JP2020125789A

JP2020125789A - Base isolation structure

Info

Publication number: JP2020125789A
Application number: JP2019017543A
Authority: JP
Inventors: 真知子安川; Machiko Yasukawa; 高木　政美; Masami Takagi; 政美高木; 龍大欄木; Ryota Maseki
Original assignee: Taisei Corp
Current assignee: Taisei Corp
Priority date: 2019-02-03
Filing date: 2019-02-03
Publication date: 2020-08-20
Anticipated expiration: 2039-02-03
Also published as: JP7182484B2

Abstract

To provide a base isolation structure capable of further reducing oscillation transmitted from a floor skeleton to a base isolation object.SOLUTION: A base isolation structure 1 reduces oscillation transmitted from a floor slab 10 to a base isolation object 20 placed on the floor slab 10 during an earthquake. Bearing sections 21 which are made of steel and spherical in shape are installed on a lower face of the base isolation object 20. The floor slab 10 is provided with a surface layer section 11, on an upper face thereof, which is brough into contact with the bearing sections 21. A friction coefficient between the surface layer section 11 and the bearing sections 21 is smaller than the same between the floor slab 10 and the bearing sections 21.SELECTED DRAWING: Figure 1

Description

本発明は、地震時に床躯体から免震対象物に伝わる揺れを低減する免震構造に関する。 The present invention relates to a seismic isolation structure that reduces shaking transmitted from a floor skeleton to a seismic isolation target during an earthquake.

従来より、床躯体上に設置した免震対象物について、地震時に床躯体から免震対象物に伝わる揺れを軽減する免震構造が提案されている。
特許文献１には、互いに摺動面で摺動接触する第一摺動部材と第二摺動部材を組み合せた摺動構造が示されている。第一摺動部材は合成樹脂からなるとともに摺動面に凹部を具備しており、第二摺動部材は合成樹脂被膜からなり、第一摺動部材の摺動面の凹部と第二摺動部材の合成樹脂被膜との間には潤滑油剤が介在されている。 2. Description of the Related Art Conventionally, there has been proposed a seismic isolation structure for a seismic isolation target object installed on a floor skeleton that reduces shaking transmitted from the floor skeleton to the seismic isolation target object during an earthquake.
Patent Document 1 discloses a sliding structure in which a first sliding member and a second sliding member that are in sliding contact with each other on sliding surfaces are combined. The first sliding member is made of synthetic resin and has a concave portion on the sliding surface, and the second sliding member is made of a synthetic resin coating, and the concave portion of the sliding surface of the first sliding member and the second sliding member. A lubricating oil is interposed between the member and the synthetic resin film.

特許文献２には、材質がコンクリートの下部基礎板と、材質がコンクリートの上部基礎板の間の全面に、低摩擦抵抗材料を配設した滑り基礎構造が示されている。低摩擦抵抗材料が黒鉛粉末単独であり、その摩擦係数が０．１５〜０．２５の範囲内である。上部基礎板内部には、空間が設けられ、この空間には、復元力装置が配設されている。
特許文献３には、構造物の躯体と、この躯体の上に設けられて設備機器が据え付けられた架台と、躯体と架台との間に設けられた防振部材と、を備える構造が示されている。この防振部材の上部と架台との間、または防振部材の下部と躯体との間には、滑り支承による免震装置が設けられている。
上述のように、建物の屋内に設置される什器および多様化する設備機器を対象として、部分的な床免震構造が提案されている。 Patent Document 2 discloses a sliding foundation structure in which a low friction resistance material is disposed on the entire surface between a lower base plate made of concrete and an upper base plate made of concrete. The low friction resistance material is graphite powder alone, and its friction coefficient is within the range of 0.15 to 0.25. A space is provided inside the upper base plate, and a restoring force device is arranged in this space.
Patent Document 3 discloses a structure including a frame of a structure, a pedestal provided on the skeleton on which facility equipment is installed, and a vibration damping member provided between the skeleton and the gantry. ing. A seismic isolation device based on a sliding bearing is provided between the upper portion of the vibration isolating member and the frame or between the lower portion of the vibration isolating member and the body.
As described above, a partial floor seismic isolation structure has been proposed for furniture and diversified equipment installed inside a building.

特開２００１−１３２７５７号公報JP, 2001-132757, A 特開２０１１−１８４９５０号公報JP, 2011-184950, A 特開２００１−２２１２８３号公報JP 2001-221283 A

本発明は、新築建物だけではなく既存建物にも容易に設置可能でかつ床躯体から免震対象物に伝わる揺れをより低減できる免震構造を提供することを目的とする。 An object of the present invention is to provide a seismic isolation structure that can be easily installed not only in a new building but also in an existing building and that can further reduce the vibration transmitted from the floor frame to the seismic isolation target.

