JP6750414B2 - A method for determining the rigidity of shock absorbers used in seismic isolation structures - Google Patents
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Description
本発明は、免震構造に用いる緩衝体の剛性決定方法に関する。 The present invention relates to a rigidity determination method for a shock absorber used in a seismic isolation structure.
鉛直方向に並ぶ上部構造（例えば建物）と下部構造（例えば基礎）との間に免震装置（例えば積層ゴム）を備えた免震構造が知られている。このような免震構造において、例えば下部構造の外周部に壁体（例えば擁壁）を設け、上部構造と下部構造との水平方向の相対変位が過大となる場合に上部構造を壁体に衝突させて変位を抑制するようにしたものも知られている（例えば、特許文献１参照）。そして、過大な地震動に対する対応として、上部構造と壁体との衝突を想定した設計が行われており、また、建物の健全性を改善するために衝突時の衝撃を緩和する緩衝体を設置する設計も考えられている。 There is known a seismic isolation structure including a seismic isolation device (e.g., laminated rubber) between an upper structure (e.g., a building) and a lower structure (e.g., foundation) arranged vertically. In such a seismic isolation structure, for example, a wall body (for example, a retaining wall) is provided on the outer peripheral portion of the lower structure, and when the horizontal relative displacement between the upper structure and the lower structure becomes excessive, the upper structure collides with the wall body. There is also known one in which the displacement is suppressed (see, for example, Patent Document 1). As a countermeasure against excessive seismic motion, the design is made assuming a collision between the upper structure and the wall, and a shock absorber is installed to mitigate the impact at the time of collision to improve the soundness of the building. Design is also being considered.
上部構造と壁体との衝突を想定した免震構造において、過大な地震動等により衝突する上部構造と壁体との間に緩衝体を備える場合には、備える緩衝体を含めて上部構造と壁体との衝突を想定した設計を行う必要があり、効果的な緩衝体を備えるためには、緩衝体を適切な剛性に設定する必要がある。しかしながら、現状では、建物毎に、また条件を違えて繰り返し衝突応答解析を行い、緩衝体の適切な剛性をポイントで探しているため効率が悪いという課題がある。 In a seismic isolation structure that is supposed to collide with the upper structure and the wall, if a buffer is provided between the upper structure and the wall that collide due to excessive earthquake motion, etc., the upper structure and the wall including the buffer are included. It is necessary to carry out the design assuming a collision with the body, and in order to provide an effective cushioning body, it is necessary to set the cushioning body to an appropriate rigidity. However, at present, there is a problem that efficiency is poor because the collision response analysis is repeatedly performed for each building and under different conditions to search for an appropriate rigidity of the buffer at a point.
本発明は、かかる課題に鑑みてなされたものであって、その主な目的は、免震構造に用いる緩衝体の適切な剛性を簡便に、効率的且つ合理的に想定できて、設計効率の向上を図ることにある。 The present invention has been made in view of such problems, and its main purpose is to easily, efficiently and rationally assume an appropriate rigidity of a shock absorber used in a seismic isolation structure, and to improve design efficiency. To improve.
かかる目的を達成するために本発明の免震構造に用いる緩衝体の剛性決定方法は、
上部構造と下部構造との間に免震装置を備え、前記上部構造又は前記下部構造の一方に属する壁体と、前記上部構造又は前記下部構造の他方とが、水平方向に離間している免震構造において、前記上部構造又は前記下部構造の前記他方と前記壁体との衝突を想定して前記免震構造に用いる緩衝体の剛性決定方法であって、
前記上部構造の質量Ｍと、前記壁体の剛性Ｋｗとの比をパラメーターとして行った前記免震構造の衝突応答解析における前記免震構造の衝突による応答値と、
前記上部構造の質量Ｍと、前記壁体と前記他方との間に前記緩衝体が介在されたときに剛性が低下したとみなされる前記壁体のみなし剛性Ｋとの比Ｋ／Ｍと、
に基づいて、前記壁体と前記他方との間に介在させる前記緩衝体の剛性Ｋｆを決定することを特徴とする免震構造に用いる緩衝体の剛性決定方法である。
In order to achieve such an object, the rigidity determination method of the shock absorber used in the seismic isolation structure of the present invention is
A seismic isolation device is provided between the upper structure and the lower structure, and the wall body belonging to one of the upper structure or the lower structure and the other of the upper structure or the lower structure are horizontally separated from each other. In a seismic structure, a method of determining the rigidity of a shock absorber used in the seismic isolation structure assuming a collision between the other of the upper structure or the lower structure and the wall body,
A response value due to a collision of the seismic isolation structure in a collision response analysis of the seismic isolation structure performed with the ratio of the mass M of the upper structure and the rigidity Kw of the wall body as a parameter;
A ratio K/M between the mass M of the superstructure and the apparent rigidity K of the wall body that is considered to have reduced rigidity when the buffer body is interposed between the wall body and the other;
Based on the above, the rigidity determination method of the buffer body used in the seismic isolation structure is characterized in that the rigidity Kf of the buffer body interposed between the wall body and the other is determined.
このような免震構造に用いる緩衝体の剛性決定方法によれば、緩衝体の適切な剛性Ｋｆを簡便に、効率的且つ合理的に想定できて、設計効率の向上を図ることが可能である。 According to such a shock absorber rigidity determination method used for the seismic isolation structure, the appropriate rigidity Kf of the shock absorber can be easily, efficiently and rationally assumed, and the design efficiency can be improved. ..
かかる免震構造に用いる緩衝体の剛性決定方法であって、
前記応答値は、前記衝突による前記上部構造の応答増幅率であることが望ましい。
A method for determining the rigidity of a shock absorber used in such a seismic isolation structure,
The response value is preferably a response amplification factor of the upper structure due to the collision.
このような免震構造に用いる緩衝体の剛性決定方法によれば、上部構造に過大な損傷や倒壊・崩壊が生じないように設計することが可能である。 According to the rigidity determination method of the shock absorber used for such a seismic isolation structure, it is possible to design so that the upper structure is not excessively damaged or collapsed/collapsed.
かかる免震構造に用いる緩衝体の剛性決定方法であって、
前記応答値は、前記衝突による前記壁体の変形量であることが望ましい。
A method for determining the rigidity of a shock absorber used in such a seismic isolation structure,
The response value is preferably a deformation amount of the wall body due to the collision.
このような免震構造に用いる緩衝体の剛性決定方法によれば、免震装置が破断したり、軸力、支持能力を失ったりしないように設計することができる。 According to the rigidity determination method of the shock absorber used in such a seismic isolation structure, it is possible to design the seismic isolation device so as not to break or lose the axial force and the supporting ability.
かかる免震構造に用いる緩衝体の剛性決定方法であって、
前記上部構造の質量Ｍと、前記壁体の剛性Ｋｗとの比Ｋｗ／Ｍを横軸とし、前記衝突の衝突速度又は入力地震動の大きさを縦軸として、前記衝突による前記上部構造の応答値と、前記衝突による前記壁体の変形量とをプロットし、前記上部構造の応答値が同値となる第一ラインと、前記壁体の変形量が同値となる第二ラインとを作成することが望ましい。
A method for determining the rigidity of a shock absorber used in such a seismic isolation structure,
The ratio Kw/M of the mass M of the superstructure and the rigidity Kw of the wall body is taken as the horizontal axis, and the collision velocity of the collision or the magnitude of the input seismic motion is taken as the vertical axis, and the response value of the superstructure due to the collision is given. And plotting the amount of deformation of the wall body due to the collision, and creating a first line in which the response value of the upper structure has the same value and a second line in which the amount of deformation of the wall member has the same value. desirable.
このような免震構造に用いる緩衝体の剛性決定方法によれば、第一ラインにより示される上部構造の応答値のクライテリアと、第二ラインにより示される壁体の変形量のクライテリアとの関係が明確になる。 According to the method for determining the rigidity of the shock absorber used for such a seismic isolation structure, the relationship between the criteria of the response value of the superstructure shown by the first line and the criteria of the deformation amount of the wall body shown by the second line is Be clear.
かかる免震構造に用いる緩衝体の剛性決定方法であって、
前記衝突速度又は前記入力地震動の大きさが所定値のときの前記第一ラインの第一Ｋｗ／Ｍ、及び、前記第二ラインの第二Ｋｗ／Ｍを算出することが望ましい。
A method for determining the rigidity of a shock absorber used in such a seismic isolation structure,
It is desirable to calculate the first Kw/M of the first line and the second Kw/M of the second line when the collision velocity or the magnitude of the input earthquake motion is a predetermined value.
このような免震構造に用いる緩衝体の剛性決定方法によれば、２本のラインによるクライテリアをともに満足する領域（設計可能領域）を推測することができる。 According to the method for determining the rigidity of the shock absorber used for such a seismic isolation structure, it is possible to estimate a region (designable region) that satisfies both criteria by two lines.
