JP3686654B2

JP3686654B2 - Seismic strengthening method and seismic strengthening structure of existing concrete container structure

Info

Publication number: JP3686654B2
Application number: JP2002365716A
Authority: JP
Inventors: 康治川上; 明天野; 和仁村松; 佳治岩佐
Original assignee: 株式会社白石
Priority date: 2002-12-17
Filing date: 2002-12-17
Publication date: 2005-08-24
Anticipated expiration: 2022-12-17
Also published as: JP2004197373A

Description

【０００１】
【発明の属する技術分野】
本発明は、建設分野におけるコンクリート製配水池などの既設箱型コンクリート容器構造物の耐震補強方法および耐震補強構造に関する。
【０００２】
【従来の技術】
従来、既設箱型容器構造物として、コンクリート製の配水池が多く建造されていると共に、最近においては、コストダウンや工期短縮に伴い鋼製のプレハブ構造を有する既設箱型容器構造物もある。
【０００３】
従来、既設構造物のなかでも、既設コンクリート構造物の耐震補強方法は、（１）既設コンクリート構造物の壁厚を増大または耐震壁を増壁する方法、（２）既設コンクリート構造物の柱を増大または増設する方法、（３）緊張部材などで既設コンクリート構造物にプレストレスを付与する方法、および（４）既設コンクリート構造物の構造部材自体を改質する方法などが知られており、なかでも前記（３）の緊張部材などで既設コンクリート構造物にプレストレスを付与する方法については、（ａ）外ケーブル方式（構造物外部に設置）による方法、および（ｂ）内ケーブル方式（構造物内部に設置）による方法が多く採用されている（例えば、特許文献１〜４参照）。
【０００４】
【特許文献１】
特開平９−２３５８８５号公報
【特許文献２】
特開平９−１５１６０９号公報
【特許文献３】
特開平５−２０２５１８号公報
【特許文献４】
特開平６−７３８９７号公報
【非特許文献１】
社団法人日本水道協会、「施設基準対応」水道施設設計指針２０００
【０００５】
【発明が解決しようとする課題】
近年、土木構造物および建築構造物の設計は、大規模地震に対する耐性も考慮するようになっており、各種構造物の設計に関する指針や示方書などがレベル２地震動（大規模地震）に対応すべく改訂作業が行われている状況である。
【０００６】
つまり、過去に建造された構造物で旧来の設計に基づくものは、大規模地震に対する耐力面が懸念されおり、何らかの耐震補強手段を講じ、最新の設計基準に対応できるよう構造物の強度を引き上げる必要がある。
【０００７】
従来技術によれば、前記それぞれの方法が相応の施工用地を必要とし、また補修などを含む補強対象が構造物全体である場合には、必然、工期も長期間に及ぶほか施工量としても相当な規模に達する。特に、前記の（１）構造物の壁厚を増大または耐震壁を増壁する方法または前記（２）構造物の柱を増大または増設する方法にあっては、既に存在するひび割れなどを閉じることができず、また新旧コンクリートの一体化には施工がさらに大規模化する。
【０００８】
また、現存にて稼働している施設（構造物）については、施工期間中の供用を長期間に渡り停止する必要も生じ、このことは同規模の仮設備を先行して建造しなければならないなど、構造物の目的・種類によっては致命的な問題へと繋がる。
【０００９】
さらに、使用目的が容器であるような内空の確保を前提とする構造物に関しては、前述にある増壁や増柱のような手段を構造物内部において採用することが実質不可能となる。
【００１０】
したがって、これら既設コンクリート容器構造物の補強箇所数を低減させ施工規模の縮小を図る一方、既設コンクリート容器構造物に必要な補強を施し、工期・工費の面でも有利な、既設コンクリート容器構造物の耐震補強方法および耐震補強構造を提供することが望まれる。
【００１１】
上記課題を解決するために、本発明は既設コンクリート容器構造物の必要箇所に対して比較的安価な外ケーブル方式を利用したプレストレス導入手段により、該外ケーブルを緊張することで構造物に同時に多方向（緊張方向および偏向）の応力成分を付与し、かつプレストレスが必要のない部材には応力成分が相殺することで限りなく現存状態を維持することによって、工期短縮と工事規模の縮小に伴う工費縮減を可能とし、さらに施工期間中の構造物の供用を阻害せず、また内空容積を変化させることのない既設コンクリート容器構造物の耐震補強方法および耐震補強構造を提供することを目的とする。
【００１２】
【課題を解決するための手段】
前記の課題を有利に解決するために、本発明においは、次のように構成されている。
【００１３】
第１発明では、側圧が作用している既設コンクリート容器構造物の耐震補強方法であって、箱型コンクリート容器構造物における各側面版の外側に沿って縦方向の緊張部材を備えた縦方向のプレストレス導入装置を横方向に間隔をおいて多数配置し、前記各縦方向のプレストレス導入装置における緊張部材の下端部を、底版部端部下面および側壁版下端部外側面に貫通するように設けた傾斜した貫通孔に挿通して、底版部および側壁版並びにこれらが共有する張り出しフランジの下端面に緊張部材固定具により係合させ、かつ前記各緊張部材の上端部を、上床版および側壁版の上端部付近であって、側壁版上端部外側面および上床版端部上面に貫通する傾斜した貫通孔に挿通すると共に定着金具に装着し、かつ縦方向の緊張部材と側壁版との間に応力偏向部材を添設し、各緊張部材を緊張定着させ、さらに隣り合う側壁版相互の隅部に横方向の貫通孔を形成し、横方向に隣り合う横方向の貫通孔に渡って緊張部材を備えた横方向のプレストレス導入装置における緊張部材を挿通し、かつ横方向の緊張部材と側壁版との間に応力偏向部材を添設し、横方向の緊張部材の両端部を側壁版または隅部補強部に緊張定着し、プレストレス導入装置の単位設置箇所当たりのプレストレス導入方向を２次元的または３次元的に多方向へ前記既設箱型コンクリート容器構造物に作用させることで、既設箱型コンクリート容器構造物に対してプレストレスを付与して耐震補強することを特徴とする。
【００１４】
第２発明では、前記既設コンクリート容器構造物の耐震補強方法において、複数のプレストレス導入設備を配置する場合、複数のプレストレス導入装置における側壁版等の面版に作用する応力成分の一部が、互いに打ち消し合うように配置し、耐震補強の上で必要部分にのみ応力が作用し、その他の部分には付与するプレストレスが互いに相殺することで不必要な偏応力を既設コンクリート容器構造物内部に残留させないようにしたことを特徴とする。
【００１５】
第３発明では、第１発明または第２発明の既設コンクリート容器構造物の耐震補強方法において、プレストレス導入の際に外ケーブル方式による緊張部材を用い、前記緊張部材に緊張力を作用させると同時に、前記緊張部材と既設コンクリート容器構造物との間に、少なくとも１つ以上の応力偏向部材を既設コンクリート容器構造物に添設することで、既設コンクリート容器構造物に作用するモーメント分布を調節するようにしたことを特徴とする
【００１６】
第４発明では、第１発明から第３発明のいずれかの既設コンクリート容器構造物の耐震補強方法において、前記既設コンクリート容器構造物は、側壁版に内水圧等の側圧が作用している既設箱型コンクリート容器構造物であることを特徴とする。
【００１７】
第５発明の既設コンクリート容器構造物の耐震補強構造においては、側圧が作用している既設コンクリート容器構造物の耐震補強構造であって、箱型コンクリート容器構造物における各側面版の外側に沿って縦方向の緊張部材を備えた縦方向のプレストレス導入装置を横方向に間隔をおいて多数配置し、前記各縦方向のプレストレス導入装置における緊張部材の下端部が、底版部端部下面および側壁版下端部外側面に貫通するように設けた傾斜した貫通孔に挿通され、底版部および側壁版並びにこれらが共有する張り出しフランジの下端面に緊張部材固定具により係合され、かつ前記各緊張部材の上端部は、上床版および側壁版の上端部付近であって、側壁版上端部外側面および上床版端部上面に貫通する傾斜した貫通孔に挿通されると共に定着金具に装着し、かつ緊張部材と側壁版との間に応力偏向部材を挟装した状態で各緊張部材を緊張定着され、さらに隣り合う側壁版相互の隅部に形成した横方向に隣り合う横方向の貫通孔に渡って緊張部材を備えた横方向のプレストレス導入装置における緊張部材が挿通され、かつ横方向の緊張部材と側壁版との間に応力偏向部材が添設され、横方向の緊張部材の両端部が壁版または隅部補強部に緊張定着されて、既設箱型コンクリート容器構造物における側壁版にてプレストレスを付与して耐震補強することを特徴とする。
【００１８】
第６発明においては、第５発明の既設コンクリート容器構造物の耐震補強構造において、複数のプレストレス導入装置における面版に作用する応力成分の一部が、互いに打ち消し合うように配置されていることを特徴とする。
【００１９】
第７発明においては、第５発明または第６発明の既設コンクリート容器構造物の耐震補強構造において、複数のプレストレス導入装置における側壁版等の面版に作用する応力成分の一部が、互いに打ち消し合うように配置されていることを特徴とする。
【００２０】
第８発明においては、第５から第７発明のいずれかに記載の既設コンクリート容器構造物の耐震補強構造において、既設コンクリート容器構造物における周側壁版の端部に、端部から面版中央部側に向うと共に面版外側面に貫通する傾斜した貫通孔が設けられ、その貫通孔に緊張部材が挿通されて、緊張部材が面版の端部に定着されていることを特徴とする。
【００２１】
【作用】
