JPH09302620A - Base-isolation stacked rubber bearing - Google Patents
Base-isolation stacked rubber bearingInfo
- Publication number
- JPH09302620A JPH09302620A JP14514396A JP14514396A JPH09302620A JP H09302620 A JPH09302620 A JP H09302620A JP 14514396 A JP14514396 A JP 14514396A JP 14514396 A JP14514396 A JP 14514396A JP H09302620 A JPH09302620 A JP H09302620A
- Authority
- JP
- Japan
- Prior art keywords
- steel wire
- earthquake
- rubber bearing
- laminated rubber
- rubber
- 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
Links
Landscapes
- Bridges Or Land Bridges (AREA)
Abstract
Description
【0001】[0001]
【発明の属する技術分野】本発明は橋梁構造物を支える
支承、特に最大級の地震の直撃にも耐え得る免震積層ゴ
ム支承の新規な構造に係る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing for supporting a bridge structure, and more particularly to a novel structure of a base-isolated laminated rubber bearing capable of withstanding a direct impact of the largest earthquake.
【0002】[0002]
【従来の技術】橋梁構造物の両端部ににそれぞれ配置す
る支承は、気温の変化に伴う構造物の伸縮を可能とする
ように支持し、自動車などの重量物が通過するときの一
過性の活荷重にも耐え、さらに地震が発生した場合に橋
梁本体がこれを支える基礎床から離脱しないように確実
に連結することも求められるなど、種々の機能を満足し
なければならない。これらの要請に対して応える最も一
般的な形態として近年は積層ゴム支承が広く慣用化され
ている。2. Description of the Related Art Bearings arranged at both ends of a bridge structure are supported so that the structure can be expanded and contracted in accordance with changes in temperature, and are temporarily used when heavy objects such as automobiles pass through. It must withstand various live loads, and must be securely connected so that the bridge body does not separate from the foundation floor that supports it in the event of an earthquake. In recent years, laminated rubber bearings have been widely used as the most general form to meet these demands.
【0003】積層ゴム支承は基礎床(橋脚構造物いわゆ
る下部工)へアンカーボルトと共に埋め込まれた下沓
と、橋梁構造物(橋桁構造物いわゆる上部工)の下フラ
ンジに取り付けた上沓との間に、ネオプレンゴムなどの
弾性体の複数の平板を重ねて積層し、かつ、補強と摺動
性を向上するために各層間に金属平板を交互に挾在した
積層体を一体的に成型した形態を指す。また、積層ゴム
支承の該基本形態に対し、さらに改良を加えて必要とす
る種々の機能の何れかを重点的に強化した従来技術もか
なり多数の提示が認められる。The laminated rubber bearing is between a lower shoe which is embedded in the foundation floor (bridge pier structure, so-called substructure) together with anchor bolts, and an upper shoe which is attached to the lower flange of the bridge structure (bridge girder structure, so-called superstructure). In addition, multiple flat plates of elastic material such as neoprene rubber are stacked and laminated, and a laminated body in which metal flat plates are alternately sandwiched between the layers to improve reinforcement and slidability is integrally molded. Refers to. In addition, a considerable number of prior arts in which any of various required functions are strengthened by further improving the basic form of the laminated rubber bearing can be recognized.
【0004】実公平3−52809号公報では、上沓1
a、下沓2aの間に重ねて取り付けるゴムの積層板を、
従来のような1枚物で形成せず図5で示すように3個1
組のゴム沓101、102、103で形成し、中央のゴ
ム沓102の上面に摩擦板104を組み込んだ構成を特
徴とする。この構成によって積層ゴム支承のうち、左右
に位置するゴム沓101,103は在来のゴム沓と同様
に緩衝機能を有し、中央部に位置するゴム沓102は、
上面に摩擦板104を有するために減衰機能を具えるの
で、桁の伸縮時の抵抗力を少なくし、また、地震時にお
ける減衰機能を発揮することができると謳っている。In Japanese Utility Model Publication No. 3-52809, Kamitsuku 1
a, a rubber laminated plate to be attached between the lower shoe 2a,
3 pieces 1 as shown in FIG.
It is characterized in that it is formed of a pair of rubber grits 101, 102, 103, and a friction plate 104 is incorporated on the upper surface of the central rubber grove 102. With this structure, the rubber crates 101 and 103 located on the left and right sides of the laminated rubber bearing have a cushioning function similarly to the conventional rubber crates, and the rubber crud 102 located at the center is
Since the friction plate 104 is provided on the upper surface of the girder, it has a damping function, so that it is possible to reduce the resistance force when the girder expands and contracts, and to exert the damping function at the time of an earthquake.