かかる免震構造に用いる緩衝体の剛性決定方法であって、
前記第一Ｋｗ／Ｍと前記第二Ｋｗ／Ｍの間を設計可能領域とすることが望ましい。
A method for determining the rigidity of a shock absorber used in such a seismic isolation structure,
It is desirable to set a designable region between the first Kw/M and the second Kw/M.
このような免震構造に用いる緩衝体の剛性決定方法によれば、設計可能な壁体剛性Ｋｗの範囲を容易に想定することができる。 According to such a rigidity determination method of the buffer body used for the seismic isolation structure, it is possible to easily assume the range of the wall rigidity Kw that can be designed.
かかる免震構造に用いる緩衝体の剛性決定方法であって、
次式に基づいて、前記Ｋ／Ｍが、前記第一Ｋｗ／Ｍと前記第二Ｋｗ／Ｍの間の値をなすべく、前記緩衝体の剛性Ｋｆを決定することが望ましい。
A method for determining the rigidity of a shock absorber used in such a seismic isolation structure,
It is desirable to determine the rigidity Kf of the shock absorber so that the K/M has a value between the first Kw/M and the second Kw/M based on the following equation.
このような免震構造に用いる緩衝体の剛性決定方法によれば、緩衝体のより適切な剛性Ｋｆを簡便に、効率的且つ合理的に想定でき、設計効率の向上を図ることが可能である。 According to such a shock absorber rigidity determination method used for the seismic isolation structure, a more appropriate rigidity Kf of the shock absorber can be simply, efficiently and rationally assumed, and the design efficiency can be improved. ..
かかる免震構造に用いる緩衝体の剛性決定方法であって、
前記応答値が、前記壁体と、前記上部構造又は前記下部構造の他方とが、水平方向に所定のクリアランスをもって離間している免震構造の衝突応答解析によるものであり、
前記壁体と、前記上部構造又は前記下部構造の他方とが、互いの間に剛性Ｋｆの緩衝体を備えると共に、前記緩衝体と前記壁体又は前記他方とが水平方向に前記所定のクリアランスをもって離間している他の免震構造の、前記衝突速度又は前記入力地震動の大きさに対する衝突応答解析の結果に基づいて特定される、前記壁体又は前記他方と前記緩衝体とが衝突し始めるときの前記衝突速度又は前記入力地震動の大きさを示す衝突開始震動レベルと、
前記緩衝体の変形代が失われるときの前記衝突速度又は前記入力地震動の大きさを示す最大変形震動レベルとの間に、
想定する前記衝突速度又は前記入力地震動の大きさが含まれるべく前記緩衝体の前記剛性Ｋｆを設定することが望ましい。
A method for determining the rigidity of a shock absorber used in such a seismic isolation structure,
The response value is based on a collision response analysis of a seismic isolation structure in which the wall body and the other of the upper structure or the lower structure are separated by a predetermined clearance in the horizontal direction,
The wall body and the other of the upper structure or the lower structure are provided with a cushioning body having a rigidity Kf between each other, and the cushioning body and the wall body or the other are provided with the predetermined clearance in the horizontal direction. When the wall body or the other and the buffer body start to collide with each other, which is specified based on the result of the collision response analysis of the other seismic isolation structure with respect to the collision velocity or the magnitude of the input earthquake motion A collision start vibration level indicating the collision velocity or the magnitude of the input seismic motion,
Between the collision velocity or the maximum deformation vibration level indicating the magnitude of the input earthquake motion when the deformation allowance of the buffer is lost,
It is desirable to set the rigidity Kf of the shock absorber so as to include the assumed collision velocity or the magnitude of the input earthquake motion.
このような免震構造に用いる緩衝体の剛性決定方法によれば、緩衝体と壁体又は他方とが水平方向に所定のクリアランスをもって離間している他の免震構造において、想定する衝突速度又は入力地震動の大きさに、より適した剛性Ｋｆの緩衝体を簡便に、効率的且つ合理的に想定できて、設計効率の向上を図ることが可能である。 According to such a method for determining the rigidity of the shock absorber used for the seismic isolation structure, in the other seismic isolation structure in which the shock absorber and the wall body or the other are horizontally separated from each other with a predetermined clearance, It is possible to easily, efficiently and rationally assume a buffer body having a rigidity Kf more suitable for the magnitude of the input seismic motion, and to improve the design efficiency.
かかる免震構造に用いる緩衝体の剛性決定方法であって、
前記応答値が、前記壁体と、前記上部構造又は前記下部構造の他方とが、水平方向に所定のクリアランスをもって離間している免震構造の衝突応答解析によるものであり、
前記免震構造の、前記壁体と前記他方とが衝突し始めるときの前記衝突速度又は前記入力地震動の大きさを示す衝突開始震動レベルと、
前記壁体と、前記上部構造又は前記下部構造の他方とが、互いの間に剛性Ｋｆの緩衝体を備えると共に、前記壁体と前記他方とが水平方向に所定のクリアランスをもって離間している他の免震構造の、前記緩衝体の変形代が失われるときの前記衝突速度又は前記入力地震動の大きさを示す最大変形震動レベルとの間であって、
前記他の免震構造にて前記緩衝体が備えられたことにより、前記免震構造の応答値より増大する領域を除く領域に、
想定する前記衝突速度又は前記入力地震動の大きさが含まれるべく前記緩衝体の前記剛性Ｋｆを設定することが望ましい。
A method for determining the rigidity of a shock absorber used in such a seismic isolation structure,
The response value is based on a collision response analysis of a seismic isolation structure in which the wall body and the other of the upper structure or the lower structure are separated by a predetermined clearance in the horizontal direction,
In the seismic isolation structure, a collision start vibration level indicating the magnitude of the collision velocity or the input earthquake motion when the wall body and the other start to collide, and
The wall body and the other of the upper structure and the lower structure are provided with a cushioning body having a rigidity Kf between them, and the wall body and the other are horizontally separated from each other with a predetermined clearance. Of the seismic isolation structure of, between the collision speed when the deformation allowance of the buffer is lost or the maximum deformation vibration level indicating the magnitude of the input earthquake motion,
By providing the buffer in the other seismic isolation structure, in the area excluding the area that increases from the response value of the seismic isolation structure,
It is desirable to set the rigidity Kf of the shock absorber so as to include the assumed collision velocity or the magnitude of the input earthquake motion.
このような免震構造に用いる緩衝体の剛性決定方法によれば、水平方向に所定のクリアランスをもって離間する壁体と他方との間に緩衝材が設けられている他の免震構造において、想定する衝突速度又は入力地震動の大きさに、より適した剛性Ｋｆの緩衝体を簡便に、効率的且つ合理的に想定できて、設計効率の向上を図ることが可能である。 According to the method for determining the rigidity of the shock absorbing body used for such a seismic isolation structure, it is assumed that the shock absorbing material is provided between the wall body and the other which are horizontally separated from each other with a predetermined clearance. It is possible to easily, efficiently and rationally assume a shock absorber having a rigidity Kf more suitable for the collision velocity or the magnitude of the input seismic motion to improve the design efficiency.
本発明によれば、免震構造に用いる緩衝体の適切な剛性を簡便に、効率的且つ合理的に想定でき、設計効率の向上を図ることが可能である。 According to the present invention, it is possible to easily, efficiently and rationally assume the appropriate rigidity of the shock absorber used for the seismic isolation structure, and to improve the design efficiency.
＝＝＝実施形態＝＝＝
＜＜免震構造について＞＞
本実施形態の免震構造は、鉛直方向に並ぶ上部構造（上部建物）と下部構造（基礎）との間に免震装置（積層ゴムなど）を備えて構成されたものである。また、下部構造の外周部には上部構造の過大変位を抑制するための免震擁壁（壁体に相当）が設けられており、当該免震擁壁には上部構造と水平方向に対向する位置に軟質の合成樹脂製の緩衝体が設けられている。緩衝体と上部構造との間には水平方向に所定のクリアランスが設けられている（換言すると、免震擁壁は下部構造に属するとともに緩衝体を有しており、免震擁壁の緩衝体と上部構造とは水平方向に所定の間隔が隔てられている）。
=== Embodiment ===
<< About seismic isolation structure >>
The seismic isolation structure of the present embodiment is configured to include a seismic isolation device (laminated rubber or the like) between an upper structure (upper building) and a lower structure (foundation) arranged vertically. In addition, a seismic isolation retaining wall (corresponding to a wall body) is installed on the outer periphery of the lower structure to suppress excessive displacement of the upper structure. The seismic isolation retaining wall horizontally faces the upper structure. A buffer made of soft synthetic resin is provided at the position to be filled. A predetermined clearance is provided in the horizontal direction between the shock absorber and the upper structure (in other words, the seismic isolation retaining wall belongs to the lower structure and has the cushion, and And the superstructure are horizontally separated by a predetermined distance).
