JP3633352B2

JP3633352B2 - Isolation structure

Info

Publication number: JP3633352B2
Application number: JP07965899A
Authority: JP
Inventors: 康則橋本; 正則藤井; 嶽中村
Original assignee: Obayashi Corp
Current assignee: Obayashi Corp
Priority date: 1999-03-24
Filing date: 1999-03-24
Publication date: 2005-03-30
Anticipated expiration: 2019-03-24
Also published as: JP2000274110A

Description

【０００１】
【発明の属する技術分野】
本発明は、基礎部上に設けられる免振対象物を、これら両者間に配置する免振装置を介して免振するようになった免振構造に関する。
【０００２】
【従来の技術】
一般に中，高層ビルとして構築される免震建築物は、基礎部と建築物との間に免振装置が介在される。この免振装置としては一般的に積層ゴムが用いられるが、これ以外にも建築物の水平移動を滑らかにする滑り支承や転がり支承等がある。ところで、免震建築物はロッキング運動などが発生した場合に、免振装置に引抜き力が発生するが、従来の免振装置ではこのような引抜き力に抵抗する術が無く、本来の免振効果を得ることができなくなってしまう。
【０００３】
そこで、近年では特開平１０−２８０７２９号公報に開示されるように、基礎部と建築物との間に引抜き力に抵抗する引抜き防止装置（引張力対応装置）を設けるようにした免振構造が提案されている。この引抜き防止装置は、基礎部側および建築物側に、互いに直角関係をもって対向配置される下部ガイドレールおよび上部ガイドレールを固定し、これら下部ガイドレールと上部ガイドレールとの間に引抜拘束部が設けられるようになっている。この引抜拘束部は、両ガイドレールに沿って移動自在に接続されて、建築物のあらゆる方向の水平変位を許容するとともに、両ガイドレールが互いに離間するのを防止して、建築物の浮き上がりを阻止するようになっている。
【０００４】
【発明が解決しようとする課題】
しかしながら、かかる従来の免振構造にあっては、引抜拘束部を設けた引抜き防止装置によって建築物に作用する引抜き力に抵抗し、積層ゴムなどの免振装置の本来の免振機能を効果的に発揮できるようになっている。ところが、この引抜き防止装置では、上，下部ガイドレールを設けてこの引抜拘束部を水平変位させるようになっており、その構成が著しく複雑化されてしまい、延いては、建築費の高騰が来されてしまう。
【０００５】
ところで、上記引抜き力に抵抗するには、基礎部と建築物との間にばね部材を介設してこのばね部材にプレストレスを導入すれば良く、該ばね部材としては従来からプレストレストコンクリートに埋設されるＰＣ鋼棒やＰＣ鋼線が用いられることになる。しかし、これらＰＣ鋼棒やＰＣ鋼線を用いてプレストレスを与える場合には、積層ゴムの気温変化による伸縮やクリープによる高さ変化、風や地震による免振装置の水平変形に起因するばね部材の伸びによって、設定したプレストレス荷重が変化してしまい、当該プレストレスを一定に維持することが難しいのみでなく、地震時などにおいて当該ばね部材が相当引張されてその復原力が大きくなりすぎると、建築物の水平移動を拘束、延いては免振装置の挙動を拘束してこれの機能を十分に引き出すことができなくなってしまうという課題があった。
【０００６】
そこで、本発明はかかる従来の課題に鑑みて成されたもので、基礎部と免振対象物との間にプレストレスを付加する皿ばねに、これの伸縮変位量に対して荷重変動が小さい荷重一定領域を備えたものを用いて引抜き抵抗力を一定とし、もって、引抜き防止装置の構成を簡略化するとともに、この引抜き防止装置が免振装置の挙動に影響するのを防止するようにした免振構造を提供すること目的とする。
【０００７】
【課題を解決するための手段】
かかる目的を達成するために本発明の免振構造は、基礎部に免振装置を介して免振対象物が支持されるとともに、基礎部と免振対象物との間に、免振装置に作用する引抜き力に抵抗する引抜き防止装置が設けられた免振構造において、上記引抜き防止装置を、上下方向変位量に対する荷重変動が小さい荷重一定領域を備えた皿ばねを用いて構成し、この皿ばねの荷重一定領域内で基礎部と免振対象物との間に引抜き力に抵抗するプレストレスを付加したことを特徴とする。
【０００８】
従って、この構成によれば引抜き防止装置を構成する皿ばねに対し、当該皿ばねの上下方向変位量に対する荷重変動が小さい荷重一定領域の範囲内で引抜き力に抵抗するプレストレスを付加したので、引抜き力の発生により基礎部と免振対象物との間の間隔が変化する場合にも、略一定のプレストレスによってこれに抵抗することができる。従って、免振装置に引抜き力が作用する場合はもちろんのこと、免振装置に温度伸縮、クリープが発生した場合や、風や地震による免振装置の水平変形に起因して皿ばねが圧縮された場合であっても、基礎部と免振対象物との間に導入したプレストレスを一定に維持することができる。また、上述したように、地震時などにおいて当該皿ばねに相当の圧縮力が作用しても、該皿ばねは上記荷重一定領域の範囲内で圧縮されるのでその復原力の変動も押さえることができ、免振対象物の水平移動を拘束、延いては免振装置の挙動を拘束することがなく、免振装置の本来の免振機能が低下されるのを抑えることができる。また、免振装置に作用する引抜き力を皿ばねに加えたプレストレスで抵抗できるため、引抜き防止装置は基本的に皿ばねを備えておれば良く、その構成を著しく簡略化することができる。
【０００９】
また、本発明の免振構造は、基礎部に免振装置を介して免振対象物が支持されるとともに、基礎部と免振対象物との間に、免振装置に作用する引抜き力に抵抗する引抜き防止装置が設けられた免振構造において、上記引抜き防止装置を、基礎部と免振対象物との間の上下変位が入力される連結部材と、この連結部材と基礎部または免振対象物との間の変位伝達経路に介装される皿ばねとを備えて構成し、この皿ばねの伸縮量に対する荷重変動が小さい荷重一定領域内で、基礎部と免振対象物との間に引抜き力に抵抗するプレストレスを付加したことを特徴とする。
【００１０】
