JP4693271B2

JP4693271B2 - Seismic isolation building

Info

Publication number: JP4693271B2
Application number: JP2001126256A
Authority: JP
Inventors: 和彦岡下
Original assignee: Sekisui Chemical Co Ltd
Current assignee: Sekisui Chemical Co Ltd
Priority date: 2001-04-24
Filing date: 2001-04-24
Publication date: 2011-06-01
Anticipated expiration: 2021-04-24
Also published as: JP2002322827A

Description

【０００１】
【発明の属する技術分野】
本発明は、免震復元装置を使用した免震建物に係り、特に、基礎等の非免震部に対して、上部建物等の免震部の回転や捩れ振動を防止できるようにした免震建物に関する。
【０００２】
【従来の技術】
従来、この種の免震構造としては、特開平６−６６３４７号公報に記載された技術がある。この技術は、免震床下面の左右方向中間部の前後位置に、鉛直軸を中心に回転自在な対の滑車を夫々取付けると共に、建屋床の左側前後位置及び右側前後位置に、前後方向に移動自在な支持部を夫々設け、左側前方位置に支持部と右側後方位置の支持部との間に、前側の一方の滑車と後側の一方の滑車に巻き掛けたワイヤを張設し、且つ右側前方位置に支持部と左側後方位置の支持部との間に、前側の他方の滑車と後側の他方の滑車に夫々巻き掛けたワイヤを張設している。
【０００３】
これは、免震部の非免震部に対する相対的な並進運動を抑制することなく、回転運動のみを確実に抑制し得るものであり、例えば地震時において免震部が非免震部に対して左右方向に相対変位しても、両ワイヤにおける各滑車に巻き掛けられて屈曲する部分が変位するだけで、両ワイヤの長さ自体は変化しないので、免震部の非免震部に対する左右方向の相対変位は何ら拘束を受けないものである。
また、弾性体により復元または水平振動絶縁する免震建物においては、通常、上部建物の重心と免震層の剛心がなるべく一致するように免震装置が設置され、１邸毎に免震層の１次固有周期と偏心を、目標値に合うような復元装置の剛性を設計する。
【０００４】
【発明が解決しようとする課題】
ところで、前記の免震構造は、免震層の剛心と上部建物の重心のずれにより、免震時に生じる捩れを強制的に並進運動に持っていくもので、捩れのエネルギーが抑制される部分の並進運動に影響を及ぼす。また、機構的にも大かがりなものとなり、施工性、実現性の面で実現が難しいという問題点があった。
また、上部建物の重心と免震層の剛心が一致するように免震装置を設置し、１邸毎に免震層の１次固有周期と偏心を目標値に合うように復元装置の剛性を設計する場合、工業化住宅のような規格化された住宅では、非効率で煩雑な作業となり、非常に高価なものとなってしまう虞がある。
【０００５】
本発明は、このような問題に鑑みてなされたものであって、その目的とするところは、機構的に小規模であり、施工性がよくコスト的にも有利な免震建物を提供することにある。また、後から補助的に付加することができ、これにより水平荷重が加わったときに捩れを小さくすることができ、地震等の水平荷重が加わったときに十分な捩れ強さを有する免震建物を提供することにある。
【０００６】
【課題を解決するための手段】
前記目的を達成すべく、請求項１に記載の発明による免震建物は、基礎と上部建物との間に免震装置を備えた免震建物であって、上部建物の外周付近の基礎と上部建物との間で、上部建物を含む免震層の重心と上部建物を含む免震層の剛心とを結ぶ線の延長線と上部建物の外周辺との交差する位置に免震装置の水平剛性の総和に対し、減衰定数が小さい低弾性の補助復元装置を設置し、前記重心と前記剛心との偏心量を小さくすることで、重心と剛心とのずれにより、水平荷重が加わったときに生じる捩れを小さくすることを特徴とする。この構成によれば、免震装置の復元に対する水平剛性の総和に対し低弾性の補助復元装置を設置することにより剛心を重心に接近させることができ、剛心と重心との偏心量を小さくできるため、水平荷重が作用したときの捩れを小さくすることができる。このため、地震力等の水平荷重に対して必要な捩れ強度を有する免震建物を最適設計することができ、構成が簡単でコストダウンが可能な免震建物を達成できる。また、工業化された住宅においては、製造、設計施工の効率化が図れる。
【０００７】
