JP6660092B2

JP6660092B2 - Pretensioning device

Info

Publication number: JP6660092B2
Application number: JP2015063897A
Authority: JP
Inventors: 金子　隆; 隆金子; 雅浩古城
Original assignee: オックスジャッキ株式会社
Priority date: 2015-03-26
Filing date: 2015-03-26
Publication date: 2020-03-04
Anticipated expiration: 2035-03-26
Also published as: JP2016182715A

Description

本発明は、プレストレストコンクリート（ＰＣ）製品を製造するときに使用されるＰＣ鋼材に、緊張力を付与するためのプレテンション付与装置に関するものである。 BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pretensioning device for applying tension to a PC steel used when manufacturing a prestressed concrete (PC) product.

この種のプレテンション付与装置には、従来から固定アバット方式と、簡易アバット方式が知られている。
固定アバット方式には、図１３（ａ）（ｂ）に示すものと、これをやや簡略化した図１４（ａ）（ｂ）に示すものがある。
図１３（ａ）（ｂ）に示すものは、緊張側の鋼製ポスト４６ａと固定側の鋼製ポスト４６ｂとを有し、緊張側の鋼製ポスト４６ａは、コンクリートアバット４５ａで固定して下端部を地盤１１に埋め込み、固定側の鋼製ポスト４６ｂもコンクリートアバット４５ｂで固定して下端部を地盤１１に埋め込み、また、前記コンクリートアバット４５ａの上に摺動可能に緊張フレーム２４を取り付け、この緊張フレーム２４に緊張側の定着用ブロック１７ａを取り付け、固定側の定着用ブロック１７ｂは、前記固定的な鋼製ポスト４６ｂに固定する。また、前記緊張フレーム２４に設けられた受け梁１８と前記鋼製ポスト４６ａとの間にジャッキ２０を取り付ける。前記緊張側の定着用ブロック１７ａと固定側の定着用ブロック１７ｂの間にＰＣ鋼材１３をそれぞれの定着部２１で連結する。 Conventionally, a fixed abutment system and a simple abutment system are known as this type of pretensioning device.
The fixed abutment system includes a system shown in FIGS. 13A and 13B and a system shown in FIGS. 14A and 14B which is a simplified version of the system shown in FIGS.
13 (a) and 13 (b) have a tension-side steel post 46a and a fixed-side steel post 46b. The tension-side steel post 46a is fixed by a concrete abutment 45a and a lower end thereof. The lower part is embedded in the ground 11 by fixing the steel post 46b on the fixed side with the concrete abutment 45b, and the tension frame 24 is slidably mounted on the concrete abutment 45a. The tension-side fixing block 17a is attached to the tension frame 24, and the fixed-side fixing block 17b is fixed to the stationary steel post 46b. Further, a jack 20 is attached between the receiving beam 18 provided on the tension frame 24 and the steel post 46a. The PC steel members 13 are connected at respective fixing portions 21 between the tension-side fixing block 17a and the fixed-side fixing block 17b.

そして、ジャッキ２０のピストンを押し出すと、緊張フレーム２４が鎖線のように押し出され、ＰＣ鋼材１３が緊張される。この緊張力の反力は、コンクリートアバット４５ａと４５ｂの重量と地盤１１で受ける。所定のテンションをかけたＰＣ鋼材１３に型枠を取り付けてコンクリートを打設し、コンクリートが固まったらジャッキ２０の緊張力を開放することでプレストレストコンクリート１２となる。 Then, when the piston of the jack 20 is pushed out, the tension frame 24 is pushed out like a chain line, and the PC steel material 13 is tensioned. The reaction force of the tension is received by the weight of the concrete abutments 45a and 45b and the ground 11. A pre-stressed concrete 12 is obtained by attaching a mold to a PC steel 13 to which a predetermined tension has been applied, casting concrete, and releasing the tension of the jack 20 when the concrete hardens.

また、図１４（ａ）（ｂ）に示すものは、前記図１３の緊張側のコンクリートアバット４５ａと固定側のコンクリートアバット４５ｂとを一体に連結した１個の固定式コンクリートアバット１０からなり、この固定式コンクリートアバット１０の底面壁１４の一部が地盤１１に埋設され、この固定式コンクリートアバット１０に、前記鋼製ポスト４６ａに代わる一方の端部壁１５ａと鋼製ポスト４６ｂに代わる他方の端部壁１５ｂを立ち上げ、一方の端部壁１５ａの内側の定着用ブロック１７と他方の端部壁１５ｂとの間に複数本のＰＣ鋼材１３をそれぞれの定着部２１で固着し、前記定着用ブロック１７の両側にテンションロッド１９を挿通し、このテンションロッド１９を前記一方の端部壁１５ａに貫通し、受け梁１８に固着する。この受け梁１８と端部壁１５ａとの間にジャッキ２０を据え付ける。 14 (a) and 14 (b) consist of one fixed concrete abutment 10 in which the concrete abutment 45a on the tension side and the concrete abutment 45b on the fixed side in FIG. 13 are integrally connected. A part of the bottom wall 14 of the fixed concrete abutment 10 is buried in the ground 11, and the fixed concrete abutment 10 has one end wall 15a that replaces the steel post 46a and the other end that replaces the steel post 46b. The PC wall 13b is raised, and a plurality of PC steel materials 13 are fixed at the respective fixing portions 21 between the fixing block 17 inside the one end wall 15a and the other end wall 15b. A tension rod 19 is inserted into both sides of the block 17, penetrates the one end wall 15 a, and is fixed to the receiving beam 18. A jack 20 is installed between the receiving beam 18 and the end wall 15a.

