JP3718114B2

JP3718114B2 - Seismic isolation structure

Info

Publication number: JP3718114B2
Application number: JP2000231718A
Authority: JP
Inventors: 哲美岡本
Original assignee: 株式会社巴コーポレーション
Priority date: 2000-07-31
Filing date: 2000-07-31
Publication date: 2005-11-16
Anticipated expiration: 2020-07-31
Also published as: JP2002047827A

Description

【０００１】
【発明の属する技術分野】
この発明は屋根架構とそれを周辺で支持する支持構造から構成される大空間構造物において、屋根架構を支持構造に免震支持させた免震構造物に関するものである。
【０００２】
【従来の技術及び発明が解決しようとする課題】
例えばオフィスビル，集合住宅，病院等のように同一の平面を持つ階が複数層に亘って連続するような構造物を免震化する場合、免震装置は図20−(a) ，(b) に示すように基礎や下層階等の下部構造と地上階等の上部構造間に設置されることにより下部構造に入力する地震力の、上部構造への伝達を低減する。
【０００３】
この場合、下部構造はいずれの水平方向に対しても十分に剛性と耐力の高い構造とされ、免震装置もいずれの水平方向に対しても同等の性能を発揮するように設計される。
【０００４】
これに対し、大空間を構成する図21に示すような屋根架構とそれを支持する支持構造からなる構造物を上記構造物と同様の方法で免震化するとすれば、免震支持される構造体の層数が少ないため、全建設費に占める免震化の費用の割合が高くなり、免震化に要する費用に対する効果の比率が小さく、不経済となる。
【０００５】
一方、体育館等においては地震時に屋根架構を含む建物全体の倒壊や損傷の防止を確保した上で、天井材や照明・スピーカ等の設備機器の落下を防止し、震災時の避難所、あるいは防災拠点としての機能を保全することが耐震対策上、重要な課題となる。
【０００６】
平成７年１月の阪神淡路大震災ではこの種の建物で、屋根架構を支持する支持構造の倒壊例はなかったものの、屋根架構が大きく揺れたために屋根架構本体が損傷を受け、天井材や設備機器の落下を誘発し、避難所として利用できなかった例が多数あった。このことから、体育館等の建物では支持構造を含めた建物全体を免震化しなくとも、屋根架構への地震力の伝達を低減することができれば、上記被害を防止することが可能である。
【０００７】
大空間構造物において屋根架構を免震化する方法には特開平8-326351号等がある。ここでは屋根架構の周囲に位置する屋根支承部と支持構造間に免震装置を設置することによりいずれの水平方向の地震動に対しても均等に免震効果が発揮されるようにしているが、屋根架構の形態によっては免震効果が期待できない場合がある。
【０００８】
例えば図１に示すように支持構造の頂部の高さが厚さに対して大きく、支持構造が壁状に連続する場合、支持構造の水平剛性は面内方向に大きく、面外方向に小さいことから、支持構造の頂部は面外方向に大きく揺れ、その揺れに伴って屋根架構に大きな上下動が生じる。このため従来は、支持構造に入力する地震力の屋根架構への伝達を低減する上で、屋根支承部と支持構造との接合部においては支持構造の面外方向には両者間の相対変位を許容する状態に接合され、面内方向には水平力の伝達が図られるようにピン接合される。
【０００９】
この種の構造物において特開平8-326351号のように屋根支承部と支持構造間に全水平方向に均等に減衰力を発揮する免震装置を設置した場合には、支持構造に入力する面外方向の水平力を屋根架構に伝達させ、強制変形を与える可能性がある。
【００１０】
特開平8-326351号では水平剛性の低い支持構造、図１の場合で言えば、支持構造の面外方向に対して水平剛性の高い免震装置が組み合わせられるため、免震装置の高い水平剛性によって支持構造に入力する水平力が免震装置を通じて屋根架構に伝達され易く、屋根架構に強制変形も生じさせ易くなり、相対変位を許容する状態に接合する場合より屋根架構の強度を増す必要が生ずるという不利な結果を招く。
【００１１】
そのように不利になることを示すために、支持構造の水平剛性が低い方向（Ｘ方向）にも一定のダンパー機能を持たせた場合とダンパー機能なしの場合の地震応答解析を実行し、屋根部材に生じる応力の違いを比較した結果の１例を図22−(a) 〜(c) に示す。ダンパーの解析モデルは、降伏せん断力及び剛性の合計が両ケースとも等しくなるように設定し、静的な水平外力に対しては同等になるようにした。
【００１２】
図22−(a) 〜(c) では、横軸に支持構造の水平剛性が低い方向（Ｘ方向）に部材軸が一致する屋根部材の部材番号をとり、縦軸にＸ方向地震（地震波はＫobe(ＪＭＡ) ＮＳ 1995)に対する屋根各部材の軸力Ｎ，せん断力Ｑ，曲げモーメントＭをそれぞれ表している。□印がダンパーなし、■印がダンパーありの場合である。
【００１３】
Ｘ方向のダンパーの降伏せん断力はＹ方向の38％程度とした。これらより明らかに、支持構造の水平剛性が低い方向（Ｘ方向）にダンパー機能を付与すると、屋根部材の応力が大きくなることが分かる。すなわち、この方向についてはダンピング効果を余り発揮させ過ぎると屋根架構に対しては不利になるので、配慮が必要である。
【００１４】
この発明は上記背景より、支持構造の水平剛性が小さい方向の屋根架構への水平力の伝達を低減する免震構造物を提案するものである。
【００１５】
【課題を解決するための手段】
本発明では屋根架構と支持構造との間に、両者間の相対水平変位を許容する機能と、相対水平変位時に減衰力を発生する機能を有する免震装置を設置し、変位許容機能と減衰力発生機能を支持構造の水平剛性が低い方向と高い方向とで相違させることにより、支持構造に入力する水平剛性の低い方向の水平力の屋根架構への伝達を低減し、屋根架構への強制変形を最小限に抑制する。
【００１６】
本発明の第１の基本構成は、免震装置によって支持構造の水平剛性が低い方向には支持構造の揺れと水平力を屋根架構に伝達させないよう、屋根架構と支持構造との間の少なくとも一定量の相対変位を生じさせ、水平剛性が高い方向には免震装置の減衰力発生機能が発揮されるまで、または発揮される間、屋根架構と支持構造との間の相対変位を許容する。免震装置は支持構造の水平剛性が高い方向には屋根架構と支持構造との間の相対変位を許容しながら、減衰力を発生する。
【００１７】
免震装置は支持構造の水平剛性が低い方向に、屋根架構を支持構造に対して少なくとも一定量の相対変位を生じさせることで、屋根架構が周辺の屋根支承部において支持構造に支持された後に自重で屋根支承部が支持構造の水平剛性が低い方向の外周側へ変位を生じるときにもその変位を自由に生じさせ、屋根支承部が支持構造に安定して支持される状態になるまで、屋根架構の自重による屋根支承部の変位を拘束しない。
【００１８】
この結果、初期状態で屋根支承部への応力の発生が回避され、併せて免震装置への応力の発生も回避されるため、免震装置の減衰力発生機能は初期応力のない状態で発揮されることになる。
【００１９】
屋根架構を支持構造に支持させ、使用状態に置いた後に屋根架構が支持構造の水平剛性が低い方向に温度変化や積雪荷重等によって伸縮する場合にも支持構造に対する相対変位が自由であることで、屋根支承部は屋根架構の伸縮に伴い、支持構造に対して変位でき、伸縮に伴う応力の負担が回避される。
【００２０】
各免震装置の変位許容機能と減衰力発生機能は支持構造の水平剛性が低い方向と高い方向とで相違するが、図２〜図４に示すように支持構造を全体的に閉じた形とすれば、いずれかの免震装置が屋根架構と支持構造との間の相対変位を自由にするときには、その免震装置に交差する方向を向く他のいずれかの免震装置が水平力を負担して減衰力を発生するため、構造物全体ではいずれの方向の地震力に対しても屋根架構に入力する水平力を低減する効果が発揮される。
【００２１】
図４のように支持構造が非対称形等、任意の平面形状を持つ場合や、屋根架構の重量配分が不均一である場合等のように支持構造と屋根架構のそれぞれの偏心が大きい場合には地震時に屋根架構が回転振動を起こし、屋根支承部の水平移動量が増幅される可能性があるが、減衰力を発揮するダンパー部材の配置等を考慮することにより、上記した支持構造と屋根架構を含めた構造物全体での任意の方向の地震力に対する応答低減効果によって屋根架構の回転振動とそれに伴う屋根支承部の移動量の増大は抑制される。
【００２２】
図６，図７に、本発明の第１の基本構成を図５に示すモデルに適用して屋根架構を免震化した場合と非免震の場合の地震応答解析結果を比較して示す。図５は梁間40ｍ×桁行50ｍ×軒高10ｍ（棟高18ｍ）で、屋根架構が鉄骨造、支持構造が鉄筋コンクリート造の一般的な体育館を想定した立体架構の解析モデルである。
【００２３】
支持構造における屋根架構の支持条件は支持構造の水平剛性が低い方向に完全に相対変位が自由で、水平剛性が高い方向には非免震の場合はピン接合、免震の場合は全免震装置の減衰力発生機能（ダンパー）の降伏耐力の合計を屋根架構自重の10％とし、荷重一変形関係をバイリニア型でモデル化した。入力地震波は観測波Kobe 1995 NSの最大加速度を200galに規準化してある。
【００２４】
図６は屋根架構の最大応答加速度の比較を、図７は屋根支承部の水平反力の比較を示しているが、ここに示すように屋根架構の最大応答加速度は非免震の場合の約50％に低下し、屋根支承部の水平反力は非免震の場合の約20〜25％まで低下しており、本発明の免震の効果が顕著に表れていることが分かる。
【００２５】
免震装置は具体的には支持構造に固定される支持部材と、支持部材上に任意の水平方向に相対変位自在に載り、屋根架構に取り付けられる屋根支承部と、支持部材と屋根支承部間に跨って設置されるダンパー部材から構成され、ダンパー部材は支持構造の水平剛性が低い方向には一定量の相対変位を生じた後に減衰力を発生し、支持構造の水平剛性が高い方向には相対変位の発生に伴い、減衰力を発生する。
【００２６】
ダンパー部材として鋼棒ダンパーを使用した場合、ダンパー部材は一端が支持部材と屋根支承部のいずれか一方に固定され、他端が他方に係合し得る状態に置かれ、支持構造の水平剛性が低い方向に一定量の相対変位を生じた後に屋根支承部、もしくは支持部材に係合し、塑性化して減衰力を発生する。
【００２７】