本発明者らは、簡易でありながら適用範囲の広い床免震構造として、床スラブの表面に潤滑剤が混入されたモルタル層または潤滑剤が混入されたセルフレベリング層を表層部として形成するとともに、この表層部上に球状で鋼製の支承部を当接させることで、摩擦係数が小さくかつ高剛性で耐久性に優れた床免震構造を実現できる点に着眼して、本発明に至った。
第１の発明の免震構造（例えば、後述の免震構造１、１Ａ）は、地震時に床躯体（例えば、後述の床スラブ１０）から当該床躯体上に設置された免震対象物（例えば、後述の免震対象物２０）に伝わる揺れを低減する免震構造であって、前記免震対象物の下面には、球状で鋼製または鋳鉄製の支承部（例えば、後述の支承部２１）が設けられ、前記床躯体の上面には、前記支承部が当接する表層部（例えば、後述の表層部１１、１１Ａ）が形成され、当該表層部と前記支承部との摩擦係数は、前記床躯体と前記支承部との摩擦係数よりも小さいことを特徴とする。 The present inventors, as a floor seismic isolation structure that is simple yet has a wide range of application, forms a mortar layer mixed with a lubricant on the surface of the floor slab or a self-leveling layer mixed with a lubricant as the surface layer portion. The present invention has been achieved by focusing on the fact that a floor steel base isolation structure having a small friction coefficient, high rigidity and excellent durability can be realized by abutting a spherical steel bearing on the surface layer. It was
The seismic isolation structure of the first invention (for example, seismic isolation structures 1 and 1A described below) is a seismic isolation target object (for example, seismic isolation structure 1 and 1A described below) installed on the floor structure (for example, a floor slab 10 described below) during the earthquake (for example, A seismic isolation structure for reducing the sway transmitted to the seismic isolation target object 20) described below, wherein a spherical steel or cast iron bearing part (for example, the bearing part 21 described later) is provided on the lower surface of the seismic isolation target object. ) Is provided, a surface layer portion (for example, surface layer portions 11 and 11A described later) with which the bearing portion abuts is formed on the upper surface of the floor skeleton, and the friction coefficient between the surface layer portion and the bearing portion is It is characterized in that it is smaller than the coefficient of friction between the floor frame and the bearing.

この発明によれば、床躯体の上面に、支承部との摩擦係数が床躯体よりも小さい表層部を設けた。よって、地震時の比較的小さな揺れでも、免震対象物が床躯体に対して水平移動するため、床躯体から免震対象物に伝わる揺れを低減でき、免震対象物の損傷や転倒を防止できる。
すなわち、免震対象物の重量および摩擦係数による慣性力以上の水平力（地震力）が免震対象物に入力されると、表層部と支承部との間で滑動が生じる。これにより、摩擦係数に重力加速度を乗じた値により求められる加速度以上の加速度が免震対象物に入力されなくなるため、免震対象物の破損や転倒を防ぐことができる。
また、床躯体上の表層部を、免震対象物の下面に設けた支承部の移動範囲のみに設ければよいので、新築建物だけでなく既存建物にも容易に免震構造を設けることができる。 According to the present invention, the surface layer portion having a smaller coefficient of friction with the support portion than that of the floor skeleton is provided on the upper surface of the floor skeleton. Therefore, even if there is a comparatively small shake during an earthquake, the seismic isolation target moves horizontally with respect to the floor skeleton, so the sway transmitted from the floor skeletal structure to the seismic isolation target can be reduced, and damage or falling of the seismic isolation target is prevented. it can.
That is, when a horizontal force (seismic force) greater than the inertial force due to the weight and friction coefficient of the seismic isolation target is input to the seismic isolation target, sliding occurs between the surface layer portion and the bearing portion. As a result, an acceleration equal to or higher than the acceleration obtained by multiplying the friction coefficient by the gravitational acceleration is not input to the seismic isolation target object, so that the seismic isolation target object can be prevented from being damaged or falling.
In addition, since the surface layer on the floor frame only needs to be provided within the range of movement of the bearings provided on the bottom surface of the seismic isolation target, it is possible to easily install seismic isolation structures not only on new buildings but also on existing buildings. it can.

第２の発明の免震構造は、前記表層部（例えば、後述の表層部１１）は、潤滑剤が混入されたモルタルまたはセルフレベリング材で形成されている、あるいは、潤滑剤が塗布された塗膜であることを特徴とする。 In the seismic isolation structure of the second invention, the surface layer portion (for example, the surface layer portion 11 described later) is formed of a mortar mixed with a lubricant or a self-leveling material, or a coating applied with a lubricant. It is characterized by being a film.