この状態で、ジャッキ２０のピストンを押し出すと、複数本のＰＣ鋼材１３にテンションがかけられる。所定のテンションをかけたＰＣ鋼材１３に型枠を取り付けてコンクリートを打設する。コンクリートが固まるまで緊張したままとし、固まったらジャッキ２０を開放すると、コンクリートの中でＰＣ鋼材１３が付着し、プレストレスが残ったコンクリートとなる（特許文献１）。 In this state, when the piston of the jack 20 is pushed out, tension is applied to the plurality of PC steel materials 13. A formwork is attached to the PC steel 13 to which a predetermined tension has been applied, and concrete is poured. When the concrete is kept tensed until it hardens, and the jack 20 is opened when it hardens, the PC steel material 13 adheres to the concrete and the prestressed concrete remains (Patent Document 1).

簡易アバット方式は、緊張側のジャッキ受け台と固定側の定着用ブロックとの間に、柱状の圧縮材を設ける。前記緊張側のジャッキ受け台は、地盤にアンカーボルトで固定した摺動板の上に摺動自在に設置する。また、後端部の定着用ブロックも地盤にアンカーボルトで固定する。この後端部の受定着用ブロックと前記前端部のジャッキ受け台の内側の受け梁との間にＰＣ鋼材を張り渡し、ジャッキでＰＣ鋼材にプレテンションをかける。そして、前記圧縮材でジャッキの反力を受ける。
所定のテンションをかけたＰＣ鋼材に型枠を取り付けてコンクリートを打設し、コンクリートが固まったらジャッキを開放すると、ストレスが入ったコンクリートとなる。 In the simple abutment method, a columnar compression member is provided between a tension-side jack cradle and a fixed-side fixing block. The tension-side jack cradle is slidably mounted on a slide plate fixed to the ground with anchor bolts. The fixing block at the rear end is also fixed to the ground with anchor bolts. A PC steel material is stretched between the rear end receiving and fixing block and the receiving beam inside the jack cradle at the front end portion, and the PC steel material is pretensioned by the jack. Then, the compressed material receives the reaction force of the jack.
When a concrete frame is attached to a PC steel material to which a predetermined tension has been applied, concrete is poured, and when the concrete is hardened, the jack is released.

特開２００７-２４５５０７号公報。JP-A-2007-245507.

前記従来の固定アバット方式を用いたものは、次のような問題点があった。
（１）図１３に示すものは、緊張側の鋼製ポスト４６ａと固定側の鋼製ポスト４６ｂとに発生する緊張力の反力が一部を地盤１１に埋めたコンクリートアバット４５ａと４５ｂの重量と地盤１１で受けるため、コンクリートアバット４５ａと４５ｂを地盤１１に埋める作業を必要とする。
（２）図１３および図１４に示すものは、構造的に緊張力に対する反力を受ける圧縮材がないため、コンクリートアバット４５ａと４５ｂ、固定式コンクリートアバット１０が大型化し、かつ、重量が大きくなる。
（３）図１３および図１４に示すものは、コンクリートアバット４５ａと４５ｂ、固定式コンクリートアバット１０を一度設置したら簡単には撤去することができず、大きさ、形状等の異なるプレストレストコンクリート製品に対応できない。
（４）図１３および図１４に示すものは、コンクリートアバット４５ａと４５ｂ、固定式コンクリートアバット１０を設置するための地盤工事が必要になり、既設の工場に設置する場合は、据え付けが困難である。 Those using the conventional fixed abutment method have the following problems.
(1) FIG. 13 shows the weight of concrete abutts 45a and 45b in which a reaction force of the tension generated between the steel post 46a on the tension side and the steel post 46b on the fixed side partially buried the ground 11. In this case, it is necessary to bury the concrete abutments 45 a and 45 b in the ground 11.
(2) The structures shown in FIGS. 13 and 14 are structurally free from any compressive material that receives a reaction force against tension, so that the concrete abutments 45a and 45b and the fixed concrete abutment 10 become large and heavy. .
(3) The thing shown in FIG. 13 and FIG. 14 cannot be easily removed once the concrete abutments 45a and 45b and the fixed concrete abutment 10 are installed, and corresponds to prestressed concrete products having different sizes and shapes. Can not.
(4) The construction shown in FIGS. 13 and 14 requires the ground work for installing the concrete abutments 45a and 45b and the fixed concrete abutment 10, and it is difficult to install the abutment in an existing factory. .