この場合、支持構造の水平剛性が低い方向に地震力が発生したとき、支持部材がいずれかの向きに屋根支承部に対して相対変位し、ダンパー部材は屋根支承部に対する相対変位可能な範囲を超えたときに屋根支承部に係合して減衰力を発生する。
【００２８】
支持構造の水平剛性が高い方向に地震力が発生したときには、支持部材が屋根支承部に対して相対変位しようとし、その相対変位開始時からダンパー部材が屋根支承部に係合して減衰力を発生する。
【００２９】
本発明の第２の基本構成では支持構造の水平剛性が低い方向と高い方向のいずれの方向にも屋根架構と支持構造との間の相対変位を許容しながら、免震装置に減衰力を発生させ、支持構造の水平剛性が低い方向の水平力に対する免震装置の抵抗力を支持構造の水平剛性が高い方向の水平力に対する抵抗力より小さくすることにより、前述の本発明の第１の基本構成と同様に支持構造の水平剛性が低い方向には支持構造の揺れと水平力の屋根架構への伝達を低減し、水平剛性が高い方向には免震装置に水平力を負担させ、減衰力を発生させる。
【００３０】
上記の第２の基本構成の場合、支持構造の水平剛性が低い方向にも相対変位の発生開始時から減衰力発生機能が発揮され、水平力を負担するが、その方向の抵抗力が直交方向の抵抗力より小さいことで、実質的には屋根架構と支持構造間の相対変位が許容されるため、屋根架構への水平力の伝達が低減され、屋根架構への強制変形が最小限に抑制される。
【００３１】
また各免震装置がいずれの方向の水平力に対しても減衰力発生機能を発揮するため、支持構造が全体的に閉じた形である図２〜図４に示す場合を含め、支持構造の平面形状に関係なく、全免震装置がいずれの方向の地震力に対しても屋根架構に入力する水平力を低減する効果を発揮する。
【００３２】
減衰力発生機能の、支持構造の水平剛性が低い方向の水平力に対する抵抗力を支持構造の水平剛性が高い方向の水平力に対する抵抗力より小さくすることは、具体的には前述の本発明の第１の基本構成における同一のダンパー部材の抵抗力を方向毎に相違させる、もしくは同一種類の複数のダンパー部材の抵抗力を方向毎に相違させて使用する、または方向毎に抵抗力の相違する種類の異なる複数のダンパー部材を組み合わせて使用することにより可能になる。
【００３３】
本発明の第２の基本構成の免震装置も具体的には支持構造に固定される支持部材と、支持部材上に任意の水平方向に相対変位自在に載り、屋根架構に取り付けられる屋根支承部と、支持部材と屋根支承部間に跨って設置されるダンパー部材から構成される。
【００３４】
ダンパー部材は支持構造の水平剛性が低い方向と高い方向のいずれの方向にも相対変位の発生と共に減衰力を発生し、ダンパー部材の支持構造の水平剛性が低い方向の水平力に対する抵抗力は支持構造の水平剛性が高い方向の水平力に対する抵抗力より小さい。
【００３５】
本発明の第２の基本構成の免震装置においてダンパー部材に鋼棒ダンパーを使用した場合に、図13に示すように例えば屋根架構をサポートで支持した状態で支持構造上に構築し、構築終了後にサポートを撤去したときには、自重による屋根架構のたわみが安定するまで、屋根支承部と一体となったベースプレートが支持部材に対して支持構造の水平剛性が低い方向の支持構造の外周側へ変位を生じようとする。
【００３６】
その結果、サポートの撤去前の時点で図14に示すように支持構造の水平剛性が低い方向に長孔状に明けられたベースプレートの挿通孔の中央部にダンパー部材の軸が位置しているときには、安定状態に至るまでの屋根支承部の変位によって図15に示すように支持構造が屋根支承部を支持した時点でダンパー部材に変形を生じさせることになり、地震力を受けない平常状態からダンパー部材を塑性化させる可能性がある。この状態で支持構造が水平剛性の低い方向に地震力を受けたときにはダンパー部材を正常に機能させることができない。
【００３７】
このような事態に対し、屋根架構の自重で屋根支承部がベースプレートと共に支持部材に対して支持構造の水平剛性が低い方向に変位を生じた状態で、ダンパー部材を屋根支承部の移動許容範囲の中央部に位置させ、屋根支承部がその方向の正負いずれの向きにも一定量の相対変位を生じた後にダンパー部材が屋根支承部に係合し得る状態に置くことにより、ダンパー部材の初期の変形と応力を回避することができ、ダンパー部材を正常に機能させることが可能になる。
【００３８】
本発明は、後述する図17〜図19に示す免震装置のように、鋼棒ダンパーとそれが貫通する挿通孔を有するベースプレートを用いることなく免震装置を構成した場合であり、屋根架構と屋根架構を支持する全体的に閉じた形の支持構造との間に、両者間の相対水平変位を許容する機能と、相対水平変位時に減衰力を発生する機能を有する免震装置を設置した免震構造物において、免震装置は、支持構造の水平剛性が低い方向に屋根架構と支持構造との間の少なくとも一定量の相対変位を生じさせ、水平剛性が高い方向に屋根架構と支持構造との間の相対変位を許容しながら減衰力を発生させるダンパー部材であり、このダンパー部材は、屋根架構と支持構造の水平剛性が高い方向の相対変位により変形する湾曲した鋼板ダンパーと、この鋼板ダンパーを水平剛性が低い方向に移動自在に案内支持する部材から構成されていることを特徴とする免震構造物である。
図 17 、図 18 の具体例では、ｙ方向に移動可能な摺動部材と屋根側に固定された一対のガイド部材の間に鋼板ダンパーが合計４枚配置され、湾曲した鋼板ダンパーの両端部がそれぞれ摺動部材、ガイド部材に固定される。支持構造上には、摺動部材をｙ方向から挟む一対のストッパーが設置され、このストッパーには摺動部材の先端が接触するｘ方向に沿う面が形成されており、これら摺動部材・ストッパー等により鋼板ダンパーをｘ方向に移動自在に案内支持する部材が構成される。なお、屋根架構は屋根支承部において支持構造上のスライディング部材によりｘ、ｙ両方向に移動自在に支持される（図 17 はダンパー機能を屋根支承部に設置、図 18 はダンパー機能を屋根支承部から分離）。
図 19 （ダンパー機能を屋根支承部から分離）の具体例では、ｙ方向に沿う梁部材の下にｙ方向に長い長円状に閉じた形の鋼板ダンパーが配置され、上下の中間部がそれぞれ梁部材、受けプレートに固定される。受けプレートの下にはｘ方向に沿う摺動部材が固定され、この摺動部材をｙ方向両側から挟む一対のストッパーが支持構造上に設置され、これら摺動部材・ストッパー等により鋼板ダンパーをｘ方向に移動自在に案内支持する部材が構成される。
図 17 〜図 19 の具体例において、スライディング部材に摩擦抵抗の極めて小さいものを用いれば、ｘ方向に一定量の相対変位のみを生じさせる免震装置が得られ、スライディング部材に摩擦抵抗のあるものを用いれば、ｘ方向にある程度の減衰力を発生させる免震装置が得られる。
本発明の鋼板ダンパーを用いた免震装置の免震構造物の場合、屋根支承部と下部構造との、支持構造の水平剛性が低いｘ方向の相対変位量を十分に確保できるので、屋根架構の構築後、そのたわみが安定するまでの屋根支承部の変位が問題になる構造物においては本発明の基本構成の鋼棒ダンパーと挿通孔を有するベースプレートを用いる免震装置の免震構造物より適している。
【００３９】
【発明の実施の形態】
本発明の第１の基本構成は図１〜図４に示すような屋根架構１と屋根架構１を支持する支持構造３との間に、両者間の相対水平変位を許容する機能と、相対水平変位時に減衰力を発生する機能を有する免震装置４を設置した免震構造物において、免震装置４が支持構造３の水平剛性が低い方向に屋根架構１と支持構造３との間の相対変位を自由に生じさせ、水平剛性が高い方向に屋根架構１と支持構造３との間の相対変位を許容しながら、水平力を負担するものである。
【００４０】
支持構造３の水平剛性が低い方向とは図１中に矢印で示す、壁状に連続する場合の支持構造３の壁厚方向を指し、水平剛性が高い方向とは壁厚方向に直交する方向を指し、支持構造３の平面形状が図３に示す円形の場合や、図４に示す不整形の場合は周方向を指す。以下、支持構造３の水平剛性が低い方向をｘ方向、水平剛性が高い方向をｙ方向と言う。
【００４１】
図８，図９に本発明の第１の基本構成で使用される免震装置４の具体例を示す。図８−(a) は屋根支承部２と支持構造３との接合部をｙ方向に見た様子を、図９はｘ方向に見た様子を示す。
【００４２】
免震装置４は支持構造３に固定される支持部材５と、支持部材５上に相対水平変位自在に重なり、屋根架構に取り付けられる屋根支承部２と、支持部材５と屋根支承部２間に跨って設置されるダンパー部材７から構成される。
【００４３】
図８，図９ではダンパー部材７として鋼棒ダンパーを軸を鉛直に向けて使用している関係で、ダンパー部材７の両端間距離を確保する必要から、支持部材５をダンパー部材７の下端が固定、もしくは接続される下部ベースプレート８と、下部ベースプレート８との間に鉛直方向に距離を隔てて配置され、ダンパー部材７の上端が接続、もしくは固定される受けプレート９から構成しているが、支持部材５の構成はこれに限られない。図８，図９の場合、下部ベースプレート８は支持構造３に直接的に固定され、受けプレート９は下部ベースプレート８上に接合されるリブプレート10上に接合される。
【００４４】
ダンパー部材７には鋼棒ダンパーを含め、鋼材を用いた鋼材ダンパー、図10に示す粘弾性体の他、オイルダンパー等の粘性ダンパー、摩擦ダンパーその他の減衰力発生装置が使用される。
【００４５】
屋根支承部２は屋根架構１がトラス構造の場合は図８−(a) ，図９に示すようにトラス部材11が集合する節点に位置する球継手12と、球継手12をベースプレート６に支持させるリブプレート13から構成される。屋根架構１が梁と桁、母屋等から構成される一般鉄骨構造の場合の屋根支承部２は図10，図11に示すように屋根架構１の周囲に位置する梁部材14の一部とそれをベースプレート６に支持させるリブプレート13から構成される。
【００４６】
ベースプレート６は受けプレート９との間にスライディング部材15を挟んで受けプレート９上に載り、両者を貫通するボルト16によって相対変位を阻害しない状態に連結される。スライディング部材15には鋼板等の両面に四フッ化エチレンシート等の低摩擦材を張り付けた板、もしくはボールやローラを用いたベアリングが使用される。ボルト16は屋根支承部２からベースプレート６に作用する引き抜き力に抵抗する役目を持つ。
【００４７】
図８−(b) ，(c) に示すようにベースプレート６と受けプレート９の少なくともいずれか一方には両者間の相対変位時のボルト16の変位を許容する長孔状や十文字状、もしくはボルト16の径より大きい円形状のボルト孔6a，9aが明けられる。図８はベースプレート６と受けプレート９の双方に方向の異なる長孔状のボルト孔6a，9aを形成した場合を示す。