従って、この構成によれば引抜き力が免振装置に作用した場合に、基礎部と免振対象物との間に生ずる変位量は連結部材を介して皿ばねに入力され、この皿ばねに導入したプレストレスによって引抜き力に抵抗することができる。このとき、皿ばねのばね特性は伸縮量に対する荷重変動が小さい荷重一定領域に設定されており、この荷重一定領域内で基礎部と免振対象物との間に上記引抜き力に抵抗するプレストレスを導入するようにしたので、引抜き力の発生により基礎部と免振対象物との間の間隔が変化する場合にも、略一定のプレストレスによってこれに抵抗できる。そして、免振装置に引抜き力が作用する場合はもちろんのこと、免振装置に温度伸縮、クリープが発生した場合や、免振装置の水平変形に起因して皿ばねが圧縮された場合であってもプレストレスを一定に維持することができる。また、地震時などにおいて当該皿ばねに相当の圧縮力が作用しても、該皿ばねの復原力の変動も押さえることができ、従って免振装置の挙動を拘束することがなく、免振装置の本来の免振機能が低下されるのを抑えることができる。
【００１１】
また、連結部材と基礎部との間および連結部材と免振対象物との間の少なくともいずれか一方に、引抜き力を伝達しつつ屈曲自在な節部材を設けることが望ましい。
【００１２】
従って、この構成によれば地震による水平変形が入力された場合も、連結部材は節部分から容易に傾斜して水平変形に追従できるため、無理な曲げ力が連結部材や皿ばねに作用するのを防止して皿ばねのばね特性が変化されるのを避け、延いては、免振装置による免振性能が低下されるのを防止できる。
【００１３】
更に、連結部材を、ＰＣ鋼棒やＰＣ鋼線等の高張力鋼で形成することが望ましい。
【００１４】
従って、この構成によれば想定を越える外力によって免振装置が引張り限界に達した場合にあっても、ＰＣ鋼棒やＰＣ鋼線等の高張力鋼が引張り余力を負担して免振装置の破壊を防止するため、フェイルセーフ機能を確保することができる。
【００１５】
更にまた、皿ばねを、基礎部または免振対象物の受圧面に着座させて配置し、この着座部に滑り機構を介在して摩擦ダンパーを構成することが望ましい。
【００１６】
従って、この構成によれば地震による水平変位力が入力された場合に、皿ばねと受圧面とが滑り機構を介して相対移動する。このとき、相対移動面に皿ばねの付勢力が作用して摩擦力が発生し、これを振動減衰力として作用させることができる。
【００１７】
【発明の実施の形態】
以下、本発明の実施形態を添付図面を参照して詳細に説明する。図１〜図５は本発明の免振構造の一実施形態を示し、図１は免振構造の要部拡大断面図、図２は免振構造に用いられるばね部材の支持部分の正面図、図３は同支持部分の平面図、図４は皿ばねのばね特性を示すグラフ、図５は免振装置が上下方向変形、並びに水平方向変形した状態を示す説明図である。
【００１８】
本発明の基本的な免振構造は、基礎部１０に免振装置１４を介して免振対象物１２が支持されるとともに、基礎部１０と免振対象物１２との間に、免振装置１４に作用する引抜き力に抵抗する引抜き防止装置２２が設けられるようになっており、引抜き防止装置２２を、上下方向変位量に対する荷重変動が小さい荷重一定領域を備えた皿ばね２６を用いて構成し、この皿ばね２６の荷重一定領域内で基礎部１０と免振対象物１２との間に引抜き力に抵抗するプレストレスを付加する。
【００１９】
また、上記引抜き防止装置２２を、基礎部１０と免振対象物１２との間の上下変位が入力される連結部材２４と、この連結部材２４と基礎部１０または免振対象物１２との間の変位伝達経路に介装される皿ばね２６とを備えて構成し、この皿ばね２６の伸縮量に対する荷重変動が小さい荷重一定領域Ｒ内で、基礎部１０と免振対象物１２との間に引抜き力に抵抗するプレストレスを付加してある。
【００２０】
このとき、連結部材２４と基礎部１０との間および連結部材２４と免振対象物１２との間に、引抜き力を伝達しつつ屈曲自在な節部材２８，２８ａを設けることが望ましく、また、上記連結部材２４を、ＰＣ鋼棒またはＰＣ鋼線で形成することが望ましい。
【００２１】
即ち、本実施形態の免振構造は図１に示すように、中，高層ビルとして構築される建築物に適用する場合に例をとって示し、基礎部１０と免振対象物としての建築物１２との間に免振装置としての積層ゴム１４が配置され、この積層ゴム１４を介して建築物１２は基礎部１０に免振支持される。
【００２２】
基礎部１０は地盤の掘削部分にコンクリートを打設してＲＣ造として構成され、これの上面には積層ゴム１４の取付け台１６が突設されている。また、建築物１２はこれの下端に設けられる大梁が鉄骨梁１８によって形成され、この鉄骨梁１８が積層ゴム１４上に支持される。この鉄骨梁１８はＨ型鋼で形成され、その下方フランジ１８ａ下面に積層ゴム１４の支持台２０が垂設されている。一方、積層ゴム１４は一般に知られるように、ゴム層と鋼板とが交互に積層される本体部分１４ａの上，下両端に取付板１４ｂ，１４ｃが固着されることにより構成され、上方の取付板１４ｂが支持台２０に固定されるとともに、下方の取付板１４が取付け台１６に固定される。
【００２３】
基礎部１０と鉄骨梁１８との間には、積層ゴム１４の近傍に引抜き防止装置２２が設けられる。この引抜き防止装置２２は図中簡略的に１つのみを示すが、実際には積層ゴム１４を中心として鉄骨梁１８の延設方向に対称に配置することが望ましい。例えば、積層ゴム１４が鉄骨梁１８の直線部分に配置される場合は、この積層ゴム１４を挟んで鉄骨梁１８の延設方向に２つの引抜き防止装置２２が設けられるとともに、鉄骨梁１８が十字状に組み合わされてその交差部分に積層ゴム１４が配置される場合は、十字状の鉄骨梁１８に沿って４つの引抜き防止装置２２が点対称に設けられることになる。
【００２４】
引抜き防止装置２２は、連結部材２４と皿ばね２６とを備えており、連結部材２４は、鉛直方向を指向して基礎部１０と鉄骨梁１８との間に配置され、基礎部１０と建築物１２との間の上下変位が入力される。一方、皿ばね２６は連結部材２４の上端部と鉄骨梁１８の下方フランジ１８ａとの間に配置され、皿ばね２６の付勢力が連結部材２４に引張り荷重として入力される。
【００２５】
連結部材２４はＰＣ鋼棒またはＰＣ鋼線によって形成され、これの上，下両端部はそれぞれ節部材としての球座部２８，２８ａを介して基礎部１０および鉄骨梁１８に取り付けられる。下方の球座部２８ａはアンカーボルト３０を介して基礎部１０に埋設固定される固定台３２に下向きに取り付けられるとともに、上方の球座部２８は、鉄骨梁１８の下方フランジ１８ａの上面に設けられて上記皿ばね２６の上端に接続される支持台３３に上向きに取り付けられる。このとき、連結部材２４はその上端部が下方フランジ１８ａに形成される開口部（または切欠部）１８ｂから上方に貫通されている。