簡易アバット方式を用いたものは、次のような問題点があった。
（１）圧縮部材で反力を受けるため、長尺製品を製造する場合、圧縮部材が座屈し、短尺製品にしか使用できない。
（２）長尺製品を製造する場合、圧縮部材が大きくなり、製品の長さやＰＣ鋼材の数などにより複数種類の圧縮材を用意しなければならない。
（３）圧縮部材は、緊張力及び部材長さに比例して縮むので、緊張時は、アンカーボルトでも反力を受ける。このため、水平方向に強度を持ったアンカーボルトが必要になる。 The one using the simple abutment method has the following problems.
(1) Since a compression member receives a reaction force, when a long product is manufactured, the compression member buckles and can be used only for a short product.
(2) When manufacturing a long product, the compression member becomes large, and a plurality of types of compression materials must be prepared depending on the length of the product and the number of PC steel materials.
(3) The compression member shrinks in proportion to the tension and the length of the member. For this reason, anchor bolts having strength in the horizontal direction are required.

本発明は、容易に設置及び撤去ができ、安価なプレテンション付与装置を提供すること、また、圧縮部材を制限なく長くでき、アンカーボルトは緊張力に対する反力を受けないプレテンション付与装置を提供することを目的とするものである。 The present invention provides an inexpensive pretensioning device that can be easily installed and removed, and also provides a pretensioning device in which a compression member can be lengthened without limitation and an anchor bolt does not receive a reaction force against tension. It is intended to do so.

本発明は、プレストレストコンクリート１２を製造のためのＰＣ鋼材１３を鋼材支持材２２と鋼材固定材２３の間に張り渡し、ジャッキ受け台２８に設けたジャッキ２０で前記ＰＣ鋼材１３に緊張力を与え、前記ジャッキ受け台２８の反力を、このジャッキ受け台２８と鋼材固定材２３の間に設けた圧縮材２６で受けるようにしたプレテンション付与装置において、前記圧縮材２６の途中の、この圧縮材２６の固有の許容座屈応力が発生座屈応力より小さくならない位置に座屈防止材２７を設置し、この座屈防止材２７に形成した挿通空間３３に前記圧縮材２６を摺動可能に遊嵌したことを特徴とする。 According to the present invention, a PC steel material 13 for producing the prestressed concrete 12 is stretched between a steel material support member 22 and a steel material fixing member 23, and a tension is applied to the PC steel material 13 by a jack 20 provided on a jack cradle 28. In a pretensioning device in which the reaction force of the jack receiving member 28 is received by the compression member 26 provided between the jack receiving member 28 and the steel fixing member 23, The buckling prevention member 27 is installed at a position where the inherent allowable buckling stress of the member 26 does not become smaller than the generated buckling stress, and the compression member 26 can slide in the insertion space 33 formed in the buckling prevention member 27. It is characterized by being loosely fitted.

従来のようなコンクリートアバットを用いなくとも、鋼材固定材２３を地盤１１にアンカー３５で固定的に取り付け、鋼材支持材２２を緊張用フレーム２４に摺動自在に取り付け、この緊張用フレーム２４を地盤１１にアンカー３５で取り付けた摺動案内板４８に摺動自在に設け、座屈防止材２７を台座２９に支柱３０と横桟３１で圧縮材２６を遊嵌する挿通空間３３を有するように井桁状に組み込み、前記台座２９をアンカー３５で地盤１１に固着することで所期の目的を達成できる。 Even without using a conventional concrete abutment, the steel fixing member 23 is fixedly attached to the ground 11 with the anchor 35, the steel supporting member 22 is slidably mounted on the tension frame 24, and the tension frame 24 is fixed to the ground. 11 is provided slidably on a slide guide plate 48 attached with an anchor 35, and a buckling prevention member 27 is provided on the pedestal 29 so as to have an insertion space 33 in which the compression member 26 is loosely fitted with the support 30 and the crosspiece 31. The intended purpose can be achieved by fixing the pedestal 29 to the ground 11 with the anchor 35 using the anchors 35.

ＰＣ鋼材１３にテンションをかけるには、ジャッキ２０による押し出しの力を用いる場合だけでなく、ジャッキ２０により、ＰＣ鋼材１３を定着した鋼材支持材２２でテンションロッド１９を介して引き込むように作用させる場合であってもよい。 In order to apply tension to the PC steel 13, not only the case where the pushing force by the jack 20 is used, but also the case where the jack 20 causes the PC steel 13 to be pulled in by the anchored steel support 22 via the tension rod 19. It may be.

圧縮材２６は、１本または複数本を連結したものからなり、所定の座屈長さの許容座屈応力が発生座屈応力より小さいとき、座屈防止材２７の設置位置は、前記圧縮材２６の固有の許容座屈応力が発生座屈応力より小さくならない位置としたことを特徴とする。 When the allowable buckling stress of a predetermined buckling length is smaller than the generated buckling stress, the installation position of the buckling prevention material 27 is 26 is a position where the inherent allowable buckling stress is not smaller than the generated buckling stress.