【００４８】
ダンパー部材７が鋼棒ダンパーである場合、ダンパー部材７は下部ベースプレート８とベースプレート６間に跨設され、例えば下端において下部ベースプレート８に固定され、上端においてベースプレート６を貫通し、ベースプレート６に水平方向に係合可能に接続される。
【００４９】
図８ではダンパー部材７が曲げ変形を起こすときにダンパー部材７に軸方向引張力を作用させず、曲げモーメントのみによってダンパー部材７を降伏させるために、ベースプレート６を貫通したダンパー部材７の上端に螺合するナット7aとベースプレート６の上面との間にクリアランスを確保し、ダンパー部材７の上端をベースプレート６に相対回転変位可能に接続している。
【００５０】
ダンパー部材７が貫通するベースプレート６の挿通孔6bは支持構造３の水平剛性が低い方向の地震力が屋根架構１に伝達せず、屋根支承部２が支持構造３に対して自由に相対変位できるよう、ｘ方向に長孔状に明けられる。挿通孔6bがｘ方向に長孔状をすることで、屋根架構１の自重や積載・積雪荷重と温度変化による屋根支承部２の相対変位が阻害されず、平常時には屋根支承部２への応力の作用が回避される。
【００５１】
この場合、挿通孔6bの長孔方向、すなわちｘ方向の屋根支承部２と支持構造３間の相対変位時には、ダンパー部材７が挿通孔6bの内周面に接触するまでダンパー部材７は機能せず、屋根架構１の伸縮が許容される。その変位を超える相対変位時にダンパー部材７が曲げ変形し、塑性化後にエネルギーを吸収する。ｙ方向の屋根支承部２と下部構造３間の相対変位時には、相対変位の開始時からダンパー部材７が曲げ変形し、塑性化してエネルギーを吸収する。
【００５２】
本発明の第２の基本構成は免震装置４がｘ方向とｙ方向のいずれの方向にも屋根架構１と支持構造３との間の相対変位を許容しながら、水平力を負担し、ｘ方向の水平力に対する免震装置４の抵抗力がｙ方向の水平力に対する抵抗力より小さい場合である。
【００５３】
図10，図11に本発明の第２の基本構成で使用される免震装置４の構成例を示す。図10−(a) はｙ方向に見た屋根支承部２と支持構造３との接合部を、図11はｘ方向に見た接合部を示す。
【００５４】
免震装置４の構成は前述の本発明の第１の基本構成で使用される免震装置４と実質的に同一であるが、方向毎に抵抗力の相違するダンパー部材71，72はｘ方向とｙ方向のいずれの方向にも相対変位の発生と共に減衰力を発生し、ｘ方向の水平力に対するダンパー部材71の抵抗力はｙ方向の水平力に対するダンパー部材72の抵抗力より小さく設定される。
【００５５】
図10，図11はｘ方向の抵抗力の小さいダンパー部材71として粘弾性体を使用し、ｙ方向の抵抗力の大きいダンパー部材72として鋼棒ダンパーを使用した場合を示すが、ｘ方向に減衰力発生機能を発揮するダンパー部材71の水平力に対する抵抗力がｙ方向に減衰力発生機能を発揮するダンパー部材72の水平力に対する抵抗力より小さければ、各方向のダンパー部材71，72のダンパーの種類は自由に選択される。
【００５６】
ダンパー部材７として鋼棒ダンパーを使用する場合でも、その断面性能を方向毎に変え、ｘ方向とｙ方向の剛性と耐力を変えれば、単一のダンパー部材７の使用によって二方向のダンパー部材71，72として機能させることができる。
【００５７】
図10，図11の場合、ｘ方向に減衰力発生機能を発揮する粘弾性体のダンパー部材71はその方向を向くリブプレート13の延長線上で支持構造３に固定される下部プレート17と、リブプレート13の両面に接合される上部プレート18，18との間に配置されて双方に接着され、リブプレート13と下部プレート17間の相対変位時に減衰力を発生する。
【００５８】
図12は本発明の基本構成においてダンパー部材を正常に機能させる場合の免震装置４の構成例を示す。この場合、ダンパー部材７には鋼棒ダンパーが使用され、ダンパー部材７は(b) に示すように、屋根架構１の自重で屋根支承部２と一体となったベースプレート６が受けプレート９に対してｘ方向に変位を生じ、安定したときに、更にｘ方向のいずれの向きにも一定量の相対変位を生じた後にベースプレート６に係合し得る状態に置かれる。
【００５９】
図13に実線で示すように屋根架構１に鉛直荷重が作用する前、すなわち建て方が完了して屋根架構１のサポートを撤去する直前の状態で、図14に示すようにベースプレート６の挿通孔6bを貫通するダンパー部材７の軸を挿通孔6bの中央に配置した場合、サポートを撤去したときには図13に破線で示すように屋根架構１が撓むと同時に、屋根支承部２に支持構造３の外側へ水平変位δｄを生じる。
【００６０】
水平変位δｄが挿通孔6bの長さの半分以上であれば、図15に示すようにダンパー部材７は挿通孔6bの端部に衝突し、更には図15−(b) に示すように強制的に曲げ変形を受ける。
【００６１】
一方、挿通孔6bの長さ方向に地震力を受けた場合にダンパー部材７が受ける水平荷重Ｈ−水平変位δの関係は、例えば図16に示すようにスリップ型とバイリニア型を合成したような履歴特性を示す。設計上、ダンパー部材７の初期状態は図16のＯ点にあり、δ＝δｄ＝０として地震時の解析が行われるが、地震発生以前に水平変位δｄを生じ、図15−(b) のようにダンパー部材７が曲がった状態にあれば、図16のＡ点のように弾性限界を超えて塑性化している可能性があり、解析結果と実際の挙動が食い違い、耐震安全上、問題になる可能性もある。
【００６２】
この問題に対し、図 12 の構成の免震装置ではサポートを撤去したときに図12−(b) に示すようにダンパー部材７の軸が挿通孔6bの中央部に位置するよう、予め図12−(a) に示すように想定される屋根支承部２の水平変位δｄ分、ベースプレート６を支持構造３の内周側へずらして配置しておくことで、屋根架構１を支持構造３に支持させた初期状態でダンパー部材７に曲げ変形を生じさせる事態を防止できる。
【００６３】
屋根支承部２の水平変位δｄが完了した状態で、ダンパー部材７の軸が挿通孔6bの中央部に位置することで、ダンパー部材７はｘ方向の正負のいずれの向きにも支持構造３に対して一定量の相対変位を生じた後に減衰力発生機能を発揮することができる。
【００６４】
図17−(a) 〜(c) は本発明における免震装置４の構成例を示す。図17−(a) は免震装置４の立面図、(b) は(a) のｆ−ｆ断面図である。屋根支承部２のベースプレート６と支持構造３の上面との間にはスライディング部材15が挿入され、屋根支承部２はベースプレート６において図17−(b) におけるｘ，ｙ両方向共に支持構造３に対して変位可能になっている。スライディング部材15は支持構造３にアンカーボルト等によって固定されるプレート等の支持部材５の上に載せられている。
【００６５】
屋根支承部２のｘ方向の両側面には支持構造３の水平剛性が高いｙ方向に沿ってガイド部材20が取り付けられ、２つのガイド部材20，20の間に摺動部材21が４枚の湾曲した鋼板ダンパー73を介して両側面のガイド部材20に接続されている。摺動部材21は屋根支承部２の中央に設けた孔2aを貫通しており、摺動部材21と屋根支承部２はｙ方向には相対変位自由である。図17では摺動部材21の各片面に、屋根支承部２の両側にそれぞれ鋼板ダンパー73を配置し、一箇所の屋根支承部２に付き、４枚の鋼板ダンパー73，73を配置した場合を示す。鋼板ダンパー73の一端は摺動部材21に、他端はガイド部材20に接続される。
【００６６】
支持構造３の、摺動部材21の両先端位置には摺動部材21の先端が常に接触し、もしくはほぼ接触し、摺動部材21を屋根支承部２に対して相対変位させるストッパー22が固定される。ストッパー22の上端には屋根架構１が風や地震動により大きく浮き上ってしまわないようにする浮き上がり防止のための突出部22ａが突設、もしくは形成される。
【００６７】
図17では突出部22ａをストッパー22に一体化していることから、摺動部材21に係合し得る位置に突出部22ａを配置しているが、屋根架構１の浮き上がりは屋根支承部２の浮き上がりを拘束することで防止できるため、屋根支承部２に一体化しているベースプレート６に係合し得る位置に浮き上がり防止部材を設置することもある。
【００６８】
図17−(c) は屋根架構１と支持構造３が地震によりｙ方向に相対変位を生じたときの、鋼板ダンパー73の変形状況を示す。摺動部材21はストッパー22に押し付けられることで屋根支承部２との間で相対変位を生じ、鋼板ダンパー73は塑性変形することにより地震エネルギーを吸収する。ｘ方向には摺動部材21はストッパー22に拘束されないため、摺動部材21がストッパー22との接触面に沿って滑ることにより自由に変位する。
【００６９】
屋根架構１の構築後、屋根架構１が安定するまで屋根支承部２がｘ方向に変位した状態で、ｘ方向のいずれの向きにも屋根支承部２を支持構造３に対して移動させる本発明の基本構成の考え方に従えば、初期状態として摺動部材21はストッパー22のｘ方向の中央部に位置するように配置され、摺動部材21のｘ方向の最大許容変位量が地震時に予測される変位量に対して十分な寸法となるように確保される。但し、万が一のために、屋根支承部２が支持構造３から脱落しないように脱落防止材を別途設けることは有意義である。
【００７０】
図18はダンパー機能を屋根支承部２から分離させ、摺動部材21と鋼板ダンパー73及びガイド部材20、並びにストッパー22を屋根支承部２からｘ方向に距離を隔てて配置した場合を示す。
【００７１】
屋根支承部２以外の屋根架構１の周辺にはガイド部材20が固定されるガイド取付部材30が固定され、支持構造３からは構造的に切り離される。摺動部材21はガイド取付部材30を貫通して配置され、摺動部材21とガイド部材20に鋼板ダンパー73が接続される。図18に示すダンパー分離型の免震装置４の性能は図17に示すダンパー一体型の場合と同じであるが、図18の場合は屋根支承部２の位置に関係なくダンパーを配置できる利点があり、配置上の自由度が高い。
【００７２】
図19は図18と同様にダンパー機能を屋根支承部２から分離させると共に、ダンパー部材７として湾曲した鋼板ダンパー73を用いた免震装置４の他の構成例を示す。
【００７３】
屋根架構１の梁部材14の下方には梁部材14に鉛直方向に対向する受けプレート９が配置され、鋼板ダンパー73は長孔状に閉じた形で屋根架構１の梁部材14に両端において固定され、中間部において受けプレート９に固定される。受けプレート９は下部ベースプレート８において支持構造３に固定され、受けプレート９の下端にはｘ方向を向く摺動部材21ａが固定される。摺動部材21ａはｙ方向両側からストッパー22，22に挟まれ、ｙ方向の変位を拘束されながら、ｘ方向には支持構造３に対して自由に変位する。