【００２６】
上，下方の球座部２８，２８ａは、同一構成のものをそれぞれ上下逆として使用するようになっており、この球座部２８，２８ａは図２，図３に示すように、回転部３４と球座台３６とを備えて構成される。回転部３４は、球状の凸部３４ａの中央部に挿通穴３４ｂが形成され、この挿通穴３４ｂに連結部材２４の端部を挿通してナット３８により固定するようになっている。
【００２７】
一方、球座台３６は、回転部３４の球状凸部３４ａを受容する球状凹部３６ａの中央部に大径の開口部３６ｂが形成され、この球状凹部３６ａに球状凸部３４ａを摺動自在に嵌合するとともに、開口部３６ｂに連結部材２４が貫通される。球座台３６の周縁部には複数の取付穴３６ｃが形成され、これら取付穴３６ｃに挿通したボルト４０を介して固定台３２および支持台３３に固定される。
【００２８】
皿ばね２６は複数の皿ばね単体を複数積層して構成され、下方フランジ１８ａの開口部１８ｂの両側に１対配置される。各皿ばね２６は上端に支持台３３が載置された状態で、下端が下方フランジ１８ａ上面に載置され、連結部材２４に作用する引張力（引抜き力）が皿ばね２６に入力される。皿ばね２６にはプレストレスが導入されるようになっていて、このプレストレスは球座部２８，２８ａのナット３８の締付け加減で調整される。
【００２９】
皿ばね２６は、図４に示すように初期の弾性勾配は大きくて２次勾配が小さな非線形となる復元力を有するばね特性として設定され、自然長（変位δ＝０）から荷重（Ｐ）が作用する初期段階では急激に立ち上がって一定の変位（δ）量に対して荷重（Ｐ）の変化幅が大きくなるが、相当の変位領域Ｒでは荷重（Ｐ）の傾斜が緩やかとなる。つまり、この傾斜が緩やかな領域Ｒでは、一定の変位（δ）量に対する荷重（Ｐ）の変化幅（ΔＰ）が小さくなり、この領域Ｒが荷重一定領域として用いられることになる。
【００３０】
そして、皿ばね２６は球座部２８，２８ａのナット３８の締付け調整により荷重一定領域Ｒ内に設定され、このときの荷重が連結部材２４にプレストレスとして作用する。従って、連結部材２４が配置される基礎部１０と建築物１２（鉄骨梁１８）との間には、皿ばね２６の荷重一定領域Ｒ内のプレストレスが付加される。ところで、皿ばね２６は、皿ばね単体の表側と裏側とを交互に積層した場合を図示したが、これに限ることなく片側のみが重合するように積層しても良く、また、表側と裏側とを複数枚づつ重合したものを交互に積層してもよく、それぞれの積層の態様によってばね定数を変化できることにより、最適なばね定数の選択が可能となる。
【００３１】
以上の構成により本実施形態の免振構造にあっては、建築物１２に引抜き力が作用して、基礎部１０と鉄骨梁１８との間の上下間隔が広がろうとした場合に、引抜き防止装置２２の連結部材２４がこれに抵抗して建築物１２の浮き上がりを阻止する。この引抜き防止装置２２は、これら連結部材２４および皿ばね２６に導入したプレストレスで引抜き力に抵抗できることから、その構成を著しく簡略化することができる。
【００３２】
そして特にこの引抜き防止装置２２では、皿ばね２６に対して、上下方向変位量に対する荷重変動が小さい荷重一定領域Ｒの範囲で引抜き力に抵抗するプレストレスを付加するようにしたので、図５（ａ）に示すように積層ゴム１４に、温度による伸縮ΔＬＴやクリープΔＬＣが発生した場合にあっても、導入したプレストレスに変動が生じることはなく、引抜き力に対して当初設定したプレストレスで適切に抵抗させることができる。同様に、同図（ｂ）に示すように地震によって皿ばね２６に相当の圧縮変形を生じさせる変位ΔＬＨが生じた場合であってもプレストレスの変動を押さえることができ、適切に引抜き力に抵抗させることができる。
【００３３】
また、地震時などにおいて積層ゴム１４が水平方向に変形するとともに当該皿ばね２６が相当圧縮されても、皿ばね２６は上記荷重一定領域Ｒの範囲内で圧縮されるのでその復原力の変動も小さく、建築物１２の水平移動を拘束、延いては積層ゴム１４の挙動を拘束することがなく、積層ゴム１４の本来の免振機能が低下されるのを抑えることができる。
【００３４】
ここで、地震により水平変形する場合に引抜き防止装置２２の皿ばね２６は、上述したように水平変形量ΔＬＨに起因して圧縮されるが、この際の傾斜は図２に示したように球座部２８，２８ａによって容易に許容される。即ち、球座部２８，２８ａは傾斜力が連結部材２４を介して入力されると、回転部３４は球状凸部３４ａと球状凹部３６ａとの摺動を伴って、同図中破線に示すように球状台３６に対して滑らかに回転する。このため、水平変形時に皿ばね２６は曲げ変形することなく伸縮し、本来のばね特性を発揮して積層ゴム１４の免振性能に影響を与えるのを防止することができる。
【００３５】
ところで、本実施形態では連結部材２４を、ＰＣ鋼棒やＰＣ鋼線等の高張力鋼で形成したので、想定を越える外力によって積層ゴム１４が引張り限界に達した場合にあっても、連結部材２４を構成する高張力鋼が引張り余力を負担して積層ゴム１４の破壊を防止することができるため、フェイルセーフ機能を確保することができる。
【００３６】
また、上記実施形態では皿ばね２６を鉄骨梁１８の下方フランジ１８ａに直接に当接させた場合を示したが、図６に示すように皿ばね２６と下方フランジ１８ａとの間に滑り機構５０を介在させて、摩擦ダンパーを構成することもできる。即ち、滑り機構５０は、皿ばね２６の下端に取り付けられる摩擦材５２と、皿ばね２６の受圧面となる下方フランジ１８ａの上面に取り付けられる滑り材５４とで構成され、摩擦材５２が滑り材５４上に滑動自在に載置される。
【００３７】
従って、この構成によれば地震による水平変位力が入力された場合に、皿ばね２６と下方フランジ１８ａとが滑り機構５０を介して相対移動することが可能となる。このとき、滑り機構５０の相対移動面、つまり、摩擦材５２と滑り材５４との間に皿ばね２６の付勢力が作用して摩擦力が発生し、この滑り機構５０が摩擦ダンパーとして機能する。従って、この滑り機構５０に発生する摩擦力を振動減衰力とすることができる。
【００３８】
また、摩擦ダンパーとして機能する滑り機構５０は、荷重一定領域Ｒに設定された皿ばね２６の付勢力が作用しているため、引抜き力が作用する場合にも常時一定した押圧力を保証でき、摩擦力を一定として安定した振動減衰力を得ることができる。
【００３９】
図７は他の実施形態を示す免振構造の要部拡大断面図で、上記実施形態と同一構成部分に同一符号を付して重複する説明を省略して述べる。
【００４０】