圧縮材２６は、座屈防止材２７の挿通空間３３を単に摺動する場合に限らず、圧縮材２６が遊嵌する挿通空間３３の遊嵌位置で前記圧縮材２６と挟持材２７のいずれか一方にピン４２を取り付け、いずれか他方に前記ピン４２が摺動する長孔４１を設けてなるものとすることができる。
また、座屈防止材２７における挿通空間３３に圧縮材２６の摺動を補助する摺動板３４を設けて座屈を確実に防止する。 The compression member 26 is not limited to the case where the compression member 26 simply slides in the insertion space 33 of the buckling prevention member 27, and may be any one of the compression member 26 and the holding member 27 at the play-fitting position of the insertion space 33 where the compression member 26 is loosely fitted. One may be provided with a pin 42 and one of the other may be provided with an elongated hole 41 through which the pin 42 slides.
In addition, a sliding plate 34 for assisting the sliding of the compression member 26 is provided in the insertion space 33 of the buckling prevention member 27 to reliably prevent buckling.

請求項１記載の発明によれば、
プレストレストコンクリート製造のためのＰＣ鋼材を鋼材支持材と鋼材固定材の間に張り渡し、ジャッキ受け台に設けたジャッキで前記ＰＣ鋼材に緊張力を与え、前記ジャッキ受け台の反力を、このジャッキ受け台と鋼材固定材の間に設けた圧縮材で受けるようにしたプレテンション付与装置において、
前記鋼材固定材を地盤にアンカーで固定的に取り付け、
前記鋼材支持材を緊張用フレームに摺動自在に取り付け、
この緊張用フレームを、地盤にアンカーで固着された摺動案内板に摺動自在に設け、
前記圧縮材の途中の、この圧縮材の固有の許容座屈応力が発生座屈応力より小さくならない位置に座屈防止材を設置し、
この座屈防止材は、台座に取り付けた支柱に形成され、前記圧縮材が遊嵌して摺動する挿通空間を有し、
前記座屈防止材の設置は、前記台座を地盤にアンカーで固定したので、前述の固定式コンクリートアバットと、簡易アバットの欠点を解消すると共に、以下の効果を有する。
（１）鋼材固定材は、地盤に固定的に取り付け、鋼材支持材は、緊張用フレームに摺動自在に取り付け、この緊張用フレームを地盤に取り付けた摺動案内板に摺動自在に設け、座屈防止材の設置は、前記台座を地盤に固定したので、膨大な基礎コンクリートを必要とせず、また、鋼製アバットの設置及び撤去が容易である。さらに、圧縮材が座屈しようとすると、その位置の座屈防止材の挿通空間で圧縮材が遊嵌して摺動することで圧縮荷重による圧縮材の縮みを考慮することなく圧縮材の座屈を防止できる。
（２）設置及び撤去が容易であることに伴い、既存設備の変更が少なくて済む。
（３）座屈防止材の数を的確にすることで、最小限の圧縮材とすることができる。
（４）不動点があるので、従来の簡易アバット方式に比べて正確な緊張管理ができる。
（５）鋼材支持材２２にスペーサを介在することで、圧縮材の取付高さを容易に変更でき、図心の高さ方向の変化に対応することができると共に、圧縮材の取付幅を容易に変更でき、図心の幅方向の変化にも容易に対応することができる。
（６）鋼材支持材、鋼材固定材、座屈防止材は、地盤に固着するだけで済み、また、座屈防止材を簡単に構成することができ、かつ、座屈を確実に防止できる。 According to the invention described in claim 1,
A PC steel material for the production of prestressed concrete is stretched between a steel support material and a steel material fixing material, a tension is applied to the PC steel material by a jack provided on a jack cradle, and the reaction force of the jack cradle is measured by the jack. In the pretensioning device to be received by the compressed material provided between the cradle and the steel fixing material,
The steel fixing material is fixedly attached to the ground with an anchor ,
The steel support material is slidably attached to the tension frame,
This tension frame is slidably provided on a sliding guide plate fixed to the ground with an anchor ,
In the middle of the compressed material, a buckling prevention material is installed at a position where the inherent allowable buckling stress of the compressed material does not become smaller than the generated buckling stress,
The buckling prevention member is formed on a column attached to the pedestal, and has an insertion space in which the compression member is loosely fitted and slides,
The installation of the buckling prevention material eliminates the above-mentioned disadvantages of the fixed concrete abutment and the simple abutment because the pedestal is fixed to the ground with an anchor, and has the following effects.
(1) The steel fixing material is fixedly attached to the ground, the steel supporting material is slidably attached to the tension frame, and the tension frame is slidably provided on a sliding guide plate attached to the ground. Since the buckle is fixed to the ground, the buckling prevention member does not require a huge amount of foundation concrete, and the installation and removal of the steel abutment is easy. Further, when the compressed material tries to buckle, the compressed material is loosely fitted and slid in the insertion space of the buckling prevention material at that position, so that the compressed material can be seated without considering shrinkage of the compressed material due to the compression load. Crouching can be prevented.
(2) Since installation and removal are easy, changes in existing equipment can be reduced.
(3) By minimizing the number of buckling prevention members, it is possible to minimize the number of compression members.
(4) Since there is a fixed point, accurate tension management can be performed as compared with the conventional simple abutment method.
(5) Since the spacer is interposed in the steel support member 22, the mounting height of the compressed material can be easily changed, and it is possible to cope with a change in the height direction of the centroid, and the mounting width of the compressed material is easily reduced. , And can easily cope with a change in the centroid width direction.
(6) The steel supporting material, the steel fixing material, and the buckling prevention material only need to be fixed to the ground, and the buckling prevention material can be easily formed, and buckling can be reliably prevented.