本発明によると、既設コンクリート容器構造物の必要箇所に対して比較的安価な外ケーブル方式を利用したプレストレス導入手段により、外ケーブルを緊張することで構造物に多方向（緊張方向および偏向）の応力成分を同時に付与することによって、工期短縮と工事規模の縮小を伴う工費縮減を可能とし、さらに構造物の施工期間中の供用を阻害せず、また内空容積を変化させることのない既設コンクリート容器構造物の耐震補強を可能とする。また、構造物耐震補強後も経年変化による構造物の劣化は拒めないものの、既設コンクリート容器構造物がアルカリ骨材反応の反応過程に位置していれば、既設コンクリート容器構造物の耐震補強後も経時的に内部応力が増加する期間にあるため、結果としてコンクリート容器構造物耐震補強後の劣化度遅延措置に繋がることも期待できる。さらに、外ケーブルによるプレストレス導入により、当初に発生していたひび割れを閉じることを可能とし、容器として使用される構造物の気密性および水密性を向上させると伴に、地震荷重に対して復元力に富む構造を有する。
【００２２】
【発明の実施の形態】
以下、本発明の一実施形態について、既設箱型コンクリート容器構造物が配水池として稼働している既設箱型コンクリート容器構造物の場合を例に採り、詳細に説明する。
【００２３】
ここで、配水池構造物は、水を常時一定量供給するために、浄水場やポンプ場で事故などの不都合が発生しても直ちに断水する事態に陥らないように貯水するための容器構造物であり、必要配水量が予め設定されている。また、配水池の特徴として、一箇所の配水池の給水区域の過大化を回避すべく、適当な大きさで区域割りをしていることから、その数も非常に多いものとなる。
【００２４】
これら旧構造物の配水池を最新の水道施設設計指針（前出、非特許文献１参照）に照らし合わせてみると、常時荷重やレベル１地震動についての安全性はおおむね確認されているものの、レベル２地震動に対しては、上床版を除く各部材の必要耐力を向上させる必要がある場合がある。
【００２５】
そこで、このような場合の既設箱型コンクリート容器構造物の耐震補強手順を、図面を参照しながら次の第１段階から第６段階の各段階に従い、以降それぞれについて説明する。
【００２６】
（第１段階）既設箱型コンクリート容器構造物１の底版部２の掘削＜既設箱型コンクリート容器構造物１の建ち上がり方向＞
（第２段階）緊張部材３の設置＜既設箱型コンクリート容器構造物１の建ち上がり方向＞
（第３段階）応力偏向部材４の設置＜既設箱型コンクリート容器構造物１の建ち上がり方向＞
（第４段階）緊張部材３、応力偏向部材４の設置＜既設コンクリート容器構造物１の平面長手方向、短手方向＞
（第５段階）緊張部材３の緊張定着
（第６段階）原形復旧
【００２７】
（第１段階）既設箱型コンクリート容器構造物１の底版部２の掘削＜既設箱型コンクリート容器構造物１の建ち上がり方向＞
図１４および図１５に示すように、既設箱型コンクリート容器構造物１の内部に多数の支柱１０を備えていると共に、内部に貯水されて、配水池としての既設箱型コンクリート容器構造物１の側壁版５等に水圧が作用している既設箱型コンクリート容器構造物１を現存状態で耐震補強するにあたって、図２に示すように、まず、既設箱型コンクリート容器構造物１に設置される緊張部材の下側定着部を施工するために、耐震補強目的の配水池となっている既設箱型コンクリート容器構造物１の底版部２の周縁部下面および側壁版５下部近傍地盤６および基礎７の必要箇所を所要深さ掘削し、作業用溝８を適宜間隔をおいて、または連続して形成する。
【００２８】
また、図示例の既設箱型コンクリート容器構造物１は、底板部２と、左右方向の各側壁版５ａ，５ｂと前後方向の側壁版５ｃ，５ｄと、上床版９と、上床版９を支持すべく底板部２に立設された多数の支柱１０とを備えている。なお、図中１１は、出入り用の人孔、１２は割栗層、１３は均しモルタル層である。
【００２９】
（第２段階）緊張部材３の設置＜既設箱型コンクリート容器構造物１の建ち上がり方向＞：
次に、図３に示すように、配水池としての既設箱型コンクリート容器構造物１の底版部２端部および側壁版５下端部が共有している外側の張り出しフランジ部１４における基端側に、構造物建ち上がり方向に設置する緊張部材３の本数分、ＰＣ鋼材の外ケーブルからなる緊張部材３が挿通可能な大きさおよび角度に前記構造物１の横方向に間隔をおいて穿孔し、緊張部材３の挿通孔１５および定着座（必要に応じ支圧プレート等を埋め込み）を設ける。この挿通孔１５は、図示の形態では、底版部２または側壁版５等の端部に、側壁版端部から側壁中間側に向うと共に、側壁外側面に貫通する傾斜した貫通孔１５であり、側壁版５にプレストレスを導入する場合は、これに近接した位置であるとよい。なお、符号２０は隅部補強部で、下部の張り出しフランジ部１４，底版部２および側壁版５と一体化される部分補強部である。
【００３０】
前記のように貫通孔１５を設け、縦方向の緊張部材３の下端を貫通孔１５に挿通後、図１に示すように、底版部２の下側において、緊張部材３の下端定着部に、緊張部材固定用の緊張部材固定具１６を装着し、底板部２および側壁版５並びに張り出しフランジ１４の下端面に係合させて、これを固定端とする。
【００３１】
さらに、図１に示すように、配水池としての既設箱型コンクリート容器構造物１の上床版９および側壁版５上端部付近に、上床版９の端部から側壁版５の中間側に向うと共に、側壁版５の外側面に貫通する傾斜した貫通孔１７を設ける。図示の実施形態では、上部の張り出しフランジ部１９が適宜部分的に撤去されて、上床版９または側壁版５と一体に、隅部補強部２０が形成され、前記貫通孔１７は、緊張部材３の上端部が挿通可能な大きさおよび角度に構造物を穿孔され、前記下側と同様、必要本数分設け、フリーとなっている緊張部材３の上端側を挿通させ、緊張部材３の上側に緊張定着可能な定着金具１８を緊張端として仮止め装着して、プレストレス導入装置２１を設置する。なお、後記の偏向部材４が必要な場合には、これを含めてプレストレス導入装置とする。
【００３２】
（第３段階）応力偏向部材の縦方向の設置＜既設箱型コンクリート容器構造物１の建ち上がり方向＞：
前記縦方向の緊張部材３と既設箱型コンクリート容器構造物１における側壁版との間に、図１に示すように、応力偏向部材４を挟装し、既設箱型コンクリート容器構造物１の側壁版５に添設する。図示の形態では、前記応力偏向部材４には、その外面側に上下方向に延長する外側支承溝を備えていると共に必要に応じ応力偏向部材４の本体に左右方向（または上下方向）に延長する緊張部材挿通用の横孔が形成されている応力偏向部材４である。なお、応力偏向部材４は、適宜、側壁版５に接着材等により固定してもよい。
【００３３】
（第４段階）緊張部材、応力偏向部材の横方向の設置＜既設箱型コンクリート容器構造物１の平面長手方向（左右方向）および短手方向（前後方向）＞：
次に、図４，図５および図６〜図８に示すように、既設箱型コンクリート容器構造物１の平面長手方向（左右方向）および短手方向（前後方向）における、緊張部材３および応力偏向部材４の設置についても、前記第１段階〜第３段階と同様、側壁版５の横方向端部の定着部を、適宜、必要に応じ隅部補強部２０を設けて補強した上で、横方向に穿孔して、貫通孔２２を形成した後、緊張部材３の一端部を挿通して、側壁版５の外側に定着金具１６を装着して、これを固定端とし、前記緊張部材３の他端部に側壁版５の外側において、緊張定着可能な定着金具１８を緊張端として仮止め装着して、また、緊張部材３と側壁版との間に、応力偏向部材４を添設して、横方向のプレストレス導入装置２１を設置する。これらの一連の手順をもって、緊張部材３を備えた各プレストレス導入装置２１の準備を完了する。
【００３４】
なお、図示の実施形態のように、外側に向って傾斜した貫通孔１５にすると、緊張部材３を側壁版５の外面に近接した位置に配置することができ、緊張部材方向のプレストレス力を大きく、また、緊張部材３の緊張力による側壁版５に作用する曲げ力を極めて小さくでき、また、既設箱型コンクリート容器構造物１本体の外壁面に近い位置に貫通孔１５を設けることができ、既設箱型コンクリート容器構造物１の容器躯体本体の加工を極力小さなものとすることができる。
【００３５】
ここで、構造物建ち上がり方向に設置する緊張部材３と、構造物平面長手方向に設置する緊張部材３または構造物平面短手方向に設置する緊張部材３とが、交叉する部分については、それぞれの緊張部材３の損傷を回避すべく、前記のように、一方の緊張部材３が応力偏向部材４の内部を貫通させるなどの必要措置を講ずる。
【００３６】
（第５段階）緊張部材の緊張：
前記、第１段階〜第４段階によって準備された、各緊張部材３を所要緊張力で緊張する。緊張力は、構造物建ち上がり方向の緊張部材３には、一箇所当たり例えば、１５００ｋＮの導入プレストレス力が導入される。
【００３７】
なお、構造物平面長手方向（左右方向）および短手方向（前後方向）は、施工の単純化を図るため、緊張部材３が構造物四囲を同時に緊張可能とすべく連続した一本の緊張部材にて囲繞し、単位面積当たり０．５Ｎ／ｍｍ^２の導入プレストレス量を既設箱型コンクリート容器構造物１に付与するようにしてもよい。
【００３８】
ただし、この緊張段階に先行して、既設箱型コンクリート容器構造物１の形状にもよるが、各緊張部材３の固定端および緊張端の保護ならびに貫通孔１５，１７，２２周辺の強度低下を補足するために、前記のように必要に応じて、貫通孔周辺の補強工（２０）を鋼製材料またはコンクリート製材料などで行い、既設箱型コンクリート容器構造物１に一体化させる。
【００３９】
また、第２段階もしくは第４段階で、緊張部材３の固定端および緊張端の施工には、直接構造物を穿孔し、貫通孔１５（１７，２２）を形成する方法の採用が困難な場合もあり、このような状況においては、図示のように、貫通孔周辺の補強工２０と併せて既設箱型コンクリート容器構造物１を補強した上で、貫通孔１５（１７，２２）の穿孔作業を行う。
【００４０】
（第６段階）原形復旧：
最後に、第１段階の緊張部材３を適宜防錆処理をした上で、図１に２点鎖線で示すように、構造物底版部２下面の基礎７の修復および掘削溝８を埋め戻して原形復旧する。
