JPH09125412A - Construction of vibration isolation of bridge pier foundation - Google Patents

Construction of vibration isolation of bridge pier foundation

Info

Publication number
JPH09125412A
JPH09125412A JP28875395A JP28875395A JPH09125412A JP H09125412 A JPH09125412 A JP H09125412A JP 28875395 A JP28875395 A JP 28875395A JP 28875395 A JP28875395 A JP 28875395A JP H09125412 A JPH09125412 A JP H09125412A
Authority
JP
Japan
Prior art keywords
footing
pier
footing portion
bridge pier
weak layer
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP28875395A
Other languages
Japanese (ja)
Inventor
Kazushi Wakita
和試 脇田
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hazama Corp
Original Assignee
Hazama Gumi Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hazama Gumi Ltd filed Critical Hazama Gumi Ltd
Priority to JP28875395A priority Critical patent/JPH09125412A/en
Publication of JPH09125412A publication Critical patent/JPH09125412A/en
Pending legal-status Critical Current

Links

Abstract

PROBLEM TO BE SOLVED: To provide a rigid bridge pier to secure a stable driving of vehicle usually or in a small scale earthquake and prevent the bridge pier from collapsing in a more violent earthquake than a specified extent and further, make the structure stable. SOLUTION: This construction is provided with the first footing 11 integrally constructed together with the bridge pier 17 and formed to have the upper face 11a, the lower face 11c, and the side faces 11b and the second footing 12 formed to surround the upper face, the lower face and the side faces of the first footing and contact the ground. Vibration isolation devices 13a, 13b attenuating the horizontal vibrations are arranged between the upper and lower faces of the first footing and the second footing. And a weak layer 14 which is broken by a larger external force than a specified strength is provided between the side faces and the bridge pier of the first footing and the second footing.

Description

【発明の詳細な説明】Detailed Description of the Invention

【0001】[0001]

【産業上の利用分野】本発明は、橋脚基礎の免震構造に
関する。
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a base isolation structure for a pier foundation.

【0002】[0002]

【従来の技術】橋梁の免震構造の先行技術としては、特
開平5−247911号公報が、橋脚基礎部に免震装置
を設けたものを提案している。この免震装置は図4に示
したように、橋脚53の下端を積層ゴム56を介してフ
ーチング55上で支持し、橋脚53の下端とフーチング
55との間にダンパー57を設置して形成されており、
地盤54に水平方向の振動が生じると、この水平振動
は、ダンパー57および積層ゴム56により減衰されて
橋脚53に伝達される。
2. Description of the Related Art As a prior art of a seismic isolation structure for a bridge, Japanese Patent Laid-Open No. 5-247911 proposes a seismic isolation device provided on a pier foundation. As shown in FIG. 4, this seismic isolation device is formed by supporting the lower end of the bridge pier 53 on the footing 55 through the laminated rubber 56 and installing a damper 57 between the lower end of the pier 53 and the footing 55. And
When horizontal vibration occurs in the ground 54, this horizontal vibration is attenuated by the damper 57 and the laminated rubber 56 and transmitted to the pier 53.

【0003】[0003]

【発明が解決しようとする課題】しかしながら上記免震
構造において、積層ゴム56は、常に水平方向の振動を
減衰できるように非拘束状態で設けられており、小規模
な地震が発生しても、変形して地震力を吸収しようとす
る。したがって、小規模な地震に対しても橋脚や橋桁等
の構造物が揺れるといった、柔な構造となり、橋梁の本
来の機能となる交通車両の安定走行の機能を失う恐れが
ある。また、かように橋脚とフーチングとの間が実質的
な非拘束状態では、構造的にも不安定になるという問題
がある。
However, in the above-described seismic isolation structure, the laminated rubber 56 is provided in an unconstrained state so that it can always damp horizontal vibrations, and even if a small earthquake occurs, It deforms and tries to absorb the seismic force. Therefore, structures such as bridge piers and bridge girders are shaken even with a small earthquake, and there is a risk that the original function of the bridge, namely, the stable running function of the traffic vehicle, may be lost. In addition, there is a problem in that the structure becomes unstable in a substantially unrestrained state between the pier and the footing.