この実施形態の引抜き防止装置２２は、ＰＣ鋼棒で形成される連結部材２４の中間部分に皿ばね２６を介在させて、基礎部１０と建築物１２との間にプレストレスを付加するようになっている。即ち、この実施形態では、皿ばね２６の付勢力をシリンダ形式をもって連結部材２４に与えるようになっており、連結部材２４を上下に分割した上方部材２４ａにケーシング６０を取り付ける一方、このケーシング６０内に下方部材２４ｂを相対移動自在に挿入し、この下方部材２４ｂの先端部に取付けた受け板６２とケーシング６０の底部６０ａとの間に皿ばね２６を挟み込むようになっている。そして、下方部材２４ｂの途中に設けたターンバックル６４を締付け調整することにより、受け板６２と底部６０ａとの間の距離を変化させて、皿ばね２６に対し荷重一定領域Ｒ内のプレストレスを導入するようになっている。
【００４１】
ところで、この実施形態では建築物１２の下端に設けられる大梁がＲＣ梁６６で構成されるようになっており、上方部材２４ａ上端部のジョイント６８はアンカーボルト７０を介してＲＣ梁６６に固定される。一方、下方部材２４ｂ下端部のジョイント７２はアンカーボルト７４を介して基礎部１０に固定される。また、ジョイント６８，７２は上記実施形態の球座部２８，２８ａに代えることもできる。
【００４２】
そして、この実施形態にあっては、ターンバックル６４の締付け調整によって荷重一定領域Ｒに設定される皿ばね２６には、上，下方部材２４ａ，２４ｂを介して基礎部１０と建築物１２との間での引抜き力に抵抗するプレストレスが導入される。そしてこのような実施形態にあっても、上記実施形態と同様の効果を発揮することができる。
【００４３】
ところで、本発明の免振構造を前記各実施形態によって詳述したが、本免振構造は、特に塔状比（アスペクト比）の高い高層建築物や、平面計画上の制約があって耐震要素の設置位置が限られた建物、および風振動受ける橋梁等に対して好ましく適用できる。
【００４４】
【発明の効果】
以上説明したように本発明の請求項１に示す免振構造にあっては、引抜き防止装置を構成する皿ばねに対し、当該皿ばねの上下方向変位量に対する荷重変動が小さい荷重一定領域の範囲内で引抜き力に抵抗するプレストレスを付加したので、引抜き力の発生により基礎部と免振対象物との間の間隔が変化する場合にも、略一定のプレストレスによってこれに抵抗することができる。従って、免振装置に引抜き力が作用する場合はもちろんのこと、免振装置に温度伸縮、クリープが発生した場合や、風や地震による免振装置の水平変形に起因して皿ばねが圧縮された場合であっても、基礎部と免振対象物との間に導入したプレストレスを一定に維持することができる。また、上述したように、地震時などにおいて当該皿ばねに相当の圧縮力が作用しても、該皿ばねは上記荷重一定領域の範囲内で圧縮されるのでその復原力の変動も押さえることができ、免振対象物の水平移動を拘束、延いては免振装置の挙動を拘束することがなく、免振装置の本来の免振機能が低下されるのを抑えることができる。また、免振装置に作用する引抜き力を皿ばねに加えたプレストレスで抵抗できるため、引抜き防止装置は基本的に皿ばねを備えておれば良く、その構成を著しく簡略化することができる。
【００４５】
また、本発明の請求項２に示す免振構造にあっては、引抜き力が免振装置に作用した場合に、基礎部と免振対象物との間に生ずる変位量は連結部材を介して皿ばねに入力され、この皿ばねに導入したプレストレスによって引抜き力に抵抗することができる。このとき、皿ばねのばね特性は伸縮量に対する荷重変動が小さい荷重一定領域に設定されており、この荷重一定領域内で基礎部と免振対象物との間に上記引抜き力に抵抗するプレストレスを導入するようにしたので、引抜き力の発生により基礎部と免振対象物との間の間隔が変化する場合にも、略一定のプレストレスによってこれに抵抗できる。そして、免振装置に引抜き力が作用する場合はもちろんのこと、免振装置に温度伸縮、クリープが発生した場合や、免振装置の水平変形に起因して皿ばねが圧縮された場合であってもプレストレスを一定に維持することができる。また、地震時などにおいて当該皿ばねに相当の圧縮力が作用しても、該皿ばねの復原力の変動も押さえることができ、従って免振装置の挙動を拘束することがなく、免振装置の本来の免振機能が低下されるのを抑えることができる。
【００４６】
また、本発明の請求項３に示す免振構造にあっては、地震による水平変形が入力された場合も、連結部材は節部分から容易に傾斜して水平変形に追従できるため、無理な曲げ力が連結部材や皿ばねに作用するのを防止して皿ばねのばね特性が変化されるのを避け、延いては、免振装置による免振性能が低下されるのを防止できる。
【００４７】
更に、本発明の請求項４に示す免振構造にあっては、想定を越える外力によって免振装置が引張り限界に達した場合にあっても、ＰＣ鋼棒やＰＣ鋼線等の高張力鋼が引張り余力を負担して免振装置の破壊を防止するため、フェイルセーフ機能を確保することができる。
【００４８】
更にまた、本発明の請求項５に示す免振構造にあっては、地震による水平変位力が入力された場合に、皿ばねと受圧面とが滑り機構を介して相対移動する。このとき、相対移動面に皿ばねの付勢力が作用して摩擦力が発生し、これを振動減衰力として作用させることができる。
【図面の簡単な説明】
【図１】本発明の一実施形態を示す免振構造の要部拡大断面図である。
【図２】本発明の一実施形態を示す免振構造に用いられるばね部材の支持部分の正面図である。
【図３】本発明の一実施形態を示す免振構造に用いられるばね部材の支持部分の平面図である。
【図４】本発明の一実施形態を示す免振構造に用いられる皿ばねのばね特性を示すグラフである。
【図５】本発明に用いられる免振装置が上下方向もしくは水平方向に変形した状態を示す説明図である。
【図６】本発明の他の実施形態を示す皿ばねの支持部分を示す要部拡大断面図である。
【図７】本発明の他の実施形態を示す免振構造の要部拡大断面図である。
【符号の説明】
１０基礎部
１２建築物（免振対象物）
１４積層ゴム（免振装置）
２２引抜き防止装置
２４連結部材
２６皿ばね
２８，２８ａ球座部（節部材）
５０滑り機構[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vibration isolation structure configured to perform vibration isolation on a vibration isolation object provided on a base portion via a vibration isolation device disposed between them.