本実施形態では、上部構造と緩衝体を備えない免震擁壁（以下、単に擁壁ともいう）との衝突を想定し、免震構造として致命的な以下の事象を防止すべく、効果的な緩衝体を備えるために、擁壁の剛性に応じて適切な剛性を備えた緩衝体を決定する。 In the present embodiment, it is effective to prevent a fatal event as a seismic isolation structure by assuming a collision with an upper structure and a seismic isolation retaining wall (hereinafter, also simply referred to as a retaining wall) that does not include a buffer. In order to provide a shock absorber, a shock absorber having appropriate rigidity is determined according to the rigidity of the retaining wall.
事象１）衝突による衝撃力で上部構造に生じる水平力、変形が増大し、過大な損傷や倒壊・崩壊が生じる。 Phenomenon 1) The horizontal force and deformation that occur in the superstructure due to the impact force due to the collision increase, resulting in excessive damage and collapse/collapse.
事象２）衝突後の擁壁の変形により、免震装置が限界変形を超えて破断したり、軸力、支持能力を失ったりする。 Phenomenon 2) Due to the deformation of the retaining wall after the collision, the seismic isolation device breaks beyond the limit deformation and loses the axial force and supporting ability.
このとき、各種剛性の緩衝体を備えた免震構造毎に衝突応答解析を行い、個々の条件において各々設計可能な擁壁の剛性及び緩衝体の剛性を探るようにすると、効率が悪く合理的でない。そこで、本実施形態では、擁壁の剛性に応じた適切な剛性を備えた緩衝体を容易に決定できる免震構造に用いる緩衝体の剛性決定方法を提供する。 At this time, it is inefficient and rational if a collision response analysis is performed for each seismic isolation structure equipped with shock absorbers of various rigidity, and the rigidity of the retaining wall and the shock absorber rigidity that can be designed under individual conditions are searched. Not. Therefore, the present embodiment provides a method for determining the rigidity of a shock absorber used in a seismic isolation structure, which makes it possible to easily determine a shock absorber having appropriate rigidity according to the rigidity of the retaining wall.
＜＜衝突応答解析について＞＞
＜衝突応答解析モデル＞
図１は、緩衝体を備えた免震擁壁を下部構造とする免震構造の衝突応答解析モデルを示す図であり、図２は、緩衝体を備えない免震擁壁を下部構造とする免震構造の衝突応答解析モデルを示す図であり、図３は、免震建物の諸元を示す表であり、図４（ａ）は、免震擁壁に備えられた緩衝体と上部構造とのクリアランスを示す図であり、図４（ｂ）は、緩衝体を備えない免震擁壁と上部構造とのクリアランスを示す図である。上部構造は各階を一質点とした多質点等価せん断型モデルとしており、図１及び図２に示すモデルの黒丸（●）は建物の一層分についての質量を示している。また図１は、剛性Ｋｆの緩衝体が免震擁壁と直列に組み込まれている点で図２と相違している。下部構造には免震擁壁が設けられており、免震擁壁には緩衝体が設けられており、図４（ａ）に示すように、上部構造１と免震擁壁２に設けられた緩衝体３との間には水平方向に所定のクリアランスＸが設けられている。また、各層の復元力特性は、弾塑性立体骨組モデルを用いた静的漸増荷重解析から得られるＱ‐σ曲線をTri-Linearにモデル化している。
<<About collision response analysis>>
<Collision response analysis model>
FIG. 1 is a diagram showing a collision response analysis model of a seismic isolation structure having a seismic isolation retaining wall as a lower structure, and FIG. 2 is a seismic isolation retaining wall having no cushion as a lower structure. It is a figure which shows the collision response analysis model of a base-isolated structure, FIG. 3 is a table which shows the specifications of a base-isolated building, and FIG. 4 (a) is a shock absorber provided in the base-isolated retaining wall, and superstructure. FIG. 4(b) is a diagram showing a clearance between the seismic isolation retaining wall that does not include a buffer and the upper structure. The superstructure is a multi-mass equivalent shear type model with each floor as one mass point, and the black circles (●) in the models shown in FIGS. 1 and 2 indicate the mass for one layer of the building. Further, FIG. 1 is different from FIG. 2 in that a shock absorber having rigidity Kf is incorporated in series with the seismic isolation retaining wall. The lower structure is provided with a seismic isolation retaining wall, and the seismic isolation retaining wall is provided with a buffer body. As shown in FIG. 4A, the seismic isolation retaining wall is provided on the upper structure 1 and the seismic isolation retaining wall 2. A predetermined clearance X is provided in the horizontal direction between the buffer body 3 and the buffer body 3. As for the restoring force characteristics of each layer, the Q-σ curve obtained from a static incremental load analysis using an elasto-plastic three-dimensional frame model is modeled as a Tri-Linear.
本発明の免震構造に用いる緩衝体の剛性決定方法では、まず、緩衝体を備えない免震擁壁を下部構造とする免震構造の衝突応答解析モデル、すなわち図２に示すモデルの衝突応答解析モデルの応答解析を行った。 In the rigidity determination method of the shock absorber used in the seismic isolation structure of the present invention, first, the collision response analysis model of the seismic isolation structure having the seismic isolation retaining wall without the shock absorber as the lower structure, that is, the collision response of the model shown in FIG. The response analysis of the analytical model was performed.
図２に示すモデルの衝突応答解析モデルは、下部構造と上部構造との間には免震層が設けられている。この免震層には、免震装置として、天然ゴム系積層ゴム支承体（ＮＲＢ）、弾性すべり支承、及び、オイルダンパーが設けられている。 In the collision response analysis model of the model shown in FIG. 2, a base isolation layer is provided between the lower structure and the upper structure. The seismic isolation layer is provided with a natural rubber-based laminated rubber bearing (NRB), an elastic slide bearing, and an oil damper as seismic isolation devices.
また、下部構造には免震擁壁が設けられており、図４（ｂ）に示すように、上部構造１と免震擁壁２との間には水平方向に所定のクリアランスＸが設けられている。なお、擁壁の外側は地盤であり、免震擁壁の剛性には、この地盤の剛性（以下、背面土剛性ともいう）も含まれる。 Further, a seismic isolation retaining wall is provided in the lower structure, and as shown in FIG. 4B, a predetermined clearance X is provided in the horizontal direction between the upper structure 1 and the seismic isolation retaining wall 2. ing. The outside of the retaining wall is the ground, and the rigidity of the seismic isolation retaining wall includes the rigidity of this ground (hereinafter also referred to as back soil rigidity).
図２中には上部構造の履歴特性および内部粘性減衰、免震装置の復元力特性（内部粘性減衰はゼロとする）を示している。また、免震擁壁は弾性とし減衰はゼロとする。免震層クリアランス（上部構造と免震擁壁と間の水平距離）は、入力地震動レベル２応答時の免震層変形に設定している。 FIG. 2 shows the hysteresis characteristics of the superstructure, the internal viscous damping, and the restoring force characteristics of the seismic isolation device (the internal viscous damping is zero). The seismic isolation retaining wall will be elastic and damping will be zero. The seismic isolation layer clearance (horizontal distance between the upper structure and the seismic isolation retaining wall) is set to the deformation of the seismic isolation layer at the time of input seismic motion level 2 response.
このようなモデルを用いて、図３に示す２つの免震建物（実施例１及び実施例２）の衝突応答解析を行った。 Using such a model, the collision response analysis of the two seismic isolated buildings (Example 1 and Example 2) shown in FIG. 3 was performed.
＜衝突応答解析＞
擁壁との衝突を想定し、上部構造の応答増幅および免震層の応答変形を評価する場合、免震擁壁剛性（背面土剛性含む）と、上部建物（上部構造）質量と、衝突速度との関係は重要な影響因子と考えられる。そこで、Ｋｗ／Ｍ（免震擁壁剛性／建物質量）をパラメーターとして免震建物の衝突応答解析を行い、上部構造の応答増幅および免震層の応答変形を評価した。ここで、応答増幅とは、基準法で定められている入力地震動による変形（応答値）に対し、それより大きい地震が発生したときにどれだけ変形するかを示す値である。本実施例では入力地震動の大きさをレベル２告示スペクトル（解放工学的基盤、乱数位相）適合波の１．０〜１．５倍（加速度倍率）とし、衝突による上部構造の応答増幅率を、レベル２地震動による応答値を基準（１．０）として評価した。
<Collision response analysis>
When the response amplification of the upper structure and the response deformation of the seismic isolation layer are evaluated assuming a collision with the retaining wall, the rigidity of the seismic isolation retaining wall (including back soil rigidity), the mass of the upper building (superstructure), and the collision speed The relationship with is considered to be an important influencing factor. Therefore, the collision response analysis of the base-isolated building was performed using Kw/M (seismic isolation retaining wall rigidity/building mass) as a parameter, and the response amplification of the superstructure and the response deformation of the seismic isolation layer were evaluated. Here, the response amplification is a value indicating how much the deformation (response value) due to the input earthquake motion defined by the standard method is deformed when an earthquake larger than that is generated. In this example, the magnitude of the input seismic motion is set to 1.0 to 1.5 times (acceleration magnification) of the level 2 notification spectrum (open engineering basis, random phase) compatible wave, and the response amplification factor of the superstructure due to collision is calculated as The response value due to the level 2 seismic motion was evaluated as a standard (1.0).