また、請求項２に記載の発明による免震建物は、前記上部建物の外周付近の下部に補助質量を設置したことを特徴とし、請求項３に記載の発明による免震建物は、前記上部建物は、ボックスラーメン構造の複数の建物ユニットを連結したものであり、最下層には前記複数の建物ユニットを設置する補強架台が位置していることを特徴としている。さらに、請求項４に記載の発明による免震建物は、前記補助質量は、前記補強架台に固定されることを特徴とし、請求項５に記載の発明による免震建物は、前記補助質量は、Ｈ型鋼で形成された前記補強架台のウェブの両側に固定されることを特徴とし、請求項６に記載の発明による免震建物は、前記補助質量は、前記補強架台にボルトで固定されることを特徴としている。
【０００８】
さらに、請求項７に記載の発明による免震建物は、基礎と上部建物との間に免震装置を備えた免震建物であって、前記上部建物の外周付近の前記基礎と前記上部建物との間の下部に補助質量を設置し、前記上部建物を含む免震層の平面的な重心と、前記上部建物を含む免震層の剛心との偏心量を小さくすることで、重心と剛心とのずれにより、水平荷重が加わったときに生じる捩れを小さくすることを特徴とする。この構成によれば、上部建物の外周下部に補助質量を設置することにより剛心を重心に接近させることができ、剛心と重心との偏心量を小さくできるため、水平荷重が作用したときの免震層の捩れを小さくすることができる。また、工業化された住宅においては、製造、設計施工の効率化が図れる。
【０００９】
請求項８に記載の発明による免震建物は、前記補助質量は、前記重心と前記剛心とを結ぶ線の延長線と前記上部建物の外周辺との交差する位置に設置することを特徴とし、請求項９に記載の発明による免震建物は、前記上部建物は、ボックスラーメン構造の複数の建物ユニットを連結したものであり、最下層には前記複数の建物ユニットを設置する補強架台が位置していることを特徴とし、請求項１０に記載の発明による免震建物は、前記補助質量は、前記補強架台に固定されることを特徴とする。
請求項１１に記載の発明による免震建物は、前記補助質量は、Ｈ型鋼で形成された前記補強架台のウェブの両側に固定させることを特徴とし、請求項１２に記載の発明による免震建物は、前記補助質量は、前記補強架台にボルトで固定されることを特徴とする。
請求項１３に記載の発明による免震建物は、前記免震装置は、免震支承装置及び復元減衰装置より構成され、前記基礎と前記補強架台との間に設置されることを特徴とし、請求項１４に記載の発明による免震建物は、前記補助復元装置は、前記基礎と前記補強架台との間に設置されることを特徴とする。
【００１０】
【発明の実施の形態】
以下、本発明に係る免震建物の一実施形態を図面に基づき詳細に説明する。図１は、本実施形態に係る免震建物の床伏せ図、図２は、図１のＡ−Ａ線から見た正面図、図３は図１のＢ−Ｂ線から見た側面図、図４は図１の補強架台上に設置される建物ユニットの概略平面図である。図１〜４において、免震建物１は基礎２と上部建物３との間に、免震支承装置４及び復元減衰装置（以下復元装置という）５を備えており、基礎２の変位を上部建物３に直接伝達しない構成となっている。免震支承装置４、復元装置５により免震装置を構成する。上部建物３は、本例ではボックスラーメン構造の建物ユニットＵ₁〜Ｕ₅を５個連結したものであり、最下層には補強架台６が位置している。
【００１１】
免震支承装置４は、上部建物３の垂直荷重を支承するものであり、本例では直動装置を直交するように固定したクロスリニアベアリング装置を上部建物３のコーナ部に対応して、基礎２と補強架台６との間に８個用いている。復元装置５は天然ゴム、クロロプレーン系ゴム、シリコーンゴム、アクリル樹脂等の弾性体で構成されており、地震時に地震エネルギーを吸収して減衰させると共に、変位を復元するものである。復元装置５は下方の支持部５ａが基礎２に固定され、上方の支持部５ｂが上部建物３の補強架台６に固定され、中間の弾性体５ｃが上下の支持部を連結している。本例では、補強架台６の梁の中間部に対応して復元装置５を７個使用している。
【００１２】
そして、免震支承装置４及び復元装置５の部分が免震層を構成し、基礎２と上部建物３との相対移動を許容して地震エネルギーを吸収、減衰する。なお、本例では免震支承装置４として、クロスリニアベアリング装置を使用し、復元装置５として、弾性体で連結した復元装置を使用しているが、免震支承装置４として、滑り支承装置や、ゴムと鋼鈑を多層に積層した積層ゴム装置等を用いてもよく、復元装置５として鉛プラグを使用する減衰装置等を用いてもよい。
【００１３】
免震層における上部建物３の平面的な重心は、重心Ｇにて示される。重心Ｇは、夫々の建物ユニットＵ₁〜Ｕ₅の重心のＸ座標、Ｙ座標と、その重量とから求めることができる。すなわち、５個の建物ユニットの重心のＸ座標がＸ₁〜Ｘ₅、Ｙ座標がＹ₁〜Ｙ₅、重量がＷ₁〜Ｗ₅であると、重心ＧのＸ、Ｙ座標Ｇｘ、Ｇｙは、それぞれ次の数１、数２で求められる。
【００１４】
【数１】