[0002]
[Prior art]
In general, a base-isolated building constructed as a middle or high-rise building has an isolation device interposed between the foundation and the building. As this vibration isolator, laminated rubber is generally used, but there are also a sliding bearing and a rolling bearing that smooth the horizontal movement of the building. By the way, when a rocking motion occurs in a base-isolated building, a pulling force is generated in the vibration isolator, but the conventional vibration isolator has no way of resisting such a pulling force, and the original vibration isolating effect. You will not be able to get.
[0003]
Therefore, in recent years, as disclosed in Japanese Patent Application Laid-Open No. 10-280729, there is provided a vibration isolating structure in which an anti-extraction device (tensile force compatible device) that resists an extraction force is provided between the foundation and the building. Proposed. In this pull-out prevention device, a lower guide rail and an upper guide rail that are arranged to face each other at a right angle are fixed to a foundation portion and a building side, and a pull-out restraining portion is provided between the lower guide rail and the upper guide rail. It is designed to be provided. This pull-out restraining part is movably connected along both guide rails to allow horizontal displacement in all directions of the building and to prevent the two guide rails from being separated from each other. It comes to stop.
[0004]
[Problems to be solved by the invention]
However, in such a conventional vibration isolating structure, the pull-out preventing device provided with the pull-out restraining portion resists the pulling force acting on the building, and the original vibration-isolating function of the vibration-isolating device such as laminated rubber is effective. It can be demonstrated to. However, in this pull-out prevention device, the upper and lower guide rails are provided to horizontally displace the pull-out restraining portion, so that the configuration is remarkably complicated and the construction cost increases. Will be.
[0005]
By the way, in order to resist the pulling force, it is only necessary to introduce a prestress to the spring member by interposing a spring member between the foundation and the building. PC steel bars and PC steel wires to be used will be used. However, when pre-stress is applied using these PC steel bars and PC steel wires, spring members are caused by expansion and contraction due to temperature changes of laminated rubber, height change due to creep, and horizontal deformation of the vibration isolator due to wind and earthquake. If the prestress load that has been set changes due to the elongation of the material, it is difficult not only to maintain the prestress at a constant level, but also when the spring member is considerably pulled and its restoring force becomes too great during an earthquake, etc. However, there is a problem that the horizontal movement of the building is restricted, and thus the behavior of the vibration isolator is restricted, and the function cannot be sufficiently extracted.
[0006]
Therefore, the present invention has been made in view of such conventional problems, and the load fluctuation is small with respect to the amount of expansion / contraction displacement of the disc spring that applies prestress between the base portion and the object to be isolated. The pull-out resistance force is made constant by using a load with a constant load area, thereby simplifying the structure of the pull-out prevention device and preventing the pull-out prevention device from affecting the behavior of the vibration isolator. The purpose is to provide an isolation structure.
[0007]
[Means for Solving the Problems]
In order to achieve such an object, the vibration isolation structure of the present invention supports the vibration isolation object on the base portion via the vibration isolation device, and the vibration isolation device between the base portion and the vibration isolation object. In the vibration isolating structure provided with a pull-out prevention device that resists the pulling force that acts, the pull-out prevention device is configured by using a disc spring having a constant load region that has a small load variation with respect to the amount of vertical displacement. A prestress that resists the pulling force is applied between the base portion and the object to be isolated within a constant load region of the spring.
[0008]
Therefore, according to this configuration, since the prestress that resists the pulling force is added to the disc spring constituting the pull-out prevention device within the range of the load constant region in which the load variation with respect to the vertical displacement amount of the disc spring is small, Even when the distance between the base portion and the object to be isolated changes due to the generation of the pulling force, it can be resisted by a substantially constant prestress. Therefore, not only when the pulling-out force acts on the vibration isolator, but also when the temperature is expanded or contracted or creep occurs in the vibration isolator, or the disc spring is compressed due to horizontal deformation of the vibration isolator due to wind or earthquake. Even if it is a case, the prestress introduced between the base part and the isolation object can be maintained constant. In addition, as described above, even if a considerable compressive force is applied to the disc spring during an earthquake or the like, the disc spring is compressed within the range of the constant load region, so that fluctuations in the restoring force can be suppressed. It is possible to restrict the horizontal movement of the object to be isolated, and thus not to restrict the behavior of the vibration isolator, and to suppress the deterioration of the original vibration isolating function of the vibration isolator. Further, since the pulling force acting on the vibration isolator can be resisted by the prestress applied to the disc spring, the pull-out preventing device basically has to be provided with the disc spring, and the configuration can be remarkably simplified.
[0009]
Further, the vibration isolation structure of the present invention supports the vibration isolation object on the base portion via the vibration isolation device, and has a pulling force acting on the vibration isolation device between the base portion and the vibration isolation object. In the vibration isolating structure provided with a resisting pull-out preventing device, the pull-out preventing device includes a connecting member to which a vertical displacement between the base portion and the vibration isolating object is input, and the connecting member and the base portion or the vibration isolating device. A disc spring interposed in the displacement transmission path between the object and the object between the foundation and the vibration isolation object within a constant load range where the load fluctuation with respect to the amount of expansion and contraction of the disc spring is small. It is characterized by adding a pre-stress that resists pulling force.
[0010]
Therefore, according to this configuration, when a pulling force acts on the vibration isolator, the amount of displacement generated between the base portion and the object to be vibration-isolated is input to the disc spring via the connecting member, and is introduced into the disc spring. The prestress can resist the pulling force. At this time, the spring characteristics of the disc spring are set to a constant load region where the load fluctuation with respect to the expansion / contraction amount is small, and the prestress that resists the pulling force between the base portion and the vibration isolation object within the constant load region. Therefore, even when the distance between the base portion and the object to be isolated changes due to the generation of the pulling force, it can be resisted by a substantially constant prestress. Of course, when the pulling force is applied to the vibration isolator, temperature expansion or contraction or creep occurs in the vibration isolator, or when the disc spring is compressed due to horizontal deformation of the vibration isolator. But prestress can be kept constant. Further, even if a considerable compressive force is applied to the disc spring during an earthquake or the like, the fluctuation of the restoring force of the disc spring can be suppressed, and therefore the behavior of the isolator is not restricted. It is possible to suppress the deterioration of the original vibration isolation function.
[0011]
In addition, it is desirable to provide a bendable node member that transmits the pulling force between at least one of the connection member and the base portion and between the connection member and the object to be isolated.
[0012]
Therefore, according to this configuration, even when horizontal deformation due to an earthquake is input, the connecting member can easily tilt from the node portion and follow the horizontal deformation, so that an excessive bending force acts on the connecting member and the disc spring. It is possible to prevent the spring characteristics of the disc spring from being changed and to prevent the vibration isolation performance of the vibration isolation device from being deteriorated.
[0013]
Furthermore, it is desirable that the connecting member is made of high-tensile steel such as a PC steel rod or PC steel wire.