＜解析結果＞
以下、図面を参照しつつ、解析結果について説明する。なお、以下の図において、縦軸の値が大きくなる側を上側とし、反対側を下側とする。また、横軸の値が大きくなる側を右側とし、反対側を左側とする。また、免震擁壁剛性Ｋｗは擁壁剛性（片持ち壁剛性）＋背面土剛性として算出している。
<Analysis result>
Hereinafter, the analysis results will be described with reference to the drawings. In the following figures, the side with the larger value on the vertical axis is the upper side and the opposite side is the lower side. In addition, the side where the value on the horizontal axis increases is the right side, and the opposite side is the left side. The seismic isolation retaining wall rigidity Kw is calculated as the retaining wall rigidity (cantilever wall rigidity) + back soil rigidity.
図５は、入力地震動レベル毎の最大応答層間変形角の増幅率を示す図であり、図６は、入力地震動レベル毎の１階最大応答層せん断力の増幅率を示す図である。ここで、最大応答層間変形角とは、各階の層間変形角のうちの最大値のことである、図の横軸はＫｗ／Ｍ（免震擁壁剛性／建物質量）であり、縦軸は増幅率（応答増幅）である。 5: is a figure which shows the amplification factor of the maximum response layer deformation angle for every input earthquake motion level, and FIG. 6 is a figure which shows the amplification factor of the 1st floor maximum response layer shear force for every input earthquake motion level. Here, the maximum response interlayer deformation angle is the maximum value of the interlayer deformation angles of each floor. The horizontal axis of the figure is Kw/M (seismic isolation retaining wall rigidity/building mass) and the vertical axis is It is the amplification factor (response amplification).
図５、図６より、最大応答層間変形角、１階最大応答層せん断力とも、Ｋｗ／Ｍが同じである場合、入力地震動レベル（地震動倍率）が大きいほど、増幅率（応答増幅）が大きくなっている。また、Ｋｗ／Ｍがある程度の値までは、Ｋｗ／Ｍが大きくなるにつれて増幅率（応答値）は増加しているが、Ｋｗ／Ｍがある程度の値以上になるとほぼ増幅率は変わらない。なお、図中太い縦線は検討建物（実施例１、実施例２）の実際のＫｗ／Ｍを示している。 From FIGS. 5 and 6, when the Kw/M is the same for both the maximum response layer deformation angle and the first floor maximum response layer shear force, the larger the input earthquake motion level (earthquake motion magnification), the greater the amplification factor (response amplification). Has become. Further, the amplification factor (response value) increases as Kw/M increases up to a certain value of Kw/M, but the amplification factor remains almost unchanged when Kw/M exceeds a certain value. The thick vertical line in the figure shows the actual Kw/M of the studied building (Example 1, Example 2).
図７は、入力地震動レベル毎の免震擁壁の最大応答変形を示す図である。図の横軸はＫｗ／Ｍ（免震擁壁剛性／建物質量）であり、縦軸は衝突後の免震擁壁変形量である。なお、免震擁壁の変形量は、免震層変形量からクリアランスの値を減算することによって求められる（つまり、免震擁壁の変形量＝免震層変形量−クリアランス）。図７より、Ｋｗ／Ｍが同じである場合、入力地震動レベル（地震動倍率）が大きいほど、擁壁変形量が大きくなっている。また、各入力地震動レベルにおいて、免震擁壁の最大応答変形はＫｗ／Ｍが大きくなるにつれて減少している。 FIG. 7 is a diagram showing the maximum response deformation of the seismic isolation retaining wall for each input earthquake motion level. The horizontal axis of the figure is Kw/M (seismic isolation retaining wall rigidity/building mass), and the vertical axis is the amount of seismic isolation retaining wall deformation after collision. The amount of deformation of the seismic isolation retaining wall is obtained by subtracting the value of the clearance from the amount of seismic isolation layer deformation (that is, the amount of deformation of the seismic isolation retaining wall=the amount of seismic isolation layer deformation-clearance). From FIG. 7, when Kw/M is the same, the larger the input earthquake motion level (earthquake motion magnification) is, the larger the deformation amount of the retaining wall is. Further, at each input seismic motion level, the maximum response deformation of the seismic isolation retaining wall decreases as Kw/M increases.
図８は、入力地震動レベル毎の各階最大応答層間変形角を示す図である。図の横軸は層間変形角であり、縦軸は上部構造（上部建物）における階である。図より、最大応答層間変形角の高さ方向の分布はレベル２応答時と似たものとなるが、応答層せん断力が降伏層せん断力を超えるとその階に変形が集中している。例えば、実施例１では２階に集中し、実施例２では１階に集中している。 FIG. 8 is a diagram showing the maximum response layer deformation angle for each floor for each input earthquake motion level. The horizontal axis of the figure is the interlayer deformation angle, and the vertical axis is the floor in the upper structure (upper building). From the figure, the distribution of the maximum response layer deformation angle in the height direction is similar to that at the level 2 response, but when the response layer shear force exceeds the yield layer shear force, the deformation concentrates on that floor. For example, the first embodiment concentrates on the second floor, and the second embodiment concentrates on the first floor.
＜＜擁壁剛性について＞＞
擁壁との衝突を想定した合理的な設計を行うためには、前述した事象１及び事象２を防止するように設計する必要がある。すなわち、上部構造が倒壊しないように応答増幅を或るクライテリア以下に抑え、かつ、免震層の応答変形が限界変形以下となるような免震擁壁剛性を設定する必要がある。以下、これらについて検討する。
<<About Retaining Wall Rigidity>>
In order to perform a rational design assuming a collision with a retaining wall, it is necessary to design to prevent the above-mentioned event 1 and event 2. That is, it is necessary to set the seismic isolation retaining wall rigidity such that the response amplification is suppressed below a certain criterion so that the upper structure does not collapse and the response deformation of the seismic isolation layer is below the critical deformation. These will be examined below.
図９は、衝突速度（入力地震動レベル）と上部構造の応答増幅率との関係を示す図である。図９の横軸はＫｗ／Ｍ（免震擁壁剛性／建物質量）である。また図９の縦軸は免震層の衝突時速度であり、入力地震動の大きさに対応している。例えば、図中のＬ１〜Ｌ６は、入力地震動レベルを示している。具体的には、Ｌ１はレベル２×１．０５倍、Ｌ２はレベル２×１．１０倍、Ｌ３はレベル２×１．２０倍、Ｌ４はレベル２×１．３０倍、Ｌ５はレベル２×１．４０倍、及び、Ｌ６はレベル２×１．５０倍の入力地震動をそれぞれ示している。 FIG. 9 is a diagram showing the relationship between the collision velocity (input seismic motion level) and the response amplification factor of the superstructure. The horizontal axis of FIG. 9 is Kw/M (seismic isolation retaining wall rigidity/building mass). The vertical axis in Fig. 9 is the velocity at the time of collision of the base isolation layer, which corresponds to the magnitude of the input seismic motion. For example, L1 to L6 in the figure indicate the input seismic motion level. Specifically, L1 is level 2×1.05 times, L2 is level 2×1.10 times, L3 is level 2×1.20 times, L4 is level 2×1.30 times, and L5 is level 2×. 1.40 times and L6 have shown the input earthquake motion of level 2x1.50 times, respectively.
この図９は、図５のデータからＫｗ／Ｍを横軸とし、衝突の衝突速度を縦軸として、衝突による上部構造の応答増幅率をプロットし、上部構造の応答増幅率が同値となるライン（第一ラインに相当）を作成した図である。 In FIG. 9, the response amplification factor of the superstructure due to collision is plotted with Kw/M as the horizontal axis and the collision velocity of the collision as the vertical axis from the data of FIG. It is a figure which created (equivalent to a 1st line).