この発明によれば、表層部を、潤滑剤を混入したモルタルまたはセルフレベリング材で形成するか、あるいは、床躯体上に潤滑剤を塗布した塗膜とした。よって、表層部の表面の潤滑剤により、表層部と支承部との間の摩擦が小さくなる。また、表層部を既存の床躯体の上に形成することで、新築建物だけでなく、既存建物にも容易に免震構造を設けることができる。
また、潤滑剤が混入されたモルタルまたはセルフレベリング材で形成された表層部は、モルタルやセルフレベリング材により高剛性を確保しながら、支承部が滑動する表層部上面においては、潤滑剤によって摩擦係数を低く抑えることができる。よって、床躯体から免震対象物に伝わる揺れをより低減できるとともに、支承部が滑動する際に表層部上面に与える摩耗を低減できる。さらに、表層部に潤滑剤を塗布して塗膜を設ける場合は、表層部の厚みを薄くできる。
また、潤滑剤をモルタルまたはセルフレベリング材に混入した場合、以下のような効果がある。
すなわち、潤滑剤をモルタルまたはセルフレベリング材に混ぜることで、潤滑剤の剥がれを抑制し、滑り性能の低下を抑えることができる。また、厚みのある表層部中に潤滑剤が満遍なく行き渡るため、支承部が常に表層部表面の潤滑剤に接することとなる。このため、表層部の表面を均す必要がなく、施工時の表層部の不陸を気にする必要がない。
また、潤滑剤をモルタルまたはセルフレベリング材内に練り込むため、潤滑剤を床躯体面に塗布した場合と比較して、潤滑剤が削り取られて舞い散ることがない。このため発塵を嫌う免震対象物にも利用できる。 According to the present invention, the surface layer portion is formed of a mortar mixed with a lubricant or a self-leveling material, or a coating film in which the lubricant is applied on the floor skeleton. Therefore, the lubricant on the surface of the surface layer portion reduces the friction between the surface layer portion and the bearing portion. Further, by forming the surface layer on the existing floor frame, it is possible to easily provide a seismic isolation structure not only for a new building but also for an existing building.
In addition, the surface layer part made of mortar or self-leveling material mixed with a lubricant ensures high rigidity by the mortar and self-leveling material, while the friction coefficient is increased by the lubricant on the upper surface part of the surface part where the bearing part slides. Can be kept low. Therefore, it is possible to further reduce the sway transmitted from the floor skeleton to the seismic isolation target, and it is possible to reduce the abrasion given to the upper surface of the surface layer portion when the support portion slides. Furthermore, when a lubricant is applied to the surface layer to form a coating film, the thickness of the surface layer can be reduced.
Further, when the lubricant is mixed in the mortar or the self-leveling material, the following effects are obtained.
That is, by mixing the lubricant with the mortar or the self-leveling material, the peeling of the lubricant can be suppressed and the deterioration of the sliding performance can be suppressed. Further, since the lubricant is evenly distributed in the thick surface layer portion, the bearing portion is always in contact with the lubricant on the surface layer surface. For this reason, it is not necessary to even the surface of the surface layer portion, and it is not necessary to worry about unevenness of the surface layer portion during construction.
Further, since the lubricant is kneaded into the mortar or the self-leveling material, the lubricant is not scraped off and scattered as compared with the case where the lubricant is applied to the floor skeleton surface. Therefore, it can be used for seismically isolated objects that dislike dusting.

第３の発明の免震構造は、前記表層部（例えば、後述の表層部１１Ａ）は、平鋼、鋼製床板、および中央部が凹んだ鋼板のいずれかで形成されていることを特徴とする。 The seismic isolation structure of the third invention is characterized in that the surface layer portion (for example, a surface layer portion 11A described later) is formed of either flat steel, a steel floor plate, or a steel plate having a recessed central portion. To do.

この発明によれば、表層部を平鋼、鋼製床板、および凹状の鋼板のいずれかで形成することで、表層部の表面が滑らかな面となり、表層部と支承部との間の摩擦が小さくなる。また、既存の床躯体の上に平鋼、鋼製床板、および凹状の鋼板のいずれかを設置するだけで表層部を形成できるので、新築建物だけでなく、既存建物にも容易に免震構造を設けることができる。 According to this invention, by forming the surface layer portion from any of flat steel, a steel floor plate, and a concave steel plate, the surface of the surface layer portion becomes a smooth surface, and the friction between the surface layer portion and the bearing portion is reduced. Get smaller. In addition, the surface layer can be formed simply by installing either flat steel, steel floorboard, or concave steel plate on the existing floor frame, so it is easy to seismically isolate the existing building as well as new buildings. Can be provided.

第４の発明の免震構造は、前記支承部は、所定間隔おきに複数配置されていることが好ましい。
この発明によれば、支承部を所定間隔おきに複数配置したので、免震対象物の重量が異なっても、簡易な構造である支承部の個数を適宜調整することで、免震対象物を確実に支持できる。よって、様々な免震対象物を低コストで免震化できる。 In the seismic isolation structure of the fourth invention, it is preferable that a plurality of the support portions are arranged at predetermined intervals.
According to the present invention, since a plurality of bearing portions are arranged at predetermined intervals, even if the weight of the seismic isolation target is different, the seismic isolation target object can be obtained by appropriately adjusting the number of the bearing portions having a simple structure. Can be reliably supported. Therefore, various seismic isolation targets can be seismically isolated at low cost.

第５の発明の免震構造は、前記潤滑剤は、黒鉛粉末または黒鉛塗料であることが好ましい。
この発明によれば、潤滑剤を黒鉛粉末または黒鉛塗料としたので、表層部の表面が、炭素原子の結晶体が規則的に配列された元素鉱物グラファイトで形成される。よって、表層部の支承部との摩擦係数を確実に小さくできる。 In the seismic isolation structure of the fifth invention, it is preferable that the lubricant is graphite powder or graphite paint.
According to the present invention, since the lubricant is graphite powder or graphite paint, the surface of the surface layer portion is formed of elemental mineral graphite in which crystal bodies of carbon atoms are regularly arranged. Therefore, the friction coefficient between the surface layer and the bearing can be surely reduced.