[0014]
Therefore, according to this configuration, even when the vibration isolator reaches the tension limit due to an external force exceeding the assumption, high tensile steel such as a PC steel rod or PC steel wire bears the extra tensile force and the vibration isolator In order to prevent destruction, a fail safe function can be secured.
[0015]
Furthermore, it is desirable that the disc spring is disposed while being seated on the pressure receiving surface of the base portion or the object to be isolated, and a friction damper is configured by interposing a sliding mechanism on the seating portion.
[0016]
Therefore, according to this configuration, when a horizontal displacement force due to an earthquake is input, the disc spring and the pressure receiving surface move relative to each other via the sliding mechanism. At this time, the urging force of the disc spring acts on the relative moving surface to generate a frictional force, which can act as a vibration damping force.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. 1 to 5 show an embodiment of the vibration isolation structure of the present invention, FIG. 1 is an enlarged cross-sectional view of a main part of the vibration isolation structure, FIG. 2 is a front view of a support portion of a spring member used in the vibration isolation structure, FIG. 3 is a plan view of the support portion, FIG. 4 is a graph showing the spring characteristics of the disc spring, and FIG. 5 is an explanatory view showing a state where the vibration isolator is deformed in the vertical direction and in the horizontal direction.
[0018]
In the basic vibration isolation structure of the present invention, the vibration isolation object 12 is supported by the base portion 10 via the vibration isolation device 14, and the vibration isolation device is interposed between the base portion 10 and the vibration isolation object 12. A pull-out prevention device 22 that resists a pull-out force acting on the pull-out force 14 is provided, and the pull-out prevention device 22 is configured by using a disc spring 26 having a constant load region in which the load fluctuation with respect to the vertical displacement amount is small. Then, a prestress that resists the pulling force is applied between the base portion 10 and the vibration isolation object 12 within the constant load region of the disc spring 26.
[0019]
Further, the pull-out preventing device 22 is connected to the connecting member 24 to which the vertical displacement between the base portion 10 and the vibration isolation object 12 is input, and between the connection member 24 and the base portion 10 or the vibration isolation object 12. And a disc spring 26 interposed in the displacement transmission path of the disc spring 26, and within the constant load region R where the load fluctuation with respect to the expansion and contraction amount of the disc spring 26 is small. A pre-stress that resists the pulling force is added.
[0020]
At this time, it is desirable to provide bendable node members 28 and 28a between the connecting member 24 and the base portion 10 and between the connecting member 24 and the vibration isolation object 12 while transmitting the pulling force. The connecting member 24 is preferably formed of a PC steel rod or a PC steel wire.
[0021]
That is, as shown in FIG. 1, the vibration isolation structure of the present embodiment is shown as an example when applied to a building constructed as a middle or high-rise building. A laminated rubber 14 as a vibration isolator is disposed between the building 12 and the building 12, and the building 12 is supported by the foundation 10 via the laminated rubber 14.
[0022]
The foundation portion 10 is constructed as RC by placing concrete on the excavation portion of the ground, and a mounting base 16 for the laminated rubber 14 projects from the upper surface thereof. The building 12 is formed with a steel beam 18 having a large beam provided at the lower end thereof, and the steel beam 18 is supported on the laminated rubber 14. The steel beam 18 is made of H-shaped steel, and a support 20 for the laminated rubber 14 is suspended from the lower surface of the lower flange 18a. On the other hand, as is generally known, the laminated rubber 14 is configured by attaching mounting plates 14b and 14c to upper and lower ends of a main body portion 14a in which rubber layers and steel plates are alternately laminated, and an upper mounting plate. 14 b is fixed to the support base 20, and the lower mounting plate 14 is fixed to the mounting base 16.
[0023]
A pull-out prevention device 22 is provided between the base portion 10 and the steel beam 18 in the vicinity of the laminated rubber 14. Although only one pull-out prevention device 22 is shown in the drawing, it is actually desirable to arrange it symmetrically in the extending direction of the steel beam 18 with the laminated rubber 14 as the center. For example, when the laminated rubber 14 is disposed in a straight portion of the steel beam 18, two pull-out preventing devices 22 are provided in the extending direction of the steel beam 18 with the laminated rubber 14 interposed therebetween, and the steel beam 18 is cross-shaped. In the case where the laminated rubber 14 is arranged at the intersection, the four pull-out prevention devices 22 are provided point-symmetrically along the cross-shaped steel beam 18.
[0024]
The pull-out prevention device 22 includes a connecting member 24 and a disc spring 26, and the connecting member 24 is disposed between the base portion 10 and the steel beam 18 in the vertical direction, and the base portion 10 and the building. A vertical displacement between 12 is input. On the other hand, the disc spring 26 is disposed between the upper end portion of the connecting member 24 and the lower flange 18 a of the steel beam 18, and the biasing force of the disc spring 26 is input to the connecting member 24 as a tensile load.
[0025]
The connecting member 24 is formed of a PC steel rod or PC steel wire, and both upper and lower end portions thereof are attached to the base portion 10 and the steel beam 18 via ball seat portions 28 and 28a as node members, respectively. The lower ball seat portion 28 a is attached downward to a fixing base 32 embedded and fixed to the base portion 10 via the anchor bolt 30, and the upper ball seat portion 28 is provided on the upper surface of the lower flange 18 a of the steel beam 18. And mounted upward on a support base 33 connected to the upper end of the disc spring 26. At this time, the upper end of the connecting member 24 is penetrated upward from an opening (or notch) 18b formed in the lower flange 18a.
[0026]
The upper and lower ball seats 28 and 28a are of the same configuration and are used upside down. As shown in FIGS. 2 and 3, the ball seats 28 and 28a are rotating parts 34, respectively. And a ball base 36. The rotating portion 34 is formed with an insertion hole 34b at the center of the spherical convex portion 34a, and the end of the connecting member 24 is inserted into the insertion hole 34b and fixed by a nut 38.
[0027]
On the other hand, the spherical base 36 has a large-diameter opening 36b formed at the center of the spherical recess 36a that receives the spherical protrusion 34a of the rotating portion 34, and the spherical protrusion 34a is slidable in the spherical recess 36a. The fitting member 24 is penetrated through the opening 36b. A plurality of mounting holes 36 c are formed in the peripheral portion of the ball seat base 36, and are fixed to the fixing base 32 and the support base 33 through bolts 40 inserted through the mounting holes 36 c.
[0028]
The disc springs 26 are configured by laminating a plurality of disc springs, and one pair is arranged on both sides of the opening 18b of the lower flange 18a. Each disc spring 26 is placed on the upper surface of the lower flange 18 a with the support base 33 placed on the upper end, and a tensile force (pulling force) acting on the connecting member 24 is input to the disc spring 26. Prestress is introduced into the disc spring 26, and this prestress is adjusted by tightening the nut 38 of the ball seats 28, 28a.