【0005】実開平2−109817号公報で開示され
た従来技術では、図6で示すように上沓1b,下沓2b
の間に挟持する積層ゴム支承が、横移動防止板105を
挟んで上下にゴム支承106,107で一体的に形成さ
れ、金属ベースプレート108の橋桁長手方向の両端部
に近接するように配置された橋桁長手方向移動防止用ス
トッパー109を立設したことを構成上の特徴とする。
この構成により橋桁長手方向の大きな水平地震力が作用
したとき、横移動防止板105が橋桁長手方向移動防止
ストッパー109に突き当って下部のゴム支承107の
剪断変形を防止すると共に、上部のゴム支承106のみ
が剪断変形するので、簡単な手段によって橋桁長手方向
の橋桁の安定性を向上できると謳っている。According to the prior art disclosed in Japanese Utility Model Laid-Open No. 2-109817, as shown in FIG. 6, an upper shoe 1b and a lower shoe 2b.
The laminated rubber bearing sandwiched between the two is integrally formed by the rubber bearings 106 and 107 with the lateral movement prevention plate 105 sandwiched therebetween, and is arranged so as to be close to both ends of the metal base plate 108 in the longitudinal direction of the bridge girder. The structural feature is that a stopper 109 for preventing movement of the bridge girder in the longitudinal direction is provided upright.
With this configuration, when a large horizontal seismic force in the longitudinal direction of the bridge girder is applied, the lateral movement prevention plate 105 abuts on the bridge girder longitudinal movement prevention stopper 109 to prevent shear deformation of the lower rubber bearing 107, and at the same time, the upper rubber bearing is supported. Since only 106 is sheared and deformed, it is stated that the stability of the bridge girder in the longitudinal direction of the bridge can be improved by a simple means.
【0006】しかし、これらの従来技術は阪神大震災発
生前の改良に係り、橋梁構造物と基礎床との連結が分断
され、大きな被害を蒙った今回のような最大級の地震が
直撃したとき、果たして完全に耐えられるか否か改めて
問い直す必要性が強調されるようになった。(財)土木
研究センターで進められている「建設省・道路橋の免震
設計法マニュアル(案)」によれば、下記の表1のよう
に作動原理別に分類した対策案が提示され、各々の具体
的な構成も例示されているが、表からも窺えるように、
積層ゴム支承をベースとしてさらに他の要件を附加した
強化策が主体を占める。However, these prior arts are related to the improvement before the Great Hanshin Earthquake, and when the connection between the bridge structure and the foundation floor was cut off and the largest earthquake such as this time, which suffered a great deal of damage, was hit directly, The necessity of re-questioning whether or not it could be completely tolerated came to be emphasized. According to the “Ministry of Construction / Seismic Isolation Design Method Manual for Road Bridges (Draft)” being promoted by the Civil Engineering Research Center, the measures proposed by the operating principle are presented as shown in Table 1 below. The specific configuration of is also illustrated, but as you can see from the table,
Mainly reinforced measures are based on laminated rubber bearings and added other requirements.
【0007】[0007]
【表1】 [Table 1]
【0008】たとえば鉛プラグ入り免震積層ゴム支承
は、図7に示すようにアンカーバーを立設した上プレー
ト1c、アンカーボルトを垂設した下プレート2cの間
に金属補強板110と積層ゴム板111とを交互に積み
重ね、一体的に加硫接着した積層構造に、嵌入孔を穿孔
して円柱状の鉛プラグ112を内嵌した構成である。ま
た、橋軸と直角方向にはサイドブロック113を立設し
て横方向の移動を防止する機能も具え、 積層ゴムは垂直方向に対する剛性が高く水平方向の剛
性が小さいため、大きな垂直荷重を支え、構造物の周期
を長周期化する。すなわち、緩衝と減衰の機能が高い。 積層ゴムの変形に伴って鉛プラグが塑性変形を起こし
地震エネルギーを吸収する。 風荷重や制動荷重などの日常の低レベルの水平力に対
しては、鉛プラグの剛性によって抵抗し揺動を防止す
る。特徴によって従来技術の積層ゴム支承に比べると、
さらに免震機能が強化すると期待されている。For example, as shown in FIG. 7, a seismically isolated laminated rubber bearing containing a lead plug has a metal reinforcing plate 110 and a laminated rubber plate between an upper plate 1c on which an anchor bar is erected and a lower plate 2c on which anchor bolts are vertically installed. This is a structure in which a lead plug 112 having a cylindrical shape is internally fitted by forming insertion holes in a laminated structure in which 111 and 111 are alternately stacked and integrally vulcanized and bonded. It also has a function to prevent lateral movement by standing side blocks 113 in the direction perpendicular to the bridge axis. The laminated rubber has a high rigidity in the vertical direction and a small rigidity in the horizontal direction, so it supports a large vertical load. , Make the cycle of the structure longer. That is, the functions of buffering and damping are high. The lead plug undergoes plastic deformation as the laminated rubber deforms, and seismic energy is absorbed. Rigidity of the lead plugs resists daily low level horizontal forces such as wind loads and braking loads, and prevents swinging. Compared to the conventional laminated rubber bearing due to its characteristics,
It is expected that the seismic isolation function will be further strengthened.