本発明によれば、新築建物だけではなく既存建物にも容易に設置可能でかつ床躯体から免震対象物に伝わる揺れをより低減できる免震構造を提供できる。 ADVANTAGE OF THE INVENTION According to this invention, the seismic isolation structure which can be easily installed not only in a new building but in an existing building, and can further reduce the sway transmitted to a seismic isolation target object from a floor frame can be provided.

本発明の第１実施形態に係る免震構造の側面図である。It is a side view of the seismic isolation structure which concerns on 1st Embodiment of this invention. 図１のＡ−Ａ断面図である。It is an AA sectional view of FIG. 本発明の第２実施形態に係る免震構造の側面図である。It is a side view of the seismic isolation structure which concerns on 2nd Embodiment of this invention. 図３のＢ−Ｂ断面図である。FIG. 4 is a sectional view taken along line BB of FIG. 3. 本発明の実施例および比較例の各試験体を示す写真である。It is a photograph which shows each test body of the example and comparative example of the present invention. 本発明の実施例および比較例の試験結果である。It is a test result of the Example and comparative example of this invention. 本発明の変形例に係る免震構造の側面図である。It is a side view of the seismic isolation structure which concerns on the modification of this invention.

本発明は、新築建物だけではなく既存建物にも容易に設置可能な免震構造として、床スラブの表面に、潤滑剤が混入されたモルタル層または潤滑剤が混入されたセルフレベリング層を表層部として形成するとともに、この表層部上に球状で鋼製または鋳鉄製の支承部を設置した床免震構造である。本発明の第１実施形態は、表層部を潤滑剤が混入されたモルタルで形成した免震構造である（図１、図２）。第２実施形態は、表層部を凹状の鋼板で形成した免震構造である（図３、図４）。
以下、本発明の実施形態を図面に基づいて説明する。以下の実施形態の説明にあたって、同一構成要件については同一符号を付し、その説明を省略もしくは簡略化する。
〔第１実施形態〕
図１は、本発明の第１実施形態に係る免震構造１の側面図であり、図２は、図１のＡ−Ａ断面図である。
免震構造１は、地震時に床スラブ１０から免震対象物２０に伝わる揺れを低減するものである。
免震対象物２０は、例えば、設備機器であり、床躯体としての床スラブ１０上に設置されている。免震対象物２０の下面の四隅には、袋ナットである支承部２１が設けられている。この袋ナットは、鋼製または鋳鉄製であり、この袋ナットの先端（下端）は、球状となっている。 The present invention, as a seismic isolation structure that can be easily installed not only in new buildings but also in existing buildings, has a mortar layer mixed with a lubricant or a self-leveling layer mixed with a lubricant on the surface of the floor slab. It is a floor seismic isolation structure in which a spherical steel or cast iron bearing is installed on the surface layer. The first embodiment of the present invention is a seismic isolation structure in which the surface layer portion is formed of mortar mixed with a lubricant (FIGS. 1 and 2). The second embodiment is a seismic isolation structure in which the surface layer portion is formed of a concave steel plate (FIGS. 3 and 4).
Embodiments of the present invention will be described below with reference to the drawings. In the following description of the embodiments, the same constituents are designated by the same reference numerals, and the description thereof will be omitted or simplified.
[First Embodiment]
FIG. 1 is a side view of a seismic isolation structure 1 according to the first embodiment of the present invention, and FIG. 2 is a sectional view taken along line AA of FIG.
The seismic isolation structure 1 reduces the sway transmitted from the floor slab 10 to the seismic isolation target object 20 during an earthquake.
The seismic isolation target 20 is, for example, a facility device, and is installed on the floor slab 10 as a floor skeleton. At the four corners of the lower surface of the seismic isolation target 20, support portions 21 that are cap nuts are provided. The cap nut is made of steel or cast iron, and the tip (lower end) of the cap nut is spherical.