[0029]
As shown in FIG. 4, the disc spring 26 is set as a spring characteristic having a non-linear restoring force in which the initial elastic gradient is large and the secondary gradient is small, and the load (P) is changed from the natural length (displacement δ = 0). In the initial stage of action, it rises rapidly and the change width of the load (P) increases with respect to a certain amount of displacement (δ), but in the considerable displacement region R, the inclination of the load (P) becomes gentle. That is, in the region R where the slope is gentle, the change width (ΔP) of the load (P) with respect to a certain amount of displacement (δ) is small, and this region R is used as the constant load region.
[0030]
The disc spring 26 is set in the constant load region R by adjusting the tightening of the nuts 38 of the ball seats 28 and 28a, and the load at this time acts on the connecting member 24 as prestress. Therefore, prestress within the constant load region R of the disc spring 26 is applied between the foundation 10 on which the connecting member 24 is disposed and the building 12 (steel beam 18). By the way, although the disc spring 26 illustrated the case where the front side and the back side of the disc spring alone were alternately laminated, the disc spring 26 is not limited to this and may be laminated so that only one side is superposed. Those obtained by polymerizing a plurality of sheets may be alternately laminated, and the spring constant can be changed depending on the form of each lamination, whereby the optimum spring constant can be selected.
[0031]
With the above-described structure, in the vibration isolating structure of the present embodiment, when a pulling force acts on the building 12 and the vertical distance between the foundation 10 and the steel beam 18 is about to be widened, the pulling prevention is performed. The connecting member 24 of the device 22 resists this and prevents the building 12 from being lifted. Since the pull-out preventing device 22 can resist the pull-out force by the prestress introduced into the connecting member 24 and the disc spring 26, the configuration can be remarkably simplified.
[0032]
In this pull-out prevention device 22 in particular, prestress is applied to the disc spring 26 so as to resist the pull-out force in the range of the constant load region R in which the load variation with respect to the vertical displacement amount is small. As shown in a), even when expansion / contraction ΔLT or creep ΔLC due to temperature occurs in the laminated rubber 14, the introduced prestress does not vary, and the prestress initially set for the pulling force is used. Can be properly resisted. Similarly, as shown in FIG. 6B, even if a displacement ΔLH that causes considerable compression deformation of the disc spring 26 is caused by an earthquake, fluctuations in prestress can be suppressed, and the pulling force can be appropriately adjusted. Can be resisted.
[0033]
Further, even if the laminated rubber 14 is deformed in the horizontal direction during an earthquake or the like and the disc spring 26 is considerably compressed, the disc spring 26 is compressed within the range of the constant load region R. It is small, restrains the horizontal movement of the building 12, and thus does not restrain the behavior of the laminated rubber 14, and can suppress the deterioration of the original vibration isolating function of the laminated rubber 14.
[0034]
Here, in the case of horizontal deformation due to an earthquake, the disc spring 26 of the pull-out prevention device 22 is compressed due to the horizontal deformation amount ΔLH as described above, but the inclination at this time is spherical as shown in FIG. It is easily allowed by the seats 28 and 28a. That is, when the tilting force is input to the ball seats 28 and 28a via the connecting member 24, the rotating part 34 is accompanied by the sliding of the spherical convex part 34a and the spherical concave part 36a, as shown by the broken line in FIG. Rotate smoothly with respect to the spherical base 36. For this reason, the disc spring 26 can be expanded and contracted without being bent and deformed in the horizontal deformation, and the original spring characteristics can be exhibited to prevent the vibration isolation performance of the laminated rubber 14 from being affected.
[0035]
By the way, in this embodiment, since the connection member 24 was formed with high-tensile steel such as a PC steel rod or a PC steel wire, even when the laminated rubber 14 reaches the tensile limit due to an external force exceeding the assumption, the connection member Since the high-strength steel constituting 24 can bear a tensile surplus force and prevent the laminated rubber 14 from being broken, a fail-safe function can be ensured.
[0036]
Moreover, although the case where the disc spring 26 was directly contact | abutted to the lower flange 18a of the steel beam 18 was shown in the said embodiment, as shown in FIG. 6, the sliding mechanism 50 is provided between the disc spring 26 and the lower flange 18a. It is also possible to configure a friction damper by interposing the above. That is, the sliding mechanism 50 includes a friction material 52 attached to the lower end of the disc spring 26 and a sliding material 54 attached to the upper surface of the lower flange 18a that serves as a pressure receiving surface of the disc spring 26. 54 is slidably mounted on 54.
[0037]
Therefore, according to this configuration, the disc spring 26 and the lower flange 18a can move relative to each other via the sliding mechanism 50 when a horizontal displacement force due to an earthquake is input. At this time, a biasing force of the disc spring 26 acts between the relative moving surface of the sliding mechanism 50, that is, between the friction material 52 and the sliding material 54 to generate a frictional force, and the sliding mechanism 50 functions as a friction damper. . Therefore, the frictional force generated in the sliding mechanism 50 can be used as the vibration damping force.
[0038]
Further, the sliding mechanism 50 functioning as a friction damper is capable of guaranteeing a constant pressing force even when a pulling force is applied, because the biasing force of the disc spring 26 set in the constant load region R is acting. A stable vibration damping force can be obtained with a constant frictional force.
[0039]
FIG. 7 is an enlarged cross-sectional view of a main part of a vibration isolation structure showing another embodiment, and the same components as those in the above embodiment are denoted by the same reference numerals and redundant description is omitted.
[0040]
The pull-out prevention device 22 of this embodiment is configured so that a prestress is applied between the foundation portion 10 and the building 12 with a disc spring 26 interposed in an intermediate portion of the connecting member 24 formed of a PC steel rod. It has become. That is, in this embodiment, the urging force of the disc spring 26 is applied to the connecting member 24 in the form of a cylinder, and the casing 60 is attached to the upper member 24a obtained by dividing the connecting member 24 vertically, The lower member 24b is inserted into the lower member 24b so as to be relatively movable, and the disc spring 26 is sandwiched between the receiving plate 62 attached to the tip of the lower member 24b and the bottom 60a of the casing 60. Then, by adjusting the tightening of the turnbuckle 64 provided in the middle of the lower member 24b, the distance between the receiving plate 62 and the bottom portion 60a is changed, and the prestress in the constant load region R is applied to the disc spring 26. It has come to introduce.
[0041]
By the way, in this embodiment, the large beam provided at the lower end of the building 12 is configured by the RC beam 66, and the joint 68 at the upper end of the upper member 24 a is fixed to the RC beam 66 via the anchor bolt 70. The On the other hand, the joint 72 at the lower end portion of the lower member 24 b is fixed to the base portion 10 via an anchor bolt 74. Further, the joints 68 and 72 can be replaced with the ball seats 28 and 28a of the above embodiment.