請求項２記載の発明によれば、前記座屈防止材の挿通空間は、台座に取り付けた支柱と、この支柱に取り付けた横桟で井桁状に組み込んだので、座屈防止材を簡単に構成することができ、かつ、座屈を確実に防止できる。
According to the second aspect of the invention, the insertion space of the buckling prevention member includes a post attached to the base, than incorporated in rungs attached to the supports in a grid shape, easy to buckling prevention member The buckling can be surely prevented.

請求項３記載の発明によれば、圧縮材を支柱で摺動自在に設けるとともに、ジャッキ受け台に連結し、このジャッキ受け台にジャッキを取り付け、このジャッキに、ＰＣ鋼材を定着した鋼材支持材でテンションロッドを介して引き込むようにしたので、既存の装置が許容座屈応力の小さな圧縮材であっても順次増設して目的のプレテンション付与装置を得ることができる。 According to the third aspect of the present invention, the compression member is slidably provided on the support, connected to the jack cradle, the jack is mounted on the jack cradle, and the PC steel material is fixed to the jack. Thus, even if the existing device is a compressed material having a small allowable buckling stress, it can be sequentially added to obtain the desired pretensioning device.

請求項４記載の発明によれば、圧縮材は、１本または複数本を連結したものからなり、所定の座屈長さの許容座屈応力が発生座屈応力より小さいとき、座屈防止材の設置位置は、前記圧縮材の固有の許容座屈応力が発生座屈応力より小さくならない位置としたので、座屈長さの長いものでも短いものでも座屈防止をより簡便な構成で可能とすることができる。 According to the invention as set forth in claim 4, the compression member is formed by connecting one or more compression members, and when the allowable buckling stress of a predetermined buckling length is smaller than the generated buckling stress, the buckling prevention member is used. The installation position of the compression member was set at a position where the inherent allowable buckling stress of the compressed material did not become smaller than the generated buckling stress, so that a longer or shorter buckling length could be prevented with a simpler configuration to prevent buckling. can do.

請求項５記載の発明によれば、座屈防止材は、台座に２枚の挟持材で圧縮材を遊嵌する挿通空間を有するように固着し、この遊嵌位置で前記圧縮材と挟持材のいずれか一方にピンを取り付け、いずれか他方に前記ピンが摺動する長孔を設けたので、井桁状に組み込み構成したものより簡単に構成できる。 According to the invention as set forth in claim 5, the buckling prevention member is fixed to the pedestal so as to have an insertion space in which the compression member is loosely fitted by two holding members, and the compression member and the holding member are fixed at the loose fitting position. A pin is attached to one of them, and an elongated hole for sliding the pin is provided on the other, so that it can be configured more easily than one that is assembled in a cross-girder shape.

請求項６記載の発明によれば、前記圧縮材は、この圧縮材の固有の許容座屈応力が発生座屈応力より大きな長さの位置に設けた連結材で順次連結し、この連結材による連結位置に座屈防止材を設置したので、井桁状に組み込み構成したものより簡便で、しかも、連結材にピンが摺動する長孔を形成しても構造上の弱点を防止できる。 According to the invention of claim 6, wherein said compression member is sequentially connected by consolidated material specific allowable buckling stress of the compression member is formed at a position of greater length than the generation buckling stress, the connecting member Since the buckling prevention member is installed at the connecting position by (1), the structure is simpler than that in which the pin is slid in the connecting member, and a structural weak point can be prevented even if the connecting member is formed with a long hole through which the pin slides.

請求項７記載の発明によれば、座屈防止材における挿通空間に圧縮材の摺動を補助する摺動板を設けたので、圧縮材が挿通空間を円滑に摺動し、座屈を確実に防止できる。 According to the invention as set forth in claim 7, since the sliding plate for assisting the sliding of the compressed material is provided in the insertion space in the buckling prevention member, the compressed material slides smoothly in the insertion space and buckling is ensured. Can be prevented.