【００４１】
以上の各段階を経て得られる補強効果を、図９（ａ）〜（ｃ）にイメージ図として示すと、既設箱型コンクリート容器構造物１の耐震補強前の状態は、図９（ａ）に示すように、既設箱型コンクリート容器構造物１が配水池として常時稼働している施設であるため、内部に貯える水の総量が一日を通して変動するものの、最大水位で図９（ａ）のような三角形の圧力勾配で現される。
【００４２】
また、図９（ｂ）に示すように、側壁版５に応力偏向部材４を介在させて、プレストレスを導入すると、側壁版５に対して上下軸方向の応力成分Ｐとこれに偏向する横方向の応力成分Ｆとが作用し、側壁版５に作用する側圧および側壁版５と底版部２と上床版９とに作用する曲げ力を打ち消すように作用し、図９（ｃ）に示すように、既設箱型コンクリート容器構造物１が安定する。
【００４３】
そして、このように、既設箱型コンクリート容器構造物１にプレストレスを導入することにより、既設箱型コンクリート容器構造物１はレベル２地震動の耐震性能を満足するものとなる。
【００４４】
さらに、既設箱型コンクリート容器構造物１に作用する常時荷重、レベル１地震時、およびレベル２地震時に、レベル２地震動にて全ての部材の発生断面力を部材の耐力内に抑えることにより、その耐震補強効果は、常時荷重で側壁版５および支柱１０部で引張応力が発生しなくなり、既存のひび割れが閉じられ、例えば、２０％〜１００％の応力低減度が得られ、レベル１地震時においては、各部材の応力が改善され、例えば、２５％〜９９％の応力低減度が得られる。
【００４５】
前記実施形態において、緊張部材３の端部の定着金具１６，１８としては、既設箱型コンクリート容器構造物１側に、当接または埋め込み配置され、緊張部材３を嵌挿される鋼製環状の支圧プレートと、これに支承され、外側に向って拡径する緊張部材挿通孔を備えた楔受け金具と、複数の断面円弧状の分割型楔とにより、緊張部材３の端部を既設箱型コンクリート容器構造物１に定着することができる。なお、定着金具１６，１８としては、その他の公知の定着金具を使用するようにしてもよい。また、貫通孔１５，１７，２２を形成するために、鋼製管体または合成樹脂製短管等を使用するとよい。
【００４６】
次に、本発明を実施してプレストレスを導入した場合の作用を図１０および図１１を参照して説明する。なお、図１１（ａ）〜（ｄ）における矢印は、プレストレス導入による作用（応力発生方向）成分である。
【００４７】
図１０（ａ）の（イ）および（ロ）に示すように、側壁版５の上下方向に鉛直状態で緊張部材３を配置し、側壁版の上下両端部で緊張定着すると、図１１（ａ）の（イ）および（ロ）に示すように、鉛直方向（Ｚ軸方向）にのみ、２次元的に、プレストレス力導入による作用（応力発生）成分を発生させることができる。なお、図１０および図１１の（ロ）において、丸印内の文字は、その軸方向にプレストレス力が作用していることを示している。
【００４８】
また、図１０（ｂ）の（イ）および（ロ）に示すように、側壁版５の上下方向に傾斜した状態で緊張部材３を配置し、側壁版５の上下両端部で緊張定着すると、図１１（ｂ）の（イ）および（ロ）に示すように、鉛直方向（Ｚ軸方向）および前後方向（Ｘ軸方向）に、２次元的にプレストレス力導入による作用（応力発生）成分を発生させることができる。
【００４９】
また、図１０（ｃ）の（イ）および（ロ）に示すように、緊張部材３を側壁版５の鉛直（上下）方向に配置すると共に応力偏向部材４を介在させ、緊張部材３を側壁版５の上下両端部で緊張定着すると、図１１（ｃ）の（イ）および（ロ）に示すように、鉛直方向（Ｚ軸方向）および左右方向（Ｙ軸方向）に、２次元的にプレストレス力導入による作用（応力発生）成分を発生させることができる。
【００５０】
また、図１０（ｄ）の（イ）および（ロ）に示すように、側壁版５の上下方向に緊張部材３を前後方向に傾斜した状態に配置し、応力偏向部材４を介在させ、緊張部材３を側壁版５の上下両端部で緊張定着すると、図１１（ｄ）の（イ）および（ロ）に示すように、鉛直方向（Ｚ軸方向）および左右方向（Ｙ軸方向）並びに、前後方向（Ｘ軸方向）に、３次元の立体内において、プレストレス力導入による作用（応力発生）成分を発生させることができる。
【００５１】
次に、側壁部５にプレストレス力を作用させることにより、底板部２を補強するとになる場合について、図１２を参照しながら説明する。
【００５２】
本発明を実施する場合、例えば地上に立設する既設箱型コンクリート容器構造物１は、底版部２に直接、プレストレス導入装置２１を設置することが難しい場合がある。このような場合には、図１２に示すように、側壁版５の下端部における底版部２と近傍のレベルに、プレストレス導入装置２１を、左右方向の側壁版５または前後方向の側壁版５に横向きに設置し、緊張部材３を緊張して左右方向の側壁部５の左右方向両端部、または前後方向の側壁版５の前後方向両端部に定着してプレストレス力Ｆを導入すると、側壁版５を介して、底版部２にプレストレス力の一部のプレストレス力ｆを導入して、底版部２を補強することができる。
【００５３】
次に、複数のプレストレス導入設備を配置する場合、複数のプレストレス導入装置２１における面版に作用する応力成分の一部が、互いに打ち消し合うように配置し、耐震補強の上で必要部分にのみ応力が作用し、その他の部分には付与するプレストレスが互いに相殺することで、不必要な偏応力を既設箱型コンクリート容器構造物１の内部に残留させないようにする場合について、図１３を参照しながら説明する。
【００５４】
図１３（ａ）に示すように、例えば、左右方向の側壁版５の左側に変位した位置に、長尺の緊張部材３（３ａ）を備えたプレストレス導入装置２１を下方に向って左側に変位するように配置し、かつ同時に、図１３（ｂ）に示すように、左右方向の側壁版５の右側に変位した位置に、短尺の緊張部材３（３ｂ）を備えたプレストレス導入装置２１を下方に向って右側に変位するように対称な角度で配置し、それぞれの緊張部材３（３ａ，３ｂ）の両端部を、側壁版５に同じ緊張力で緊張して定着すると、図１３（ｃ）に示すように、水平方向の応力成分Ｔが互いに打ち消しあって釣り合いがとれ、上下方向のプレストレス力の合力Ｐを側壁版５に作用させることができる。
【００５５】
既設箱型コンクリート容器構造物１に構造的な特徴があって、水平方向の応力成分を付与させないようにするには、前記のようにすればよい。同様に各側壁版５にも同様に適用でき、また、例えば９０°配置を変えれば、上下方向の応力成分が互いに打ち消しあって釣り合いがとれ、水平方向のプレストレス力の合力を側壁版５に作用させることができる。なお、各緊張部材３（３ａ，３ｂ）の集合部Ｐは、側壁版５に水平方向の引張力が作用しないで、圧縮力が作用するように、右側（または下側）配置の緊張部材３は左側（上側）に、左側（または上側）配置の緊張部材３は右側（または下側）に多少変位して配置するとよい。また同様に、各緊張部材３（３ａ，３ｂ）の集合部は、側壁版５に鉛直方向の引張力が作用しないで、圧縮力が作用するように、下側配置の緊張部材３ｂは上側に、上側配置の緊張部材３ａは下側に多少変位して配置するとよい。
【００５６】
本発明を実施する場合、緊張部材３としては、例えば、ＰＣケーブルまたはＰＣ鋼棒等のＰＣ鋼材を使用するとよい。また、前記実施形態においては、緊張部材３の端部定着構造として、楔式の定着構造を示したが、楔式以外にも、適宜公知の定着手段を採用するようにしてもよい。また、既設コンクリート容器構造物としては、既設箱型コンクリート容器構造物以外にも、多角形あるいは円筒状の既設コンクリート容器構造物に適用するようにしてもよい。
【００５７】
【発明の効果】
本発明の既設コンクリート容器構造物の耐震補強方法によると、既設コンクリート容器構造物の部分的に緊張部材を備えたプレストレス導入装置を設置して耐震補強する形態であるので、既設コンクリート容器構造物の躯体全体を施工する場合に比べて、施工が容易であり、工期の短縮と工事規模の縮小が可能となり、したがって、耐震補強工費を縮減することができる。また、稼働施設となっている既設箱型コンクリート容器構造物については、稼動させながら耐震補強することができ、また、既設箱型コンクリート容器構造物の内空容積を変化させることなく、既設箱型コンクリート容器構造物の耐震補強が可能となることから、施工前の現状をそのまま維持することができる。また、構造物耐震補強後も経年変化による構造物の劣化は拒めないものの、既設箱型コンクリート容器構造物がアルカリ骨材反応の反応過程に位置していれば、既設箱型コンクリート容器構造物の耐震補強後も経時的に内部応力が増加する期間にあるため、結果としてコンクリート構造物耐震補強後の劣化度遅延措置に繋がることも期待できる。さらに、外ケーブルによるプレストレス導入により、当初に発生していたひび割れを閉じることを可能とし、容器として使用される構造物の気密性および水密性を向上させると共に、地震荷重に対して復元力に富む構造を有する。
【００５８】
また、請求項２のようにすると、複数のプレストレス導入設備を配置する場合に、複数のプレストレス導入装置における面版に作用する応力成分の一部が、互いに打ち消し合うように配置することにより、耐震補強の上で必要部分にのみ応力が作用し、その他の部分には付与するプレストレスが互いに相殺することで不必要な偏応力を既設箱型コンクリート容器構造物内部に残留させないようにすることができる。
【００５９】
また、請求項３または４のようにすると、緊張部材と既設箱型コンクリート容器構造物との間に、少なくとも１つ以上の応力偏向部材を既設箱型コンクリート容器構造物に添設することにより、既設箱型コンクリート容器構造物に作用するモーメント分布を調節するようにしたので、側壁版に水圧などによる曲げモーメントが作用していても、側壁版等に作用する曲げモーメントを軽減して、側壁版ひいては既設箱型コンクリート容器構造物全体の耐震性を向上させることができ、特に、既設箱型コンクリート容器構造物の側壁版に内水圧等の側圧が作用している既設箱型コンクリート容器構造物に適用すると効果的に耐震性を向上させることができる。