図９に示すように、実施例１、実施例２とも良く似た形となっている。図９の右下がりのラインは、上部構造の最大応答層間変形角のクライテリアを示すラインである。例えば、上部構造の最大応答層間変形角を２．０以下に設計したい場合、黒四角（■）を結ぶラインよりも下側（応答増幅率が小さい側）にすればよい。これにより、上部構造に過大な損傷や倒壊・崩壊が生じること（事象１）を抑制できる。 As shown in FIG. 9, the shapes are very similar to those of the first and second embodiments. The line in the lower right of FIG. 9 is a line showing the criteria of the maximum response interlayer deformation angle of the upper structure. For example, when it is desired to design the maximum response interlayer deformation angle of the upper structure to be 2.0 or less, it may be set below the line connecting the black squares (■) (the side where the response amplification factor is small). As a result, it is possible to suppress the occurrence of excessive damage or collapse/collapse of the superstructure (Event 1).
また、図１０は、衝突速度（入力地震動レベル）と免震擁壁変形量との関係を示す図である。図１０の縦軸及び横軸は図９と同じである。 In addition, FIG. 10 is a diagram showing the relationship between the collision speed (input seismic motion level) and the amount of seismic isolation retaining wall deformation. The vertical axis and the horizontal axis in FIG. 10 are the same as those in FIG.
この図１０は図７のデータからＫｗ／Ｍを横軸とし、衝突の衝突速度を縦軸として、衝突による免震擁壁の変形量をプロットし、免震擁壁の変形量が同値となるライン（第二ラインに相当）を作成した図である。 This FIG. 10 plots the deformation amount of the seismic isolation retaining wall due to the collision with Kw/M as the horizontal axis and the collision velocity of the collision as the vertical axis from the data of FIG. 7, and the deformation amount of the seismic isolation retaining wall becomes the same value. It is the figure which created the line (equivalent to the second line).
図１０においても、実施例１、実施例２とも良く似た形となっている。１０の右上がりのラインは免震擁壁（換言すると免震層）の変形量のクライテリアを示している。例えば、免震擁壁の最大変形を２０ｍｍ以下（免震層の変形量を２０ｍｍ＋クリアランス以下）に設計したい場合、黒四角（■）を結ぶラインよりも下側（変形量が小さい側）にすればよい。これにより、免震装置が破断したり、軸力、支持能力を失ったりすること（事象２）を抑制できる。 Also in FIG. 10, the shape is very similar to that of the first and second embodiments. The line to the right of 10 indicates the criteria for the amount of deformation of the seismic isolation retaining wall (in other words, the seismic isolation layer). For example, if you want to design the maximum deformation of the seismic isolation retaining wall to be 20 mm or less (the amount of deformation of the seismic isolation layer is 20 mm + clearance or less), slide it below the line connecting the black squares (■) (the side where the amount of deformation is small). Good. As a result, it is possible to prevent the seismic isolation device from breaking or losing axial force and supporting ability (event 2).
図１１は、上部構造と擁壁との衝突を用いた設計の概念図である。この図１１は、図９の右下がりのライン（第一ライン）と図１０の右上がりのライン（第二ライン）との２本のラインを組み合わせた図である。前述したように、右下がりのラインは、上部構造の最大応答層間変形角のクライテリア（例えば、レベル２応答層間変形角×１．５）を示しており、また、右上がりのラインは、免震層の最大応答変形のクライテリア（例えば、積層ゴムの限界変形量）を示している。これにより、上部構造の最大応答層間変形角のクライテリアと、免震層の最大応答変形のクライテリアとの関係が明確になる。 FIG. 11 is a conceptual diagram of a design using the collision between the upper structure and the retaining wall. FIG. 11 is a diagram in which two lines, that is, the line descending to the right of FIG. 9 (first line) and the line rising to the right of FIG. 10 (second line) are combined. As described above, the line descending to the right indicates the criteria of the maximum response layer deformation angle of the superstructure (for example, level 2 response layer deformation angle x 1.5), and the line rising to the right shows seismic isolation. The criteria of the maximum response deformation of the layer (for example, the limit deformation amount of the laminated rubber) are shown. This clarifies the relationship between the criteria for the maximum response deformation angle of the superstructure and the criteria for the maximum response deformation of the base isolation layer.
この２本のラインによるクライテリアをともに満足する領域（２つのラインのそれぞれ下側の領域）が設計可能領域であり、入力地震動レベルを設定すれば、設計可能なＫｗ／Ｍの範囲を容易に推測することができる。すなわち、図１１に示すように、設定した入力地震動レベルのとき（換言すると、衝突速度が所定値のとき）の右上がりのラインのＫｗ／Ｍ値（第一Ｋｗ／Ｍに相当）と、右上がりのラインのＫｗ／Ｍ値（第二Ｋｗ／Ｍに相当）との間の領域が設計可能領域となる。上部構造の質量Ｍは既知であるので、上記２つのＫｗ／Ｍを算出することにより擁壁剛性Ｋｗの範囲は容易に算出できる。 The area that can satisfy the criteria of these two lines (the area under each of the two lines) is the designable area, and if the input seismic motion level is set, the designable Kw/M range can be easily estimated. can do. That is, as shown in FIG. 11, the Kw/M value (corresponding to the first Kw/M) of the line rising to the right at the set input earthquake motion level (in other words, when the collision speed is a predetermined value) and the right The area between the rising line and the Kw/M value (corresponding to the second Kw/M) is the designable area. Since the mass M of the upper structure is known, the range of the retaining wall rigidity Kw can be easily calculated by calculating the above two Kw/M.
＜緩衝体の剛性について＞
次に、対象となる免震建物、すなわち、上部構造の質量Ｍ１、擁壁剛性Ｋｗ１の免震建物が、想定される入力地震動レベルの地震動下において、上部構造に過大な損傷や倒壊・崩壊が生じること（事象１）を抑制し、免震装置が破断したり、軸力、支持能力を失ったりすること（事象２）を抑制するために、介在すべき緩衝体の剛性を求める。
<About the rigidity of the buffer>
Next, the target seismic isolated building, that is, the seismic isolated building with the mass M1 of the upper structure and the retaining wall rigidity Kw1 is subject to excessive damage or collapse/collapse of the upper structure under the assumed input earthquake motion level earthquake motion. In order to suppress the occurrence (Event 1) and to prevent the seismic isolation device from breaking or losing the axial force and the supporting ability (Event 2), the rigidity of the cushioning body to be interposed is obtained.
緩衝体は、軟質の合成樹脂でなり、図４（ａ）に示すように、免震擁壁２の、上部構造体１と水平方向に対向する位置に設けられており、緩衝体３と上部構造１との間には水平方向に所定のクリアランスＸが設けられている。このときの所定のクリアランスＸは、上述し図４（ｂ）に示した、緩衝体が設けられていない免震建物の上部構造１と免震擁壁２とのクリアランスＸと等しく設定している。 The shock absorber is made of a soft synthetic resin, and is provided at a position of the seismic isolation retaining wall 2 facing the upper structure 1 in the horizontal direction, as shown in FIG. A predetermined clearance X is provided in the horizontal direction between the structure 1 and the structure 1. The predetermined clearance X at this time is set to be equal to the clearance X between the seismic isolated retaining wall 2 and the superstructure 1 of the seismic isolated building in which the cushioning body is not provided, as described above and shown in FIG. 4B. ..
前述した対象となる免震建物における上部構造の質量Ｍ、緩衝体を備えた擁壁剛性ＫからＫｗ／Ｍ値を算出する。想定される入力地震動レベルにおける対象となる免震建物のＫｗ／Ｍ値（Ｋ／Ｍとする）を図１１にプロットした図が、例えば、図１２（図中×印）のように示されたとする。 The Kw/M value is calculated from the mass M of the superstructure in the target seismic isolated building and the rigidity K of the retaining wall provided with the buffer body. The Kw/M value (assumed to be K/M) of the target seismic isolated building at the assumed input ground motion level is plotted in FIG. 11, for example, as shown in FIG. 12 (marked with X). To do.
図１２は、剛性Ｋｆの緩衝体を備えた免震建物のＫｗ／Ｍ値を示す図である。 FIG. 12 is a diagram showing a Kw/M value of a base-isolated building provided with a shock absorber having rigidity Kf.
図１２に示すように、プロットした値は、右下がりのライン（第一ライン）より上側に位置するので、設計可能領域から外れている。そこで、免震擁壁剛性を小さくすることと等価な効果が得るために、上部構造と免震擁壁との間に緩衝体を介在させることとし、設計可能領域となるような緩衝体の剛性を設定する。 As shown in FIG. 12, the plotted values are located above the line to the right (first line), and thus are outside the designable region. Therefore, in order to obtain an effect equivalent to reducing the rigidity of the seismic isolation retaining wall, a buffer is interposed between the upper structure and the seismic isolation retaining wall, and the rigidity of the buffer is designed so that it can be designed. To set.