【0004】本発明は前記問題点を解決せんとしたもの
であり、その目的は、常時および小規模地震発生時に
は、車両の安定走行を確保するような剛な橋脚を提供
し、所定強度以上の地震時には橋脚の崩壊を免れ、さら
に構造上も安定的な橋脚基礎の免震構造を提供すること
にある。
The present invention has been made to solve the above-mentioned problems, and an object thereof is to provide a rigid pier for ensuring stable running of a vehicle at all times and at the time of occurrence of a small-scale earthquake, and to provide a rigid pier having a predetermined strength or more. The aim is to provide a base isolation structure for the pier foundation, which is free from collapse of the pier during an earthquake and structurally stable.

【0005】[0005]

【課題を解決するための手段】本発明は、前記目的に鑑
みてなされたものであり、その要旨は、橋脚フーチング
が、橋脚と一体に設けると共に上下面及び側面を備える
ように形成した第一のフーチング部と、この第一のフー
チング部の下面及び側面を囲んで地盤に接するように形
成した第二のフーチング部とを備え、前記第一のフーチ
ング部の下面と前記第二のフーチング部との間に水平方
向の振動を減衰する免震装置を配置し、前記第一のフー
チング部の側面と前記第二のフーチング部との間に、所
定強度以上の外力によって破壊する弱層部を設けること
を特徴とする橋脚基礎の免震構造にある。
DISCLOSURE OF THE INVENTION The present invention has been made in view of the above-mentioned object, and its gist is to provide a pier footing integrally formed with a pier and having upper and lower surfaces and side surfaces. Footing portion and a second footing portion formed so as to contact the ground by surrounding the lower surface and the side surface of the first footing portion, the lower surface of the first footing portion and the second footing portion A seismic isolation device for damping horizontal vibrations is arranged between the first footing portion and the second footing portion, and a weak layer portion is provided between the second footing portion and the side surface of the first footing portion to be destroyed by an external force of a predetermined strength or more. It is characterized by the seismic isolation structure of the pier foundation.

【0006】本発明の別の要旨は、橋脚フーチングが、
橋脚と一体に設けると共に上下面及び側面を備えるよう
に形成した第一のフーチング部と、この第一のフーチン
グ部の上面、下面及び側面を囲んで地盤に接するように
形成した第二のフーチング部とを備え、前記第一のフー
チング部の上面及び下面と、前記第二のフーチング部と
の間に水平方向の振動を減衰する免震装置を配置し、前
記第一のフーチング部の側面及び橋脚と、前記第二のフ
ーチング部との間に、所定強度以上の外力によって破壊
する弱層部を設けることを特徴とする橋脚基礎の免震構
造にある。
Another gist of the present invention is that a pier footing is
A first footing portion formed integrally with the pier and having upper and lower surfaces and side surfaces, and a second footing portion formed so as to surround the upper surface, lower surface and side surfaces of the first footing portion and contact the ground. And a seismic isolation device for damping horizontal vibrations is arranged between the upper and lower surfaces of the first footing portion and the second footing portion, and the side surface of the first footing portion and the pier And a weak layer portion that is destroyed by an external force of a predetermined strength or more is provided between the second footing portion and the second footing portion.

【0007】本発明の橋脚基礎の免震構造において、弱
層部とは、所定強度以上の外力、例えば震度6以上程度
の地震動等による水平振動では破壊し、この所定強度以
下の外力では破壊しないような構造であれば良い。かよ
うな弱層部は、第一のフーチング部の側面に鋼板を固定
し、この鋼板と対向する第二のフーチング部の内面に別
の鋼板を固定し、これら対向する鋼板の間に複数の鉄筋
を溶接することにより形成しても良い。また、これ以外
に弱層部は、第一および第二のフーチング部のコンクリ
ートの圧縮強度より低い圧縮強度を持つ材料を、これら
対向する鋼板の間に打設し、所定以上の外力に対して破
壊するように形成することができる。
In the seismic isolation structure of the pier foundation of the present invention, the weak layer portion is destroyed by an external force having a predetermined strength or more, for example, horizontal vibration due to seismic motion having a seismic intensity of about 6 or more, and is not broken by an external force having a predetermined strength or less. Any structure may be used. In such a weak layer portion, a steel plate is fixed to the side surface of the first footing portion, another steel plate is fixed to the inner surface of the second footing portion facing the steel plate, and a plurality of steel plates are provided between the facing steel sheets. It may be formed by welding a reinforcing bar. In addition, in addition to this, the weak layer portion is formed by placing a material having a compressive strength lower than that of the concrete of the first and second footing portions between the steel plates facing each other, and applying an external force of a predetermined value or more. It can be formed to break.