【００６０】
また、請求項５のようにすると、本発明の既設コンクリート容器構造物の耐震補強構造によると、既設コンクリート容器構造物を構成する面版の外側に沿って、緊張部材を備えたプレストレス導入装置を縦方向または横方向あるいは傾斜した方向に複数配置すると共に、前記各緊張部材を緊張させて、その両端部を面版に定着させて、既設コンクリート容器構造物における面版に対してプレストレスを付与するだけで、簡単な構造で、既設コンクリート容器構造物を容易に耐震補強することができる。
【００６１】
また、請求項６のようにすると、複数のプレストレス導入装置における面版に作用する応力成分の一部が、互いに打ち消し合うように配置されていると、既設コンクリート容器構造物に応力成分の一部を既設コンクリート容器構造物に作用させたくない場合にも、容易に打ち消した状態で作用させることができ、したがって、他の応力成分のみを効果的に作用させることができる。
【００６２】
また、請求項７のようにすると、複数の緊張部材を側壁版の外側に交叉するように配置する場合に、外側に緊張部材支承部と内側に緊張部材挿通孔を備えた応力偏向部材が配置されていると、交差配置される方向の異なる緊張部材相互を容易に所定の位置に配置することができる。
【００６３】
また、請求項８のようにすると、既設箱型コンクリート容器構造物における周側壁版の端部に、端部から面版中央部側に向うと共に面版外側面に貫通する傾斜した貫通孔が設けられ、その貫通孔に緊張部材が挿通されて、緊張部材が面版の端部に定着されているので、緊張部材を側壁版の外面に近接した位置に配置することができ、緊張部材方向のプレストレス力を大きく、また、緊張部材の緊張力による側壁版に作用する曲げ力を極めて小さくでき、また、既設箱型コンクリート容器構造物本体の壁中心側に近づくことなく、外壁面に近い位置に貫通孔を設けることができ、既設箱型コンクリート容器構造物の容器躯体本体の加工を極力小さなものとすることができる。
【図面の簡単な説明】
【図１】本発明を実施して既設箱型コンクリート容器構造物を耐震補強している状態を示す縦断側面図である。
【図２】本発明を実施するために、既設箱型コンクリート容器構造物の下部地盤を掘削した状態を示す縦断側面図である。
【図３】本発明を実施して、既設箱型コンクリート容器構造物の緊張部材定着部を補強すると共に、緊張部材挿通用の傾斜した挿通孔を形成した状態を示す縦断側面図である。
【図４】本発明を実施して、既設箱型コンクリート容器構造物の緊張部材定着部を補強すると共に、左右方向の緊張部材挿通用の傾斜した挿通孔を形成した状態を示す横断平面図である。
【図５】本発明を実施して、既設箱型コンクリート容器構造物の緊張部材定着部を補強すると共に、前後方向の緊張部材挿通用の傾斜した挿通孔を形成した状態を示す横断平面図である。
【図６】本発明を実施して、既設箱型コンクリート容器構造物を耐震補強した状態を示す概略縦断側面図である。
【図７】図６の一部横断概略平面図である。
【図８】横方向の緊張部材を定着部を示す一部切欠横断平面図である。
【図９】本発明における既設箱型コンクリート容器構造物の耐震補強方法の説明図であって、（ａ）は現状の既設箱型コンクリート容器構造物における側壁版に静水圧による曲げモーメントが作用し、側壁版に外向きの曲げ力が作用し、上床版と底版部に箱内側に内向きの曲げ力が作用していることを示す説明図、（ｂ）は側壁版に矢印で示すプレストレスを導入すると共に応力偏向部材を使用して、静水圧に対向する偏向力をさせることを示す説明図、（ｃ）は（ａ）と（ｂ）に示す作用状態に対応するために、本発明の耐震補強方法および耐震補強構造を側壁版に適用した状態を示す縦断側面図である。
【図１０】本発明を実施してプレストレスを導入した場合の作用を示す説明図である。
【図１１】本発明を実施してプレストレスを導入した場合の作用成分を示す説明図である。
【図１２】（ａ）は本発明を実施して既設箱型コンクリート容器構造物の周側壁版を耐震補強した場合に底板部へ作用する場合の説明図である。
【図１３】（ａ）〜（ｃ）は、本発明を実施して、プレストレスが相殺する場合の例を示す説明図である。
【図１４】既設箱型コンクリート容器構造物の一例を示す縦断側面図である。
【図１５】既設箱型コンクリート容器構造物の一例を示す一部横断平面図である。
【符号の説明】
１既設箱型コンクリート容器構造物
２底版部
３緊張部材
４応力偏向部材
５（５ａ〜５ｄ）側壁版
６地盤
７基礎
８作業用溝
９上床版
１０支柱
１１人孔
１２割栗層
１３均しモルタル
１４張り出しフランジ部
１５貫通孔
１６緊張部材固定具
１７貫通孔
１８定着金具
１９上部の張り出し部
２０隅部補強部
２１プレストレス導入装置
２２貫通孔[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a seismic reinforcement method and a seismic reinforcement structure for an existing box-type concrete container structure such as a concrete reservoir in the construction field.
[0002]
[Prior art]
Conventionally, many concrete reservoirs have been constructed as existing box-type container structures, and recently, there are also existing box-type container structures having a steel prefabricated structure in accordance with cost reduction and construction period shortening.
[0003]
Conventionally, among existing structures, the method for seismic reinforcement of existing concrete structures is (1) A method of increasing the wall thickness of an existing concrete structure or increasing a seismic wall; (2) A method of increasing or expanding the pillars of an existing concrete structure; (3) A method of applying prestress to an existing concrete structure with a tension member or the like; and (4) Methods for modifying the structural members of existing concrete structures are known, and above all, (3) As for the method of applying prestress to existing concrete structures with tension members, etc., (a) by the external cable system (installed outside the structure) and (b) by the internal cable system (installed inside the structure) Many methods are employed (see, for example, Patent Documents 1 to 4).
[0004]
[Patent Document 1]
JP-A-9-235858
[Patent Document 2]
JP-A-9-151609
[Patent Document 3]
JP-A-5-202518
[Patent Document 4]
JP-A-6-73897
[Non-Patent Document 1]
Japan Waterworks Association, “Facility Standards” Water Supply Facility Design Guidelines 2000
[0005]
[Problems to be solved by the invention]
In recent years, civil engineering structures and building structures have been designed to take into account resistance to large-scale earthquakes, and guidelines and specifications regarding the design of various structures are compatible with Level 2 ground motions (large-scale earthquakes). The situation is being revised accordingly.
[0006]
In other words, structures that were built in the past and based on traditional designs are concerned about the strength of large-scale earthquakes, and some seismic reinforcement measures are taken to increase the strength of the structures to meet the latest design standards. There is a need.