より具体的には、想定される入力地震動レベルＬにおける設計可能領域は、Ｋｗ１／Ｍ（第一Ｋｗ／Ｍ）からＫｗ２／Ｍ（第二Ｋｗ／Ｍ）の範囲なので、Ｋ／Ｍが、Ｋｗ１／Ｍ（第一Ｋｗ／Ｍ）からＫｗ２／Ｍ（第二Ｋｗ／Ｍ）の範囲となるようなＫ及び緩衝体の剛性Ｋｆを、緩衝体剛性Ｋｆと擁壁剛性Ｋｗの直列接続時の剛性を示す（式１）により求める。 More specifically, the designable region at the assumed input earthquake ground motion level L is in the range of Kw1/M (first Kw/M) to Kw2/M (second Kw/M), so K/M is Kw1. /M (first Kw/M) to Kw2/M (second Kw/M) in the range of K and the rigidity Kf of the shock absorber, the rigidity when the shock absorber rigidity Kf and the retaining wall rigidity Kw are connected in series. Is obtained by (Equation 1).
この算出結果に基づいて、本実施形態における免震建物に備える緩衝体の適切な剛性を決定することが可能である。 Based on this calculation result, it is possible to determine the appropriate rigidity of the shock absorber provided in the seismic isolated building in the present embodiment.
＜設定した緩衝体の特性の確認＞
次に、上記の方法により設定された緩衝体が免震建物に備えられた際に、所望の剛性Ｋｆとしての効果が得られるか、すなわち、適切な緩衝体であるか否かを確認する。
<Checking the characteristics of the set buffer>
Next, it is confirmed whether or not the effect as the desired rigidity Kf is obtained when the shock absorber set by the above method is provided in the seismic isolated building, that is, whether or not the shock absorber is an appropriate shock absorber.
緩衝体の特性の確認は、過大地震時に擁壁と衝突する上部構造に緩衝体を設置した場合の上部構造の応答低減効果を、時刻歴応答解析を行うことにより確認する。具体的には、クリアランス（衝突位置）、及び緩衝体の復元力特性をパラメーターとし、様々な地震動レベルでの緩衝体による上部構造の応答低減効果を図１に示した応答解析モデルにより確認する。本実施形態では、緩衝体と弾性の擁壁ばねを直列にモデル化することで、衝突による影響を模擬するモデルとする。本解析においては、擁壁ばねは、緩衝体の効果をより顕著に把握するために十分に剛とみなせる剛性（例えば、Ｋｗ＝１０００００ｋＮ／ｍｍ）とする。 To confirm the characteristics of the shock absorber, the response reduction effect of the superstructure when the shock absorber is installed in the superstructure that collides with the retaining wall during an excessive earthquake is confirmed by performing time history response analysis. Specifically, using the clearance (collision position) and the restoring force characteristic of the shock absorber as parameters, the response reduction effect of the superstructure by the shock absorber at various seismic motion levels is confirmed by the response analysis model shown in FIG. In the present embodiment, the shock absorber and the elastic retaining wall spring are modeled in series to simulate a collision effect. In this analysis, the retaining wall spring has a rigidity (for example, Kw=100000 kN/mm) that can be regarded as sufficiently rigid in order to more clearly grasp the effect of the buffer body.
入力地震波は、レベル２告示スペクトル適合波（神戸ＥＷ位相、表層地盤の特性を考慮）の加速度を１．５倍〜２．１８倍まで０．０２倍刻みで増加させ、倍率が１．５４倍で免震層の変形が５００ｍｍに達し、衝突回数が１回となるように設定している。すなわち、上部構造と、免震擁壁に設けられた緩衝体との所定のクリアランスを５００ｍｍに設定している。 The input seismic wave increases the acceleration of the level 2 notification spectrum compatible wave (Kobe EW phase, considering the characteristics of the surface ground) from 1.5 times to 2.18 times in 0.02 times increments, and the magnification is 1.54 times. The deformation of the seismic isolation layer reaches 500 mm and the number of collisions is set to 1. That is, the predetermined clearance between the upper structure and the shock absorber provided on the seismic isolation retaining wall is set to 500 mm.
図１３は、緩衝体の復元力特性を示す図である。解析ケースは、擁壁ばねのみとするＣａｓｅＡと、図１３に示す復元力を有する緩衝体を設置するＣａｓｅＢとの２つのケースとする。また、緩衝体の変形代は１００ｍｍとする。 FIG. 13 is a diagram showing the restoring force characteristic of the buffer body. There are two analysis cases, Case A having only a retaining wall spring, and Case B having a cushioning body having a restoring force shown in FIG. Further, the deformation allowance of the buffer body is 100 mm.
図１４は、緩衝体を備えた場合の上部構造の応答解析結果を示す図である。横軸を地震波倍率、縦軸を最大応答値（1階層間変形角）とする。ＣａｓｅＡ、Ｂともに地震波倍率１．５４倍で擁壁・緩衝体に上部構造が衝突する。また、ＣａｓｅＢでは、地震波倍率１．９倍前後で緩衝体の変形代が０となり応答値は急激に増加することが確認された。 FIG. 14 is a diagram showing a response analysis result of the upper structure in the case where the buffer body is provided. The horizontal axis is the seismic wave magnification, and the vertical axis is the maximum response value (deformation angle between layers). In Cases A and B, the seismic wave magnification is 1.54 times, and the superstructure collides with the retaining wall/buffer. Also, in Case B, it was confirmed that the deformation allowance of the buffer body became 0 and the response value drastically increased when the seismic wave magnification was about 1.9 times.
このため、剛性Ｋｆの緩衝体を上記モデルの如く使用した場合には、衝突開始震動レベルを示す地震動倍率１．５４倍（図１４におけるαのライン）から最大変形震動レベルを示す地震波倍率１．９倍（図１４におけるβのライン）の間に、想定される地震動レベルが含まれている場合には、剛性Ｋｆの緩衝体が剛性Ｋｆとして効果を発揮することが確認でき、想定される地震動レベルが含まれていない場合には、剛性Ｋｆの緩衝体が剛性Ｋｆとして効果を発揮しないことが確認できる。よって、想定される地震動レベルが地震動倍率１．５４倍から地震波倍率１．９倍の間に含まれている場合に、本実施形態の免震建物に備える緩衝体の剛性をＫｆと決定する。 For this reason, when a shock absorber having rigidity Kf is used as in the above model, the seismic wave magnification of 1.54 times (line α in FIG. 14) indicating the collision start vibration level to the seismic wave magnification of 1. When the expected seismic motion level is included between 9 times (β line in FIG. 14), it can be confirmed that the buffer body having the rigidity Kf exerts an effect as the rigidity Kf, and the expected seismic motion is confirmed. When the level is not included, it can be confirmed that the buffer body having the rigidity Kf does not exhibit the effect as the rigidity Kf. Therefore, when the assumed earthquake motion level is included between the earthquake motion magnification of 1.54 times and the seismic wave magnification of 1.9 times, the rigidity of the shock absorber provided in the seismic isolated building of the present embodiment is determined as Kf.
本実施形態の免震構造に用いる緩衝体の剛性決定方法によれば、緩衝体の適切な剛性Ｋｆを簡便に、効率的且つ合理的に想定でき、設計効率の向上を図ることが可能である。 According to the rigidity determination method of the shock absorber used in the seismic isolation structure of the present embodiment, the appropriate rigidity Kf of the shock absorber can be easily and efficiently and reasonably assumed, and the design efficiency can be improved. ..
また、上部構造に過大な損傷や倒壊・崩壊が生じないように設計することが可能であり、免震装置が破断したり、軸力、支持能力を失ったりしないように設計することも可能である。 It is also possible to design the superstructure so that it will not be excessively damaged, collapsed, or collapsed, and designed so that the seismic isolation device does not break or lose its axial force or support capacity. is there.
また、図１１に示す、Ｋｗ／Ｍを横軸とし、衝突の衝突速度を縦軸とした衝突応答解析の結果に示された、上部構造の応答増幅率が同値となるライン及び免震擁壁の変形量が同値となるラインにより、上部構造の応答値のクライテリアと、壁体の変形量のクライテリアとの関係が明確になる。そして、これら２本のラインによるクライテリアをともに満足する領域（設計可能領域）を推測することができ、設計可能な壁体剛性Ｋｗの範囲を容易に想定することができる。 In addition, the line and seismic isolation retaining wall where the response amplification factor of the superstructure has the same value as shown in the result of the collision response analysis in which Kw/M is the horizontal axis and the collision velocity of the collision is the vertical axis shown in FIG. The line that makes the deformation amount of the same value becomes clear, the relationship between the criterion of the response value of the superstructure and the criterion of the deformation amount of the wall becomes clear. Then, it is possible to estimate a region (designable region) that satisfies both the criteria of these two lines, and it is possible to easily assume the range of the wall rigidity Kw that can be designed.
そして、緩衝体のより適切な剛性Ｋｆを簡便に、効率的且つ合理的に想定でき、設計効率の向上を図ることが可能である。 Further, a more appropriate rigidity Kf of the shock absorber can be easily, efficiently and rationally assumed, and the design efficiency can be improved.