【0009】[0009]
【発明が解決しようとする課題】ここで例示した代表的
な従来技術は、日常の温度変化をはじめ地震などの緊急
時においても橋梁と橋脚の相対的な横方向の位置変動が
両者の連結を断ち切って離脱、さらに脱落の可能性を最
大の課題として捉え、積層ゴム支承の横方向への移動防
止に焦点を当てた解決手段を提起した点で共通する。も
ちろん、図5の従来技術でも従来の緩衝機能に摩擦力に
よる減衰機能を加えたことによって、垂直荷重は各ゴム
支承が分担するため剪断抵抗力を小さくできると説き、
図7の従来技術でも鉛プラグの挿入が垂直方向の強化に
全く無関係ではないと評価はできるが、直接、垂直方向
の激しい上下運動に抵抗する能力向上を目指した構成と
は言えず、垂直方向の震動に対しては、なお、強化の必
要性が残っていると判断せざるを得ない。The typical prior art illustrated here is such that the relative lateral positional fluctuations of the bridge and the bridge pier can connect the two even in an emergency such as an earthquake such as daily temperature change. It is common to point out the possibility of disconnection and disconnection as well as the possibility of falling off, and to propose a solution that focuses on preventing lateral movement of the laminated rubber bearing. Of course, even in the conventional technique of FIG. 5, it is explained that the vertical load is shared by each rubber bearing by adding the damping function by the friction force to the conventional cushioning function, so that the shear resistance can be reduced.
Although it can be evaluated that the insertion of the lead plug has nothing to do with the vertical strengthening even in the conventional technique of FIG. 7, it cannot be said that the configuration is aimed directly at improving the ability to resist the severe vertical movement in the vertical direction. With respect to the earthquake, there is no choice but to judge that the need for strengthening remains.
【0010】阪神大震災後の河川や高速道路などの被害
の実態を精緻に調査した結果、最大級の地震による上下
方向への波動は予想以上に激しく、従来技術が特に水平
方向の揺動に重点をおいて強化を図ってきた定説に一石
を投じた考察が注目を集めた。本発明は新たに知見され
た橋梁など構造物の課題に取り組み、直接的な強化手段
によって災害から公共の財産を守る新たな免震積層ゴム
支承の提供を目的とするものである。As a result of a detailed investigation of the actual conditions of damage to rivers and highways after the Great Hanshin Earthquake, the vertical vibration due to the largest earthquake was more severe than expected, and the prior art focused on horizontal oscillation. Attention was paid to the consideration that put a stone in the dogma which has been trying to strengthen. The present invention addresses the newly discovered problems of structures such as bridges, and aims to provide a new seismic isolation laminated rubber bearing that protects public property from a disaster by direct reinforcement means.
【0011】[0011]
【課題を解決するための手段】本発明に係る免震積層ゴ
ム支承は、橋梁構造物と基礎床との間に介装し上沓1と
下沓2間に複数のゴム平板3と金属平板4を交互に重ね
合わせた積層ゴム支承を基本とし、最大級の地震に伴う
垂直荷重に耐え得るように位置とサイズを計算したPC
鋼線5を、全てのゴム板3を貫通して上沓、下沓にそれ
ぞれ固着したことを構成上の特徴とする。なお、本発明
でいうPC鋼線とは、鋼線を撚って形成した撚り線だけ
でなく、単独の引き抜き加工を受けて成形したより大径
のPC鋼棒も含むものとする。A base-isolated laminated rubber bearing according to the present invention comprises a plurality of rubber flat plates 3 and metal flat plates which are interposed between a bridge structure and a foundation floor and are interposed between an upper shoe 1 and a lower shoe 2. Based on laminated rubber bearings that are alternately stacked with No. 4, a PC whose position and size have been calculated to withstand the vertical load associated with the largest earthquake
The structural feature is that the steel wire 5 penetrates all the rubber plates 3 and is fixed to the upper and lower shoes respectively. The PC steel wire referred to in the present invention includes not only a stranded wire formed by twisting a steel wire, but also a PC steel rod having a larger diameter formed by a single drawing process.