【００７４】
屋根架構１が支持構造３に対してｙ方向に相対水平変位を生じたときには、鋼板ダンパー73がｙ方向に塑性変形することにより地震エネルギーを吸収する。図19に示すタイプのダンパー部材７によれば、風等に対する屋根支承部２の浮上り防止策が別途必要となるが、装置寸法が図17，図18の場合よりもコンパクトになる利点がある。
【００７５】
図17〜図19に示す免震装置４の構成例によれば、ダンパー部材７としてベースプレート６の挿通孔6bを貫通する鋼棒ダンパーを使用する図８〜図16に示す免震装置４の場合のように図13に示す屋根架構１の屋根支承部２の変位に伴い、挿通孔6bの端部にダンパー部材７が押し付けられ、ダンパー部材７に過大な初期変形と初期応力を生じさせることがない。また図示するように免震装置４の構成部材の組立をボルト止めにすれば、変形した鋼板ダンパー73の取替え作業が鋼棒ダンパーを使用する場合より容易に行える。
【００７６】
また図17〜図19に示す免震装置４の構成例は図 8 、 9 の本発明の第１の基本構成あるいは図 10 、 11 の本発明の第２の基本構成における免震装置４の構成例の別案とも位置付けられる。すなわち、図17〜図19では主にｙ方向にダンパー機能を働かせているが、スライディング部材15として摩擦抵抗のあるものを使うと、ｘ方向にもある程度のダンピング効果が生じ、ｙ方向には本来のダンパー機能に加えて摩擦抵抗もダンピング効果に寄与する。従って支持構造３の水平剛性が低い方向（ｘ方向）の抵抗力が、水平剛性が高い方向（ｙ方向）の抵抗力よりも小さい免震構造物であるので、図 10 、 11 の本発明の第２の基本構成の具体例の１つに位置付けられる。
【００７７】
一方、スライディング部材15として摩擦抵抗の極めて小さいものを用い、且つｘ方向に一定量の変位可能寸法を確保すれば、図 8 、 9 の本発明の第１の基本構成の具体例となる。
【００７８】
なお、図示した例ではダンパー部材７として鋼材を用いた場合を示しているが、ダンパー部材７には摩擦系や粘（弾）性系のダンパーを使用することもできる。
【００７９】
【発明の効果】
本発明では屋根架構と支持構造との間に、両者間の相対水平変位を許容する機能と、相対水平変位時に減衰力を発生する機能を有する免震装置を設置することにより、支持構造の水平剛性が低い方向には屋根架構と支持構造との間の少なくとも一定量の相対変位を生じさせるため、支持構造に入力する水平剛性の低い方向の水平力の屋根架構への伝達を低減し、屋根架構への強制変形を回避することができる。
【００８０】
また水平剛性が高い方向には減衰力発生機能が発揮されるまで、または発揮される間、屋根架構と支持構造との間の相対変位を許容しながら、免震装置に水平力を負担させ、減衰力を発生させるため、いずれかの免震装置が屋根架構と支持構造との間の相対変位を自由にするときには、その免震装置に交差する方向を向く他のいずれかの免震装置が水平力を負担して減衰力を発生することになり、構造物全体ではいずれの方向の地震力に対しても屋根架構に入力する水平力を低減する効果が発揮される。
【００８１】
免震装置は支持構造の水平剛性が低い方向に、屋根架構を支持構造に対して自由に相対変位させることで、屋根架構が周辺の屋根支承部において支持構造に支持された後に自重で屋根支承部が支持構造の水平剛性が低い方向の外周側へ変位を生じるときにもその変位を自由に生じさせるため、屋根支承部を支持構造に支持させたときの屋根支承部への過大な応力の発生を回避でき、併せて免震装置は初期応力のない状態で減衰力発生機能を発揮することができる。
【００８２】
屋根架構を支持構造に支持させ、使用状態に置いた後に屋根架構が支持構造の水平剛性が低い方向に温度変化や積雪荷重等によって伸縮する場合にも支持構造に対する相対変位が自由であることで、屋根支承部は屋根架構の伸縮に伴い、支持構造に対して変位でき、伸縮に伴う応力の負担が回避される。
【００８３】
支持構造が非対称形等、任意の平面形状を持つ場合や、屋根架構の重量配分が不均一である場合等のように支持構造と屋根架構のそれぞれの偏心が大きい場合にも、ダンパー部材を適正に配置すること等により支持構造と屋根架構を含めた構造物全体での任意の方向の地震力に対する応答低減効果によって屋根架構の回転振動とそれに伴う屋根支承部の移動量の増大を抑制できる。
【００８４】
また、支持構造の水平剛性が低い方向と高い方向のいずれの方向にも屋根架構と支持構造との間の相対変位を許容しながら、免震装置に水平力を負担させ、支持構造の水平剛性が低い方向の水平力に対する免震装置の抵抗力を支持構造の水平剛性が高い方向の水平力に対する抵抗力より小さくすれば、支持構造の水平剛性が低い方向にも支持構造の揺れと水平力の屋根架構への伝達を最小限に抑制できる。
【００８５】
免震装置は支持構造の水平剛性が高い方向には水平力を負担して減衰力を発生するため、構造物全体ではいずれの方向の地震力に対しても屋根架構に入力する水平力を低減する効果が得られる。
【００８６】
また、屋根架構の自重で屋根支承部が支持部材に対して支持構造の水平剛性が低い方向に変位を生じた状態で、ダンパー部材を屋根支承部の移動許容範囲の中央部に位置させることにより、屋根架構構築後のサポート撤去に伴う屋根支承部の水平移動によるダンパー部材の初期の変形と応力を回避することができる。
【００８７】
鋼棒ダンパーとそれが貫通する挿通孔を有するベースプレートを用いて免震装置を構成する場合には屋根支承部における浮き上がり防止機構の確保は簡単に行える一方、屋根架構の構築後、そのたわみが安定するまでの屋根支承部の変位が問題になる構造物において免震装置の相対水平変位の許容寸法を十分に確保することが困難になる欠点があるが、本発明のように鋼板ダンパーを用い鋼棒ダンパーとベースプレートを用いることなく免震装置を構成した場合には、免震装置の相対水平変位の許容寸法を十分に確保することができるため、ダンパー部材の初期変形と初期応力を回避することができる。
【００８８】
また本発明のように鋼板ダンパーを用い鋼棒ダンパーとそれが貫通する挿通孔を有するベースプレートを用いることなく免震装置を構成した場合には、ボルトのみを用いて免震装置を構成することができるため、ダンパー部材の取替えが容易であり、新築の場合に限らず、既存構造物への適用も可能である。
【図面の簡単な説明】
【図１】本発明の免震構造物の概要を示した縦断面図である。
【図２】支持構造が四角形の場合の図１のＡ−Ａ線断面図である。
【図３】支持構造が円形の場合の図１のＡ−Ａ線断面図である。
【図４】支持構造が不整形の場合の図１のＡ−Ａ線断面図である。
【図５】地震応答解析で使用した立体架構のモデルを示した斜視図である。
【図６】屋根架構の最大応答加速度の比較を示したグラフである。
【図７】屋根支承部の水平反力の比較を示したグラフである。
【図８】(a) はトラス構造の場合の本発明の第１の基本構成における屋根支承部と免震装置との関係を示した図２におけるｙ方向の立面図、(b) は(a) のａ−ａ線断面図、(c) は(a) のｂ−ｂ線断面図である。
【図９】図８−(a) の図２におけるｘ方向の立面図である。
【図１０】(a) は一般鉄骨構造の場合の本発明の第２の基本構成における屋根支承部と免震装置との関係を示した図２におけるｙ方向の立面図、(b) は(a) のｃ−ｃ線断面図である。
【図１１】図10−(a) の図２におけるｘ方向の立面図である。
【図１２】(a) は屋根支承部の移動前のダンパー部材とベースプレートとの関係を示した平面図、(b) は屋根支承部の移動後の関係を示した平面図である。
【図１３】屋根支承部が屋根架構の自重で移動するときの様子を示した立面図である。
【図１４】(a) は屋根支承部の移動前にダンパー部材をベースプレートの挿通孔の中央部に配置したときの様子を示した平面図、(b) は(a) のｄ−ｄ線断面図である。
【図１５】(a) は屋根支承部の移動後の様子を示した平面図、(b) は(a) のｅ−ｅ線断面図である。
【図１６】図15の場合にダンパー部材が受ける水平荷重Ｈと水平変位δの関係を示したグラフである。
【図１７】本発明の免震装置であり、(a) はダンパー部材として鋼板ダンパーを用いた免震装置の立面図、(b) は(a) のｆ−ｆ線断面図、(c) は屋根架構と支持構造がｙ方向に相対水平変位を生じた状態における鋼板ダンパーの変形状態を示したｆ−ｆ線断面図である。
【図１８】図17に示す免震装置のダンパー部材を屋根支承部から分離させた場合を示した立面図である。
【図１９】(a) は図18に示すダンパー部材の変形例を示した立面図、(b) は(a) の側面図、(c) は(a) のｇ−ｇ線断面図である。
【図２０】(a) ，(b) は従来の免震構造物の例を示した立面図である。
【図２１】他の免震構造物の例を示した立面図である。
【図２２】(a) は免震装置に、Ｘ方向にもダンパー機能がある場合とない場合の地震応答解析結果の内、屋根部材に生じた軸力の相違を示したグラフ、(b) は免震装置に、Ｘ方向にもダンパー機能がある場合とない場合の地震応答解析結果の内、屋根部材に生じたせん断力の相違を示したグラフ、(c) は免震装置に、Ｘ方向にもダンパー機能がある場合とない場合の地震応答解析結果の内、屋根部材に生じた曲げモーメントの相違を示したグラフである。
【符号の説明】
１……屋根架構、２……屋根支承部、2a……孔、３……支持構造、４……免震装置、５……支持部材、６……ベースプレート、6a……ボルト孔、6b……挿通孔、７，71，72……ダンパー部材、73……鋼板ダンパー、7a……ナット、８……下部ベースプレート、９……受けプレート、9a……ボルト孔、10……リブプレート、11……トラス部材、12……球継手、13……リブプレート、14……梁部材、15……スライディング部材、16……ボルト、17……下部プレート、18……上部プレート、20……ガイド部材、21……摺動部材、21ａ……摺動部材、22……ストッパー、30……ガイド取付け部材。[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a seismic isolation structure in which a roof frame is supported by a support structure in a seismic isolation manner in a large space structure including a roof frame and a support structure that supports the roof frame in the periphery.