[0007]
According to the prior art, when each of the above methods requires a suitable construction site, and the object to be reinforced including repairs is the entire structure, the construction period is inevitably long and the construction amount is also considerable. Reach a certain scale. In particular, the above (1) A method for increasing the wall thickness of a structure or increasing a seismic wall, or (2) In the method of increasing or adding the pillars of the structure, the existing cracks cannot be closed, and the construction is further enlarged to integrate the old and new concrete.
[0008]
In addition, for facilities (structures) that are currently in operation, it is necessary to stop the operation during the construction period for a long period of time, which means that temporary equipment of the same scale must be built in advance. Depending on the purpose and type of the structure, it can lead to fatal problems.
[0009]
Furthermore, regarding a structure based on the premise of securing an inner space where the purpose of use is a container, it is practically impossible to employ means such as the above-mentioned increased walls and additional columns inside the structure.
[0010]
Therefore, while reducing the number of reinforcement points of these existing concrete container structures and reducing the scale of construction, the existing concrete container structures are provided with the necessary reinforcement, which is advantageous in terms of construction period and cost. It would be desirable to provide a seismic reinforcement method and a seismic reinforcement structure.
[0011]
In order to solve the above-mentioned problem, the present invention simultaneously applies to a structure by tensioning the outer cable by means of a prestress introduction means using a relatively inexpensive outer cable system for a necessary portion of an existing concrete container structure. By applying stress components in multiple directions (tension direction and deflection) and maintaining the existing state as much as possible by offsetting the stress components for members that do not require pre-stress, the construction period and construction scale can be reduced. The purpose is to provide a seismic reinforcement method and a seismic reinforcement structure for existing concrete container structures that can reduce the construction costs involved, and do not hinder the use of the structure during the construction period and do not change the internal volume. And
[0012]
[Means for Solving the Problems]
In order to solve the above-mentioned problem advantageously, the present invention is configured as follows.
[0013]
In the first invention, the seismic reinforcement method for an existing concrete container structure on which a lateral pressure is applied, A large number of longitudinal prestress introduction devices having longitudinal tension members along the outside of each side plate in the box-shaped concrete container structure are arranged at intervals in the lateral direction, and each longitudinal prestress introduction is performed. The lower end portion of the tension member in the apparatus is inserted into an inclined through-hole provided so as to penetrate the bottom surface of the bottom plate end portion and the outer surface of the bottom end portion of the side wall plate, and the bottom plate portion, the side wall plate, and the overhanging flange shared by them The lower end surface is engaged with a tension member fixing tool, and the upper end portion of each tension member penetrates the upper side surface of the upper side plate and the upper side of the upper side plate near the upper end of the upper floor plate and the side wall plate. Insert through the inclined through-hole and attach to the fixing bracket, and attach a stress deflecting member between the longitudinal tension member and the side wall plate to fix each tension member and fix the adjacent side wall plates to each other. Corner A lateral tension member and a side wall plate are formed by inserting a tension member in a lateral prestress introduction device having a lateral through hole and having a tension member across a lateral through hole adjacent in the lateral direction. A stress deflecting member is attached between the two ends, and both ends of the tension member in the lateral direction are tension-fixed to the side wall plate or the corner reinforcing portion, Prestress introduction direction per unit installation location of the prestress introduction device is two-dimensionally or three-dimensionally arranged in multiple directions Box type By acting on a concrete container structure, Box type It is characterized by prestressing the concrete container structure and reinforcing it seismically.
[0014]
In 2nd invention, in the seismic reinforcement method of the said existing concrete container structure, when arrange | positioning several prestress introduction equipment, in several prestress introduction apparatus Side wall version etc. Arrangement is made so that part of the stress components acting on the plate slash each other, stress acts only on the necessary parts on the seismic reinforcement, and the prestress applied to the other parts cancels each other. It is characterized in that the necessary partial stress is not left inside the existing concrete container structure.
[0015]
In the third invention, in the seismic reinforcement method for an existing concrete container structure of the first invention or the second invention, a tension member using an external cable system is used at the time of introducing prestress, and at the same time a tension force is applied to the tension member The moment distribution acting on the existing concrete container structure is adjusted by attaching at least one stress deflecting member to the existing concrete container structure between the tension member and the existing concrete container structure. Characterized by
[0016]
According to a fourth invention, in the seismic reinforcement method for an existing concrete container structure according to any one of the first to third inventions, the existing concrete container structure is an existing box in which a side pressure such as internal water pressure acts on a side wall plate. It is a type concrete container structure.
[0017]
In the seismic reinforcement structure of the existing concrete container structure of the fifth invention, the seismic reinforcement structure of the existing concrete container structure on which the side pressure is acting, A large number of longitudinal prestress introduction devices having longitudinal tension members along the outside of each side plate in the box-shaped concrete container structure are arranged at intervals in the lateral direction, and each longitudinal prestress introduction is performed. The lower end of the tension member in the apparatus is inserted into an inclined through-hole provided so as to penetrate the bottom surface of the bottom plate end and the outer surface of the bottom end of the side wall, and below the bottom plate and the side plate and the overhanging flange shared by them. An inclined surface that is engaged with an end surface by a tension member fixture, and an upper end portion of each tension member is near the upper end portion of the upper floor slab and the side wall plate, and penetrates the outer side surface of the upper side of the side wall plate and the upper surface of the upper floor plate end portion. Each tension member is tension-fixed in a state where the stress deflection member is sandwiched between the tension member and the side wall plate while being inserted into the through-hole and attached to the fixing bracket. The tension member in the lateral prestress introducing device provided with the tension member is inserted through the formed lateral through hole adjacent to the lateral direction, and the stress deflection member is interposed between the lateral tension member and the side wall plate. Is attached, and both ends of the tension member in the lateral direction are tension-fixed to the wall plate or the corner reinforcement. Existing Box type It is characterized in that prestress is applied to the side wall plate in the concrete container structure to strengthen the earthquake resistance.
[0018]
In the sixth invention, in the seismic reinforcement structure of the existing concrete container structure according to the fifth invention, a part of the stress components acting on the face plate in the plurality of prestress introduction devices are arranged to cancel each other. It is characterized by.
[0019]
In the seventh invention, in the seismic reinforcement structure of the existing concrete container structure of the fifth invention or the sixth invention, in the plurality of prestress introduction devices Side wall version etc. A part of the stress components acting on the surface plate is arranged so as to cancel each other.
[0020]
According to an eighth aspect of the present invention, in the seismic reinforcement structure for an existing concrete container structure according to any one of the fifth to seventh aspects, the end portion of the peripheral side wall plate in the existing concrete container structure is extended from the end portion to the center portion of the face plate. An inclined through-hole is provided which extends to the side and penetrates the outer surface of the slab, and a tension member is inserted into the through-hole so that the tension member is fixed to the end portion of the stencil.
[0021]
[Action]
According to the present invention, the pre-stress introduction means using a relatively inexpensive external cable system for a necessary portion of the existing concrete container structure is multi-directional to the structure by tensioning the outer cable (tension direction and deflection). By simultaneously applying the stress component, it is possible to reduce the construction cost along with the shortening of the construction period and the construction scale, and further, the existing capacity that does not hinder the use of the structure during construction and does not change the internal volume Enables seismic reinforcement of concrete container structures. Even after seismic reinforcement of the structure, deterioration of the structure due to secular change cannot be rejected, but if the existing concrete container structure is located in the reaction process of the alkali-aggregate reaction, after the seismic reinforcement of the existing concrete container structure Since the internal stress increases over time, it can be expected to lead to measures for delaying deterioration after concrete container structure seismic reinforcement. In addition, the introduction of pre-stress with an external cable makes it possible to close the cracks that originally occurred, improve the airtightness and watertightness of the structure used as a container, and restore it against earthquake loads. It has a powerful structure.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described in detail, taking as an example the case of an existing box-type concrete container structure operating as a distribution reservoir.
[0023]
Here, the reservoir structure is a container structure for storing water so that water will not be immediately shut down even if an inconvenience such as an accident occurs at a water purification plant or pumping station in order to supply a constant amount of water. The required water distribution amount is set in advance. In addition, as a characteristic of the distribution reservoir, since the area is divided in an appropriate size in order to avoid an excessive increase in the water supply area of one distribution reservoir, the number of distribution reservoirs is very large.
[0024]
When these reservoirs of old structures are compared with the latest water supply facility design guidelines (see above, Non-Patent Document 1), the safety of constant loads and level 1 ground motions is generally confirmed, but the level For 2 earthquake motions, it may be necessary to improve the required proof stress of each member except the upper floor slab.
[0025]
Then, the seismic reinforcement procedure of the existing box-type concrete container structure in such a case will be described below in accordance with the following first to sixth steps with reference to the drawings.
[0026]
(First stage) Excavation of bottom slab part 2 of existing box-type concrete container structure 1 <Building direction of existing box-type concrete container structure 1>
(Second stage) Installation of the tension member 3 <Building direction of the existing box-type concrete container structure 1>
(Third Stage) Installation of Stress Deflection Member 4 <Upward Direction of Existing Box-shaped Concrete Container Structure 1>
(Fourth stage) Installation of the tension member 3 and the stress deflection member 4 <Planar longitudinal direction and short direction of the existing concrete container structure 1>
(Fifth stage) Tension fixation of the tension member 3
(6th stage) Original shape restoration
[0027]
(First stage) Excavation of bottom slab part 2 of existing box-type concrete container structure 1 <Building direction of existing box-type concrete container structure 1>
As shown in FIGS. 14 and 15, the existing box-type concrete container structure 1 is provided with a large number of support columns 10 and stored in the interior of the existing box-type concrete container structure 1. When the existing box-type concrete container structure 1 in which water pressure is applied to the side wall plate 5 or the like is seismically reinforced in the existing state, first, as shown in FIG. 2, the tension installed in the existing box-type concrete container structure 1 In order to construct the lower fixing part of the member, the bottom surface of the bottom slab part 2 of the existing box-type concrete container structure 1 serving as a distribution reservoir for the purpose of seismic reinforcement, and the ground 6 and the foundation 7 near the lower part of the side wall slab 5 A necessary portion is excavated to a required depth, and the working grooves 8 are formed at appropriate intervals or continuously.