【0012】日常、橋梁に負荷する程度の外力に対して
は、従来技術と同様に垂直荷重に対しては積層ゴムの垂
直方向の剛性によって対抗し、水平荷重に対しては積層
ゴムの剪断変形とPC鋼線の曲げ剛性によって対抗す
る。しかし、地震発生の非常事態が発生したとき、垂直
方向の波動に対しては予め計算した通りにきわめて強大
なPC鋼線の抗張力で対抗するから、最大級の地震に遭
遇しても十分耐えて上沓と積層ゴム支承間、および積層
ゴム支承と下沓間の離脱を許さず、確実に積層ゴム支承
の一体的な集合行動を守り抜く。また、地震時の水平方
向の震動に対しては横方向への引張り力の分力が加わる
ために、PC鋼線には垂直力以外に水平力の合成した張
力が働くが、PC鋼線の最高水準の強度がこの合成した
外力に対抗して積層ゴム支承を一体的に拘束し、両者の
分断を防止して橋梁・橋脚間の離脱を許容しない作用が
現われる。[0012] In the same manner as in the prior art, an external force that is applied to the bridge on a daily basis is countered by vertical rigidity of the laminated rubber against a vertical load, and shear deformation of the laminated rubber against a horizontal load. And the bending rigidity of PC steel wire. However, when an emergency situation occurs, the vertical wave motion is countered by the extremely strong tensile strength of the PC steel wire, as calculated in advance, so it is possible to withstand even the largest earthquake. It does not allow separation between the upper shoe and the laminated rubber bearings, and between the laminated rubber bearing and the lower shoe, and reliably protects the integrated behavior of the laminated rubber bearings. In addition, since a tensile force component in the lateral direction is applied to the horizontal vibration during an earthquake, the combined tension of horizontal force acts on the PC steel wire in addition to the vertical force. The strength of the highest level counteracts this combined external force, integrally restrains the laminated rubber bearing, prevents the separation of both, and does not allow separation between the bridge and pier.
【0013】また、前記構成を基本とし、上沓1、下沓
2内に固着したPC鋼線5を内嵌するために上下沓に穿
孔した嵌入孔11,21の開口端を垂直方向に対して、
tanα=1/5〜1/10 の範囲に含まれる傾斜
角αで拡径する円錐面12,22で形成する要件を附加
すれば理想的な実施の形態となる。すなわち、前記のよ
うにPC鋼線には地震などの異常な震動時には垂直方向
の引張り力と水平方向の横揺れの合成した斜めの曲げ応
力が加わる。PC鋼線の端部は上下沓の内部に固着して
拘束され、端部から上下沓内に穿孔されたほぼ同径の嵌
入孔を通って最上層または最下層の積層ゴム板内へ嵌入
しているから、剛性の高い上下沓表面と剛性の低いゴム
平板表面が接する境界面では、PC鋼線に最大の曲げ応
力が集中し、PC鋼線の外周が鋭く折り曲げられこの位
置で切断する可能性も否定できない。そのために上下沓
の表面近くの嵌入孔内周面を開口部に向って拡径した円
錐面で形成し、PC鋼線の変形を緩やかな屈曲に変える
ことによって鋭角的な曲げに基づく破断作用を緩和する
ことができる。傾斜角αは前記のような限定を加える
が、tanαが1/5よりも大きいと、PC鋼線による
積層ゴム支承の固定拘束作用が過小に失してその免震作
用が最大級の地震に対抗できなくなるし、tanαが1
/10よりも小さいと嵌入孔の側面に突き当って曲げ応
力の集中作用を受け、切断する懸念が現われるので、前
記のようにαの範囲を限定した。On the basis of the above construction, the opening ends of the fitting holes 11 and 21 drilled in the upper and lower gears for fitting the PC steel wire 5 fixed in the upper gear 1 and the lower gear 2 in the vertical direction. hand,
An ideal embodiment can be obtained by adding the requirement of forming the conical surfaces 12 and 22 whose diameter is expanded at the inclination angle α included in the range of tan α = 1/5 to 1/10. That is, as described above, the PC steel wire is subjected to an oblique bending stress, which is a combination of a tensile force in the vertical direction and a horizontal roll, during an abnormal vibration such as an earthquake. The end of the PC steel wire is fixedly fixed inside the upper and lower troughs and fitted into the laminated rubber plate of the uppermost layer or the lowermost layer through the fitting holes formed in the upper and lower troughs from the ends. Therefore, the maximum bending stress concentrates on the PC steel wire at the boundary surface where the upper and lower rake surfaces with high rigidity and the rubber flat plate surface with low rigidity are in contact, and the outer circumference of the PC steel wire is sharply bent and can be cut at this position. Sex cannot be denied. For this reason, the inner peripheral surface of the insertion hole near the surface of the upper and lower shoes is formed by a conical surface whose diameter is expanded toward the opening, and the deformation of the PC steel wire is changed to a gentle bending, so that the breaking action based on an acute angle bending is performed. Can be relaxed. Although the inclination angle α is limited as described above, if tan α is larger than ⅕, the fixed restraint action of the laminated rubber bearing by the PC steel wire is excessively lost and the seismic isolation action becomes the largest earthquake. You can't compete and tan α is 1
If it is smaller than / 10, there is a concern that it may hit the side surface of the fitting hole and be subjected to a concentration action of bending stress, resulting in cutting. Therefore, the range of α is limited as described above.