[0002]
[Prior art and problems to be solved by the invention]
  For example, when isolating a structure such as an office building, an apartment house, or a hospital where floors having the same plane are continuous across multiple layers, the seismic isolation device is shown in FIGS. 20- (a) and (b). ) As shown in Fig. 2, it is installed between the lower structure such as the foundation and lower floors and the upper structure such as the ground floor to reduce the transmission of seismic force input to the lower structure to the upper structure.
[0003]
  In this case, the lower structure is a structure having sufficiently high rigidity and proof strength in any horizontal direction, and the seismic isolation device is designed to exhibit the same performance in any horizontal direction.
[0004]
  On the other hand, if a structure consisting of a roof frame that constitutes a large space and a support structure that supports the roof frame is to be seismically isolated in the same manner as the above structure, the structure that is seismically isolated and supported Since the number of body layers is small, the ratio of the seismic isolation cost to the total construction cost is high, and the ratio of the effect to the cost required for the seismic isolation is small and uneconomical.
[0005]
  On the other hand, gymnasiums, etc. ensure the prevention of collapse and damage of the entire building including the roof frame in the event of an earthquake, and prevent the fall of equipment such as ceiling materials, lighting, speakers, etc. Preserving the function as a disaster prevention base is an important issue for earthquake resistance.
[0006]
  Although there were no examples of collapse of the support structure that supported the roof frame in the Great Hanshin-Awaji Earthquake in January 1995, the roof frame itself was damaged due to large shaking of the roof frame, and ceiling materials and equipment were damaged. There were a number of cases that could not be used as an evacuation center due to the fall of equipment. For this reason, in buildings such as gymnasiums, the above-mentioned damage can be prevented if the transmission of seismic force to the roof frame can be reduced without making the entire building including the support structure seismic isolation.
[0007]
  Japanese Patent Laid-Open No. 8-326351 discloses a method for isolating a roof frame in a large space structure. Here, by installing a seismic isolation device between the roof bearing part located around the roof frame and the support structure, the seismic isolation effect is evenly demonstrated against any horizontal seismic motion. Depending on the form of the roof frame, the seismic isolation effect may not be expected.
[0008]
  For example, as shown in FIG. 1, when the height of the top of the support structure is large with respect to the thickness and the support structure is continuous in a wall shape, the horizontal rigidity of the support structure is large in the in-plane direction and small in the out-of-plane direction. Therefore, the top of the support structure is greatly shaken in the out-of-plane direction, and a large vertical movement is generated in the roof frame with the shake. For this reason, conventionally, in order to reduce the transmission of seismic force input to the support structure to the roof frame, relative displacement between the two in the out-of-plane direction of the support structure is caused at the joint between the roof support and the support structure. It is joined in an allowable state, and in the in-plane direction, it is pin-joined so that a horizontal force can be transmitted.
[0009]
  In this type of structure, when a seismic isolation device that exhibits a damping force evenly in all horizontal directions is installed between the roof support and the support structure as disclosed in JP-A-8-326351, the surface that is input to the support structure There is a possibility that an outward horizontal force is transmitted to the roof frame to cause forced deformation.
[0010]
  In JP-A-8-326351, a support structure with low horizontal rigidity, in the case of FIG. 1, a seismic isolation apparatus with high horizontal rigidity is combined with the out-of-plane direction of the support structure. Therefore, the horizontal force input to the support structure is easily transmitted to the roof frame through the seismic isolation device, and it is easy to cause forced deformation of the roof frame, and it is necessary to increase the strength of the roof frame compared to the case where the relative displacement is allowed. This has the adverse consequence of producing.
[0011]
  In order to show this disadvantage, the seismic response analysis was performed with and without the damper function in the direction in which the horizontal rigidity of the support structure is low (X direction). An example of the result of comparing the differences in stress generated in the members is shown in FIGS. 22- (a) to (c). The damper analysis model was set so that the sum of the yield shear force and stiffness was the same in both cases, and was equivalent to the static horizontal external force.
[0012]
  22- (a) to (c), the horizontal axis represents the member number of the roof member whose member axis coincides with the direction in which the horizontal rigidity of the support structure is low (X direction), and the vertical axis represents the X direction earthquake (the seismic wave is Represents the axial force N, shear force Q, and bending moment M of each roof member relative to Kobe (JMA) NS 1995). □ indicates that there is no damper, and ■ indicates that there is a damper.
[0013]
  The yield shearing force of the damper in the X direction was about 38% in the Y direction. Obviously, the stress of the roof member increases when the damper function is given in the direction in which the horizontal rigidity of the support structure is low (X direction). In other words, if the damping effect is excessively exerted in this direction, it will be disadvantageous for the roof frame, so care must be taken.
[0014]
  The present invention proposes a seismic isolation structure that reduces the transmission of horizontal force to a roof frame in a direction in which the horizontal rigidity of the support structure is small.
[0015]
[Means for Solving the Problems]
  In the present invention, a seismic isolation device having a function of allowing relative horizontal displacement between the roof frame and the support structure and a function of generating damping force at the time of relative horizontal displacement is installed. By differentiating the generation function between the direction in which the horizontal rigidity of the support structure is low and the direction in which the support structure is low, the transmission of the horizontal force in the direction of low horizontal rigidity that is input to the support structure to the roof frame is reduced and forced deformation to the roof frame To minimize.
[0016]
  The first basic configuration of the present invention is as follows:The seismic isolation device causes at least a certain amount of relative displacement between the roof frame and the support structure so as not to transmit the shaking and horizontal force of the support structure to the roof frame in the direction where the horizontal rigidity of the support structure is low. In the higher direction, relative displacement between the roof frame and the support structure is allowed until or until the damping force generation function of the seismic isolation device is exhibited. The seismic isolation device generates a damping force while allowing a relative displacement between the roof frame and the support structure in a direction in which the horizontal rigidity of the support structure is high.
[0017]
  The seismic isolation device generates at least a certain amount of relative displacement of the roof frame with respect to the support structure in a direction where the horizontal rigidity of the support structure is low, so that the roof frame is supported by the support structure at the surrounding roof support. When the roof support part is displaced by its own weight to the outer peripheral side in the direction where the horizontal rigidity of the support structure is low, the displacement is freely generated, and until the roof support part is stably supported by the support structure, Does not restrain the displacement of the roof support due to the weight of the roof frame.
[0018]
  As a result, in the initial state, generation of stress on the roof bearing is avoided, and stress generation on the seismic isolation device is also avoided. Will be.
[0019]
  Even when the roof frame is supported by the support structure and placed in use, the roof frame can be expanded and contracted due to temperature changes, snow loads, etc. in a direction where the horizontal rigidity of the support structure is low. The roof support portion can be displaced with respect to the support structure as the roof frame expands and contracts, thereby avoiding the stress caused by the expansion and contraction.
[0020]
  The displacement tolerance function and the damping force generation function of each seismic isolation device differ between the direction in which the horizontal rigidity of the support structure is low and the direction in which the support structure is low, but as shown in FIGS. Thus, when any seismic isolation device frees the relative displacement between the roof frame and the support structure, any other seismic isolation device facing the direction that intersects the seismic isolation device bears the horizontal force. Since the damping force is generated, the entire structure exhibits the effect of reducing the horizontal force input to the roof frame against the seismic force in any direction.
[0021]
  When the eccentricity of the support structure and the roof frame is large, such as when the support structure has an arbitrary shape such as an asymmetric shape as shown in FIG. 4 or when the weight distribution of the roof frame is uneven. There is a possibility that the roof frame will rotate and vibrate in the event of an earthquake, and the horizontal movement of the roof support may be amplified. By taking into account the arrangement of the damper member that exhibits the damping force, the above-mentioned support structure and roof frame Due to the effect of reducing the response to seismic force in any direction in the entire structure including the structure, the rotational vibration of the roof frame and the accompanying increase in the amount of movement of the roof support are suppressed.
[0022]
  6 and 7,First basic configuration of the present inventionIs applied to the model shown in FIG. 5 to compare the seismic response analysis results between the case where the roof frame is isolated and the case where it is not isolated. Fig. 5 shows an analysis model of a three-dimensional frame assuming a general gymnasium with 40m between beams x 50m girder x 10m eaves height (building height 18m), roof structure is steel frame and support structure is reinforced concrete.
[0023]
  The support conditions for the roof frame in the support structure are completely free of relative displacement in the direction where the horizontal rigidity of the support structure is low. The total yield strength of the damping force generation function (damper) of the equipment was 10% of the roof frame's own weight, and the load-deformation relationship was modeled as a bilinear type. The input seismic wave is normalized to 200 gal maximum acceleration of the observed wave Kobe 1995 NS.
[0024]
  Fig. 6 shows the comparison of the maximum response acceleration of the roof frame, and Fig. 7 shows the comparison of the horizontal reaction force of the roof bearing part. As shown here, the maximum response acceleration of the roof frame is about The horizontal reaction force of the roof bearing portion is reduced to about 20 to 25% in the case of non-isolation, and it can be seen that the effect of the isolation of the present invention is remarkably exhibited.
[0025]
  Specifically, the seismic isolation device includes a support member fixed to the support structure, a roof support portion that is mounted on the support member so as to be relatively displaceable in an arbitrary horizontal direction, and is attached to the roof frame, and between the support member and the roof support portion. It is composed of damper members that are installed across the base, and the damper member generates a damping force after a certain amount of relative displacement in the direction where the horizontal rigidity of the support structure is low, and in the direction where the horizontal rigidity of the support structure is high. A damping force is generated with the occurrence of the relative displacement.
[0026]
  DaWhen a steel rod damper is used as the damper member, one end of the damper member is fixed to one of the support member and the roof support, and the other end is placed in a state where the other end can be engaged with the other. After a certain amount of relative displacement is generated in the low direction, it engages with the roof support or the support member and plasticizes to generate a damping force.
[0027]
  In this case, when a seismic force is generated in a direction where the horizontal rigidity of the support structure is low, the support member is displaced relative to the roof support in either direction, and the damper member has a range in which relative displacement with respect to the roof support is possible. When it exceeds, it engages with the roof bearing and generates damping force.
[0028]
  When seismic force is generated in the direction where the horizontal rigidity of the support structure is high, the support member tries to displace relative to the roof support, and the damper member engages with the roof support from the beginning of the relative displacement and the damping force is applied. appear.
[0029]
  Second basic configuration of the present inventionThen, while allowing the relative displacement between the roof frame and the support structure in both the low and high horizontal directions of the support structure, a damping force is generated in the seismic isolation device, and the horizontal rigidity of the support structure is increased. By making the resistance of the seismic isolation device against the horizontal force in the low direction smaller than the resistance against the horizontal force in the direction where the horizontal rigidity of the support structure is high,First basic configuration of the present invention described aboveIn the same way as in the case where the horizontal rigidity of the support structure is low, the vibration of the support structure and transmission of the horizontal force to the roof frame are reduced, and in the direction where the horizontal rigidity is high, the seismic isolation device bears the horizontal force and the damping force is reduced. generate.