[0028]
Further, the existing box-type concrete container structure 1 in the illustrated example supports the bottom plate portion 2, the left and right side wall plates 5 a and 5 b, the front and rear side wall plates 5 c and 5 d, the upper floor plate 9, and the upper floor plate 9. As many as possible, a plurality of support columns 10 are provided on the bottom plate 2. In the figure, 11 is an entrance / exit human hole, 12 is a split chestnut layer, and 13 is a leveling mortar layer.
[0029]
(Second stage) Installation of the tension member 3 <Building direction of the existing box-type concrete container structure 1>:
Next, as shown in FIG. 3, on the base end side of the overhanging flange portion 14 shared by the bottom plate portion 2 end portion and the side wall plate 5 lower end portion of the existing box-type concrete container structure 1 as a distribution reservoir. The number of tension members 3 installed in the direction in which the structure is built up is perforated at intervals in the lateral direction of the structure 1 at a size and angle through which the tension member 3 made of an external cable of PC steel can be inserted, An insertion hole 15 for the tension member 3 and a fixing seat (embedding a supporting plate or the like if necessary) are provided. In the form shown in the figure, the insertion hole 15 is an inclined through hole 15 that extends from the side wall plate end to the side wall intermediate side and penetrates the side wall outer surface at the end of the bottom plate portion 2 or the side wall plate 5, In the case where prestress is introduced into the side wall plate 5, it is preferable that the side plate 5 be located in the vicinity thereof. Reference numeral 20 denotes a corner reinforcing portion, which is a partial reinforcing portion integrated with the lower overhanging flange portion 14, the bottom plate portion 2 and the side wall plate 5.
[0030]
As described above, the through hole 15 is provided, and after the lower end of the tension member 3 in the vertical direction is inserted into the through hole 15, as shown in FIG. A tension member fixing tool 16 for fixing the tension member is mounted and engaged with the bottom plate 2, the side wall plate 5, and the lower end surface of the overhanging flange 14, and this is used as a fixed end.
[0031]
Further, as shown in FIG. 1, in the vicinity of the upper floor slab 9 and the side wall slab 5 upper end portion of the existing box-type concrete container structure 1 as a distribution reservoir, from the end of the upper floor slab 9 toward the intermediate side of the side wall slab 5 An inclined through hole 17 that penetrates the outer surface of the side wall plate 5 is provided. In the illustrated embodiment, the upper overhanging flange portion 19 is partly removed as appropriate, and the corner reinforcing portion 20 is formed integrally with the upper floor slab 9 or the side wall slab 5, and the through hole 17 includes the tension member 3. The structure is perforated to a size and an angle at which the upper end of the tension member 3 can be inserted, and, as with the lower side, the required number is provided, the upper end side of the tension member 3 that is free is inserted, and the tension member 3 is The pre-stress introduction device 21 is installed by temporarily fixing the fixing bracket 18 capable of tension fixation as a tension end. In addition, when the later-described deflection member 4 is required, a prestress introducing device including this is used.
[0032]
(Third Stage) Installation of Stress Deflection Member in Vertical Direction <Upward Direction of Existing Box-shaped Concrete Container Structure 1>:
As shown in FIG. 1, a stress deflecting member 4 is sandwiched between the longitudinal tension member 3 and the side wall plate of the existing box-type concrete container structure 1, and the side wall of the existing box-type concrete container structure 1. Attached to plate 5. In the illustrated embodiment, the stress deflection member 4 is provided with an outer support groove extending in the vertical direction on the outer surface side, and is extended in the left-right direction (or vertical direction) on the main body of the stress deflection member 4 as necessary. It is the stress deflection | deviation member 4 in which the horizontal hole for tension member insertion is formed. The stress deflecting member 4 may be appropriately fixed to the side wall plate 5 with an adhesive or the like.
[0033]
(Fourth stage) Installation of tension members and stress deflecting members in the horizontal direction <plane longitudinal direction (left-right direction) and short-side direction (front-rear direction) of the existing box-type concrete container structure 1>:
Next, as shown in FIGS. 4, 5, and 6 to 8, the tension member 3 and the stress in the plane longitudinal direction (left-right direction) and short-side direction (front-rear direction) of the existing box-type concrete container structure 1. Regarding the installation of the deflecting member 4, as in the first to third stages, the fixing part at the lateral end of the side wall plate 5 is appropriately reinforced by providing the corner reinforcing part 20 as necessary. After piercing in the lateral direction to form the through-hole 22, one end of the tension member 3 is inserted, and the fixing bracket 16 is attached to the outside of the side wall plate 5, and this is used as a fixed end. The fixing bracket 18 capable of tension fixing is temporarily attached to the other end of the side wall plate 5 as a tension end on the outside of the side wall plate 5, and the stress deflection member 4 is attached between the tension member 3 and the side wall plate. Then, the prestress introduction device 21 in the lateral direction is installed. With these series of procedures, the preparation of each prestress introducing device 21 provided with the tension member 3 is completed.
[0034]
As shown in the illustrated embodiment, when the through-hole 15 is inclined toward the outside, the tension member 3 can be disposed at a position close to the outer surface of the side wall plate 5, and the pre-stress force in the tension member direction is increased. The bending force acting on the side wall plate 5 due to the tension force of the tension member 3 can be made extremely small, and the through hole 15 can be provided at a position close to the outer wall surface of the existing box-type concrete container structure 1 main body. The processing of the container housing body of the existing box-type concrete container structure 1 can be made as small as possible.
[0035]
Here, the tension member 3 installed in the structure building up direction and the tension member 3 installed in the structure plane longitudinal direction or the tension member 3 installed in the structure plane short direction intersect each other. In order to avoid damage to the tension member 3, as described above, one of the tension members 3 takes necessary measures such as passing through the inside of the stress deflection member 4.
[0036]
(5th stage) Tension of tension member:
Each tension member 3 prepared in the first to fourth stages is tensioned with a required tension force. As for the tension force, for example, an introduction prestress force of 1500 kN is introduced into the tension member 3 in the direction of building up the structure.
[0037]
The structure plane longitudinal direction (left-right direction) and short-side direction (front-rear direction) are a single tension member that is continuous so that the tension member 3 can simultaneously tension the surrounding structure of the structure in order to simplify the construction. At 0.5 N / mm per unit area ² The pre-stress amount of 1 may be applied to the existing box-type concrete container structure 1.
[0038]
However, prior to this tension stage, depending on the shape of the existing box-type concrete container structure 1, protection of the fixed ends and tension ends of the tension members 3 and strength reduction around the through holes 15, 17, and 22 are reduced. In order to supplement, as described above, the reinforcement work (20) around the through hole is performed with a steel material or a concrete material as necessary, and is integrated with the existing box-type concrete container structure 1.
[0039]
In addition, in the second stage or the fourth stage, when the fixed end and the tension end of the tension member 3 are applied, it is difficult to employ a method of directly drilling a structure and forming the through holes 15 (17, 22). In such a situation, as shown in the figure, the existing box-type concrete container structure 1 is reinforced together with the reinforcement work 20 around the through-hole, and the through-hole 15 (17, 22) is drilled. I do.
[0040]
(Step 6) Restoring the original shape:
Finally, after appropriately applying rust prevention treatment to the tension member 3 in the first stage, as shown by a two-dot chain line in FIG. 1, the foundation 7 on the bottom surface of the structure bottom plate portion 2 is repaired and the excavation groove 8 is backfilled. Restore the original shape.
[0041]
When the reinforcement effect obtained through each of the above steps is shown as an image diagram in FIGS. 9A to 9C, the state of the existing box-type concrete container structure 1 before the seismic reinforcement is shown in FIG. 9A. Thus, since the existing box-type concrete container structure 1 is a facility that is constantly operating as a distribution reservoir, the total amount of water stored inside varies throughout the day, but at the maximum water level as shown in FIG. It is represented by a triangular pressure gradient.
[0042]
Further, as shown in FIG. 9B, when the stress deflecting member 4 is interposed in the side wall plate 5 and prestress is introduced, the stress component P in the vertical axis direction with respect to the side wall plate 5 and the lateral deflection deflected thereto. As shown in FIG. 9C, the direction stress component F acts to counteract the side pressure acting on the side wall plate 5 and the bending force acting on the side wall plate 5, the bottom plate portion 2, and the upper floor plate 9. In addition, the existing box-type concrete container structure 1 is stabilized.
[0043]
Thus, by introducing prestress into the existing box-type concrete container structure 1, the existing box-type concrete container structure 1 satisfies the seismic performance of level 2 earthquake motion.