【0014】[0014]
【発明の実施の形態】図1は本発明の実施の形態を示す
縦断正面図であり、図(A)が全体図、図(B)が上沓
内のPC鋼線端部を拡大して示す部分図である。上沓1
と下沓2との間にはネオプレーンゴムなどのゴム平板3
とステンレス製の金属平板4とが交互に累積を繰り返し
積層ゴム支承を形成している。金属平板4が剛性の補強
と水平方向への摺動性を向上させる目的で挾在している
ことは言うまでもない。この図の実施形態では4層のゴ
ム平板を示しているが、橋梁の規模、サイズ、荷重量の
多寡によって2〜20層程度の広い範囲からの選定が行
なわれる。1 is a vertical sectional front view showing an embodiment of the present invention, FIG. 1 (A) is an overall view, and FIG. 1 (B) is an enlarged view of an end of a PC steel wire in an upper shoe. FIG. Upper shoe 1
A rubber flat plate 3 such as neoprene rubber between the lower shoe 2 and the lower shoe 2.
And the metal flat plate 4 made of stainless steel are alternately accumulated repeatedly to form a laminated rubber bearing. It goes without saying that the metal flat plate 4 is present for the purpose of reinforcing rigidity and improving slidability in the horizontal direction. In the embodiment shown in this figure, a four-layer rubber flat plate is shown, but selection is made from a wide range of about 2 to 20 layers depending on the scale, size and load amount of the bridge.
【0015】すべてのゴム平板3と金属平板4を共通し
て貫通し、上端が上沓1内に、下端が下沓2内にそれぞ
れ固着されるPC鋼線5を必要な本数と配置を選択して
取り付ける。必要な本数とは最大級の地震の直撃があっ
たとき、積層ゴム支承の断面積全体に想定される垂直方
向の引張り力の総絶対量に対し、十分に耐えられる対抗
力をPC鋼線材(高抗張力鋼)の単位断面積当りの抗張
力から算出し、市販のPC鋼線単品の断面積から割り出
せばよく、その本数を積層ゴム支承の断面に均等に配分
して位置を設定することによって特定される。Select the necessary number and arrangement of PC steel wires 5 that penetrate all the rubber flat plates 3 and the metal flat plates 4 in common, and the upper end is fixed inside the upper gear 1 and the lower end is fixed inside the lower gear 2. Then install. What is the required number? When a direct earthquake hits one of the largest, the opposing force that can withstand the total absolute tensile force in the vertical direction that is assumed for the entire cross-sectional area of the laminated rubber bearing is PC steel wire ( It can be calculated from the tensile strength per unit cross-sectional area of (high tensile strength steel) and can be calculated from the cross-sectional area of a commercially available PC steel wire single item, and the number is specified by evenly distributing it to the cross section of the laminated rubber bearing and setting the position. To be done.
【0016】PC鋼線5が挿通するための嵌入孔11,
21が上沓1、下沓2内に穿孔されるが、その内周面の
開口端近くには外開きの拡径した円錐面12,22が形
成される。拡径する傾斜角αは、 tanα=1/5〜
1/10 の範囲が妥当であり、とくに1/8が最適
の傾斜角である。この円錐面が端部に形成されているか
ら、PC鋼線に曲げ変形が強いられたときでも鋭角的な
屈折が起こらず、緩やかな屈曲線を描く変形に置換され
て外力の集中がなく、PC鋼線の破断を防止できる。こ
の図の場合はPC鋼線はPC鋼棒と呼ばれる種類に属
し、上下両端部に雄ネジを螺刻しワッシャ14,24と
硬質ゴム環15,25を介して締結ナット13および2
3によって締結し、上沓または下沓へ強固に固着され
る。A fitting hole 11 for inserting the PC steel wire 5,
21 is bored in the upper shoe 1 and the lower shoe 2, and conical surfaces 12 and 22 having an outward opening and having an enlarged diameter are formed near the open end of the inner circumferential surface thereof. The inclination angle α for expanding the diameter is tan α = 1/5
A range of 1/10 is appropriate, and 1/8 is the optimum tilt angle. Since this conical surface is formed at the end, sharp bending does not occur even when bending deformation is applied to the PC steel wire, and it is replaced with deformation that draws a gentle bending line, and concentration of external force does not occur. It is possible to prevent the PC steel wire from breaking. In the case of this figure, the PC steel wire belongs to a type called a PC steel rod, and male and female screws are threaded on the upper and lower ends of the PC steel wire, and the fastening nuts 13 and 2 are inserted through the washers 14 and 24 and the hard rubber rings 15 and 25.
It is fastened by 3 and is firmly fixed to the upper shoe or the lower shoe.