本発明によるプレテンション付与装置の実施例１を示すもので、（ａ）は、平面図、（ｂ）は、一部切り欠いた正面図、（ｃ）は、（ｂ）の一部の拡大図である。1 shows a first embodiment of a pretensioning device according to the present invention, wherein (a) is a plan view, (b) is a partially cutaway front view, and (c) is an enlarged view of a part of (b). FIG. （ａ）は、図１の拡大した左側面図、（ｂ）図１の右側面図である。(A) is an enlarged left side view of FIG. 1, and (b) is a right side view of FIG. 1. 本発明のプレテンション付与装置に使用した座屈防止材２７の斜視図である。It is a perspective view of the buckling prevention material 27 used for the pretension provision apparatus of this invention. 本発明のプレテンション付与装置に使用した座屈防止材２７の一部切り欠いた拡大正面図である。FIG. 3 is an enlarged front view of a buckling prevention member 27 used in the pretensioning device of the present invention, with a portion cut away. 図４における側面図である。It is a side view in FIG. 本発明の実施例２におけるプレテンション付与装置を側方から見た断面図である。It is sectional drawing which looked at the pretension provision apparatus in Example 2 of this invention from the side. 図６における座屈防止材２７の拡大断面図である。FIG. 7 is an enlarged sectional view of a buckling prevention member 27 in FIG. 6. 図６の一部の正面図である。FIG. 7 is a front view of a part of FIG. 6. 図８における２本の圧縮材２６の連結状態を示す分解斜視図である。FIG. 9 is an exploded perspective view showing a connection state of two compression members 26 in FIG. 8. 本発明の実施例２のプレテンション付与装置の緊張側を示すもので、（ａ）は、平面図、（ｂ）は、正面図、（ｃ）は、左側面図である。FIG. 6A is a plan view, FIG. 5B is a front view, and FIG. 5C is a left side view, showing a tension side of the pretensioning device according to the second embodiment of the present invention. 本発明のプレテンション付与装置に使用して１度で複数個のプレストレストコンクリート１２を製造する状態の平面図である。It is a top view in the state where a plurality of prestressed concretes 12 are manufactured at one time using the pretensioning device of the present invention. 異なる形状のプレストレストコンクリート１２を製造する例を示す説明図で、（ａ）は、断面Ｌ字形の製造例を示し、（ｂ）は、断面コ字形の製造例を示し、（ｃ）は、断面Ｔ字形の製造例を示している。It is explanatory drawing which shows the example which manufactures the prestressed concrete 12 of a different shape, (a) shows the example of manufacture of an L-shaped cross section, (b) shows the example of manufacture of a U-shaped cross section, (c) is a cross section The example of manufacture of a T shape is shown. 従来の固定式コンクリートアバットのプレテンション付与装置を示すもので、（ａ）は、１部省略した平面図、（ｂ）は、同上の正面図である。1A and 1B show a conventional fixed concrete abutment pretensioning apparatus, in which FIG. 1A is a plan view in which one part is omitted, and FIG. 1B is a front view of the same. 従来の他の固定式コンクリートアバットのプレテンション付与装置を示すもので、（ａ）は、断面した正面図、（ｂ）は、同上の平面図である。Fig. 3 shows another conventional pretensioning device for a fixed concrete abutment, in which (a) is a cross-sectional front view, and (b) is a plan view of the same.

本発明は、プレストレストコンクリート製造のためのＰＣ鋼材１３を鋼材支持材２２と鋼材固定材２３の間に張り渡し、ジャッキ受け台２８に設けたジャッキ２０で前記ＰＣ鋼材１３に緊張力を与え、前記ジャッキ受け台２８の反力を、このジャッキ受け台２８と鋼材固定材２３の間に設けた圧縮材２６で受けるようにしたプレテンション付与装置において、前記圧縮材２６の途中の、この圧縮材２６の固有の許容座屈応力が発生座屈応力より小さくならない位置に座屈防止材２７を設置し、この座屈防止材２７に形成した挿通空間に前記圧縮材２６を摺動可能に遊嵌する。 According to the present invention, the PC steel 13 for the production of prestressed concrete is stretched between the steel support 22 and the steel fixing member 23, and a tension is applied to the PC steel 13 by the jack 20 provided on the jack cradle 28. In a pretensioning device in which the reaction force of the jack receiving base 28 is received by the compressed material 26 provided between the jack receiving base 28 and the steel fixing member 23, the compression member 26 is located in the middle of the compressed member 26. The buckling prevention member 27 is installed at a position where the inherent allowable buckling stress of the above does not become smaller than the generated buckling stress, and the compression member 26 is loosely slidably fitted into the insertion space formed in the buckling prevention member 27. .

ＰＣ鋼材１３にテンションをかけるには、ジャッキ２０による押し出しの力を用いる場合だけでなく、ジャッキ２０により、ＰＣ鋼材１３を定着した鋼材支持材２２でテンションロッド１９を介して引き込むように作用させる場合であってもよい。具体的には、圧縮材２６を支柱５３で摺動自在に設けるとともに、ジャッキ受け台２８に連結し、このジャッキ受け台２８にジャッキ２０を取り付け、このジャッキ２０に、ＰＣ鋼材１３を定着した鋼材支持材２２でテンションロッド１９を介して引き込むように構成する。 In order to apply tension to the PC steel 13, not only the case where the pushing force by the jack 20 is used, but also the case where the jack 20 causes the PC steel 13 to be pulled in by the anchored steel support 22 via the tension rod 19. It may be. Specifically, the compression member 26 is slidably provided on the support column 53, and is connected to the jack receiving base 28. The jack 20 is attached to the jack receiving base 28, and the PC steel material 13 is fixed to the jack 20. The support member 22 is configured to be pulled in via the tension rod 19.