【0008】本発明の橋脚基礎の免震構造において、第
一のフーチング部を橋脚と一体に設けるとは、例えば、
第一のフーチング部と橋脚とを、鉄筋又は/及び鉄骨コ
ンクリートを一体に打設して構築したり、または、第一
のフーチング部を鉄筋又は/及び鉄骨コンクリートで構
築し、鋼管又は/及び鋼管コンクリートにより構築した
橋脚をアンカーボルト等により一体に固定しても良い。
In the base isolation structure of the pier foundation of the present invention, the provision of the first footing portion integrally with the pier means, for example,
The first footing portion and the bridge pier are constructed by integrally casting reinforcing bars and / or steel-framed concrete, or the first footing section is constructed by reinforcing bars and / or steel-framed concrete, and steel pipes and / or steel pipes are constructed. The pier constructed with concrete may be fixed integrally with anchor bolts or the like.

【0009】[0009]

【実施例】以下に、本発明の実施例を添付図面に基づい
て詳細に説明する。図1は、本発明の橋脚基礎の免震構
造の断面図であり、図2は図1における弱層部の拡大断
面図である。図1において、橋脚フーチング1は、第一
のフーチング部11と第二のフーチング部12とを備え
るように形成する。すなわち、第一のフーチング部11
は鉄筋鉄骨コンクリート等によって橋脚17と一体に形
成し、且つ、上面11a、下面11c及び側面11bを
備えるような立体形状に形成し、一方、第二のフーチン
グ部12は、第一のフーチング部11の上面11a、下
面11c及び側面11bと、橋脚17の下端部表面との
間に所定長のクリアランスを保持するように囲んで形成
し、且つ、その下面が基礎杭16の杭頭によって支持さ
れるように形成する。かように形成された第一のフーチ
ング部11の上面11a及び下面11cと、第二のフー
チング部12の内面とのクリアランスには、それぞれ積
層ゴム13a,13bのような免震装置を挟着し、ま
た、第一のフーチング部11の側面11bと、第二のフ
ーチング部12の内面とのクリアランスには弱層部14
を設け、さらに橋脚17の下端部表面と、第二のフーチ
ング部12の内面とのクリアランスにも弱層部14’を
設ける。この弱層部14,14’を所定強度以上の外
力、例えば震度6以上程度の地震動等によって生じる水
平振動によって破壊するように形成する。
Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a sectional view of a base isolation structure of a pier foundation of the present invention, and FIG. 2 is an enlarged sectional view of a weak layer portion in FIG. In FIG. 1, the pier footing 1 is formed so as to include a first footing portion 11 and a second footing portion 12. That is, the first footing portion 11
Is formed integrally with the bridge pier 17 by reinforced steel frame concrete or the like, and is formed into a three-dimensional shape having the upper surface 11a, the lower surface 11c and the side surface 11b, while the second footing portion 12 is the first footing portion 11 Is formed so as to maintain a predetermined length of clearance between the upper surface 11a, the lower surface 11c and the side surface 11b of the pier 17 and the lower end surface of the pier 17, and the lower surface is supported by the pile head of the foundation pile 16. To form. Seismic isolation devices such as laminated rubbers 13a and 13b are sandwiched between the upper surface 11a and the lower surface 11c of the first footing portion 11 thus formed and the inner surface of the second footing portion 12, respectively. Also, the weak layer portion 14 is provided in the clearance between the side surface 11b of the first footing portion 11 and the inner surface of the second footing portion 12.
Further, a weak layer portion 14 ′ is also provided in the clearance between the lower end surface of the pier 17 and the inner surface of the second footing portion 12. The weak layer portions 14 and 14 'are formed so as to be destroyed by an external force having a predetermined strength or more, for example, horizontal vibration caused by a seismic motion having a seismic intensity of 6 or more.