床スラブ１０の上面には、潤滑剤としての黒鉛粉末が混入されたモルタルで形成された表層部１１が設けられている。ここで、黒鉛粉末の重量は、既往の研究成果を踏まえて、モルタルに混入しても強度変化を生じさせないとされている、セメント重量の５％以下とした。また、黒鉛粉末の最大粒径は、後述の検証実験結果に基づき、８０μｍ〜４００μｍ程度が好ましい。この表層部１１の上面には、免震対象物２０の支承部２１が当接しており、表層部１１の上面と支承部２１との摩擦係数は、床スラブ１０の上面と支承部２１との摩擦係数よりも小さくなっている。
また、表層部１１の厚さは、５ｍｍ〜３０ｍｍ程度である。また、この表層部１１の設置範囲は、平面視で、支承部２１周囲の所定範囲であり、地震時における支承部２１の移動範囲を含んでいる。なお、表層部１１を、免震対象物２０が設置された室の床スラブ１０の一部に限らず、床スラブ１０の全面に設けてもよい。 On the upper surface of the floor slab 10, a surface layer portion 11 made of mortar mixed with graphite powder as a lubricant is provided. Here, the weight of the graphite powder is set to 5% or less of the weight of the cement, which is considered not to cause the strength change even when mixed into the mortar based on the past research results. Further, the maximum particle size of the graphite powder is preferably about 80 μm to 400 μm based on the verification experiment result described later. The bearing portion 21 of the seismic isolation target 20 is in contact with the upper surface of the surface layer portion 11, and the friction coefficient between the upper surface of the surface layer portion 11 and the bearing portion 21 is the same as that between the upper surface of the floor slab 10 and the bearing portion 21. It is smaller than the friction coefficient.
Moreover, the thickness of the surface layer portion 11 is about 5 mm to 30 mm. Further, the installation range of the surface layer part 11 is a predetermined range around the support part 21 in plan view, and includes the movement range of the support part 21 at the time of an earthquake. The surface layer portion 11 may be provided not only on a part of the floor slab 10 in the room where the seismic isolation target 20 is installed but also on the entire surface of the floor slab 10.

また、床スラブ１０の表層部１１には、免震対象物２０を囲んで、免震対象物２０の移動を規制する壁部１２が設けられている。具体的には、壁部１２は、側面視で、免震対象物２０の下端よりも高く、平面視で、免震対象物２０からクリアランスとして所定寸法ｔだけ離れている。このクリアランスの寸法ｔは、具体的には、５０ｍｍ〜１００ｍｍ程度である。
この壁部１２は、ゴム材または気泡化成品などの緩衝材で形成されており、壁部１２の下部が表層部１１または床スラブ１０に固定されている。この壁部１２の固定方法としては、接着剤を使用してもよいし、表層部１１のモルタルや床スラブ１０のコンクリートに埋設してもよいし、表層部１１または床スラブ１０にボルトで固定してもよい。 Further, the surface layer 11 of the floor slab 10 is provided with a wall 12 that surrounds the seismic isolation target 20 and restricts movement of the seismic isolation target 20. Specifically, the wall portion 12 is higher than the lower end of the seismic isolation target object 20 in a side view, and is separated from the seismic isolation target object 20 by a predetermined dimension t as a clearance in a plan view. Specifically, the dimension t of this clearance is about 50 mm to 100 mm.
The wall portion 12 is formed of a cushioning material such as a rubber material or a foamed chemical product, and the lower portion of the wall portion 12 is fixed to the surface layer portion 11 or the floor slab 10. As a method of fixing the wall portion 12, an adhesive may be used, or the wall portion 12 may be embedded in mortar of the surface layer portion 11 or concrete of the floor slab 10, or fixed to the surface layer portion 11 or the floor slab 10 with bolts. You may.

本実施形態によれば、以下のような効果がある。
（１）床スラブ１０の上面に、支承部２１との摩擦係数が床スラブ１０よりも小さい表層部１１を設けた。よって、地震時の比較的小さな揺れでも、免震対象物２０が床スラブ１０に対して水平移動するため、床スラブ１０から免震対象物２０に伝わる揺れを低減でき、免震対象物２０の損傷や転倒を防止できる。
すなわち、免震対象物２０の重量および摩擦係数による慣性力以上の水平力（地震力）が免震対象物２０に入力されると、表層部１１と支承部２１との間で滑動が生じる。これにより、摩擦係数に重力加速度を乗じた値により求められる加速度以上の加速度が免震対象物２０に入力されなくなるため、免震対象物２０の破損や転倒を防ぐことができる。
また、床スラブ１０上の表層部１１を、免震対象物２０の下面に設けた支承部２１の移動範囲のみに設ければよいので、新築建物だけでなく既存建物にも容易に免震構造を設けることができる。 According to this embodiment, there are the following effects.
(1) On the upper surface of the floor slab 10, the surface layer portion 11 having a smaller coefficient of friction with the support portion 21 than that of the floor slab 10 is provided. Therefore, the seismic isolation target object 20 moves horizontally with respect to the floor slab 10 even with a relatively small shake during an earthquake, and thus the shaking transmitted from the floor slab 10 to the seismic isolation target object 20 can be reduced, and the seismic isolation target object 20 It can prevent damage and falls.
That is, when a horizontal force (seismic force) greater than the inertial force due to the weight and friction coefficient of the seismic isolation target object 20 is input to the seismic isolation target object 20, sliding occurs between the surface layer portion 11 and the support portion 21. As a result, an acceleration equal to or higher than the acceleration obtained by multiplying the friction coefficient by the gravitational acceleration is not input to the seismic isolation target object 20, so that the seismic isolation target object 20 can be prevented from being damaged or falling.
Further, since the surface layer portion 11 on the floor slab 10 may be provided only in the moving range of the support portion 21 provided on the lower surface of the seismic isolation target object 20, the seismic isolation structure can be easily applied not only to a new building but also to an existing building. Can be provided.