【００１５】
【数２】

【００１６】
【数３】

【００１７】
【数４】

なお、前記した各建物ユニットＵ₁〜Ｕ₅のバネ定数は、例えば１つの建物ユニットの下辺を固定し、上辺に水平力を作用させたときに上辺が水平方向に変形するが、このとき加えた水平力と、水平方向の変形との傾きが剛性を表すバネ定数である。
【００１８】
そして、重心Ｇと剛心Ｋが一致しないと、水平荷重が作用したとき免震層において捩れが生じる。重心Ｇと剛心Ｋとの間の距離を偏心距離とすると、偏心距離の大小が地震や風力等の水平荷重に対する建物の捩れ強さの一つの指標となる。すなわち、水平荷重は建物の重心Ｇに作用し、重心Ｇと剛心Ｋが一致しないと、建物は水平方向に変形すると共に、剛心Ｋ回りの回転力が作用する。そして、偏心距離が大きい建物は建物の角部で部分的に過大な変形を強いられる部材が生じ、それらの部材に損傷が生じることがある。
【００１９】
本発明は、前記のように生じる捩れを少なくするものである。重心Ｇと剛心Ｋとを結ぶ線の延長線Ｌと、上部建物３の外周辺との交差する位置に補助復元装置１０が設置されている。補助復元装置１０は、前記したように水平荷重が作用したときに免震層の捩れを小さくするものであり、復元装置５と比較して減衰定数が小さく設定された低弾性の装置が採用されている。すなわち、補助復元装置１０は水平剛性の総和に対し低弾性の復元装置である。そして、補助復元装置１０は基礎２のフーティング２ａと補強架台６との間に設置されている。
【００２０】
前記の如く構成された本実施形態の免震建物の動作について以下に説明する。この種の弾性体により復元または水平振動を絶縁する免震建物では、通常、上部建物３の重心Ｇと免震層の剛心Ｋがなるべく一致するように免震装置が設置されるが、工業化住宅のような規格化された住宅における免震を実現するためには、１邸ごとに免震層の１次固有周期と偏心を目標値に合うように復元装置５の剛性を設計していたのでは、非効率で煩雑な作業となり、非常に高価なものとなってしまう。
【００２１】
本例の免震建物１も、１次固有周期及び重心Ｇと剛心Ｋの偏心が目標値に合致せず、地震等により水平荷重が作用した場合、重心Ｇと剛心Ｋによる捩れ力７が生じる。この捩れ力７は上部建物３の外周付近に位置する補助復元装置１０による反対方向の捩れ抵抗力８によって打ち消される。すなわち、捩れ抵抗力８は回転中心である剛心Ｋに対して捩れ力７を打ち消すように作用する。このように、補助復元装置１０を付けるだけの簡単な構成で、捩れを小さくすることができる。このため、免震建物１は、剛心Ｋ回りの回転力を小さくでき、外周部の部材の過大な変形を防止することができ、最適な免震性能を実現できる。
【００２２】
次に、本発明の他の実施形態を図５に基づき説明する。図５（ａ）は本発明に係る免震建物の他の実施形態の床伏せ図、（ｂ）は補助質量部分の断面図である。なお、この実施形態は前記した実施形態に対し、補助復元装置に代わって補助質量を用いたことを特徴とする。そして、他の実質的に同等の構成については、同じ参照符号を付して詳細な説明は省略する。図５において、重心Ｇと剛心Ｋとを結ぶ線の延長線Ｌと、上部建物３の外周付近の下部である補強架台６との交差する位置Ｍに補助質量１１が設置されている。この補助質量１１は、例えば上部建物３の質量をｍとし、重心Ｇと剛心Ｋとの距離をＬ１、剛心Ｋと位置Ｍとの距離をＬ２としたとき、｛（Ｌ１／Ｌ２）×ｍ｝程度の質量を有する鉄等の金属製の塊状のもので構成され、補強架台６のＨ型鋼を両側より挟んでボルト締め等により固定されている。
【００２３】
この実施形態においては、前記した実施形態と同様に地震等により水平荷重が作用した場合、重心Ｇと剛心Ｋの偏心による捩れ力７が生じるが、この捩れ力７は上部建物３の外周付近に位置する補助質量１１によって生じる同方向の捩れ抵抗力９によって打ち消される。すなわち、捩れ抵抗力９は回転中心である剛心Ｋに対して、捩れ力７を打ち消すように作用する。このように、補助質量１１を付けるだけの簡単な構成で、捩れを小さくすることができ、前記の実施形態と同様の効果を得ることができる。
【００２４】
なお、前記した実施形態では、重心Ｇと剛心Ｋを結ぶ延長線Ｌと、上部建物３の外周辺との交差する一方の位置に補助復元装置１０または補助質量１１を設置する例を示したが、延長線Ｌと外周辺の交差する両方の位置に設置するようにしてもよい。この場合は、補助復元装置１０は減衰定数が半分程度のものを使用し、補助質量１１は１／２の質量のものを使用することができる。
【００２５】
また、一方に補助復元装置１０を、他方に補助質量１１を設置してもよい。免震復元装置として、クロスリニアベアリングを使用した免震支承装置と、復元減衰装置を用いた例を示したが、復元減衰装置のみでもよい。補助質量として塊状の部材を付加する例を示したが、捩れが生じたときに負荷となって捩れ抵抗力が得られるものであれば、直方体状、円柱状等、形状は問わない。
【００２６】
【発明の効果】
以上の説明から理解できるように、本発明の免震建物は、低弾性で簡易な補助復元装置を上部建物の外周位置に補助的に設置するだけで、免震層における捩れを小さくすることができる。このため、施工性がよく経済的である。また、免震周期に及ぼす水平剛性の影響を最大限に押えているので、様々なプランの工業化住宅において設計値通りの免震性能を実現することができる。さらに、上部建物の外周位置に補助質量を設置するだけの簡単な構成で、前記した補助復元装置の場合と同様の効果を得ることができる。
【図面の簡単な説明】
【図１】本発明に係る免震建物の一実施形態の床伏せ図。
【図２】図１のＡ−Ａ線から見た正面図。
【図３】図１のＢ−Ｂ線から見た側面図。
【図４】図１の補強架台上に設置される建物ユニットの概略平面図。
【図５】（ａ）は本発明に係る免震建物の他の実施形態の床伏せ図、（ｂ）は補助質量部分の断面図。
【符号の説明】
１免震建物
２基礎
３上部建物
４免震支承装置（免震装置）
５復元減衰装置（免震装置）
６補強架台
７捩れ力
８、９捩れ抵抗力
１０補助復元装置
１１補助質量
Ｕ₁〜Ｕ₅ 建物ユニット
Ｇ重心
Ｋ剛心
Ｌ延長線
Ｍ補助質量の位置[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a base-isolated building using a base-isolated restoration device, and in particular, a base-isolated system that can prevent rotation and torsional vibration of base-isolated parts such as foundations against non-base-isolated parts such as foundations. Concerning buildings.
[0002]
[Prior art]
Conventionally, as this type of seismic isolation structure, there is a technique described in JP-A-6-66347. This technology attaches a pair of pulleys that can rotate around the vertical axis to the front and rear positions in the left and right middle part of the bottom surface of the base isolation floor, and moves in the front and rear direction to the left and right front and back positions of the building floor. A flexible support part is provided, and a wire wound around one pulley on the front side and one pulley on the rear side is stretched between the support part on the left front position and the support part on the right rear position. A wire wound around the other pulley on the front side and the other pulley on the rear side is stretched between the support portion at the front position and the support portion at the left rear position.
[0003]
This is to ensure that only the rotational motion can be suppressed without suppressing the relative translational motion of the base isolation portion relative to the non-base isolation portion. Even if they are relatively displaced in the left-right direction, the length of both wires does not change because only the portions of the wires that are wound around the pulleys and bent are displaced, and the length of both wires does not change. The relative displacement in the direction is unconstrained.
In addition, in a base-isolated building that is restored or insulated by horizontal vibration with an elastic body, a base-isolator is usually installed so that the center of gravity of the upper building matches the rigidity of the base-isolated layer as much as possible. The rigidity of the restoration device is designed so that the primary natural period and the eccentricity of the first and second eccentricity meet the target values.
[0004]
[Problems to be solved by the invention]