さらに、想定する衝突速度又は入力地震動の大きさに、より適した剛性Ｋｆの緩衝体を簡便に、効率的且つ合理的に想定でき、設計効率の向上を図ることが可能である。 Further, it is possible to easily, efficiently and rationally assume a shock absorber having a rigidity Kf more suitable for the assumed collision velocity or the magnitude of the input seismic motion, and it is possible to improve the design efficiency.
＝＝＝その他の実施形態について＝＝＝
上記実施形態は、本発明の理解を容易にするためのものであり、本発明を限定して解釈するためのものではない。本発明は、その趣旨を逸脱することなく、変更、改良され得ると共に、本発明にはその等価物が含まれることはいうまでもない。特に、以下に述べる実施形態であっても、本発明に含まれるものである。
=== Regarding Other Embodiments ===
The above embodiment is for facilitating the understanding of the present invention and is not for limiting the interpretation of the present invention. It goes without saying that the present invention can be modified and improved without departing from the spirit thereof and that the present invention includes equivalents thereof. In particular, the embodiments described below are also included in the present invention.
前述の実施形態では、基礎（下部構造）と上部建物（上部構造）との間に免震層を設けており、下部構造の外周部に上部構造の過大変位を抑制するための免震擁壁を設けていたが、これには限らない。例えば、構造物を上下に分割した場合における上層部分と下層部分の間に免震層を設置してもよい。この場合、免震層よりも下側の構造体に壁（壁体）を設けてもよいし、免震層よりも上側の構造体に壁（壁体）を設けてもよい。なお、この場合、壁体の剛性には背面土剛性は含まれない。 In the above-described embodiment, a seismic isolation layer is provided between the foundation (substructure) and the upper building (superstructure), and the seismic isolation holder for suppressing excessive displacement of the superstructure is provided on the outer periphery of the substructure. There was a wall, but it is not limited to this. For example, a seismic isolation layer may be installed between the upper layer portion and the lower layer portion when the structure is divided into upper and lower parts. In this case, a wall (wall body) may be provided in the structure below the seismic isolation layer, or a wall (wall) may be provided in the structure above the seismic isolation layer. In this case, the rigidity of the back wall does not include the rigidity of the back wall.
また、前述の実施形態では、２本のライン（上部構造の最大応答層間変形角のクライテリアを示すライン、及び、免震層の最大応答変形のクライテリアを示すライン）から免震擁壁の剛性Ｋｗの範囲を想定していたがこれには限らない。例えば、免震擁壁の剛性Ｋｗの最大値又は最小値が予め定まっているような場合、何れか一本のラインから免震擁壁の剛性Ｋｗの範囲を想定してもよい。 Further, in the above-described embodiment, the rigidity Kw of the seismic isolation retaining wall is calculated from two lines (a line indicating the criteria of the maximum response interlayer deformation angle of the upper structure and a line indicating the criteria of the maximum response deformation of the seismic isolation layer). However, the range is not limited to this. For example, when the maximum value or the minimum value of the rigidity Kw of the seismic isolation retaining wall is predetermined, the range of the rigidity Kw of the seismic isolation retaining wall may be assumed from any one line.
また、前述の実施形態では、上部構造の応答値として応答増幅率を評価していたがこれには限られない。例えば、応答値そのものを評価してもよい。 Further, in the above-described embodiment, the response amplification factor is evaluated as the response value of the upper structure, but the present invention is not limited to this. For example, the response value itself may be evaluated.
また、図９〜図１１では、縦軸を衝突速度にしていたが、縦軸を入力地震動レベルにしてもよい。 Further, in FIGS. 9 to 11, the vertical axis represents the collision velocity, but the vertical axis may represent the input seismic motion level.
図１５は、クリアランスＸの上部構造と擁壁との間に緩衝体が備えられている状態を示す図である。 FIG. 15 is a diagram showing a state in which a shock absorber is provided between the upper structure of the clearance X and the retaining wall.
上記実施形態においては、上部構造と擁壁に備えられた緩衝体とのクリアランスＸと、衝突応答解析モデルにて想定した上部構造と擁壁とのクリアランスＸとを等しくした例（以下、ＴｙｐｅＡという）について説明したが、既存の免震建物に緩衝体を設ける場合等には、図１５に示すように、上部構造と擁壁とが水平方向にクリアランスＸをもった免震建物の上部構造と擁壁との間に緩衝体を設ける例（以下、ＴｙｐｅＢという）も考えられる。 In the above embodiment, an example in which the clearance X between the upper structure and the buffer provided on the retaining wall is equal to the clearance X between the upper structure and the retaining wall assumed in the collision response analysis model (hereinafter referred to as Type A). ) Has been described, but when a shock absorber is provided in an existing seismic isolated building, as shown in FIG. 15, the superstructure and the retaining wall have a horizontal clearance X, An example of providing a buffer between the retaining wall and the retaining wall (hereinafter referred to as Type B) is also conceivable.
図１６（ａ）は、上部構造と緩衝体とのクリアランスＸの場合の上部構造の応答解析結果を示す図であり、図１６（ｂ）は、クリアランスＸの上部構造と擁壁との間に緩衝体が備えられている場合の上部構造の応答解析結果を示す図である。 FIG. 16A is a diagram showing a response analysis result of the superstructure in the case of the clearance X between the superstructure and the buffer body, and FIG. 16B is between the superstructure of the clearance X and the retaining wall. It is a figure which shows the response analysis result of an upper structure when a buffer is provided.
図１６（ａ）のαのラインは、緩衝体が設けられていない場合において上部構造が擁壁と衝突するときの地震動レベルまたはＴｙｐｅＡにおいて上部構造が緩衝体と衝突し始めるときの地震動レベルを示している。図１６（ａ）のβのラインは、ＴｙｐｅＡにおいて緩衝体の変形代がなくなり擁壁に直接衝突したときと同じ応答値となるときの震動レベルを示している。 The line α in FIG. 16( a) indicates the seismic-motion level when the upper structure collides with the retaining wall in the case where the buffer is not provided, or the seismic-motion level when the upper structure starts to collide with the buffer in Type A. ing. The β line in FIG. 16A indicates the vibration level when the type A has no deformation allowance and the response value is the same as when it directly collides with the retaining wall.
また、図１６（ｂ）のαのラインは、緩衝体が設けられていない場合において上部構造が擁壁と衝突するときの地震動レベルを示している。図１６（ｂ）のβのラインは、ＴｙｐｅＡにおいて緩衝体の変形代がなくなり擁壁に直接衝突したときと同じ応答値となるときの震動レベルを示している。図１６（ｂ）のγのラインは、ＴｙｐｅＢにおいて上部構造が緩衝体と衝突し始めるときの地震動レベルを示している。 Further, the line α in FIG. 16B shows the seismic motion level when the upper structure collides with the retaining wall when the buffer is not provided. The β line in FIG. 16B shows the vibration level when the type A has no deformation allowance and has the same response value as when it directly collides with the retaining wall. The line γ in FIG. 16B shows the seismic-motion level when the upper structure starts to collide with the buffer body in Type B.
クリアランスＸの上部構造と擁壁との間に緩衝体が備えられているＴｙｐｅＢの場合には、上部構造と緩衝体とがクリアランスＸをもったＴｙｐｅＡの場合よりも早く、すなわち水平変位が小さいうちに、緩衝体と上部構造とが衝突する。衝突が早まることにより、図１６（ｂ）に示すＴｙｐｅＢの場合には、図１６（ａ）に示すＴｙｐｅＡの場合には存在しなかった、応答値が増大する領域（γのラインとαのラインとの間の領域）が存在する。このため、ＴｙｐｅＢの場合には、応答値が増大する領域（γのラインとαのラインとの間の領域）を避けて、想定される地震動レベルが、応答値が減少される領域（αのラインとβのラインとの間の領域）に含まれるように、免震建物に備える緩衝体の剛性を決定する。 In the case of Type B in which a buffer is provided between the upper structure of the clearance X and the retaining wall, it is faster than in the case of Type A in which the upper structure and the buffer have the clearance X, that is, while the horizontal displacement is small. Then, the shock absorber and the upper structure collide. Due to the faster collision, in the case of Type B shown in FIG. 16(b), there is a region in which the response value increases (the line of γ and the line of α, which did not exist in the case of Type A shown in FIG. 16(a). The area between and) exists. Therefore, in the case of Type B, the region where the response value increases is avoided (the region between the line of γ and the line of α) in the region where the response value decreases (the region of α The rigidity of the shock absorber provided in the base-isolated building is determined so that it is included in the area between the line and the line of β).