（２）表層部１１を、潤滑剤を混入したモルタルで形成した。よって、表層部１１の表面の潤滑剤により、表層部１１と支承部２１との間の摩擦が小さくなるので、地震が発生していない状態では、支承部２１が表層部１１上を滑動することはないが、地震発生時には、支承部２１が表層部１１上を滑動する。また、表層部１１を既存の床スラブの上に形成することで、新築建物だけでなく、既存建物にも容易に免震構造を設けることができる。
表層部１１のモルタルに黒鉛粉末を混ぜることで、黒鉛粉末の剥がれを抑制し、滑り性能の低下を抑えることができる。また、厚みのある表層部１１中に黒鉛が満遍なく行き渡るため、支承部２１が常に表層部１１表面の黒鉛に接することとなる。このため、表層部１１の表面を均す必要がなく、施工時の表層部１１の不陸を気にする必要がない。
また、黒鉛粉末をモルタル内に練り込むため、黒鉛塗料を床躯体面に塗布した場合と比較して、黒鉛が削り取られて舞い散ることがない。このため発塵を嫌う免震対象物２０にも利用できる。 (2) The surface layer portion 11 is formed of mortar mixed with a lubricant. Therefore, the lubricant on the surface of the surface layer portion 11 reduces the friction between the surface layer portion 11 and the bearing portion 21, so that the bearing portion 21 slides on the surface layer portion 11 when no earthquake occurs. However, when an earthquake occurs, the support portion 21 slides on the surface layer portion 11. Further, by forming the surface layer portion 11 on the existing floor slab, it is possible to easily provide a seismic isolation structure not only for a newly built building but also for an existing building.
By mixing the graphite powder with the mortar of the surface layer portion 11, it is possible to suppress the peeling of the graphite powder and the deterioration of the sliding performance. Further, since the graphite is evenly distributed in the thick surface layer portion 11, the support portion 21 is always in contact with the graphite on the surface of the surface layer portion 11. For this reason, it is not necessary to even the surface of the surface layer portion 11, and it is not necessary to care about the unevenness of the surface layer portion 11 during construction.
Further, since the graphite powder is kneaded into the mortar, the graphite is not scraped off and scattered as compared with the case where the graphite coating is applied to the floor skeleton surface. Therefore, it can also be used for the seismic isolation target object 20 that does not like dust.

（３）支承部２１を免震対象物２０の四隅に配置したので、免震対象物の重量が異なっても、簡易な構造である支承部２１の個数を適宜調整することで、免震対象物を確実に支持できる。よって、様々な免震対象物を低コストで免震化できる。 (3) Since the support portions 21 are arranged at the four corners of the seismic isolation target object 20, even if the weight of the seismic isolation target object is different, by appropriately adjusting the number of the support portion 21 having a simple structure, the seismic isolation target object can be obtained. Can reliably support things. Therefore, various seismic isolation targets can be seismically isolated at low cost.

（４）潤滑剤を黒鉛粉末としたので、表層部１１の表面が、炭素原子の結晶体が規則的に配列された元素鉱物グラファイトで形成される。よって、表層部１１の支承部２１との摩擦係数を確実に小さくできる。
（５）壁部１２を免震対象物２０の外周に所定のクリアランスｔを確保して設置したので、想定を上回る大地震が発生した際には、免震対象物２０の移動を壁部１２で規制できる。また、壁部１２を緩衝材で形成したので、免震対象物２０が壁部１２に衝突しても、免震対象物２０を損傷させることはない。 (4) Since the lubricant is graphite powder, the surface of the surface layer portion 11 is formed of elemental mineral graphite in which crystals of carbon atoms are regularly arranged. Therefore, the friction coefficient between the surface layer portion 11 and the support portion 21 can be surely reduced.
(5) Since the wall portion 12 is installed on the outer periphery of the seismic isolation target object 20 with a predetermined clearance t secured, when the unexpected earthquake occurs, the movement of the seismic isolation target object 20 is prevented. Can be regulated by. Further, since the wall portion 12 is formed of the cushioning material, even if the seismic isolation target object 20 collides with the wall portion 12, the seismic isolation target object 20 is not damaged.

〔第２実施形態〕
図３は、本発明の第２実施形態に係る免震構造１Ａの側面図であり、図４は、図３のＢ−Ｂ断面図である。
本実施形態では、表層部１１Ａおよび壁部１２Ａの構成が、第１実施形態と異なる。
すなわち、表層部１１Ａおよび壁部１２Ａは、凹状の鋼板で一体に形成されており、支承部２１の直下の近傍にのみ設けられている。
具体的には、表層部１１Ａは平板状であり、床スラブ１０に接着剤で固定されている。壁部１２Ａは、表層部１１Ａの周縁部に設けられている。この壁部１２Ａは、側面視で、免震対象物２０の下端よりも低くなっている。また、壁部１２Ａは、平面視で、支承部２１からクリアランスとして所定寸法ｔだけ離れている。このクリアランスの寸法ｔは、具体的には、５０ｍｍ〜１００ｍｍ程度である。 [Second Embodiment]
3 is a side view of the seismic isolation structure 1A according to the second embodiment of the present invention, and FIG. 4 is a sectional view taken along line BB of FIG.
In this embodiment, the configurations of the surface layer portion 11A and the wall portion 12A are different from those in the first embodiment.
That is, the surface layer portion 11A and the wall portion 12A are integrally formed of a concave steel plate, and are provided only in the vicinity immediately below the support portion 21.
Specifically, the surface layer portion 11A has a flat plate shape and is fixed to the floor slab 10 with an adhesive. The wall portion 12A is provided on the peripheral portion of the surface layer portion 11A. The wall portion 12A is lower than the lower end of the seismic isolation target object 20 in a side view. Further, the wall portion 12A is separated from the support portion 21 by a predetermined dimension t as a clearance in a plan view. Specifically, the dimension t of this clearance is about 50 mm to 100 mm.