By the way, the above-mentioned seismic isolation structure forcibly brings the torsion generated in the base isolation to the translational motion due to the deviation of the rigidity of the seismic isolation layer and the center of gravity of the upper building. Affects the translational movement of In addition, it has a problem in terms of mechanism and is difficult to realize in terms of workability and feasibility.
In addition, the seismic isolation device is installed so that the center of gravity of the upper building matches the stiffness of the seismic isolation layer, and the rigidity of the restoration device is adjusted so that the primary natural period and eccentricity of the seismic isolation layer match the target value for each house. When designing a housing, a standardized house such as an industrialized house may be inefficient and cumbersome and may be very expensive.
[0005]
The present invention has been made in view of such problems, and an object of the present invention is to provide a seismically isolated building that is mechanically small in scale, has good workability, and is advantageous in terms of cost. It is in. In addition, it can be added afterwards so that the torsion can be reduced when a horizontal load is applied, and the seismic isolation building has sufficient torsional strength when a horizontal load such as an earthquake is applied. Is to provide.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, a base-isolated building according to the first aspect of the present invention is a base-isolated building having a base-isolating device between the foundation and the upper building, and the foundation and the upper part in the vicinity of the outer periphery of the upper building. The seismic isolation device is placed horizontally at the position where the extension line of the line connecting the center of gravity of the base isolation layer including the upper building and the rigid center of the base isolation layer including the upper building intersects the outer periphery of the upper building. By installing a low-elasticity auxiliary restoration device with a small damping constant for the total stiffness, and reducing the amount of eccentricity between the center of gravity and the rigid core , a horizontal load was applied due to the deviation between the center of gravity and the rigid core . It is characterized in that the twist generated sometimes is reduced. According to this configuration, it is possible to bring the rigid center closer to the center of gravity by installing a low-elasticity auxiliary restoring device with respect to the total horizontal rigidity for the restoration of the seismic isolation device , and to reduce the eccentric amount between the rigid center and the center of gravity. Therefore, the torsion when a horizontal load is applied can be reduced. For this reason, it is possible to optimally design a base-isolated building having a torsional strength necessary for a horizontal load such as seismic force, and to achieve a base-isolated building that has a simple configuration and can reduce costs. In industrialized houses, manufacturing, design and construction can be made more efficient .
[0007]
Further, the base-isolated building according to the invention of claim 2 is characterized in that an auxiliary mass is installed in the lower part of the vicinity of the outer periphery of the upper building, and the base-isolated building of the invention according to claim 3 Is a structure in which a plurality of building units having a box ramen structure are connected, and a reinforcement base for installing the plurality of building units is located in the lowermost layer. Furthermore, the base-isolated building according to the invention described in claim 4 is characterized in that the auxiliary mass is fixed to the reinforcing frame, and the base-isolated building according to claim 5 is characterized in that the auxiliary mass is The seismic isolation building according to claim 6, wherein the auxiliary mass is fixed to the reinforcing frame with bolts. The base frame is fixed to both sides of the web of the reinforcing frame formed of H-shaped steel. It is characterized by.
[0008]
Furthermore, the base-isolated building according to the invention of claim 7 is a base-isolated building having a base-isolating device between the foundation and the upper building, and the foundation and the upper building near the outer periphery of the upper building. Auxiliary mass is installed in the lower part of the space between the center of gravity and the center of gravity of the seismic isolation layer including the upper building and the stiffness of the base isolation layer including the upper building are reduced. It is characterized in that twist caused when a horizontal load is applied due to deviation from the center is reduced. According to this configuration, by installing an auxiliary mass in the lower part of the outer periphery of the upper building, the center of gravity can be brought closer to the center of gravity, and the amount of eccentricity between the center of gravity and the center of gravity can be reduced. The torsion of the seismic isolation layer can be reduced. In industrialized houses, manufacturing, design and construction can be made more efficient.