【0010】上記弱層部14と14’とは同様な構成で
形成することができるので、以下、弱層部14のみにつ
いて更に詳細に説明する。弱層部14は図2に示したよ
うに、第一のフーチング部11の側面11bに固定され
た鋼板14cと、この鋼板14cと対向する第二のフー
チング部12の内面に固定された鋼板14aと、これら
鋼板14aと14cとの間に溶接して固定した複数の鉄
筋14bとで構成され、使用する鉄筋14bの強度、直
径及び配設本数を適宜調節することにより、弱層部14
を所望の破壊強度にすることができる。かような弱層部
14において、地震等によって第二のフーチング部12
から水平方向の振動が伝わると、弱層部14の鉄筋14
bは鋼板14aと14cとから圧縮力を受け、水平方向
の振動が所定強度以上に達して、圧縮力が全ての鉄筋1
4bの圧縮耐力の総和を越えると、鉄筋14bは座屈し
て破壊する。
Since the weak layer portions 14 and 14 'can be formed with the same structure, only the weak layer portion 14 will be described in more detail below. As shown in FIG. 2, the weak layer portion 14 includes a steel plate 14c fixed to the side surface 11b of the first footing portion 11 and a steel plate 14a fixed to the inner surface of the second footing portion 12 facing the steel plate 14c. And a plurality of reinforcing bars 14b welded and fixed between the steel plates 14a and 14c, and by appropriately adjusting the strength, diameter and number of the reinforcing bars 14b to be used, the weak layer portion 14
Can have a desired breaking strength. In such a weak layer portion 14, due to an earthquake or the like, the second footing portion 12 is
When horizontal vibration is transmitted from the
b receives a compressive force from the steel plates 14a and 14c, the horizontal vibration reaches a predetermined strength or more, and the compressive force is applied to all the reinforcing bars 1.
When the sum of the compressive strength of 4b is exceeded, the reinforcing bar 14b buckles and breaks.

【0011】上記構成の橋脚フーチング1において、第
一のフーチング部11の鉛直荷重は、その下面11cで
積層ゴム13bを介して第二のフーチング部12によっ
て支持され、また第一のフーチング部11を回転させよ
うとする曲げ応力が橋脚17から作用した場合には、そ
の上面11aに積層ゴム13aを介して配置された第二
のフーチング部12が回転を拘束するよう作用し、さら
に橋脚フーチング1に水平方向の振動が作用した場合、
第一のフーチング部11と第二のフーチング部12とが
異なる周期で振動しないように弱層部14,14’によ
って拘束する。
In the pier footing 1 having the above structure, the vertical load of the first footing portion 11 is supported by the second footing portion 12 via the laminated rubber 13b on the lower surface 11c thereof, and the first footing portion 11 is also supported. When the bending stress to rotate is applied from the pier 17, the second footing portion 12 arranged on the upper surface 11a via the laminated rubber 13a acts to restrain the rotation, and further the pier footing 1 is attached. When horizontal vibration is applied,
The first footing portion 11 and the second footing portion 12 are restrained by the weak layer portions 14 and 14 'so as not to vibrate at different cycles.

【0012】なお本発明の免震構造おいては、図1に示
すように、積層ゴム13a,13bの損傷等を検査して
維持管理するために、第一のフーチング部11と第二の
フーチング部12とのクリアランスまで連通する孔15
を、第二のフーチング部12に形成しても良い。
In the seismic isolation structure of the present invention, as shown in FIG. 1, the first footing portion 11 and the second footing portion 11 are used to inspect and maintain the laminated rubbers 13a and 13b for damage and the like. Hole 15 that communicates with the clearance with the portion 12
May be formed in the second footing portion 12.

【0013】上述のような橋脚基礎が設けられた地盤に
おいて、例えば、地震等により水平方向の振動が発生す
ると、この振動は地盤から第二のフーチング部12に伝
達される。そして、この水平方向の振動が所定強度以下
の場合、弱層部14,14’は破壊せずに第二のフーチ
ング部12から第一のフーチング部11及び橋脚17の
下端部に、振動が伝達される。したがって、積層ゴム1
3a,13bには水平方向の力が作用せず変形が生じな
いため、第一のフーチング部11と第二のフーチング部
12とは剛な構造を保持することができて、この剛構造
により水平方向の振動に対抗することができる。
When horizontal vibration occurs in the ground provided with the pier foundation as described above due to an earthquake or the like, this vibration is transmitted from the ground to the second footing portion 12. When the horizontal vibration is less than the predetermined strength, the weak layer portions 14 and 14 'are not destroyed and the vibration is transmitted from the second footing portion 12 to the lower end portions of the first footing portion 11 and the pier 17. To be done. Therefore, the laminated rubber 1
Since horizontal force does not act on 3a and 13b and deformation does not occur, the first footing portion 11 and the second footing portion 12 can maintain a rigid structure, and this rigid structure allows the horizontal structure to be maintained. It is possible to counter directional vibration.

