case where the present embodiment is applied to joining of steel pipe piles will be described. It is assumed that the outer joint pipe 1 and the inner joint pipe 11 are welded to the ends of the steel pipe piles 31a and 32a to be joined in advance in a factory or the like.
[0042]
As shown in FIG. 11A, when the steel pipe pile 31a to which the outer joint pipe 1 was joined was driven into a state of joining the upper steel pipe pile 32a, the inner joint pipe 11 was joined to the tip. The steel pipe pile 32a is positioned and positioned above the steel pipe pile 31a, and is lowered by the rolling force due to its own weight of the steel pipe pile 32a. As shown in FIG. 11B, an inclined surface provided at the upper end of the outer joint pipe 1 3 and the inclined surface 17 provided below the engagement protrusion 16 of the inner joint pipe 11 to bend each of the divided pieces 8a of the outer joint pipe 1 to expand the diameter of the main body portion 8 and Insert into tube 1.
[0043]
When the steel pipe pile 32a is continuously lowered, the engaging projections 16 of the inner joint pipe 11 are lowered along the inner peripheral surface of the outer joint pipe 1, and the divided pieces 8a of the outer joint pipe 1 are further bent and expanded. When the step portion 13 (contact portion) comes into contact with the upper end portion 2 of the outer joint pipe 1, the rolling down is stopped. The state at this time is shown in FIG.
[0044]
In this state, if the bolt 35 which is a diameter reducing means inserted into the bolt insertion hole 7 of the outer joint pipe 1 is screwed into the bolt hole 18 of the inner joint pipe 11 and tightened, each divided piece of the outer joint pipe 1 is separated. 8a is attracted by the bolt 35 and returns to its original state (reduced in diameter), and as shown in FIG. 12, its inner wall comes into contact with or comes close to the outer wall of the inner joint pipe 11, and the engaging projection 16 is locked. The upper and lower steel pipe piles 31a, 32a are firmly joined via the outer joint pipe 1 and the inner joint pipe 11 by being locked to the portion 5.
[0045]
In the present embodiment, substantially the same effect as in the case of Embodiment 1 can be obtained. However, since the lower inner peripheral surface of the main body 8 of the outer joint pipe 1 is provided with the concave portion 4, The rigidity of this portion is reduced, and each divided piece 8a can be easily bent as in the case of the second embodiment.
[0046]
In each of the above embodiments, the steel pipe pile 31a to which the outer joint pipe 1 is joined is driven into the ground, and the steel pipe pile 31a to which the inner joint pipe 11 is joined to the steel pipe pile 31a is lowered by its own weight. Although the case of joining has been described, the steel pipe pile 32a to which the inner joint pipe 11 is joined is cast into the ground, and the steel pipe pile 31a to which the outer joint pipe 1 is joined is lowered by its own weight to bring the outer joint pipe 1 inside. The steel pipe piles 32a and 31a may be joined by fitting and joining to the joint pipe 11.
[0047]
【The invention's effect】
The present invention provides an outer joint pipe having a locking portion on an inner peripheral surface and joined to one steel pipe, and an engaging projection provided on an outer peripheral surface for locking to a locking portion of the outer joint pipe, and the other. An inner joint pipe joined to a steel pipe, and a diameter increasing function is given to the outer joint pipe, or a diameter reducing function is given to the inner joint pipe, and the inner joint pipe is pressed into the outer joint pipe to reduce the diameter. The outer joint pipe is reduced in diameter by the means, or the inner joint pipe is expanded by the diameter-expanding means, and the engaging projection is locked to the locking portion of the outer joint pipe, so the structure is simple and construction is possible. Therefore, it is possible to obtain a highly reliable steel pipe joint structure that can reduce the cost.
[Brief description of the drawings]
FIG. 1 is a schematic view of a joint structure for a steel pipe, a part of which is shown in cross section according to Embodiment 1 of the present invention.
FIG. 2 is an explanatory diagram illustrating an example of a procedure for installing the joint structure according to the first embodiment;
FIG. 3 is a partially omitted longitudinal sectional view showing a state where two steel pipes are joined by the joint structure of the first embodiment.
FIG. 4 is an explanatory diagram of a main part of another example of the first embodiment.
FIG. 5 is a longitudinal sectional view of a joint structure of a steel pipe with a part omitted according to a second embodiment of the present invention.
FIG. 6 is a longitudinal sectional view in which a part of another example of the second embodiment is omitted.
FIG. 7 is a longitudinal sectional view in which a part of still another example of the second embodiment is omitted.
FIG. 8 is an explanatory view of a main part of a steel pipe joint structure according to Embodiment 3 of the present invention and an inner surface explanatory view of a split piece of an inner joint pipe.
FIG. 9 is an explanatory diagram of an example of a construction procedure according to the third embodiment.
FIG. 10 is a schematic diagram of a joint structure of a steel pipe, a part of which is shown in cross section according to Embodiment 4 of the present invention.
FIG. 11 is an explanatory diagram illustrating an example of a construction procedure according to the fourth embodiment.
FIG. 12 is a partially omitted cross-sectional view showing a state where two steel pipes are joined by the joint structure according to the fourth embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Outer joint pipe 2 Upper end part 5 Locking part 7, 18a Bolt insertion hole 8, 14 Main body part 11 Inner joint pipe 12 Large diameter part 13 Step part (contact part)
8a, 14a Split pieces 9, 15 Slits 16 Engagement projections 7a, 18 Bolt holes 19 Nuts 20 Grooves 21 Fittings 31, 32 Steel pipes 31a, 32a Steel pipe pile 35 Bolt

Claims

An outer joint pipe having a locking portion on the inner peripheral surface and joined to one steel pipe,
An engaging projection is provided on the outer peripheral surface for engaging with the engaging portion of the outer joint pipe, and an inner joint pipe joined to the other steel pipe,
The outer joint pipe is provided with a diameter increasing function, or the inner joint pipe is provided with a diameter reducing function, and the inner joint pipe is press-fitted into the outer joint pipe, and the outer joint pipe is reduced in diameter by reducing means. A joint structure for steel pipes, wherein the inner joint pipe is expanded in diameter by a diameter expanding means and its engaging projection is locked to a locking portion of the outer joint pipe.