[0009]
The base-isolated building according to claim 8 is characterized in that the auxiliary mass is installed at a position where an extension of a line connecting the center of gravity and the rigid center and an outer periphery of the upper building intersect. In the base-isolated building according to claim 9, the upper building is obtained by connecting a plurality of building units having a box ramen structure, and a reinforcement base for installing the plurality of building units is located in the lowermost layer. The seismic isolation building according to the invention of claim 10 is characterized in that the auxiliary mass is fixed to the reinforcing frame.
The base-isolated building according to the invention described in claim 11 is characterized in that the auxiliary mass is fixed to both sides of the web of the reinforcing frame made of H-shaped steel. The auxiliary mass is fixed to the reinforcing frame with a bolt.
A base-isolated building according to a thirteenth aspect of the present invention is characterized in that the base isolation device is composed of a base isolation support device and a restoration damping device, and is installed between the foundation and the reinforcement base. The seismic isolation building according to the invention described in item 14 is characterized in that the auxiliary restoring device is installed between the foundation and the reinforcing frame.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, one embodiment of a base-isolated building concerning the present invention is described in detail based on a drawing. 1 is a floor plan view of a base-isolated building according to the present embodiment, FIG. 2 is a front view seen from the line AA in FIG. 1, and FIG. 3 is a side view seen from the line BB in FIG. FIG. 4 is a schematic plan view of a building unit installed on the reinforcing mount of FIG. 1-4, the base-isolated building 1 is provided with a base-isolated bearing device 4 and a restoring and attenuating device (hereinafter referred to as a restoring device) 5 between the foundation 2 and the upper building 3, and the displacement of the foundation 2 is changed to the upper building. 3 is not directly transmitted. The seismic isolation device is constituted by the seismic isolation bearing device 4 and the restoration device 5. In this example, the upper building 3 is formed by connecting _five building units U _{1 to} U ₅ having a box ramen structure, and the reinforcing frame 6 is located in the lowermost layer.
[0011]
The seismic isolation bearing device 4 supports the vertical load of the upper building 3. In this example, a cross linear bearing device in which the linear motion device is fixed so as to be orthogonal to the corner portion of the upper building 3 is used as a foundation. Eight are used between 2 and the reinforcing frame 6. The restoring device 5 is made of an elastic body such as natural rubber, chloroprene rubber, silicone rubber, acrylic resin, etc., and absorbs and attenuates the seismic energy and restores the displacement during an earthquake. In the restoring device 5, the lower support portion 5 a is fixed to the foundation 2, the upper support portion 5 b is fixed to the reinforcing mount 6 of the upper building 3, and an intermediate elastic body 5 c connects the upper and lower support portions. In this example, seven restoring devices 5 are used corresponding to the intermediate part of the beam of the reinforcing frame 6.
[0012]
The parts of the seismic isolation bearing device 4 and the restoration device 5 constitute a seismic isolation layer, which allows relative movement between the foundation 2 and the upper building 3 to absorb and attenuate seismic energy. In this example, a cross linear bearing device is used as the seismic isolation bearing device 4 and a restoring device connected by an elastic body is used as the restoring device 5. However, as the seismic isolation bearing device 4, a sliding bearing device, Alternatively, a laminated rubber device in which rubber and steel plates are laminated in multiple layers may be used, and a damping device using a lead plug may be used as the restoring device 5.
[0013]
The planar center of gravity of the upper building 3 in the seismic isolation layer is indicated by the center of gravity G. The center of gravity G can be obtained from the X and Y coordinates of the center of gravity of each of the building units U _{1 to} U ₅ and the weight thereof. That is, if the X coordinate of the center of gravity of five building units is X _{1 to} X ₅ , the Y coordinate is Y ₁ to Y ₅ , and the weight is W _{1 to} W ₅ , the X, Y coordinates Gx, Gy of the center of gravity G are Are obtained by the following