圧縮材２６は、１本または複数本を連結したものからなり、所定の座屈長さの許容座屈応力が発生座屈応力より小さいとき、座屈防止材２７の設置位置は、前記圧縮材２６の固有の許容座屈応力が発生座屈応力より小さくならない位置に設定する。 When the allowable buckling stress of a predetermined buckling length is smaller than the generated buckling stress, the installation position of the buckling prevention material 27 is 26 is set to a position where the inherent allowable buckling stress does not become smaller than the generated buckling stress.

座屈防止材２７は、台座２９に２枚の挟持材４０で圧縮材２６を遊嵌する挿通空間３３を有するように固着し、この遊嵌位置で前記圧縮材２６と挟持材２７のいずれか一方にピン４２を取り付け、いずれか他方に前記ピン４２が摺動する長孔４１を設けてなるものとすることができる。この場合、圧縮材２６は、この圧縮材２６の固有の許容座屈応力が発生座屈応力より大きな長さの位置に設けた無垢の連結材３９で順次連結し、この連結材３９による連結位置に座屈防止材２７を設置する。
また、座屈防止材２７における挿通空間３３に圧縮材２６の摺動を補助する摺動板３４を設けて座屈を確実に防止する。 The buckling prevention member 27 is fixed to the pedestal 29 with two holding members 40 so as to have an insertion space 33 in which the compression member 26 is loosely fitted. At this loose fitting position, any one of the compression member 26 and the holding member 27 is used. One may be provided with a pin 42 and one of the other may be provided with an elongated hole 41 through which the pin 42 slides. In this case, the compression members 26 are sequentially connected by a solid connection member 39 provided at a position where the allowable buckling stress inherent to the compression member 26 is greater than the generated buckling stress. The buckling prevention material 27 is installed in the.
In addition, a sliding plate 34 for assisting the sliding of the compression member 26 is provided in the insertion space 33 of the buckling prevention member 27 to reliably prevent buckling.

本発明によるプレテンション付与装置の実施例１を図１ないし図５に基づき説明する。
図１（ｃ）に示すように、ＰＣ鋼材１３の緊張部側の地盤１１の上に摺動案内板４８を据付け、この摺動案内板４８の上に緊張用フレーム２４の台座５４を載せ、この台座５４を摺動支持具４９で挟み付けるようにして、この摺動支持具４９を前記摺動案内板４８とともに地盤１１にアンカー３５で固着することにより、前記緊張用フレーム２４が摺動案内板４８の上で摺動可能に支持されている。
この緊張用フレーム２４には、前記ＰＣ鋼材１３を支持する鋼材支持材２２が進退自在に搭載され、また、ジャッキ受け台２８が固定的に設けられ、このジャッキ受け台２８と前記鋼材支持材２２との間にジャッキ２０が搭載される。図１（ａ）（ｂ）に示すように、前記緊張用フレーム２４から所定の距離を置いた前記ＰＣ鋼材１３の固定部側における地盤１１の上に鋼材固定材２３がアンカー３５により固着される。
前記鋼材支持材２２は、鋼材支持材２２の形状に応じて高さを調整できるように上面と下面にスペーサ４７が介在されて前記緊張用フレーム２４に摺動自在に搭載されている。 First Embodiment A pretensioning device according to a first embodiment of the present invention will be described with reference to FIGS.
As shown in FIG. 1 (c), a sliding guide plate 48 is installed on the ground 11 on the side of the tension portion of the PC steel material 13, and the pedestal 54 of the tensioning frame 24 is placed on the sliding guide plate 48. By fixing the pedestal 54 to the ground 11 with the anchor 35 together with the slide guide plate 48 by sandwiching the pedestal 54 with the slide support 49, the tension frame 24 can slide the slide guide. It is slidably supported on a plate 48.
A steel support 22 for supporting the PC steel 13 is mounted on the tension frame 24 so as to be able to move forward and backward, and a jack support 28 is fixedly provided. The jack support 28 and the steel support 22 are fixed. Is mounted between them. As shown in FIGS. 1 (a) and 1 (b), a steel fixing material 23 is fixed by an anchor 35 on the ground 11 at a fixing portion side of the PC steel material 13 at a predetermined distance from the tension frame 24. .
The steel support member 22 is slidably mounted on the tensioning frame 24 with spacers 47 interposed between the upper and lower surfaces so that the height can be adjusted according to the shape of the steel support member 22.