本実施形態によれば、上述の（１）、（３）、（５）に加えて、以下のような効果がある。
（６）表層部１１Ａを鋼板で形成したので、表層部１１Ａの表面が滑らかな面となり、表層部１１Ａと支承部２１との間の摩擦が小さくなる。また、表層部１１Ａを既存の床スラブ１０の上に形成することで、新築建物だけでなく、既存建物にも容易に免震構造を設けることができる。 According to this embodiment, in addition to the above (1), (3), and (5), the following effects are obtained.
(6) Since the surface layer portion 11A is formed of a steel plate, the surface of the surface layer portion 11A becomes a smooth surface, and the friction between the surface layer portion 11A and the support portion 21 is reduced. In addition, by forming the surface layer portion 11A on the existing floor slab 10, it is possible to easily provide a seismic isolation structure not only for a newly built building but also for an existing building.

〔表層部のすべり性能の検証実験〕
表層部のすべり性能を検証する実験を行った。具体的には、表層部として、以下の４つの試験体を製作した。
第１試験体（比較例）は、通常のモルタルを用いて製作し、表面（すべり面）を金鏝で仕上げたものである。この第１試験体に対しては、支承部としてＦＣＤ（ダクタイル鋳鉄）の袋ナットを用意し、さらにこの袋ナットの表面を磨いたものを用いた。
第２試験体（実施例）は、黒鉛粉末を混入したモルタルを用いて製作し、表面（すべり面）を金鏝で仕上げたものである。この第２試験体に対しては、支承部として鋼製の袋ナットを用いた。
第３試験体（実施例）は、通常のモルタルを用いて製作し、表面（すべり面）を金鏝で仕上げて黒鉛塗料を塗布したものである。この第３試験体に対しては、第２試験体と同様に、支承部として鋼製の袋ナットを用いた。
第４試験体（実施例）は、鋼板である。この第４試験体に対しては、支承部としてドライサーフェス鋼（ＷＤ１９００）製の袋ナットを用いた。 [Verification experiment of slip performance of surface layer]
An experiment was conducted to verify the slip performance of the surface layer. Specifically, the following four test bodies were manufactured as the surface layer part.
The first test body (comparative example) was manufactured using ordinary mortar, and the surface (sliding surface) was finished with a metal iron. For the first test body, a cap nut of FCD (ductile cast iron) was prepared as a bearing, and the surface of the cap nut was polished and used.
The second test body (Example) was manufactured using mortar mixed with graphite powder, and the surface (sliding surface) was finished with a metal iron. For the second test body, a steel cap nut was used as a bearing.
The third test body (Example) was manufactured using ordinary mortar, the surface (sliding surface) was finished with a metal iron and coated with graphite paint. As with the second test body, a steel cap nut was used as a support for the third test body.
The fourth test body (Example) is a steel plate. For the fourth test body, a cap nut made of dry surface steel (WD1900) was used as a bearing.

図５に、本発明の実施例および比較例の各試験体を示す。図５に示すように、表層部は、２００ｍｍ×２００ｍｍ×５０ｍｍのモルタル板である。免震対象物は、三角形状の鋼板の上に２００ｍｍ×２００ｍｍ×２５ｍｍのコンクリート板を２枚重ねたものである。また、支承部は、三角形状の鋼板の下面の３箇所に設けた袋ナットである。
以上の４つの試験体に対して、引張荷重に対する変位を測定し、引張荷重および変位に基づいて摩擦係数を求めた。図６（ａ）〜（ｄ）は、第１〜第４試験体についての試験結果である。
この試験結果より、第１試験体の摩擦係数が０．５程度、第２試験体の摩擦係数が０．３程度、第３試験体の摩擦係数が０．２程度、第４試験体の摩擦係数が０．１６程度となることが判る。第２試験体および第３試験体については、第１試験体と比べて、黒鉛潤滑の効果により摩擦係数が下がったと考えられる。また、第４試験体については、表面が滑らかであるため、第１試験体に比べて低い摩擦係数を示したと考えられる。 FIG. 5 shows each test body of the example of the present invention and the comparative example. As shown in FIG. 5, the surface layer portion is a mortar plate of 200 mm×200 mm×50 mm. The seismic isolation target is a concrete plate of 200 mm×200 mm×25 mm stacked on a triangular steel plate. The bearings are cap nuts provided at three locations on the lower surface of the triangular steel plate.
The displacement with respect to the tensile load was measured for the above four test bodies, and the friction coefficient was obtained based on the tensile load and the displacement. 6A to 6D show the test results of the first to fourth test bodies.
From this test result, the friction coefficient of the first test body is about 0.5, the friction coefficient of the second test body is about 0.3, the friction coefficient of the third test body is about 0.2, and the friction coefficient of the fourth test body is It can be seen that the coefficient is about 0.16. It is considered that the friction coefficient of the second test body and the third test body was lower than that of the first test body due to the effect of graphite lubrication. Further, it is considered that the fourth test body had a lower friction coefficient than the first test body because the surface was smooth.