equations

1 and 2, respectively.
[0014]
[Expression 1]

[0015]
[Expression 2]

[0016]
[Equation 3]

[0017]
[Expression 4]

Note that the spring constant of each of the building units U _{1 to} U ₅ described above is, for example, that when the lower side of one building unit is fixed and a horizontal force is applied to the upper side, the upper side is deformed in the horizontal direction. The slope of the horizontal force and the horizontal deformation is the spring constant representing the rigidity.
[0018]
If the center of gravity G and the rigid center K do not match, twisting occurs in the seismic isolation layer when a horizontal load is applied. Assuming that the distance between the center of gravity G and the rigid center K is an eccentric distance, the magnitude of the eccentric distance is an index of the torsional strength of the building against horizontal loads such as earthquakes and wind power. That is, the horizontal load acts on the center of gravity G of the building, and if the center of gravity G and the rigid center K do not coincide, the building is deformed in the horizontal direction and a rotational force around the rigid center K acts. In a building having a large eccentric distance, members that are forced to be excessively deformed at the corners of the building are generated, and the members may be damaged.
[0019]
The present invention reduces the twist that occurs as described above. The auxiliary restoration device 10 is installed at a position where the extension line L of the line connecting the center of gravity G and the rigid center K intersects the outer periphery of the upper building 3. The auxiliary restoring device 10 reduces the torsion of the seismic isolation layer when a horizontal load is applied as described above, and a low-elasticity device in which the damping constant is set smaller than that of the restoring device 5 is adopted. ing. That is, the auxiliary restoring device 10 is a restoring device having low elasticity with respect to the total horizontal rigidity. The auxiliary restoring device 10 is installed between the footing 2 a of the foundation 2 and the reinforcing mount 6.
[0020]
The operation of the base-isolated building of this embodiment configured as described above will be described below. In a base-isolated building in which restoration or horizontal vibration is insulated by this type of elastic body, the base-isolation device is usually installed so that the center of gravity G of the upper building 3 and the rigid core K of the base isolation layer coincide as much as possible. In order to realize seismic isolation in a standardized house such as a house, the rigidity of the restoring device 5 was designed so that the primary natural period and eccentricity of the seismic isolation layer matched the target value for each house. Then, it becomes inefficient and cumbersome work, and becomes very expensive.
[0021]
In the base-isolated building 1 of this example, when the primary natural period and the eccentricity of the center of gravity G and the stiffness K do not match the target values and a horizontal load is applied due to an earthquake or the like, the torsional force 7 caused by the gravity center G and the stiffness K Occurs. This torsional force 7 is canceled out by the torsional resistance force 8 in the opposite direction by the auxiliary restoring device 10 located near the outer periphery of the upper building 3. That is, the torsional resistance force 8 acts so as to cancel the torsional force 7 against the rigid center K that is the center of rotation. In this way, the twist can be reduced with a simple configuration in which the auxiliary restoration device 10 is simply attached. For this reason, the seismic isolation building 1 can reduce the rotational force around the rigid core K, can prevent excessive deformation of the members on the outer peripheral portion, and can realize optimal seismic isolation performance.
[0022]