[0030]
  Second basic configuration described aboveIn this case, the damping force generation function is exerted from the beginning of the generation of relative displacement even in the direction where the horizontal rigidity of the support structure is low, and the horizontal force is borne, but the resistance force in that direction is smaller than the resistance force in the orthogonal direction. Since the relative displacement between the roof frame and the support structure is substantially allowed, the transmission of the horizontal force to the roof frame is reduced, and the forced deformation to the roof frame is minimized.
[0031]
  In addition, since each seismic isolation device exhibits a damping force generation function for horizontal force in any direction, the support structure including the case shown in FIGS. Regardless of the planar shape, all the seismic isolation devices exhibit the effect of reducing the horizontal force input to the roof frame for seismic forces in any direction.
[0032]
  Specifically, it is necessary to make the resistance force of the damping force generation function smaller than the horizontal force in the direction where the horizontal rigidity of the support structure is low than the horizontal force in the direction where the horizontal rigidity of the support structure is high.First basic configuration of the present invention described aboveThe resistance force of the same damper member in each direction is made different for each direction, or the resistance forces of the same type of damper members are made different for each direction, or a plurality of different types of resistance forces that are different for each direction are used. This is possible by using a combination of damper members.
[0033]
  Second basic configuration of the present inventionSpecific seismic isolation deviceInA support member fixed to the support structure, a roof support part mounted on the support member so as to be relatively displaceable in an arbitrary horizontal direction, and attached to the roof frame, and a damper member installed across the support member and the roof support part Consists of
[0034]
  The damper member generates a damping force along with the occurrence of relative displacement both in the direction of low and high horizontal rigidity of the support structure, and supports the resistance force against the horizontal force in the direction of low horizontal rigidity of the damper member support structure. The horizontal rigidity of the structure is less than the resistance to horizontal force in the direction of higher direction.
[0035]
  Second basic configuration of the present inventionWhen a steel rod damper is used as a damper member in the seismic isolation device, for example, as shown in Fig. 13, when the roof frame is built on the support structure with the support supported, and the support is removed after the construction is completed, Until the deflection of the roof frame is stabilized, the base plate integrated with the roof support portion tends to be displaced toward the outer peripheral side of the support structure in the direction in which the horizontal rigidity of the support structure is low with respect to the support member.
[0036]
  As a result, when the shaft of the damper member is located at the center of the insertion hole of the base plate opened in the shape of a long hole in the direction in which the horizontal rigidity of the support structure is low as shown in FIG. 14 before the support is removed When the support structure supports the roof support portion as shown in FIG. 15 due to the displacement of the roof support portion until the stable state is reached, the damper member is deformed, and the damper is released from the normal state where no seismic force is applied. There is a possibility of plasticizing the member. In this state, when the support structure receives the seismic force in the direction of low horizontal rigidity, the damper member cannot function normally.
[0037]
  Against this situation,Position the damper member at the center of the allowable range of movement of the roof support, with the roof frame being displaced in the direction where the horizontal rigidity of the support structure is low with respect to the support member together with the base plate due to the weight of the roof frame. Avoid initial deformation and stress of the damper member by placing the damper member in a state where it can engage the roof bearing after a certain amount of relative displacement in both positive and negative directions in the direction. Thus, the damper member can function normally.
[0038]
  The present inventionWhen the seismic isolation device is configured without using a base plate having a steel rod damper and an insertion hole through which it penetrates, as in the seismic isolation device shown in FIGS.It is an exemption that has a function of allowing relative horizontal displacement between the roof frame and the overall closed support structure that supports the roof frame, and a function of generating a damping force at the time of relative horizontal displacement. In seismic isolation structures where seismic devices are installed, the seismic isolation device causes at least a certain amount of relative displacement between the roof frame and the support structure in a direction where the horizontal rigidity of the support structure is low, and in a direction where the horizontal rigidity is high. A damper member that generates a damping force while allowing a relative displacement between the roof frame and the support structure, and the damper member is a curved steel plate that is deformed by a relative displacement in a direction in which the horizontal rigidity of the roof frame and the support structure is high. A seismic isolation structure comprising a damper and a member that guides and supports the steel plate damper in a direction having low horizontal rigidity.
  Figure 17 The figure 18 In this specific example, a total of four steel plate dampers are arranged between a sliding member movable in the y direction and a pair of guide members fixed on the roof side, and both ends of the curved steel plate damper are respectively sliding members, It is fixed to the guide member. A pair of stoppers are provided on the support structure to sandwich the sliding member from the y direction, and the stopper is formed with a surface along the x direction where the tip of the sliding member comes into contact. A member for guiding and supporting the steel plate damper so as to be movable in the x direction is configured by the above. Note that the roof frame is supported by the sliding member on the support structure so as to be movable in both the x and y directions at the roof support (see FIG. 17 The damper function is installed in the roof support part. 18 Separated the damper function from the roof bearing).
  Figure 19 In a specific example of (separate the damper function from the roof support), a steel plate damper closed in a long oval shape in the y direction is disposed under the beam member along the y direction, and the upper and lower intermediate portions are respectively beam members. , Fixed to the receiving plate. A sliding member extending along the x direction is fixed below the receiving plate, and a pair of stoppers sandwiching the sliding member from both sides in the y direction are installed on the support structure. A member for guiding and supporting in a movable manner in the direction is configured.
  Figure 17 ~ Figure 19 In this example, if a sliding member having a very small frictional resistance is used, a seismic isolation device that produces only a certain amount of relative displacement in the x direction can be obtained. If a sliding member having a frictional resistance is used, x A seismic isolation device that produces a certain amount of damping force in the direction is obtained.
  In the case of the seismic isolation structure of the seismic isolation device using the steel plate damper of the present invention,The horizontal rigidity of the support structure between the roof bearing and the substructure is low.xIn a structure where the displacement of the roof support is a problem until the deflection becomes stable after the construction of the roof frame, the relative displacement in the direction can be secured sufficiently.The seismic isolation device using the steel plate damper of the basic configuration of the present invention and the base plate having the insertion holeMore suitable than seismic isolation structures.
[0039]
DETAILED DESCRIPTION OF THE INVENTION
  First basic configuration of the present inventionBetween the roof frame 1 as shown in FIGS. 1 to 4 and the support structure 3 that supports the roof frame 1, a function that allows relative horizontal displacement between the two, and a function that generates a damping force at the time of relative horizontal displacement In the seismic isolation structure in which the seismic isolation device 4 is installed, the seismic isolation device 4 freely causes relative displacement between the roof frame 1 and the support structure 3 in the direction in which the horizontal rigidity of the support structure 3 is low, and the horizontal The horizontal force is borne while allowing the relative displacement between the roof frame 1 and the support structure 3 in the direction of high rigidity.
[0040]
  The direction in which the horizontal rigidity of the support structure 3 is low indicates the wall thickness direction of the support structure 3 when it is continuous in a wall shape, as indicated by an arrow in FIG. 1, and the direction in which the horizontal rigidity is high is a direction orthogonal to the wall thickness direction. In the case where the planar shape of the support structure 3 is a circle shown in FIG. 3 or the irregular shape shown in FIG. 4, it indicates the circumferential direction. Hereinafter, the direction in which the horizontal rigidity of the support structure 3 is low is referred to as the x direction, and the direction in which the horizontal rigidity is high is referred to as the y direction.
[0041]
  8 and 9First basic configuration of the present inventionA specific example of the seismic isolation device 4 used in FIG. FIG. 8- (a) shows a state where the joint between the roof support 2 and the support structure 3 is viewed in the y direction, and FIG. 9 shows a state where the joint is viewed in the x direction.
[0042]
  The seismic isolation device 4 includes a support member 5 fixed to the support structure 3, a support member 5 that overlaps the support member 5 so as to be relatively horizontally displaceable, and is attached to the roof frame, and between the support member 5 and the roof support member 2. It is comprised from the damper member 7 installed ranging.
[0043]
  In FIG. 8 and FIG. 9, since the steel rod damper is used as the damper member 7 with its axis oriented vertically, it is necessary to secure the distance between both ends of the damper member 7. The lower base plate 8 to be fixed or connected and the lower base plate 8 are arranged at a distance in the vertical direction, and the upper end of the damper member 7 is composed of a receiving plate 9 to be connected or fixed. The configuration of the support member 5 is not limited to this. In the case of FIGS. 8 and 9, the lower base plate 8 is directly fixed to the support structure 3, and the receiving plate 9 is joined on the rib plate 10 joined on the lower base plate 8.
[0044]
  The damper member 7 includes steel dampers including steel rod dampers, a viscoelastic body shown in FIG. 10, a viscous damper such as an oil damper, a friction damper, and other damping force generators.
[0045]
  When the roof frame 1 is a truss structure, the roof support portion 2 supports the ball joint 12 located at the node where the truss members 11 gather as shown in FIGS. 8A and 9, and the ball joint 12 supported by the base plate 6. It is comprised from the rib plate 13 to be made. When the roof frame 1 is a general steel structure composed of beams, girders, purlins, etc., the roof support 2 is a part of the beam member 14 located around the roof frame 1 as shown in FIGS. Is formed from a rib plate 13 that is supported by the base plate 6.
[0046]
  The base plate 6 is placed on the receiving plate 9 with the sliding member 15 interposed between the receiving plate 9 and the base plate 6 is connected to the base plate 6 in a state in which relative displacement is not hindered by a bolt 16 penetrating the base plate 6. As the sliding member 15, a plate in which a low friction material such as a tetrafluoroethylene sheet is attached to both surfaces of a steel plate or the like, or a bearing using a ball or a roller is used. The bolt 16 has a function of resisting a pulling force acting on the base plate 6 from the roof support portion 2.
[0047]
  As shown in FIGS. 8B and 8C, at least one of the base plate 6 and the receiving plate 9 has a long hole shape, a cross shape, or a bolt that allows displacement of the bolt 16 at the time of relative displacement between the two. Circular bolt holes 6a and 9a having a diameter larger than 16 are opened. FIG. 8 shows a case where elongated hole-shaped bolt holes 6a and 9a having different directions are formed in both the base plate 6 and the receiving plate 9. FIG.
[0048]
  When the damper member 7 is a steel rod damper, the damper member 7 extends between the lower base plate 8 and the base plate 6, for example, is fixed to the lower base plate 8 at the lower end, penetrates the base plate 6 at the upper end, and horizontally extends to the base plate 6. To be engageable with each other.
[0049]
  In FIG. 8, when the damper member 7 undergoes bending deformation, an axial tensile force is not applied to the damper member 7, and the damper member 7 is yielded only by a bending moment, so that the damper member 7 penetrates the base plate 6 at the upper end of the damper member 7. A clearance is secured between the nut 7a to be screwed and the upper surface of the base plate 6, and the upper end of the damper member 7 is connected to the base plate 6 so as to be capable of relative rotational displacement.