【0014】一方、所定強度以上の水平方向の振動が発
生すると、弱層部14,14’は破壊し、第一のフーチ
ング部11は積層ゴム13a,13bのみを介して第二
のフーチング部12に支持されるようになり、積層ゴム
13a,13bは水平方向に変形可能となる。したがっ
て、第二のフーチング部12に水平方向の振動が伝達す
ると、積層ゴム13a,13bが変形して振動を減衰
し、第一のフーチング部11及び橋脚17に伝えるの
で、橋脚フーチング1は柔な構造となって橋脚17の崩
壊を防止することができる。
On the other hand, when a horizontal vibration of a predetermined strength or more is generated, the weak layer portions 14 and 14 'are destroyed, and the first footing portion 11 has the second footing portion 12 through only the laminated rubbers 13a and 13b. The laminated rubbers 13a and 13b can be deformed in the horizontal direction. Therefore, when the horizontal vibration is transmitted to the second footing portion 12, the laminated rubbers 13a and 13b are deformed to damp the vibration and are transmitted to the first footing portion 11 and the pier 17, so that the pier footing 1 is soft. The structure makes it possible to prevent the pier 17 from collapsing.

【0015】次に、図1と異なる橋脚基礎の免震構造に
ついて、図3を参照して説明する。図3の橋脚フーチン
グ20において図1の橋脚フーチング1と異なるのは、
第二のフーチング部22を、第一のフーチング部21の
下面21c及び側面21bとの間に所定長のクリアラン
スを保持するように形成し、このクリアランスに積層ゴ
ム23を挟着し、弱層部24を形成した点である。すな
わち、第一のフーチング部21の上面には、図1の積層
ゴム13aに相当する積層ゴムを設けず、また第二のフ
ーチング部22には、図1の積層ゴム13aの上方に形
成された第二のフーチング部12に相当する部分を形成
せず、さらに橋脚27の下端部表面には図1の弱層部1
4’に相当する部分を形成しないという点で、図3の橋
脚フーチング20は図1の橋脚フーチング1と異なる。
Next, a seismic isolation structure of the pier foundation different from that shown in FIG. 1 will be described with reference to FIG. The pier footing 20 of FIG. 3 differs from the pier footing 1 of FIG. 1 in that
The second footing portion 22 is formed so as to maintain a predetermined length of clearance between the lower surface 21c and the side surface 21b of the first footing portion 21, and the laminated rubber 23 is sandwiched in this clearance to form the weak layer portion. 24 is the point formed. That is, the laminated rubber corresponding to the laminated rubber 13a of FIG. 1 is not provided on the upper surface of the first footing portion 21, and the second footing portion 22 is formed above the laminated rubber 13a of FIG. A portion corresponding to the second footing portion 12 is not formed, and the lower surface of the pier 27 has a weak layer portion 1 shown in FIG.
The pier footing 20 of FIG. 3 differs from the pier footing 1 of FIG. 1 in that it does not form a portion corresponding to 4 ′.

【0016】以上の相違点以外の構成、すなわち橋脚2
7、第一のフーチング部21、積層ゴム23および弱層
部24は図1の免震構造と同様に形成することができ、
さらに図1と同様に、積層ゴム23を維持管理するため
に、第一のフーチング部21の下面21cと第二のフー
チング部22とのクリアランスに地上から連通する孔を
形成しても良い。
A structure other than the above-mentioned differences, that is, the pier 2
7, the first footing portion 21, the laminated rubber 23 and the weak layer portion 24 can be formed similarly to the seismic isolation structure of FIG.
Further, as in the case of FIG. 1, in order to maintain and manage the laminated rubber 23, a hole communicating with the clearance between the lower surface 21c of the first footing portion 21 and the second footing portion 22 from the ground may be formed.