Next, another embodiment of the present invention will be described with reference to FIG. FIG. 5A is a floor plan view of another embodiment of the seismic isolation building according to the present invention, and FIG. 5B is a cross-sectional view of the auxiliary mass portion. In addition, this embodiment is characterized in that an auxiliary mass is used instead of the auxiliary restoring device in contrast to the above-described embodiment. Other substantially equivalent configurations are denoted by the same reference numerals, and detailed description thereof is omitted. In FIG. 5, an auxiliary mass 11 is installed at a position M where an extension line L of a line connecting the center of gravity G and the rigid center K intersects with a reinforcing mount 6 which is a lower portion near the outer periphery of the upper building 3. For example, when the mass of the upper building 3 is m, the distance between the center of gravity G and the rigid center K is L1, and the distance between the rigid center K and the position M is L2, the auxiliary mass 11 is {(L1 / L2) × m}, which is made of a metal lump such as iron having a mass of about m}, and is fixed by bolting or the like with the H-shaped steel of the reinforcing frame 6 sandwiched from both sides.
[0023]
In this embodiment, when a horizontal load is applied due to an earthquake or the like as in the above-described embodiment, a torsional force 7 due to the eccentricity of the center of gravity G and the rigid center K is generated. This torsional force 7 is near the outer periphery of the upper building 3. Is counteracted by the torsional resistance 9 in the same direction produced by the auxiliary mass 11 located at That is, the twisting resistance force 9 acts on the rigid center K that is the center of rotation so as to cancel the twisting force 7. In this way, the twist can be reduced with a simple configuration in which only the auxiliary mass 11 is attached, and the same effect as in the above embodiment can be obtained.
[0024]
In the above-described embodiment, an example in which the auxiliary restoration device 10 or the auxiliary mass 11 is installed at one position where the extension line L connecting the center of gravity G and the rigid center K intersects the outer periphery of the upper building 3 is shown. However, you may make it install in the position where both the extension line L and an outer periphery cross | intersect. In this case, the auxiliary restoring device 10 can be one having an attenuation constant of about half, and the auxiliary mass 11 can be one having a half mass.
[0025]
Further, the auxiliary restoring device 10 may be installed on one side and the auxiliary mass 11 may be installed on the other side. Although the example using the seismic isolation bearing device using the cross linear bearing and the restoration attenuation device is shown as the earthquake isolation restoration device, only the restoration attenuation device may be used. Although an example in which a massive member is added as the auxiliary mass has been shown, the shape may be any shape such as a rectangular parallelepiped or a column as long as a torsional resistance can be obtained when a twist occurs.
[0026]
【The invention's effect】
As can be understood from the above description, the seismic isolation building of the present invention can reduce the twist in the seismic isolation layer only by auxiliary installation of a low-elasticity and simple auxiliary restoring device at the outer peripheral position of the upper building. it can. For this reason, workability is good and economical. In addition, since the influence of horizontal rigidity on the seismic isolation cycle is suppressed to the maximum, seismic isolation performance as designed can be achieved in industrialized houses with various plans. Furthermore, the same effect as in the case of the auxiliary restoring device described above can be obtained with a simple configuration in which auxiliary mass is simply installed at the outer peripheral position of the upper building.
[Brief description of the drawings]
FIG. 1 is a floor plan view of an embodiment of a base-isolated building according to the present invention.
FIG. 2 is a front view as seen from line AA in FIG.
3 is a side view as seen from the line BB in FIG. 1. FIG.
4 is a schematic plan view of a building unit that is installed on the reinforcing frame in FIG. 1;
5A is a floor plan view of another embodiment of the seismic isolation building according to the present invention, and FIG. 5B is a cross-sectional view of the auxiliary mass portion.
[Explanation of symbols]
1 Seismic Isolation Building 2 Foundation 3 Upper Building 4 Seismic Isolation Device (Seismic Isolation Device)
5 Restoration damping device (Seismic isolation device)
6 position of the reinforcing frame 7 torsional force 8,9 torsional resistance 10 assisting restoration device 11 auxiliary mass U ₁ ~U ₅ building unit G centroid K Tsuyoshikokoro L extension M auxiliary mass