[0050]
  The insertion hole 6b of the base plate 6 through which the damper member 7 passes does not transmit the seismic force in the direction in which the horizontal rigidity of the support structure 3 is low to the roof frame 1, and the roof support 2 can be freely displaced relative to the support structure 3. As shown in FIG. Since the insertion hole 6b is elongated in the x direction, the relative weight of the roof frame 2 due to its own weight, load / snow load, and temperature change is not hindered, and stress on the roof frame 2 is normal. Is avoided.
[0051]
  In this case, when the relative displacement between the roof support portion 2 and the support structure 3 in the long hole direction of the insertion hole 6b, that is, in the x direction, the damper member 7 does not function until the damper member 7 contacts the inner peripheral surface of the insertion hole 6b. The expansion and contraction of the roof frame 1 is allowed. When the relative displacement exceeds the displacement, the damper member 7 is bent and deformed, and absorbs energy after plasticization. At the time of relative displacement between the roof bearing portion 2 and the lower structure 3 in the y direction, the damper member 7 is bent and deformed from the start of the relative displacement, and plasticizes to absorb energy.
[0052]
  The second basic configuration of the present invention isThe seismic isolation device 4 bears a horizontal force while allowing relative displacement between the roof frame 1 and the support structure 3 in both the x direction and the y direction, and the seismic isolation device 4 against the horizontal force in the x direction. This is a case where the resistance force is smaller than the resistance force against the horizontal force in the y direction.
[0053]
  10 and 11Second basic configuration of the present inventionThe example of a structure of the seismic isolation apparatus 4 used by is shown. FIG. 10- (a) shows the joint between the roof bearing part 2 and the support structure 3 as seen in the y direction, and FIG. 11 shows the joint as seen in the x direction.
[0054]
  The structure of the seismic isolation device 4 isFirst basic configuration of the present invention described aboveThe damper members 71 and 72, which are substantially the same as the seismic isolation device 4 used in the above, but have different resistances in each direction, have a damping force along with the occurrence of relative displacement in both the x and y directions. The resistance force of the damper member 71 against the horizontal force in the x direction is set to be smaller than the resistance force of the damper member 72 against the horizontal force in the y direction.
[0055]
  10 and 11 show a case where a viscoelastic body is used as the damper member 71 having a small resistance in the x direction and a steel rod damper is used as the damper member 72 having a large resistance in the y direction. If the resistance force against the horizontal force of the damper member 71 that exhibits the force generation function is smaller than the resistance force against the horizontal force of the damper member 72 that exhibits the damping force generation function in the y direction, the damper members 71 and 72 in each direction The type is freely selected.
[0056]
  Even when a steel rod damper is used as the damper member 7, if the cross-sectional performance is changed for each direction and the rigidity and proof stress in the x direction and the y direction are changed, the damper member 71 in two directions can be obtained by using the single damper member 7. , 72 can function.
[0057]
  10 and 11, a viscoelastic damper member 71 which exhibits a damping force generating function in the x direction is formed by a lower plate 17 fixed to the support structure 3 on the extension line of the rib plate 13 facing the direction, and a rib. It arrange | positions between the upper plates 18 and 18 joined to both surfaces of the plate 13, is adhere | attached on both, and a damping force generate | occur | produces at the time of the relative displacement between the rib plate 13 and the lower plate 17. FIG.
[0058]
  Figure 12When the damper member functions normally in the basic configuration of the present inventionThe structural example of the seismic isolation apparatus 4 is shown. In this case, a steel rod damper is used as the damper member 7, and the damper member 7 has a base plate 6 integrated with the roof support portion 2 by its own weight of the roof frame 1, as shown in FIG. When the displacement is caused in the x direction and is stabilized, a certain amount of relative displacement is caused in any direction in the x direction, and then the base plate 6 is engaged.
[0059]
  As shown by a solid line in FIG. 13, before a vertical load is applied to the roof frame 1, that is, in a state just before the building is completed and the support of the roof frame 1 is removed, as shown in FIG. When the shaft of the damper member 7 passing through 6b is arranged in the center of the insertion hole 6b, the roof frame 1 is bent as shown by the broken line in FIG. A horizontal displacement δd is generated outward.
[0060]
  If the horizontal displacement δd is more than half of the length of the insertion hole 6b, the damper member 7 collides with the end of the insertion hole 6b as shown in FIG. 15, and further forced as shown in FIG. 15- (b). Undergoes bending deformation.
[0061]
  On the other hand, the relationship between the horizontal load H and the horizontal displacement δ received by the damper member 7 when receiving a seismic force in the length direction of the insertion hole 6b is, for example, that a slip type and a bilinear type are combined as shown in FIG. Shows the history characteristics. By design, the initial state of the damper member 7 is at point O in FIG. 16, and the analysis at the time of the earthquake is performed with δ = δd = 0. However, the horizontal displacement δd occurs before the occurrence of the earthquake, and FIG. 15- (b) If the damper member 7 is in a bent state, it may be plasticized beyond the elastic limit as shown by point A in FIG. 16, and the analysis result and actual behavior will be different, which is a problem in terms of seismic safety. There is also a possibility.
[0062]
  For this problem,Figure 12 Seismic isolation device of the compositionThen, when the support is removed, as shown in FIG. 12- (b), the roof bearing is assumed in advance as shown in FIG. 12- (a) so that the shaft of the damper member 7 is positioned at the center of the insertion hole 6b. By displacing the base plate 6 toward the inner peripheral side of the support structure 3 by the horizontal displacement δd of the portion 2, bending deformation occurs in the damper member 7 in the initial state in which the roof frame 1 is supported by the support structure 3. Can be prevented.
[0063]
  With the horizontal displacement δd of the roof support portion 2 completed, the damper member 7 is positioned at the center of the insertion hole 6b so that the damper member 7 can be attached to the support structure 3 in both positive and negative directions in the x direction. On the other hand, the damping force generation function can be exhibited after a certain amount of relative displacement has occurred.
[0064]
  Figure 17- (a)-(c)The present inventionThe structural example of the seismic isolation apparatus 4 is shown. FIG. 17- (a) is an elevation view of the seismic isolation device 4, and FIG. 17 (b) is an ff cross-sectional view of (a). A sliding member 15 is inserted between the base plate 6 of the roof support part 2 and the upper surface of the support structure 3, and the roof support part 2 is in the base plate 6 with respect to the support structure 3 in both the x and y directions in FIG. Can be displaced. The sliding member 15 is placed on a support member 5 such as a plate fixed to the support structure 3 by anchor bolts or the like.
[0065]
  Guide members 20 are attached to both side surfaces of the roof support portion 2 in the x direction along the y direction where the horizontal rigidity of the support structure 3 is high, and four sliding members 21 are provided between the two guide members 20 and 20. It is connected to the guide members 20 on both sides through a curved steel plate damper 73. The sliding member 21 passes through a hole 2a provided in the center of the roof support portion 2, and the sliding member 21 and the roof support portion 2 are relatively free to be displaced in the y direction. In FIG. 17, the steel plate dampers 73 are arranged on both sides of the roof support part 2 on each side of the sliding member 21, and the four steel plate dampers 73, 73 are arranged on one roof support part 2. Show. One end of the steel plate damper 73 is connected to the sliding member 21 and the other end is connected to the guide member 20.
[0066]
  A stopper 22 that fixes the relative displacement of the sliding member 21 with respect to the roof support portion 2 is fixed at both ends of the sliding member 21 of the support structure 3. Is done. At the upper end of the stopper 22, a protruding portion 22a for preventing the roof frame 1 from being lifted up greatly by wind or earthquake motion is provided or formed.
[0067]
  In FIG. 17, since the protrusion 22 a is integrated with the stopper 22, the protrusion 22 a is arranged at a position where the protrusion 22 a can be engaged with the sliding member 21, but the roof frame 1 is lifted by the roof support 2. Since it can prevent by restraining, it may install a floating prevention member in the position which can be engaged with the base plate 6 integrated with the roof support part 2. FIG.
[0068]
  FIG. 17- (c) shows a deformation state of the steel plate damper 73 when the roof frame 1 and the support structure 3 are relatively displaced in the y direction by an earthquake. The sliding member 21 is pressed against the stopper 22 to cause a relative displacement with respect to the roof support portion 2, and the steel plate damper 73 absorbs seismic energy by plastic deformation. Since the sliding member 21 is not restrained by the stopper 22 in the x direction, the sliding member 21 is freely displaced by sliding along the contact surface with the stopper 22.
[0069]
  After the construction of the roof frame 1, the roof support part 2 is moved relative to the support structure 3 in any direction in the x direction with the roof support part 2 displaced in the x direction until the roof frame 1 is stabilized.Basic configuration of the present inventionAccording to the idea, the sliding member 21 is positioned so as to be positioned at the center of the stopper 22 in the x direction as an initial state, and the maximum allowable displacement amount of the sliding member 21 in the x direction is the amount of displacement predicted at the time of the earthquake. To ensure sufficient dimensions. However, as a precaution, it is meaningful to separately provide a fall-off prevention material so that the roof support portion 2 does not fall off the support structure 3.
[0070]
  FIG. 18 shows a case where the damper function is separated from the roof support portion 2 and the sliding member 21, the steel plate damper 73, the guide member 20, and the stopper 22 are arranged at a distance from the roof support portion 2 in the x direction.
[0071]
  A guide mounting member 30 to which the guide member 20 is fixed is fixed around the roof frame 1 other than the roof support portion 2 and is structurally separated from the support structure 3. The sliding member 21 is disposed through the guide attachment member 30, and a steel plate damper 73 is connected to the sliding member 21 and the guide member 20. The performance of the damper isolation type seismic isolation device 4 shown in FIG. 18 is the same as that of the damper integrated type shown in FIG. 17, but in the case of FIG. 18, there is an advantage that the damper can be arranged regardless of the position of the roof support 2. There is a high degree of freedom in arrangement.
[0072]
  FIG. 19 shows another example of the structure of the seismic isolation device 4 that uses the curved steel plate damper 73 as the damper member 7 while separating the damper function from the roof bearing portion 2 as in FIG.
[0073]
  Below the beam member 14 of the roof frame 1, a receiving plate 9 that is vertically opposed to the beam member 14 is arranged, and the steel plate damper 73 is fixed to the beam member 14 of the roof frame 1 at both ends in a closed shape. And fixed to the receiving plate 9 at the intermediate portion. The receiving plate 9 is fixed to the support structure 3 at the lower base plate 8, and a sliding member 21 a facing the x direction is fixed to the lower end of the receiving plate 9. The sliding member 21a is sandwiched between the stoppers 22 and 22 from both sides in the y direction, and freely displaced with respect to the support structure 3 in the x direction while restraining displacement in the y direction.
[0074]
  When the roof frame 1 undergoes a relative horizontal displacement in the y direction with respect to the support structure 3, the steel plate damper 73 absorbs seismic energy by plastic deformation in the y direction. The damper member 7 of the type shown in FIG. 19 requires an additional measure for preventing the roof support 2 from rising against the wind, etc., but has the advantage that the apparatus dimensions are more compact than those in FIGS. .