【0017】PC鋼線が撚り鋼線で形成しているとき
は、前例のように両端に雄ネジを螺刻してナットで締結
することができないから、図2(A)(B)(C)のよ
うな公知技術を適用して上沓、下沓に固着する。すなわ
ち、下沓2Aへ固着するPC鋼線5Aの下端に対して
は、専用機(ヘッディングマシン)によって図(C)の
ように球状にヘッド51を成形して、アンカーヘッド2
6の凹部内へ嵌入係止し、PC鋼線5Aの上端は図
(B)のように適宜必要な長さに切断して上沓1A内を
挿通し、アンカーヘッド16内でウェッジ17を打ち込
んで傾斜面の楔作用によってPC鋼線の端部を係止する
構成を採っている。When the PC steel wire is formed of twisted steel wire, it is not possible to thread male threads on both ends and fasten it with nuts as in the previous example, and therefore, as shown in FIGS. 2 (A) (B) (C). ) Is applied to fix the upper and lower shoes. That is, for the lower end of the PC steel wire 5A fixed to the lower shoe 2A, a dedicated machine (heading machine) is used to form a spherical head 51 as shown in FIG.
(6) The upper end of the PC steel wire 5A is cut to an appropriate length as shown in FIG. (B) and inserted through the upper shoe 1A, and the wedge 17 is driven in the anchor head 16 Thus, the end portion of the PC steel wire is locked by the wedge action of the inclined surface.
【0018】[0018]
【実施例】図3は本発明の具体的な実施例を想定した縦
断正面図(A)と平面図(B)である。上沓1、下沓2
はそれぞれ750mm×750mm×38mmのSS4
00の鋼板で形成し、上沓1は桁下フランジKに溶接
し、下沓2は橋脚のベースプレートPに溶接固定してい
る。上沓と下沓の間には4枚の厚さ22mmのネオプレ
ーンゴムで製作したゴム平板3と厚さ2mmのステンレ
ス平板4を交互に累積して積層ゴム支承を形成してい
る。設計条件としては、 橋長×巾員=50m×18m(主桁6本) 主桁一本当りの反力:15tonf×50m×1/2×1/6=62.5
tonf→100tonf沓を使用 PC鋼線の降伏点応力:δa=78.5kgf/mm2 最大級の地震の垂直震度係数:0.4(現在確定してい
ないが旧基準1の4倍として考える) 地震の垂直荷重Fv=62.5×0.4=25tonf PC鋼線の引張力f=78.5×(π/4)×9.22=78.5×6
6.43=5214kgf 6本使用するとF6=5.214×6=31.284tonf Fv=25tonf<F6=31.284tonf として計算すると、図(B)に示す6箇所の位置に外径
9.2mmのPC鋼線を6本上下に貫通強化することに
よって最大級の地震の直撃に遭っても積層ゴム支承内で
の分断が起こらない確証が得られた。FIG. 3 is a vertical sectional front view (A) and a plan view (B) assuming a specific embodiment of the present invention. Upper shoe 1, lower shoe 2
Are SS4 of 750mm x 750mm x 38mm respectively
No. 00 steel plate, the upper shoe 1 is welded to the girder lower flange K, and the lower shoe 2 is welded and fixed to the base plate P of the pier. Between the upper shoe and the lower shoe, four rubber flat plates 3 made of neoprene rubber having a thickness of 22 mm and a stainless flat plate 4 having a thickness of 2 mm are alternately accumulated to form a laminated rubber bearing. The design conditions are: bridge length x width = 50m x 18m (6 main girders) Reaction force per main girder: 15tonf x 50m x 1/2 x 1/6 = 62.5
tonf → 100 tonf shavings used Stress at yield point of PC steel wire: δa = 78.5kgf / mm 2 Vertical seismic coefficient of the largest earthquake: 0.4 (not confirmed at present, but considered as 4 times of old standard 1) Earthquake vertical Load Fv = 62.5 × 0.4 = 25tonf Tensile force of PC steel wire f = 78.5 × (π / 4) × 9.2 2 = 78.5 × 6
6.43 = 5214kgf 6 present Use is calculated as F 6 = 5.214 × 6 = 31.284tonf Fv = 25tonf <F 6 = 31.284tonf, the PC steel wire having an outer diameter of 9.2mm at the position of the six shown in FIG. (B) It was confirmed that by strengthening the six vertical penetrations, no division occurs in the laminated rubber bearing even if the largest earthquake hits directly.