Claims

A seismic isolation building with a seismic isolation device between the foundation and the upper building,
Between the foundation near the outer periphery of the upper building and the upper building, an extension of a line connecting the center of gravity of the base isolation layer including the upper building and the rigid center of the base isolation layer including the upper building and the outside of the upper building For the total horizontal rigidity of the seismic isolation device at the position where it intersects the surroundings , install a low elasticity auxiliary restoration device with a small damping constant ,
A base-isolated building in which the amount of eccentricity between the center of gravity and the rigid core is reduced to reduce torsion caused when a horizontal load is applied due to a deviation between the center of gravity and the rigid center .

The base-isolated building according to claim 1 , wherein an auxiliary mass is installed in a lower portion near the outer periphery of the upper building.

The said upper building connects several building units of a box ramen structure, The reinforcement stand which installs these building units is located in the lowest layer, The Claim 1 characterized by the above-mentioned. Seismic isolation building.

The base-isolated building according to claim 3, wherein the auxiliary mass is fixed to the reinforcing frame.

The base-isolated building according to claim 3, wherein the auxiliary mass is fixed to both sides of the web of the reinforcing frame formed of H-shaped steel.

The seismic isolation building according to claim 3, wherein the auxiliary mass is fixed to the reinforcing frame with a bolt.

A seismic isolation building with a seismic isolation device between the foundation and the upper building,
Auxiliary mass is installed in the lower part between the foundation and the upper building near the outer periphery of the upper building ,
By reducing the amount of eccentricity between the planar center of gravity of the base isolation layer including the upper building and the rigidity of the base isolation layer including the upper building , a horizontal load was applied due to the deviation between the center of gravity and the center of rigidity . A base-isolated building characterized by reducing the torsion that occurs sometimes.

The seismic isolation building according to claim 7, wherein the auxiliary mass is installed at a position where an extension of a line connecting the center of gravity and the rigid center intersects with an outer periphery of the upper building.

The said upper building connects several building units of a box ramen structure, The reinforcement stand which installs these building units is located in the lowest layer, The Claim 7 characterized by the above-mentioned. Base-isolated building.

The base-isolated building according to claim 9, wherein the auxiliary mass is fixed to the reinforcing frame.

The base-isolated building according to claim 9, wherein the auxiliary mass is fixed on both sides of the web of the reinforcing frame formed of H-shaped steel.

The base-isolated building according to claim 9, wherein the auxiliary mass is fixed to the reinforcing frame with a bolt.

The said seismic isolation apparatus is comprised from a seismic isolation support apparatus and a restoration | damping attenuation apparatus, and is installed between the said foundation and the said reinforcement mount frame, The any one of Claims 3-6 or Claims 9-12 The base-isolated building described in any of the above.

The seismic isolation building according to any one of claims 3 to 6, wherein the auxiliary restoration device is installed between the foundation and the reinforcing frame.