[0044]
Furthermore, by suppressing the generated cross-sectional force of all members within the proof strength of the member by level 2 earthquake motion at the time of the normal load acting on the existing box-type concrete container structure 1, the level 1 earthquake, and the level 2 earthquake, The seismic strengthening effect is that tensile stress does not occur at the side wall plate 5 and the column 10 part under constant load, the existing cracks are closed, and for example, a stress reduction degree of 20% to 100% is obtained, and at the time of level 1 earthquake The stress of each member is improved, and for example, a stress reduction degree of 25% to 99% is obtained.
[0045]
In the above-described embodiment, the fixing metal fittings 16 and 18 at the ends of the tension member 3 are in contact with or embedded in the existing box-type concrete container structure 1 side, and the steel annular support into which the tension member 3 is inserted. The end of the tension member 3 is formed in an existing box shape by a pressure plate, a wedge receiving metal fitting provided with a tension member insertion hole that is supported by the pressure plate and expands toward the outside, and a plurality of divided wedges having an arc-shaped cross section. It can be fixed to the concrete container structure 1. As the fixing brackets 16 and 18, other known fixing brackets may be used. Moreover, in order to form the through-holes 15, 17, and 22, it is good to use a steel pipe body or a synthetic resin short pipe.
[0046]
Next, the operation when the present invention is implemented and prestress is introduced will be described with reference to FIGS. In addition, the arrow in Fig.11 (a)-(d) is an effect | action (stress generation direction) component by prestress introduction | transduction.
[0047]
As shown in (a) and (b) of FIG. 10 (a), when the tension member 3 is arranged vertically in the vertical direction of the side wall plate 5 and the tension is fixed at both upper and lower end portions of the side wall plate, FIG. As shown in (i) and (b) of (), the action (stress generation) component due to the introduction of the prestress force can be generated two-dimensionally only in the vertical direction (Z-axis direction). In FIG. 10 and FIG. 11 (B), the characters in circles indicate that a prestressing force is acting in the axial direction.
[0048]
10B, when the tension member 3 is disposed in a state where the side wall plate 5 is inclined in the vertical direction and the tension is fixed at both upper and lower end portions of the side wall plate 5, As shown in (b) and (b) of FIG. 11B, the action (stress generation) component due to the two-dimensional introduction of prestress force in the vertical direction (Z-axis direction) and the front-rear direction (X-axis direction). Can be generated.
[0049]
Further, as shown in FIGS. 10 (c) (b) and (b), the tension member 3 is arranged in the vertical (vertical) direction of the side wall plate 5 and the stress deflecting member 4 is interposed, so that the tension member 3 is disposed on the side wall. When tension is fixed at the upper and lower ends of the plate 5, as shown in FIGS. 11C and 11B, two-dimensionally in the vertical direction (Z-axis direction) and the left-right direction (Y-axis direction). It is possible to generate an action (stress generation) component by introducing a prestress force.
[0050]
Further, as shown in FIGS. 10 (d) (a) and 10 (b), the tension member 3 is disposed in the state of being inclined in the front-rear direction in the vertical direction of the side wall plate 5, and the stress deflecting member 4 is interposed to When the member 3 is tension-fixed at both upper and lower end portions of the side wall plate 5, as shown in FIGS. 11D and 11B, the vertical direction (Z-axis direction), the left-right direction (Y-axis direction), and An action (stress generation) component due to the introduction of a prestress force can be generated in a three-dimensional solid in the front-rear direction (X-axis direction).
[0051]
Next, a case where the bottom plate portion 2 is reinforced by applying a prestressing force to the side wall portion 5 will be described with reference to FIG.
[0052]
When carrying out the present invention, it may be difficult for the existing box-type concrete container structure 1 standing on the ground, for example, to install the prestress introduction device 21 directly on the bottom plate portion 2. In such a case, as shown in FIG. 12, the prestress introducing device 21 is connected to the side wall plate 5 in the left-right direction or the side wall plate 5 in the front-rear direction at a level near the bottom plate portion 2 at the lower end portion of the side wall plate 5. When the prestressing force F is introduced by fixing the tension member 3 to the left and right end portions of the left and right side wall portions 5 or the front and rear direction end portions of the side wall plate 5 in the front and rear direction. Through the plate 5, a part of the prestressing force f can be introduced into the bottom plate portion 2 to reinforce the bottom plate portion 2.
[0053]
Next, when arranging a plurality of prestress introduction facilities, a part of the stress components acting on the surface plate in the plurality of prestress introduction devices 21 are arranged so as to cancel each other out, so that the necessary parts can be obtained for seismic reinforcement. FIG. 13 shows a case where unnecessary stress is prevented from remaining inside the existing box-type concrete container structure 1 because the stress acts only on the other parts and the prestress applied to the other parts cancels each other. The description will be given with reference.
[0054]
As shown in FIG. 13 (a), for example, the prestress introduction device 21 provided with the long tension member 3 (3a) is moved downward to the left side at the position displaced to the left side of the side wall plate 5 in the left-right direction. At the same time as shown in FIG. 13 (b), the prestress introducing device 21 is provided with a short tension member 3 (3b) at a position displaced to the right side of the side wall plate 5 in the left-right direction. Are arranged at symmetrical angles so as to be displaced downward and to the right, and both ends of the respective tension members 3 (3a, 3b) are fixed to the side wall plate 5 with the same tension force and fixed. As shown in c), the stress components T in the horizontal direction cancel each other and are balanced, and the resultant force P of the prestress force in the vertical direction can be applied to the side wall plate 5.
[0055]
The existing box-type concrete container structure 1 has structural features, and the above-described method may be used in order not to apply a horizontal stress component. Similarly, each side wall plate 5 can be similarly applied. For example, if the arrangement is changed by 90 °, the stress components in the vertical direction cancel each other out to be balanced, and the resultant force of the horizontal prestress force is applied to the side wall plate 5. Can act. In addition, the gathering part P of each tension member 3 (3a, 3b) is the tension member 3 of right side (or lower side) arrangement | positioning so that a compressive force may act, without the tensile force of a horizontal direction acting on the side wall version 5. FIG. The tension members 3 arranged on the left side (upper side) and on the left side (or upper side) may be arranged slightly displaced on the right side (or lower side). Similarly, the tension members 3b (3a, 3b) are arranged so that the tension members 3b arranged on the lower side are placed on the upper side so that a compressive force acts on the side wall plate 5 without applying a vertical tensile force. The tension member 3a arranged on the upper side may be arranged with a slight displacement on the lower side.
[0056]
When practicing the present invention, as the tension member 3, for example, a PC steel material such as a PC cable or a PC steel rod may be used. In the above-described embodiment, a wedge-type fixing structure is shown as the end fixing structure of the tension member 3, but a known fixing unit may be appropriately employed in addition to the wedge type. In addition to the existing box-type concrete container structure, the existing concrete container structure may be applied to a polygonal or cylindrical existing concrete container structure.
[0057]
【The invention's effect】
According to the seismic strengthening method for an existing concrete container structure of the present invention, the existing concrete container structure has a form in which a prestress introduction device having a tension member is partially installed and is seismically strengthened. Compared with the case of constructing the entire body of the construction, the construction is easier, the construction period can be shortened and the construction scale can be reduced, and therefore the seismic reinforcement work cost can be reduced. In addition, the existing box-type concrete container structures that are operating facilities can be seismically reinforced while operating, and the existing box-type concrete container structures can be reinforced without changing the internal volume of the existing box-type concrete container structures. Since the seismic reinforcement of the concrete container structure is possible, the current state before construction can be maintained as it is. In addition, even after seismic reinforcement of the structure, deterioration of the structure due to secular change cannot be refused, but if the existing box-type concrete container structure is positioned in the reaction process of the alkali aggregate reaction, the existing box-type concrete container structure Since the internal stress increases over time even after seismic reinforcement, it can be expected that this will lead to measures to delay deterioration after concrete structure seismic reinforcement. In addition, the introduction of pre-stress by the external cable makes it possible to close the cracks that originally occurred, improve the air tightness and water tightness of the structure used as a container, and provide a restoring force against earthquake loads. It has a rich structure.
[0058]
According to the second aspect of the present invention, when a plurality of prestress introduction facilities are arranged, a part of the stress components acting on the surface plate in the plurality of prestress introduction devices are arranged so as to cancel each other. In addition, the stress acts only on the necessary parts on the seismic reinforcement, and the prestress applied to the other parts cancels each other, so that unnecessary partial stress does not remain inside the existing box-type concrete container structure. be able to.
[0059]
Further, according to claim 3 or 4, by attaching at least one stress deflecting member to the existing box-type concrete container structure between the tension member and the existing box-type concrete container structure, Since the moment distribution acting on the existing box-type concrete container structure is adjusted, the bending moment acting on the side wall plate, etc. is reduced even if a bending moment due to water pressure acts on the side wall plate. As a result, it is possible to improve the earthquake resistance of the existing box-type concrete container structure as a whole, especially for the existing box-type concrete container structure in which side pressure such as internal water pressure acts on the side wall plate of the existing box-type concrete container structure. When applied, it can effectively improve earthquake resistance.
[0060]
According to the fifth aspect of the present invention, according to the seismic reinforcement structure for an existing concrete container structure of the present invention, a prestress introducing device provided with a tension member along the outer side of the face plate constituting the existing concrete container structure Are arranged in a vertical direction, a horizontal direction, or an inclined direction, and each tension member is tensioned and both ends thereof are fixed to the surface plate, thereby prestressing the surface plate in the existing concrete container structure. By simply applying, the existing concrete container structure can be easily seismically reinforced with a simple structure.