【0017】地震等によって地盤に水平方向の振動が生
じた場合、図3の橋脚フーチング20においても橋脚フ
ーチング1と同様な作用や効果が得られる。すなわち、
水平方向の振動が所定強度以下の場合、弱層部24は破
壊せずに第二のフーチング部22、第一のフーチング部
21及び橋脚27を剛な構造として一体に拘束し、積層
ゴム23には水平方向の力が作用せず変形が生じない。
したがって、この剛な構造により水平方向の振動に対抗
することができる。
When the ground vibrates in the horizontal direction due to an earthquake or the like, the pier footing 20 shown in FIG. 3 has the same action and effect as the pier footing 1. That is,
When the vibration in the horizontal direction is equal to or less than the predetermined strength, the weak layer portion 24 is not broken and the second footing portion 22, the first footing portion 21 and the pier 27 are integrally restrained as a rigid structure, and the laminated rubber 23 is restrained. Does not deform due to no horizontal force.
Therefore, this rigid structure can resist horizontal vibrations.

【0018】一方、水平方向の振動が所定強度以上に達
すると、弱層部14は破壊し、積層ゴム23は水平方向
に変形可能となる。したがって、第二のフーチング部2
2に水平方向の振動が伝達すると積層ゴム23が変形し
て振動を減衰し、橋脚フーチング20は柔な構造となっ
て橋脚27の崩壊を防止することができる。
On the other hand, when the horizontal vibration reaches or exceeds a predetermined strength, the weak layer portion 14 is broken and the laminated rubber 23 can be deformed in the horizontal direction. Therefore, the second footing portion 2
When the horizontal vibration is transmitted to 2, the laminated rubber 23 is deformed to damp the vibration, and the pier footing 20 has a flexible structure to prevent the pier 27 from collapsing.

【0019】[0019]

【発明の効果】本発明の橋脚基礎の免震構造では、第一
及び第二のフーチング部の間に水平方向の振動を減衰す
る免震装置と、所定強度以上の外力によって破壊する弱
層部とを設けたので、常時及び所定強度以下の地震時に
は、弱層部が第一及び第二のフーチング部を一体に連結
して剛な構造として維持し、この剛構造によって外力に
対抗すると共に車両の安定走行を確保することが可能と
なる。また所定強度以上の地震時には、第一及び第二の
フーチング部の間を剛に連結する弱層部が破壊し、第一
及び第二のフーチング部の間に介在する免震装置が水平
方向の振動を減衰するように作用し、これによって橋脚
の崩壊を防止することができる。
According to the seismic isolation structure for a pier foundation of the present invention, a seismic isolation device for damping horizontal vibration between the first and second footing portions and a weak layer portion that is destroyed by an external force of a predetermined strength or more. Since it is provided, the weak layer portion integrally connects the first and second footing portions to maintain a rigid structure at all times and at the time of an earthquake with a predetermined strength or less, and the rigid structure resists external force and the vehicle It is possible to secure stable running of the vehicle. In addition, during an earthquake with a certain strength or more, the weak layer that rigidly connects the first and second footing parts is destroyed, and the seismic isolation device that is interposed between the first and second footing parts moves horizontally. It acts to damp vibrations, which can prevent the pier from collapsing.

【図面の簡単な説明】[Brief description of the drawings]

【図1】本発明の橋脚基礎の免震構造の概略断面図であ
る。
FIG. 1 is a schematic sectional view of a base isolation structure for a pier foundation of the present invention.

【図2】図1における弱層部の拡大断面図である。FIG. 2 is an enlarged sectional view of a weak layer portion in FIG.

【図3】図1とは異なる橋脚基礎の免震構造の概略断面
図である。
FIG. 3 is a schematic sectional view of a base isolation structure for a pier foundation different from that in FIG.

【図4】従来例を示す概略図である。FIG. 4 is a schematic view showing a conventional example.

【符号の説明】[Explanation of symbols]

1,20 橋脚フーチング 11,21 第一のフーチング部 11a 第一のフーチング部上面 11b,21b 第一のフーチング部側面 11c,21c 第一のフーチング部下面 12,22 第二のフーチング部 13a,13b,23 積層ゴム(免震装置) 14,14’,24 弱層部 17,27 橋脚 1,20 Bridge pier footing 11,21 First footing portion 11a First footing portion upper surface 11b, 21b First footing portion side surface 11c, 21c First footing portion lower surface 12,22 Second footing portion 13a, 13b, 23 Laminated rubber (seismic isolation device) 14, 14 ', 24 Weak layer 17, 27 Pier

Claims (2)