Claims (9)
前記上部構造の質量Ｍと、前記壁体の剛性Ｋｗとの比をパラメーターとして行った前記免震構造の衝突応答解析における前記免震構造の衝突による応答値と、
前記上部構造の質量Ｍと、前記壁体と前記他方との間に前記緩衝体が介在されたときに剛性が低下したとみなされる前記壁体のみなし剛性Ｋとの比Ｋ／Ｍと、
に基づいて、前記壁体と前記他方との間に介在させる前記緩衝体の剛性Ｋｆを決定することを特徴とする免震構造に用いる緩衝体の剛性決定方法。 A seismic isolation device is provided between the upper structure and the lower structure, and the wall body belonging to one of the upper structure or the lower structure and the other of the upper structure or the lower structure are horizontally separated from each other. In a seismic structure, a method of determining the rigidity of a shock absorber used in the seismic isolation structure assuming a collision between the other of the upper structure or the lower structure and the wall body,
A response value due to a collision of the seismic isolation structure in a collision response analysis of the seismic isolation structure performed with the ratio of the mass M of the upper structure and the rigidity Kw of the wall body as a parameter;
A ratio K/M between the mass M of the superstructure and the apparent rigidity K of the wall body that is considered to have reduced rigidity when the buffer body is interposed between the wall body and the other;
Based on the above, the rigidity Kf of the buffer body interposed between the wall body and the other body is determined, and the rigidity determination method of the buffer body used in the seismic isolation structure is characterized.
前記応答値は、前記衝突による前記上部構造の応答増幅率であることを特徴とする免震構造に用いる緩衝体の剛性決定方法。 A method for determining the rigidity of a shock absorber used in the seismic isolation structure according to claim 1,
The said response value is the response amplification factor of the said upper structure by the said collision, The rigidity determination method of the shock absorber used for the base isolation structure characterized by the above-mentioned.
前記応答値は、前記衝突による前記壁体の変形量であることを特徴とする免震構造に用いる緩衝体の剛性決定方法。 A method for determining the rigidity of a shock absorber used in the seismic isolation structure according to claim 1,
The said response value is the deformation|transformation amount of the said wall body by the said collision, The rigidity determination method of the buffer body used for the base isolation structure characterized by the above-mentioned.
前記上部構造の質量Ｍと、前記壁体の剛性Ｋｗとの比Ｋｗ／Ｍを横軸とし、前記衝突の衝突速度又は入力地震動の大きさを縦軸として、前記衝突による前記上部構造の応答値と、前記衝突による前記壁体の変形量とをプロットし、前記上部構造の応答値が同値となる第一ラインと、前記壁体の変形量が同値となる第二ラインとを作成することを特徴とする免震構造に用いる緩衝体の剛性決定方法。 A method for determining the rigidity of a shock absorber used in the seismic isolation structure according to claim 1,
The ratio Kw/M of the mass M of the superstructure to the rigidity Kw of the wall is taken as the horizontal axis, and the collision velocity of the collision or the magnitude of the input seismic motion is taken as the vertical axis, and the response value of the superstructure due to the collision is given. And plotting the amount of deformation of the wall body due to the collision, and creating a first line in which the response value of the upper structure has the same value and a second line in which the amount of deformation of the wall member has the same value. A method for determining the rigidity of a shock absorber used for a characteristic seismic isolation structure.
前記衝突速度又は前記入力地震動の大きさが所定値のときの前記第一ラインの第一Ｋｗ／Ｍ、及び、前記第二ラインの第二Ｋｗ／Ｍを算出することを特徴とする免震構造に用いる緩衝体の剛性決定方法。 A method for determining the rigidity of a shock absorber used in the seismic isolation structure according to claim 4,
A seismic isolation structure characterized by calculating the first Kw/M of the first line and the second Kw/M of the second line when the collision velocity or the magnitude of the input seismic motion is a predetermined value. Method for determining the rigidity of a buffer used in.
前記第一Ｋｗ／Ｍと前記第二Ｋｗ／Ｍの間を設計可能領域とすることを特徴とする免震構造に用いる緩衝体の剛性決定方法。 A method for determining the rigidity of a shock absorber used in the seismic isolation structure according to claim 5,
A rigidity determination method of a shock absorber used in a seismic isolation structure, characterized in that a designable region is between the first Kw/M and the second Kw/M.
次式に基づいて、前記Ｋ／Ｍが、前記第一Ｋｗ／Ｍと前記第二Ｋｗ／Ｍの間の値をなすべく、前記緩衝体の剛性Ｋｆを決定することを特徴とする免震構造に用いる緩衝体の剛性決定方法。
A method for determining the rigidity of a shock absorber used in the seismic isolation structure according to claim 6,
The seismic isolation structure characterized in that the rigidity Kf of the shock absorber is determined such that the K/M has a value between the first Kw/M and the second Kw/M based on the following equation. Method for determining the rigidity of a buffer used in.
前記応答値が、前記壁体と、前記上部構造又は前記下部構造の他方とが、水平方向に所定のクリアランスをもって離間している免震構造の衝突応答解析によるものであり、
前記壁体と、前記上部構造又は前記下部構造の他方とが、互いの間に剛性Ｋｆの緩衝体を備えると共に、前記緩衝体と前記壁体又は前記他方とが水平方向に前記所定のクリアランスをもって離間している他の免震構造の、前記衝突速度又は前記入力地震動の大きさに対する衝突応答解析の結果に基づいて特定される、前記壁体又は前記他方と前記緩衝体とが衝突し始めるときの前記衝突速度又は前記入力地震動の大きさを示す衝突開始震動レベルと、
前記緩衝体の変形代が失われるときの前記衝突速度又は前記入力地震動の大きさを示す最大変形震動レベルとの間に、
想定する前記衝突速度又は前記入力地震動の大きさが含まれるべく前記緩衝体の前記剛性Ｋｆを設定することを特徴とする免震構造に用いる緩衝体の剛性決定方法。 A method for determining the rigidity of a shock absorber used in the seismic isolation structure according to any one of claims 4 to 7,
The response value is based on a collision response analysis of a seismic isolation structure in which the wall body and the other of the upper structure or the lower structure are separated by a predetermined clearance in the horizontal direction,
The wall body and the other of the upper structure or the lower structure are provided with a cushioning body having a rigidity Kf between each other, and the cushioning body and the wall body or the other are provided with the predetermined clearance in the horizontal direction. When the wall body or the other and the buffer body start to collide with each other, which is specified based on the result of the collision response analysis of the other seismic isolation structure with respect to the collision velocity or the magnitude of the input earthquake motion A collision start vibration level indicating the collision velocity or the magnitude of the input seismic motion,
Between the collision velocity or the maximum deformation vibration level indicating the magnitude of the input earthquake motion when the deformation allowance of the buffer is lost,
A method for determining the rigidity of a shock absorber used in a seismic isolation structure, wherein the rigidity Kf of the shock absorber is set so as to include the assumed collision velocity or the magnitude of the input earthquake motion.
前記応答値が、前記壁体と、前記上部構造又は前記下部構造の他方とが、水平方向に所定のクリアランスをもって離間している免震構造の衝突応答解析によるものであり、
前記免震構造の、前記壁体と前記他方とが衝突し始めるときの前記衝突速度又は前記入力地震動の大きさを示す衝突開始震動レベルと、
前記壁体と、前記上部構造又は前記下部構造の他方とが、互いの間に剛性Ｋｆの緩衝体を備えると共に、前記壁体と前記他方とが水平方向に所定のクリアランスをもって離間している他の免震構造の、前記緩衝体の変形代が失われるときの前記衝突速度又は前記入力地震動の大きさを示す最大変形震動レベルとの間であって、
前記他の免震構造にて前記緩衝体が備えられたことにより、前記免震構造の応答値より増大する領域を除く領域に、
想定する前記衝突速度又は前記入力地震動の大きさが含まれるべく前記緩衝体の前記剛性Ｋｆを設定することを特徴とする免震構造に用いる緩衝体の剛性決定方法。
A method for determining the rigidity of a shock absorber used in the seismic isolation structure according to any one of claims 4 to 7,
The response value is based on a collision response analysis of a seismic isolation structure in which the wall body and the other of the upper structure or the lower structure are separated by a predetermined clearance in the horizontal direction,
In the seismic isolation structure, a collision start vibration level indicating the magnitude of the collision velocity or the input earthquake motion when the wall body and the other start to collide, and
The wall body and the other of the upper structure and the lower structure are provided with a cushioning body having a rigidity Kf between them, and the wall body and the other are horizontally separated from each other with a predetermined clearance. Of the seismic isolation structure of, between the collision speed when the deformation allowance of the buffer is lost or the maximum deformation vibration level indicating the magnitude of the input earthquake motion,
By providing the buffer in the other seismic isolation structure, in the area excluding the area that increases from the response value of the seismic isolation structure,
A method for determining the rigidity of a shock absorber used in a seismic isolation structure, wherein the rigidity Kf of the shock absorber is set so as to include the assumed collision velocity or the magnitude of the input earthquake motion.
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