[0075]
  According to the configuration example of the seismic isolation device 4 shown in FIGS. 17 to 19, in the case of the seismic isolation device 4 shown in FIGS. 8 to 16, which uses a steel rod damper that penetrates the insertion hole 6 b of the base plate 6 as the damper member 7. As shown in FIG. 13, with the displacement of the roof support portion 2 of the roof frame 1, the damper member 7 is pressed against the end portion of the insertion hole 6 b, thereby causing excessive initial deformation and initial stress to the damper member 7. Absent. Further, as shown in the figure, if the components of the seismic isolation device 4 are assembled with bolts, the deformed steel plate damper 73 can be replaced more easily than when a steel rod damper is used.
[0076]
  Moreover, the example of a structure of the seismic isolation apparatus 4 shown in FIGS.Figure 8 , 9 1st basic configuration or diagram of the present invention Ten , 11 The second basic configuration of the present inventionIt is positioned as another plan of the configuration example of the seismic isolation device 4 in FIG. That is, in FIG. 17 to FIG. 19, the damper function is mainly operated in the y direction. However, if a sliding member 15 having a frictional resistance is used, a certain amount of damping effect is generated in the x direction. In addition to the damper function, frictional resistance also contributes to the damping effect. Therefore, since the resistance force in the direction where the horizontal rigidity of the support structure 3 is low (x direction) is a seismic isolation structure which is smaller than the resistance force in the direction where the horizontal rigidity is high (y direction),Figure Ten , 11 The second basic configuration of the present inventionIt is positioned as one of the specific examples.
[0077]
  On the other hand, if a sliding member 15 with extremely low frictional resistance is used and a certain amount of displaceable dimension is secured in the x direction,Figure 8 , 9 The first basic configuration of the present inventionThis is a specific example.
[0078]
  Although the illustrated example shows the case where a steel material is used as the damper member 7, a friction system or a viscous (elastic) damper can also be used for the damper member 7.
[0079]
【The invention's effect】
  The present inventionThen, by installing a seismic isolation device between the roof frame and the support structure that has the function of allowing relative horizontal displacement between the two and the function of generating damping force at the time of relative horizontal displacement, the horizontal rigidity of the support structure is increased. In the lower direction, at least a certain amount of relative displacement between the roof frame and the support structure is generated, so that the transmission of horizontal force in the direction of low horizontal rigidity input to the support structure to the roof frame is reduced. Can be avoided.
[0080]
  In addition, the seismic isolation device bears the horizontal force while allowing the relative displacement between the roof frame and the support structure until the damping force generation function is exhibited in the direction where the horizontal rigidity is high, or while it is exerted. When any seismic isolation device releases the relative displacement between the roof frame and the support structure in order to generate a damping force, any other seismic isolation device that faces away from the seismic isolation device The damping force is generated by bearing the horizontal force, and the effect of reducing the horizontal force input to the roof frame with respect to the seismic force in any direction is exhibited in the whole structure.
[0081]
  The seismic isolation device freely displaces the roof frame relative to the support structure in a direction where the horizontal rigidity of the support structure is low, so that the roof support is supported by its own weight after it is supported by the support structure at the surrounding roof support part. When the roof supports are supported by the support structure, excessive stress is applied to the roof support. Generation can be avoided, and the seismic isolation device can exhibit a damping force generation function without initial stress.
[0082]
  Even when the roof frame is supported by the support structure and placed in use, the roof frame can be expanded and contracted due to temperature changes, snow loads, etc. in a direction where the horizontal rigidity of the support structure is low. The roof support portion can be displaced with respect to the support structure as the roof frame expands and contracts, thereby avoiding the stress caused by the expansion and contraction.
[0083]
  Even when the support structure has an arbitrary plane shape such as an asymmetric shape, or when the eccentricity of the support structure and the roof frame is large, such as when the weight distribution of the roof frame is not uniform, the damper member is appropriate. Therefore, the rotational vibration of the roof frame and the accompanying increase in the amount of movement of the roof support portion can be suppressed by the effect of reducing the response to the seismic force in any direction in the entire structure including the support structure and the roof frame.
[0084]
  Also,The horizontal rigidity of the support structure is low by allowing the seismic isolation device to bear a horizontal force while allowing relative displacement between the roof frame and the support structure in both the low and high directions of the support structure. The resistance of the seismic isolation device to the horizontal force in the direction is smaller than the resistance to the horizontal force in the direction where the horizontal rigidity of the support structure is high.if,Direction of low horizontal rigidity of support structureAlsoIt is possible to minimize the shaking of the support structure and the transmission of horizontal force to the roof frame.
[0085]
  The seismic isolation device bears a horizontal force in the direction where the horizontal rigidity of the support structure is high and generates a damping force, so the entire structure reduces the horizontal force that is input to the roof frame in response to seismic forces in any direction. Effect is obtained.
[0086]
  Also,Position the damper member in the center of the allowable range of movement of the roof support part while the roof support part is displaced in the direction in which the horizontal rigidity of the support structure is lower than the support member due to the weight of the roof frame.By lettingIt is possible to avoid the initial deformation and stress of the damper member due to the horizontal movement of the roof support part due to the support removal after the construction of the roof frame.
[0087]
  When constructing a seismic isolation device using a steel plate damper and a base plate with an insertion hole through which it penetrates, it is easy to secure a lift prevention mechanism at the roof bearing, but the deflection is stable after the construction of the roof frame. However, there is a drawback that it is difficult to secure sufficient permissible dimensions for the relative horizontal displacement of the seismic isolation device in the structure where the displacement of the roof support until it is a problem,Use steel plate damper as in the present inventionWhen the seismic isolation device is configured without using the steel bar damper and base plate, the allowable horizontal displacement of the seismic isolation device can be sufficiently secured, so that the initial deformation and initial stress of the damper member are avoided. be able to.
[0088]
  AlsoUse steel plate damper as in the present inventionWhen the seismic isolation device is configured without using the steel rod damper and the base plate having the insertion hole through which it penetrates, it is possible to configure the seismic isolation device using only bolts, so the damper member can be easily replaced. Yes, not only for new construction, but also for existing structures.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing an outline of a seismic isolation structure of the present invention.
FIG. 2 is a cross-sectional view taken along line AA of FIG. 1 when the support structure is a quadrangle.
FIG. 3 is a cross-sectional view taken along line AA of FIG. 1 when the support structure is circular.
4 is a cross-sectional view taken along line AA of FIG. 1 when the support structure is irregular.
FIG. 5 is a perspective view showing a model of a three-dimensional frame used in an earthquake response analysis.
FIG. 6 is a graph showing a comparison of maximum response acceleration of a roof frame.
FIG. 7 is a graph showing a comparison of horizontal reaction force of a roof bearing portion.
[Fig. 8] (a) is for truss structureIn the first basic configuration of the present invention2 is an elevation view in the y direction in FIG. 2 showing the relationship between the roof bearing and the seismic isolation device, (b) is a cross-sectional view along line aa in (a), and (c) is along line bb in (a). It is sectional drawing.
FIG. 9 is an elevational view in the x direction in FIG. 2 of FIG. 8 (a).
Fig. 10 (a) shows the case of a general steel structureIn the second basic configuration of the present inventionFIG. 2 is an elevation view in the y direction in FIG. 2 showing the relationship between the roof support and the seismic isolation device, and FIG.
11 is an elevational view in the x direction in FIG. 2 of FIG. 10- (a).
[Fig. 12] (a) is before the roof support is movedofFIG. 4B is a plan view showing the relationship between the damper member and the base plate, and FIG. 5B is a plan view showing the relationship after the roof support portion is moved.
FIG. 13 is an elevational view showing a state in which the roof support part moves by the weight of the roof frame.
14A is a plan view showing a state in which a damper member is disposed in the center of the insertion hole of the base plate before the roof support portion is moved, and FIG. 14B is a cross-sectional view taken along the line dd in FIG. FIG.
FIG. 15A is a plan view showing a state after the roof support is moved, and FIG. 15B is a sectional view taken along line ee of FIG.
16 is a graph showing the relationship between the horizontal load H received by the damper member and the horizontal displacement δ in the case of FIG.
FIG. 17The seismic isolation device of the present invention,(a) is an elevation view of a seismic isolation device using a steel plate damper as a damper member, (b) is a sectional view taken along line ff of (a), (c) is a roof frame and a support structure relatively horizontally in the y direction. It is the ff sectional view taken on the line which showed the deformation | transformation state of the steel plate damper in the state which produced the displacement.
18 is an elevational view showing a case where the damper member of the seismic isolation device shown in FIG. 17 is separated from the roof support portion. FIG.
19 (a) is an elevation view showing a modification of the damper member shown in FIG. 18, (b) is a side view of (a), and (c) is a sectional view taken along the line gg of (a). is there.
20 (a) and 20 (b) are elevation views showing an example of a conventional seismic isolation structure.
FIG. 21 is an elevational view showing an example of another seismic isolation structure.
FIG. 22 (a) is a graph showing the difference in axial force generated on the roof member among the seismic response analysis results when the seismic isolation device has a damper function in the X direction and FIG. 22 (b). Is a graph showing the difference in the shearing force generated on the roof member in the seismic response analysis results with and without the damper function in the X direction, and (c) is the X It is the graph which showed the difference in the bending moment which arose in the roof member among the seismic response analysis results with and without the damper function in the direction.
[Explanation of symbols]
  DESCRIPTION OF SYMBOLS 1 ... Roof frame, 2 ... Roof support part, 2a ... Hole, 3 ... Support structure, 4 ... Seismic isolation device, 5 ... Support member, 6 ... Base plate, 6a ... Bolt hole, 6b ... … Through holes, 7, 71, 72 ... damper members, 73 ... steel plate dampers, 7a ... nuts, 8 ... lower base plate, 9 ... receiving plate, 9a ... bolt holes, 10 ... rib plates, 11 ··· Truss member, 12 ··· Ball joint, 13 ··· Rib plate, 14 ··· Beam member, 15 ··· Sliding member, 16 ··· Bolt, 17 ··· Lower plate, 18 ··· Upper plate, 20 ··· Guide 21, sliding member, 21a ... sliding member, 22 ... stopper, 30 ... guide mounting member.

Claims

A seismic isolation device having a function of allowing relative horizontal displacement between the roof frame and a generally closed support structure for supporting the roof frame and a function of generating a damping force at the time of relative horizontal displacement. In the installed seismic isolation structure, the seismic isolation device causes at least a certain amount of relative displacement between the roof frame and the support structure in a direction where the horizontal rigidity of the support structure is low, and the roof frame in a direction where the horizontal rigidity is high. A damper member that generates a damping force while allowing a relative displacement between the support structure, the damper member is a curved steel plate damper that is deformed by a relative displacement in a direction in which the horizontal rigidity of the roof frame and the support structure is high, and A base-isolated structure comprising a member for guiding and supporting the steel plate damper in a direction in which the horizontal rigidity is low .