【特許請求の範囲】[Claims] 【請求項1】 橋脚フーチングが、橋脚と一体に設けら
れると共に上面、下面及び側面を備えるように形成した
第一のフーチング部と、この第一のフーチング部の上
面、下面及び側面を囲んで地盤に接するように形成した
第二のフーチング部とを備え、 前記第一のフーチング部の上面及び下面と、前記第二の
フーチング部との間に水平方向の振動を減衰する免震装
置を配置し、 前記第一のフーチング部の側面及び橋脚と、前記第二の
フーチング部との間に、所定強度以上の外力によって破
壊する弱層部を設けることを特徴とする橋脚基礎の免震
構造。
1. A first footing portion having a pier footing integrally formed with the pier and having an upper surface, a lower surface and a side surface, and a ground surrounding the upper surface, the lower surface and the side surface of the first footing portion. A second footing portion formed so as to be in contact with the second footing portion, and a seismic isolation device for damping horizontal vibrations is arranged between the upper and lower surfaces of the first footing portion and the second footing portion. A base isolation structure of a pier foundation, characterized in that a weak layer portion that is destroyed by an external force of a predetermined strength or more is provided between the side surface and the pier of the first footing portion and the second footing portion.
【請求項2】 橋脚フーチングが、橋脚と一体に設ける
と共に上面、下面及び側面を備えるように形成した第一
のフーチング部と、この第一のフーチング部の下面及び
側面を囲んで地盤に接するように形成した第二のフーチ
ング部とを備え、 前記第一のフーチング部の下面と前記第二のフーチング
部との間に水平方向の振動を減衰する免震装置を配置
し、 前記第一のフーチング部の側面と前記第二のフーチング
部との間に、所定強度以上の外力によって破壊する弱層
部を設けることを特徴とする橋脚基礎の免震構造。
2. A pier footing is provided integrally with the pier and has a first footing portion formed so as to have an upper surface, a lower surface and a side surface, and surrounds the lower surface and the side surface of the first footing portion to contact the ground. A second footing portion formed on the first footing portion, and a seismic isolation device for damping horizontal vibrations is arranged between the lower surface of the first footing portion and the second footing portion. A base isolation structure for a pier foundation, wherein a weak layer portion that is destroyed by an external force of a predetermined strength or more is provided between the side surface of the portion and the second footing portion.
JP28875395A 1995-11-07 1995-11-07 Construction of vibration isolation of bridge pier foundation Pending JPH09125412A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP28875395A JPH09125412A (en) 1995-11-07 1995-11-07 Construction of vibration isolation of bridge pier foundation

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP28875395A JPH09125412A (en) 1995-11-07 1995-11-07 Construction of vibration isolation of bridge pier foundation

Publications (1)

Publication Number Publication Date
JPH09125412A true JPH09125412A (en) 1997-05-13

Family

ID=17734266

Family Applications (1)

Application Number Title Priority Date Filing Date
JP28875395A Pending JPH09125412A (en) 1995-11-07 1995-11-07 Construction of vibration isolation of bridge pier foundation

Country Status (1)

Country Link
JP (1) JPH09125412A (en)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006070679A (en) * 2004-09-01 2006-03-16 Yoshisuke Kamiya Continuous girder bridge in which triangle structures having damping/supporting devices at lower ends are connected by girder
JP2009030243A (en) * 2007-07-24 2009-02-12 Ohbayashi Corp Base-isolated structure and base-isolating method for bridge
JP2010053527A (en) * 2008-08-26 2010-03-11 Ihi Corp Structure
CN102535504A (en) * 2012-03-21 2012-07-04 北京国道通公路设计研究院股份有限公司 Seismic isolation foundation for bridge
CN103643627A (en) * 2013-12-20 2014-03-19 中铁二院工程集团有限责任公司 Damping structure for continuous rigid frame pier with limited constraint

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006070679A (en) * 2004-09-01 2006-03-16 Yoshisuke Kamiya Continuous girder bridge in which triangle structures having damping/supporting devices at lower ends are connected by girder
JP2009030243A (en) * 2007-07-24 2009-02-12 Ohbayashi Corp Base-isolated structure and base-isolating method for bridge
JP2010053527A (en) * 2008-08-26 2010-03-11 Ihi Corp Structure
CN102535504A (en) * 2012-03-21 2012-07-04 北京国道通公路设计研究院股份有限公司 Seismic isolation foundation for bridge
CN103643627A (en) * 2013-12-20 2014-03-19 中铁二院工程集团有限责任公司 Damping structure for continuous rigid frame pier with limited constraint

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