【0019】別の実施例として図4に示すように日常の
温度変化に伴う発生応力とPC鋼線の材力との検討を計
算した結果を示す。図4は変形図であってPC鋼線の変
形前の位置5′(点線)が発生応力によって5(実戦)
の位置まで変形したことを示している。設計条件は、 桁長:L=40m 鋼の線膨張係数:α=12×10-6 温度変化:Δt=±25℃ 支承高:I=200mm PC鋼線のヤング係数:E=2×106Kgf/mm2 として外気の温度変化とPC鋼線の材力を計算する。As another example, as shown in FIG. 4, the results of calculation of the examination of the stress generated due to daily temperature changes and the material strength of PC steel wire are shown. FIG. 4 is a deformation diagram, and the position 5 '(dotted line) of the PC steel wire before deformation is 5 (actual battle) due to the generated stress
It has been transformed to the position of. Design conditions are: Girder length: L = 40 m Steel linear expansion coefficient: α = 12 × 10 −6 Temperature change: Δt = ± 25 ° C. Bearing height: I = 200 mm Young's modulus of PC steel wire: E = 2 × 10 6 The temperature change of the outside air and the strength of the PC steel wire are calculated as Kgf / mm 2 .
【0020】 温度変化による桁の移動量ΔLは、 ΔL=L×α×Δt=40×103×12×10-6×2
5=12mm PC鋼線の伸びΔIは、 ΔI=(I2+ΔL2)1/2−I=(2002+122)1/2
−200=0.36mm 作用応力σは、 σ=E×ΔI/I=2.0×106×0.36/200
=36Kgf/mm2であり、PC鋼線の安全率として規格さ
れている78.5Kgf/mm2よりも遥かに低いから余裕を
以てクリアできる。The shift amount ΔL of the digit due to the temperature change is ΔL = L × α × Δt = 40 × 10 3 × 12 × 10 −6 × 2
5 = 12 mm The elongation ΔI of the PC steel wire is ΔI = (I 2 + ΔL 2 ) 1/2 −I = (200 2 +12 2 ) 1/2
-200 = 0.36 mm Working stress σ is σ = E × ΔI / I = 2.0 × 10 6 × 0.36 / 200
= A 36 Kgf / mm 2, can be cleared with a margin because much lower than 78.5Kgf / mm 2 which is standardized as a safety factor of PC steel wire.
【0021】[0021]
【発明の効果】本発明は以上に述べた通り日常の使用状
態において定常的に負荷する水平、垂直方向への外力に
対しては、従来技術以上に強化された機能を果たす。そ
の上、最大級の地震が直撃した場合には、水平方向だけ
での抵抗力だけでなく、今回の災害調査の結果、改めて
強く指摘を受けた垂直方向の激しい震動に対しても十分
耐え得る新たな機能が加わり、万全の態勢を都市機能に
具える効果が得られ、その意味で最新の従来技術に比べ
ても明らかに凌駕する。また、本発明は実施形態として
図示した2〜3の形態に留まらず、従来技術の全ての形
態にPC鋼線を挿通し直すという比較的簡単な補強工事
によって飛躍的な能力向上に結び付けることができるか
ら、たとえば図5、図6、図7などの既設の構造に、新
たな本発明の要件を追加することによって防災機能が格
段に改善できるという利点も看過し難い効果である。As described above, the present invention exerts a strengthened function over the prior art with respect to the external force in the horizontal and vertical directions which is constantly loaded in the daily use condition. In addition, when the largest earthquake hits directly, it can withstand not only horizontal resistance, but also the strong vertical tremor that was strongly pointed out again as a result of this disaster investigation. With the addition of new functions, the city's functions are fully prepared, and in that sense, it is clearly superior to the latest conventional technology. Further, the present invention is not limited to the two or three embodiments illustrated as the embodiments, and can be connected to a dramatic improvement in performance by the relatively simple reinforcement work of reinserting the PC steel wire in all the prior art forms. Therefore, for example, the advantage that the disaster prevention function can be remarkably improved by adding the requirement of the present invention to the existing structure shown in FIG. 5, FIG. 6, FIG.
【0022】請求項2に係る発明独自の効果は桁長の大
きい橋梁の適用に対してきわめて信頼性を高める点にあ
る。PC鋼線自体は既述のようにきわめて強靭であり引
張り強度が高いが、曲げ応力が局部的に集中するとその
鋭角的に屈折した部分が耐え切れずに切断する可能性も
なくはない。したがって桁長が大きく水平方向への移動
量の大きい長大な連結桁の橋梁については、過大な張力
を分散吸収するために曲げ方向を緩やかな屈曲に置換す
る構成がきわめて効果的であり、橋梁構造全体の非常時
における耐性の信頼性を大幅に昂進する効果が顕著であ
る。The effect peculiar to the invention according to claim 2 resides in that the reliability is extremely improved for the application of a bridge having a large girder length. As described above, the PC steel wire itself is extremely tough and has a high tensile strength. However, if the bending stress is locally concentrated, there is a possibility that the sharply bent portion will not endure and will be cut. Therefore, for bridges with long girders that have a large girder length and large horizontal movement, it is extremely effective to replace the bending direction with a gentle bend in order to disperse and absorb excessive tension. The effect of significantly improving the reliability of resistance in an overall emergency is remarkable.