[0042]
In this embodiment, the disc spring 26 set in the constant load region R by the tightening adjustment of the turnbuckle 64 is connected to the foundation 10 and the building 12 via the upper and lower members 24a and 24b. Prestress is introduced that resists the pulling force between them. Even in such an embodiment, the same effects as in the above embodiment can be exhibited.
[0043]
By the way, although the isolation structure of this invention was explained in full detail by said each embodiment, this isolation structure is a high-rise building with a high tower-like ratio (aspect ratio) especially, and there are restrictions on a plan plan. Can be preferably applied to buildings with limited installation positions and bridges subjected to wind vibration.
[0044]
【The invention's effect】
As described above, in the vibration isolation structure shown in claim 1 of the present invention, the range of the constant load region in which the load fluctuation with respect to the vertical displacement amount of the disc spring is small with respect to the disc spring constituting the pull-out prevention device. Since a prestress that resists the pulling force is added, even when the distance between the foundation and the object to be isolated changes due to the generation of the pulling force, it can resist this by a substantially constant prestress. it can. Therefore, not only when the pulling-out force acts on the vibration isolator, but also when the temperature is expanded or contracted or creep occurs in the vibration isolator, or the disc spring is compressed due to horizontal deformation of the vibration isolator due to wind or earthquake. Even if it is a case, the prestress introduced between the base part and the isolation object can be maintained constant. In addition, as described above, even if a considerable compressive force is applied to the disc spring during an earthquake or the like, the disc spring is compressed within the range of the constant load region, so that fluctuations in the restoring force can be suppressed. It is possible to restrict the horizontal movement of the object to be isolated, and thus not to restrict the behavior of the vibration isolator, and to suppress the deterioration of the original vibration isolating function of the vibration isolator. Further, since the pulling force acting on the vibration isolator can be resisted by the prestress applied to the disc spring, the pull-out preventing device basically has to be provided with the disc spring, and the configuration can be remarkably simplified.
[0045]
Further, in the vibration isolating structure according to claim 2 of the present invention, when a pulling force acts on the vibration isolator, the amount of displacement generated between the base portion and the vibration isolating object is via the connecting member. The pulling force can be resisted by the prestress input to the disc spring and introduced into the disc spring. At this time, the spring characteristics of the disc spring are set to a constant load region where the load fluctuation with respect to the expansion / contraction amount is small, and the prestress that resists the pulling force between the base portion and the vibration isolation object within the constant load region. Therefore, even when the distance between the base portion and the object to be isolated changes due to the generation of the pulling force, it can be resisted by a substantially constant prestress. Of course, when the pulling force is applied to the vibration isolator, temperature expansion or contraction or creep occurs in the vibration isolator, or when the disc spring is compressed due to horizontal deformation of the vibration isolator. But prestress can be kept constant. Further, even if a considerable compressive force is applied to the disc spring during an earthquake or the like, the fluctuation of the restoring force of the disc spring can be suppressed, and therefore the behavior of the isolator is not restricted. It is possible to suppress the deterioration of the original vibration isolation function.
[0046]
Further, in the vibration isolating structure described in claim 3 of the present invention, even when horizontal deformation due to an earthquake is input, the connecting member can easily be inclined from the node portion and follow the horizontal deformation, so It is possible to prevent the force from acting on the connecting member and the disc spring to avoid changing the spring characteristics of the disc spring, and to prevent the vibration isolation performance of the vibration isolator from being lowered.
[0047]
Furthermore, in the vibration isolating structure shown in claim 4 of the present invention, even when the vibration isolator reaches the tension limit due to an external force exceeding the assumption, a high strength steel such as a PC steel bar or a PC steel wire. However, since the load of the tension is prevented and the vibration isolator is prevented from being destroyed, the fail-safe function can be ensured.
[0048]
Furthermore, in the vibration isolating structure shown in claim 5 of the present invention, when a horizontal displacement force due to an earthquake is input, the disc spring and the pressure receiving surface relatively move via the sliding mechanism. At this time, the urging force of the disc spring acts on the relative moving surface to generate a frictional force, which can act as a vibration damping force.
[Brief description of the drawings]
FIG. 1 is an enlarged cross-sectional view of a main part of a vibration isolation structure showing an embodiment of the present invention.
FIG. 2 is a front view of a support portion of a spring member used in the vibration isolation structure showing an embodiment of the present invention.
FIG. 3 is a plan view of a support portion of a spring member used in the vibration isolation structure showing an embodiment of the present invention.
FIG. 4 is a graph showing the spring characteristics of a disc spring used in the vibration isolation structure showing an embodiment of the present invention.
FIG. 5 is an explanatory view showing a state where the vibration isolator used in the present invention is deformed in the vertical direction or in the horizontal direction.
FIG. 6 is an enlarged cross-sectional view of a main part showing a support portion of a disc spring showing another embodiment of the present invention.
FIG. 7 is an enlarged cross-sectional view of a main part of a vibration isolation structure showing another embodiment of the present invention.
[Explanation of symbols]
10 foundation 12 building (object to be isolated)
14 Laminated rubber (isolation device)
22 Pull-out prevention device 24 Connecting member 26 Belleville spring 28, 28a Ball seat (node member)
50 Sliding mechanism

Claims

The base is supported by an isolation device via an isolation device, and an anti-extraction device is provided between the foundation and the isolation object to prevent extraction force acting on the isolation device. In the vibration structure,
The pull-out prevention device is configured by using a disc spring having a constant load region in which the load variation with respect to the vertical displacement is small, and the pull-out device is pulled between the foundation portion and the isolation object within the constant load region of the disc spring. A vibration isolation structure characterized by the addition of prestress that resists force.

The base is supported by an isolation device via an isolation device, and an anti-extraction device is provided between the foundation and the isolation object to prevent extraction force acting on the isolation device. In the vibration structure,
The pull-out prevention device is interposed in a connecting member to which a vertical displacement between the base portion and the vibration isolation object is input, and a displacement transmission path between the connection member and the base portion or the vibration isolation object. It is configured with a disc spring, and a prestress that resists the pulling force is added between the foundation and the object to be isolated within a constant load region where the load fluctuation relative to the amount of expansion and contraction of the disc spring is small. A vibration isolation structure.

3. A node member that can be bent while transmitting a pulling force is provided between at least one of the connecting member and the base portion and between the connecting member and the object to be isolated. Vibration isolation structure.

The vibration isolation structure according to claim 2 or 3, wherein the connecting member is made of high-tensile steel such as a PC steel rod or PC steel wire.

5. The disc spring according to claim 1, wherein the disc spring is disposed on a pressure receiving surface of a base portion or a vibration-isolating object, and a friction damper is formed by interposing a sliding mechanism on the seat portion. The isolation structure described in 1.