なお、本発明は前記実施形態に限定されるものではなく、本発明の目的を達成できる範囲での変形、改良等は本発明に含まれるものである。
上述の第１実施形態では、表層部１１を、潤滑剤としての黒鉛粉末が混入されたモルタルで形成したが、これに限らず、潤滑剤として、表層部を、二硫化モリブデンや４フッ化エチレン樹脂が混入されたモルタルで形成してもよい。あるいは、表層部を、潤滑剤としての黒鉛粉末、二硫化モリブデン、４フッ化エチレン樹脂のいずれかが混入されたセルフレベリング材で形成してもよいし、表層部を、床スラブ上に黒鉛塗料を塗布した塗膜としてもよい。
また、上述の各実施形態では、表層部１１、１１Ａに壁部１２、１２Ａを設けたが、これに限らない。例えば、壁部１２、１２Ａを設けなくてもよい。あるいは、図７に示すように、表層部１１Ｂを支承部２１の直下近傍にのみ設けるとともに、壁部１２Ｂを床スラブ１０上に設け、壁部１２Ｃを免震対象物２０の下面に設けて、壁部１２Ｂ、１２Ｃ同士が接触することで、免震対象物２０の移動を規制してもよい。この場合、平面視で、壁部１２Ｂと壁部１２Ｃとは、クリアランスとして所定寸法ｔだけ離れている。このクリアランスの寸法ｔは、具体的には、５０ｍｍ〜１００ｍｍ程度である。
また、上述の各実施形態の表層部１１、１１Ａは、新築建物の床スラブ１０の上面に構築してもよいし、既存建物の床スラブ１０の上面に構築してもよい。 It should be noted that the present invention is not limited to the above-described embodiment, and modifications, improvements, etc. within the scope of achieving the object of the present invention are included in the present invention.
In the above-described first embodiment, the surface layer portion 11 is formed of mortar mixed with graphite powder as a lubricant. However, the present invention is not limited to this. As a lubricant, the surface layer portion may be molybdenum disulfide or tetrafluoroethylene. It may be formed of mortar mixed with a resin. Alternatively, the surface layer portion may be formed of a self-leveling material in which any one of graphite powder as a lubricant, molybdenum disulfide, and tetrafluoroethylene resin is mixed, and the surface layer portion may be formed on a floor slab with a graphite coating. It may be a coated film.
Further, in each of the above-described embodiments, the wall portions 12 and 12A are provided on the surface layer portions 11 and 11A, but the present invention is not limited to this. For example, the walls 12 and 12A may not be provided. Alternatively, as shown in FIG. 7, the surface layer portion 11B is provided only in the vicinity immediately below the support portion 21, the wall portion 12B is provided on the floor slab 10, and the wall portion 12C is provided on the lower surface of the seismic isolation target 20, The movement of the seismic isolation target object 20 may be restricted by contact between the wall portions 12B and 12C. In this case, the wall portion 12B and the wall portion 12C are separated by a predetermined dimension t as a clearance in a plan view. Specifically, the dimension t of this clearance is about 50 mm to 100 mm.
Further, the surface layer portions 11 and 11A of each of the above-described embodiments may be constructed on the upper surface of the floor slab 10 of a new building, or may be constructed on the upper surface of the floor slab 10 of an existing building.

１、１Ａ、１Ｂ…免震構造１０…床スラブ（床躯体）
１１、１１Ａ、１１Ｂ…表層部
１２、１２Ａ、１２Ｂ、１２Ｃ…壁部２０…免震対象物２１…支承部 1, 1A, 1B... Seismic isolation structure 10... Floor slab (floor skeleton)
11, 11A, 11B... Surface layer part 12, 12A, 12B, 12C... Wall part 20... Seismic isolation target 21... Bearing part

Claims

A seismic isolation structure that reduces shaking transmitted from the floor structure to the seismic isolation target installed on the floor structure during an earthquake,
On the lower surface of the seismic isolation target, a spherical steel or cast iron bearing is provided,
On the upper surface of the floor skeleton, a surface layer portion with which the support portion abuts is formed,
A seismic isolation structure characterized in that a friction coefficient between the surface layer portion and the bearing portion is smaller than a friction coefficient between the floor frame and the bearing portion.

The seismic isolation structure according to claim 1, wherein the surface layer portion is formed of a mortar mixed with a lubricant or a self-leveling material, or a coating film coated with a lubricant.

The seismic isolation structure according to claim 1, wherein the surface layer portion is formed of any one of a flat steel plate, a steel floor plate, and a steel plate having a recessed central portion.