【図1】本発明の実施の形態を示す縦断正面図(A)と
要部の拡大図(B)である。FIG. 1 is a vertical front view (A) showing an embodiment of the present invention and an enlarged view (B) of a main part.
【図2】本発明の別の実施形態を示す縦断正面図
(A)、上沓とPC鋼線の固定部の拡大図(B)、およ
び下沓とPC鋼線の固定部の拡大図(C)である。FIG. 2 is a vertical sectional front view showing another embodiment of the present invention (A), an enlarged view of a fixed portion of an upper shoe and a PC steel wire (B), and an enlarged view of a fixed portion of a lower shoe and a PC steel wire ( C).
【図3】本発明実施例の縦断正面図(A)と平面図
(B)である。FIG. 3 is a vertical front view (A) and a plan view (B) of an embodiment of the present invention.
【図4】別の実施例の計算手順を説明する縦断正面図で
ある。FIG. 4 is a vertical sectional front view for explaining a calculation procedure of another embodiment.
【図5】従来技術の縦断正面図である。FIG. 5 is a vertical sectional front view of a conventional technique.
【図6】別の従来技術の縦断正面図である。FIG. 6 is a vertical sectional front view of another conventional technique.
【図7】さらに別の従来技術の斜視図である。FIG. 7 is a perspective view of yet another prior art.
1 上沓 2 下沓 3 ゴム平板 4 金属平板 5 PC鋼線 21 嵌入孔 22 円錐面 α 傾斜角 1 Upper shoe 2 Lower shoe 3 Rubber flat plate 4 Metal flat plate 5 PC steel wire 21 Fitting hole 22 Conical surface α Inclination angle
Claims (2)
1と下沓2間に複数のゴム平板3と金属平板4を交互に
重ね合わせた積層ゴム支承において、最大級の地震に伴
う垂直荷重に耐え得るようにしたPC鋼線5を、全ての
ゴム板3を貫通して上沓、下沓にそれぞれ固着したこと
を特徴とする免震積層ゴム支承。1. A laminated rubber bearing in which a plurality of rubber flat plates 3 and metal flat plates 4 are alternately stacked between an upper shoe 1 and a lower shoe 2 and interposed between a bridge structure and a foundation floor. A seismically isolated laminated rubber bearing characterized in that a PC steel wire 5 adapted to withstand the vertical load caused by an earthquake penetrates all rubber plates 3 and is fixed to the upper and lower shoes respectively.
着したPC鋼線5を内嵌するために該上下沓に穿孔した
嵌入孔11,21の内周面開口端を垂直方向に対して、
tanα=1/5〜1/10 の範囲に含まれる傾斜
角αで拡径する円錐面12,22で形成することを特徴
とする免震積層ゴム支承。2. The inner peripheral surface open ends of the fitting holes 11 and 21 formed in the upper and lower shoes in order to fit the PC steel wire 5 fixed in the upper and lower shoes 1 and 2 in the vertical direction. Against
A seismically isolated laminated rubber bearing characterized by being formed by conical surfaces 12 and 22 that expand in diameter at an inclination angle α included in the range of tan α = 1/5 to 1/10.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP14514396A JPH09302620A (en) | 1996-05-14 | 1996-05-14 | Base-isolation stacked rubber bearing |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP14514396A JPH09302620A (en) | 1996-05-14 | 1996-05-14 | Base-isolation stacked rubber bearing |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH09302620A true JPH09302620A (en) | 1997-11-25 |
Family
ID=15378419
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP14514396A Pending JPH09302620A (en) | 1996-05-14 | 1996-05-14 | Base-isolation stacked rubber bearing |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH09302620A (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2007132044A (en) * | 2005-11-09 | 2007-05-31 | Nitta Ind Corp | Elastic support for structure |
JP2012041810A (en) * | 2010-07-23 | 2012-03-01 | Ihi Infrastructure Systems Co Ltd | Bearing device |
JP2012092906A (en) * | 2010-10-27 | 2012-05-17 | Ihi Infrastructure Systems Co Ltd | Bearing device |
-
1996
- 1996-05-14 JP JP14514396A patent/JPH09302620A/en active Pending
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2007132044A (en) * | 2005-11-09 | 2007-05-31 | Nitta Ind Corp | Elastic support for structure |
JP4740720B2 (en) * | 2005-11-09 | 2011-08-03 | ニッタ株式会社 | Elastic bearings for structures |
JP2012041810A (en) * | 2010-07-23 | 2012-03-01 | Ihi Infrastructure Systems Co Ltd | Bearing device |
JP2012092906A (en) * | 2010-10-27 | 2012-05-17 | Ihi Infrastructure Systems Co Ltd | Bearing device |
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