[0061]
According to the sixth aspect of the present invention, when a part of the stress components acting on the surface plate in the plurality of prestress introduction devices are arranged so as to cancel each other, the existing concrete container structure has one stress component. Even when it is not desired to cause the portion to act on the existing concrete container structure, it can be acted in a state where it is easily canceled, and therefore only other stress components can be effectively acted on.
[0062]
According to another aspect of the present invention, when a plurality of tension members are arranged so as to cross the outside of the side wall plate, a stress deflection member having a tension member support portion on the outside and a tension member insertion hole on the inside is arranged. If it is made, the tension member from which the direction arrange | positioned crossing mutually can be easily arrange | positioned in a predetermined position.
[0063]
According to another aspect of the present invention, an inclined through-hole is provided at the end portion of the peripheral side wall plate in the existing box-type concrete container structure that extends from the end portion toward the center portion of the surface plate and penetrates the outer surface of the surface plate. Since the tension member is inserted into the through hole and the tension member is fixed to the end portion of the face plate, the tension member can be disposed at a position close to the outer surface of the side wall plate, The prestressing force can be increased, the bending force acting on the side wall plate due to the tensioning force of the tensioning member can be extremely small, and the position close to the outer wall without approaching the wall center side of the existing box-type concrete container structure body A through-hole can be provided in the container box, and the processing of the container housing body of the existing box-type concrete container structure can be made as small as possible.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional side view showing a state where an existing box-type concrete container structure is seismically reinforced by implementing the present invention.
FIG. 2 is a longitudinal side view showing a state in which a lower ground of an existing box-type concrete container structure is excavated in order to carry out the present invention.
FIG. 3 is a longitudinal side view illustrating a state in which the present invention is implemented to reinforce a tension member fixing portion of an existing box-type concrete container structure and an inclined insertion hole for tension member insertion is formed.
FIG. 4 is a cross-sectional plan view showing a state in which the tension member fixing portion of the existing box-type concrete container structure is implemented and an inclined insertion hole for inserting the tension member in the left-right direction is formed by implementing the present invention. is there.
FIG. 5 is a cross-sectional plan view showing a state in which the tension member fixing portion of the existing box-type concrete container structure is implemented and the inclined insertion hole for inserting the tension member in the front-rear direction is formed by implementing the present invention. is there.
FIG. 6 is a schematic longitudinal sectional side view showing a state in which the present invention is implemented and the existing box-type concrete container structure is reinforced with earthquake resistance.
7 is a partial cross-sectional schematic plan view of FIG. 6. FIG.
FIG. 8 is a partially cutaway plan view showing a fixing portion of a lateral tension member.
FIG. 9 is an explanatory diagram of a seismic reinforcement method for an existing box-type concrete container structure according to the present invention, in which (a) shows a bending moment due to hydrostatic pressure acting on a side wall plate in an existing box-type concrete container structure. FIG. 5 is an explanatory view showing that an outward bending force acts on the side wall plate and an inward bending force acts on the inner side of the box on the upper floor plate and the bottom plate portion, and (b) is a prestress indicated by an arrow on the side wall plate. And (c) is an explanatory diagram showing that a deflecting force opposite to the hydrostatic pressure is applied using a stress deflecting member, and (c) corresponds to the action states shown in (a) and (b). It is a vertical side view which shows the state which applied the seismic reinforcement method and seismic reinforcement structure of this to the side wall version.
FIG. 10 is an explanatory diagram showing the action when prestress is introduced by implementing the present invention.
FIG. 11 is an explanatory diagram showing active components when pre-stress is introduced by implementing the present invention.
FIG. 12 (a) is an explanatory view when acting on the bottom plate portion when the present invention is implemented and the peripheral side wall plate of the existing box-type concrete container structure is seismically reinforced.
FIGS. 13A to 13C are explanatory diagrams showing an example in which the present invention is implemented and prestress cancels out.
FIG. 14 is a longitudinal side view showing an example of an existing box-type concrete container structure.
FIG. 15 is a partial cross-sectional plan view showing an example of an existing box-type concrete container structure.
[Explanation of symbols]
1 Existing box-type concrete container structure
2 Bottom plate
3 Tension members
4 Stress deflection member
5 (5a-5d) Side wall version
6 ground
7 Basics
8 Working groove
9 Upper floor version
10 props
11 Human holes
12% chestnut layer
13 Leveling mortar
14 Overhang flange
15 Through hole
16 Tension member fixture
17 Through hole
18 Fixing bracket
19 Upper overhang
20 Corner reinforcement
21 Prestress introduction device
22 Through hole

Claims

A seismic reinforcement method for an existing concrete container structure in which a lateral pressure is applied, and a longitudinal prestress introduction device including a longitudinal tension member along the outside of each side plate in a box-shaped concrete container structure. A large number of laterally spaced apart inclined penetrating holes provided so as to penetrate the lower end of the tension member in each longitudinal prestress introducing device to the bottom surface of the bottom plate end and the outer surface of the bottom of the side wall plate The bottom plate portion and the side wall plate are inserted into the holes and engaged with the lower end surfaces of the overhanging flange shared by these by the tension member fixing tool, and the upper end portions of the tension members are near the upper end portions of the upper floor plate and the side wall plate. A stress deflecting portion that is inserted into an inclined through-hole penetrating the outer side surface of the upper end portion of the side wall plate and the upper surface of the upper end portion of the upper floor plate and is attached to the fixing bracket, and between the longitudinal tension member and the side wall plate. And tensioning and fixing each tension member, further forming a horizontal through hole at the corner between adjacent side wall plates, and providing a tension member across the horizontal through hole adjacent in the horizontal direction. The tension member in the lateral prestress introduction device is inserted, and a stress deflection member is provided between the lateral tension member and the side wall plate, and both ends of the horizontal direction tension member are side wall plate or corner reinforcement. The existing box-type concrete is fixed by applying tension to the existing box-type concrete container structure two-dimensionally or three-dimensionally in multiple directions in the direction of prestress introduction per unit installation location of the prestress introduction device . A method for seismic reinforcement of an existing concrete container structure, wherein prestressing is applied to the container structure to perform seismic reinforcement.

In the seismic reinforcement method for an existing concrete container structure, when a plurality of prestress introduction facilities are arranged, a part of stress components acting on a surface plate such as a side wall plate in the plurality of prestress introduction devices cancel each other. So that stress is applied only to the necessary parts on the seismic reinforcement, and the prestress applied to the other parts cancels each other so that unnecessary partial stress does not remain inside the existing concrete container structure. The earthquake-proof reinforcement method of the existing concrete container structure of Claim 1 characterized by the above-mentioned.

At the time of introducing prestress, a tension member using an external cable system is used to apply a tension force to the tension member, and at least one stress deflecting member is provided between the tension member and the existing concrete container structure. The method for seismic reinforcement of an existing concrete container structure according to claim 1 or 2, wherein the moment distribution acting on the existing concrete container structure is adjusted by being attached to the existing concrete container structure. .

The existing concrete container structure according to any one of claims 1 to 3, wherein the existing concrete container structure is an existing box-type concrete container structure in which a side pressure such as internal water pressure acts on a side wall plate. Seismic reinforcement method for objects.

A seismic reinforcement structure for an existing concrete container structure on which a lateral pressure is applied, and a longitudinal prestress introduction device having a longitudinal tension member along the outside of each side plate in the box-shaped concrete container structure. A large number of laterally spaced intervals, and slanted penetrations provided so that the lower end of the tension member in each of the vertical prestress introduction devices penetrates the bottom surface of the bottom plate end and the outer bottom surface of the side wall plate The bottom plate portion and the side wall plate, and the lower end surface of the overhanging flange shared by them are engaged by the tension member fixing tool, and the upper end portions of the tension members are near the upper end portions of the upper floor plate and the side wall plate. And inserted into an inclined through-hole penetrating the outer side surface of the upper end portion of the side wall plate and the upper surface of the upper end portion of the upper floor plate, and attached to the fixing bracket, and sandwiching the stress deflection member between the tension member and the side wall plate. In this state, the tension members are tension-fixed, and the tension in the lateral prestress introduction device having the tension members is formed across the laterally adjacent lateral through holes formed at the corners of the adjacent side wall plates. Existing members are inserted into the box , and stress deflecting members are attached between the lateral tension member and the side wall plate, and both ends of the lateral tension member are tension-fixed to the wall plate or the corner reinforcing portion . seismic reinforcement structure of existing concrete container structures characterized by earthquake-proof reinforcement by applying a pre-stress in the side wall plate in the mold the concrete container structure.

The seismic resistance of an existing concrete container structure according to claim 5, wherein a part of stress components acting on a surface slab such as a side wall slab in a plurality of prestress introduction devices are arranged so as to cancel each other. Reinforced structure.

The stress deflecting member provided with a tension member support portion on the outside and a tension member insertion hole on the inside is disposed at an intersection of the tension members having different directions in a plurality of prestress introduction devices. A seismic reinforcement structure for an existing concrete container structure according to 5 or 6.

The end of the peripheral side wall plate in the existing concrete container structure is provided with an inclined through hole that extends from the end to the center side of the surface plate and penetrates the outer surface of the surface plate, and a tension member is inserted into the through hole. The seismic reinforcement structure for an existing concrete container structure according to any one of claims 5 to 7, wherein the tension member is fixed to an end portion of the face plate.