An outer joint pipe having a locking portion on an inner peripheral surface, a plurality of bolt insertion holes provided in a circumferential direction of a lower portion of the locking portion, and a lower end portion joined to one steel pipe;
A plurality of divided pieces are formed by a slit having an outer diameter substantially equal to the inner diameter of the outer joint pipe and formed in an axial direction, and an engaging projection is provided on an outer peripheral surface of the outer joint pipe so as to be engaged with a locking portion of the outer joint pipe. An inner joint pipe having a main body part provided with a bolt hole corresponding to a bolt insertion hole of the outer joint pipe at a lower part of the engagement protrusion, and an upper end part joined to the other steel pipe,
After the main body of the inner joint pipe is press-fitted into the outer joint pipe, a bolt inserted into the bolt insertion hole is screwed into the bolt hole to expand the inner joint pipe and lock the engaging projection. A joint structure for a steel pipe characterized by being locked to a part.

An outer joint pipe having a locking portion on an inner peripheral surface, a plurality of bolt holes provided in a lower portion of the locking portion, and a lower end portion joined to one steel pipe;
A plurality of divided pieces are formed by a slit having an outer diameter substantially equal to the inner diameter of the outer joint pipe and formed in an axial direction, and an engaging projection is provided on an outer peripheral surface of the outer joint pipe so as to be engaged with a locking portion of the outer joint pipe. An inner joint pipe having a main body portion provided with a fitting portion that opens at a lower end portion corresponding to a bolt hole of the outer joint tube at a lower portion of the engagement protrusion, and an upper end portion is joined to the other steel pipe. With
The main body of the inner joint pipe is press-fitted into the outer joint pipe, and the fitting portion is fitted to a bolt screwed into a bolt hole from inside the outer joint pipe, and the bolt is further screwed into the inner joint pipe. A joint structure for a steel pipe, wherein a diameter of a joint pipe is increased and the engaging projection is locked to a locking portion.

The joint structure for a steel pipe according to claim 2 or 3, wherein a concave groove is provided on an inner peripheral surface or an outer peripheral surface between the large diameter portion of the main body portion of the inner joint pipe and the engagement projection.

A main body in which a plurality of divided pieces are formed by slits provided in the axial direction, a locking portion is provided on an inner peripheral surface of the divided piece, and a plurality of bolt insertion holes are provided in a circumferential direction above the locking portion. Having an outer joint pipe joined to one steel pipe,
An outer diameter is substantially equal to an inner diameter of the outer joint pipe, and an outer peripheral surface has an engagement protrusion for engaging with a locking portion of the outer joint pipe, and a bolt of the outer joint pipe is provided above the engagement protrusion. A bolt hole is provided corresponding to the insertion hole, and an inner joint pipe whose upper end is joined to the other steel pipe,
After the inner joint pipe is press-fitted into the outer joint pipe, a bolt inserted into the bolt insertion hole is screwed into the bolt hole to reduce the diameter of the outer joint pipe, and the engaging protrusion is engaged with a locking portion. A steel pipe joint structure characterized by being stopped.

Joining the outer joint pipe of claim 2 to one steel pipe and joining the inner joint pipe of claim 2 or 4 to the other steel pipe;
Press-fitting the inner joint pipe into the outer joint pipe;
A bolt inserted into a bolt insertion hole of the outer joint pipe is screwed into a bolt hole of the inner joint pipe, the inner joint pipe is expanded in diameter, and an engagement protrusion is engaged with a locking portion of the outer joint pipe. Stopping the steel pipe.

Joining the outer joint pipe of claim 3 to one steel pipe and joining the inner joint pipe of claim 3 or 4 to the other steel pipe;
Screwing a bolt into the bolt hole from the inside of the outer joint pipe;
A step of press-fitting the inner joint pipe into the outer joint pipe and fitting the fitting portion to the bolt;
Screwing the bolt into the bolt hole to expand the diameter of the inner joint pipe, and locking the engaging projection to the locking portion of the outer joint pipe. .

A method of joining the outer joint pipe of claim 5 to one steel pipe and joining the inner joint pipe to the other steel pipe;
Press-fitting the inner joint pipe into the outer joint pipe;
A bolt inserted into the bolt insertion hole of the outer joint pipe is screwed into a bolt hole of the inner joint pipe, the outer joint pipe is reduced in diameter, and the engagement protrusion of the inner joint pipe is engaged with the outer joint pipe. And a step of engaging with a stop.

The steel pipe is a steel pipe pile, and the inner joint pipe joined to the other steel pipe pile is press-fitted into the outer joint pipe joined to one steel pipe pile by the weight of one of the steel pipe piles. Item 7. The method for joining steel pipes according to Item 6, 7, or 8.