前記鋼材支持材２２と鋼材固定材２３の間には、コンクリートにプレストレスを与えるための複数本のＰＣ鋼材１３が貫通して張られ、それぞれ定着部２１で固定される。このＰＣ鋼材１３をジャッキ２０で緊張するときの緊張力の反力を支えるための圧縮材２６が前記ジャッキ受け台２８と鋼材固定材２３との間に取り付けられる。この圧縮材２６は、従来は、緊張力の反力に耐えうる形状のものが使用されていた。
これに対し、本発明では、途中に座屈防止材２７を介在することで、圧縮材２６の部材サイズ（例えば肉厚）を上げなくても座屈せずに緊張力の反力に耐えることができるようにしたことを特徴としている。 A plurality of PC steel materials 13 for applying a prestress to concrete are penetrated between the steel support material 22 and the steel fixing material 23, and are fixed by the fixing portions 21. A compression member 26 for supporting a reaction force of the tension when the PC steel member 13 is tightened by the jack 20 is attached between the jack cradle 28 and the steel member fixing member 23. Conventionally, the compression member 26 has a shape capable of withstanding a reaction force of tension.
On the other hand, in the present invention, by interposing the buckling prevention member 27 in the middle, it is possible to withstand the reaction force of the tension without buckling without increasing the member size (for example, the wall thickness) of the compression member 26. It is characterized by being made possible.

更に詳しくは、前記圧縮材２６は、座屈長さの短いものを複数本直線的に連結し、この連結した圧縮材２６の途中の所定箇所（例えば連結箇所）に座屈防止材２７を介在する。具体的には、図４に示すように、互いに連結しようとする圧縮材２６の端部にフランジ３６を設け、補強片３７で補強し、ボルト３８で順次連結する。圧縮材２６のサイズをどのように設定するか、その計算例は、後述する。
本実施例では、前記圧縮材２６は、運搬、組み立てその他の作業性を考慮して座屈長さの短いものを複数本直線的に連結しているが、前記鋼材支持材２２と鋼材固定材２３の間を１本の圧縮材２６とすることもできる。 More specifically, a plurality of compression members 26 having a short buckling length are linearly connected, and a buckling prevention member 27 is interposed at a predetermined position (for example, a connection point) in the middle of the connected compression members 26. I do. Specifically, as shown in FIG. 4, a flange 36 is provided at an end portion of the compression members 26 to be connected to each other, reinforced by a reinforcing piece 37, and sequentially connected by a bolt 38. An example of how to set the size of the compressed material 26 and a calculation example thereof will be described later.
In the present embodiment, the compression member 26 is formed by connecting a plurality of members having a short buckling length linearly in consideration of transportation, assembly and other workability. One compression member 26 can be formed between the two members 23.

この圧縮材２６の連結個所には、座屈防止材２７を地盤１１にアンカー３５で固定する。本実施例では、座屈防止材２７の固定する位置を圧縮材２６の連結個所としているが、この位置は、後述するように、圧縮材２６の固有の許容座屈応力が発生座屈応力より小さくならない位置であればよい。
この座屈防止材２７は、図３、図４及び図５に示すように、前記圧縮材２６の一辺が例えば、３０ｃｍの正方形の角筒状とすると、この圧縮材２６の１辺の約２倍の長さの２個の台座２９を用意し、これらの台座２９に、それぞれ圧縮材２６の幅よりやや広い間隔で２本ずつの支柱３０を直立して取り付け、これらの支柱３０に、圧縮材２６に直交する方向と圧縮材２６の長さ方向に、それぞれ上下に横桟３１ａと３１ｂ、連結桟３２ａと３２ｂを取付けて井桁状に組み立てる。すると、２本の支柱３０と３０、上下の横桟３１ａと３１ｂによって挿通空間３３が形成される。この挿通空間３３の全内周面には、圧縮材２６が円滑に摺動するためのステンレス板などからなる摺動板３４が固着される。
このようにして形成された座屈防止材２７は、圧縮材２６の連結個所に、より正確には、圧縮材２６の有する許容座屈応力が発生座屈応力より小さくならないような地盤１１の位置に、アンカー３５にて固定する。 A buckling prevention member 27 is fixed to the ground 11 with an anchor 35 at a connection point of the compression member 26. In the present embodiment, the position where the buckling prevention member 27 is fixed is set as the connection point of the compression member 26. However, as described later, the allowable buckling stress inherent in the compression member 26 is smaller than the generated buckling stress. Any position that does not become smaller may be used.
As shown in FIG. 3, FIG. 4 and FIG. 5, when one side of the compressed material 26 is, for example, a 30 cm square prism, as shown in FIGS. Two pedestals 29 having a double length are prepared. On each of these pedestals 29, two columns 30 are mounted upright at intervals slightly wider than the width of the compression member 26, and the columns 30 are compressed. The horizontal bars 31a and 31b and the connecting bars 32a and 32b are attached to the upper and lower sides in the direction orthogonal to the member 26 and the length direction of the compressed member 26, respectively, and are assembled in a grid. Then, an insertion space 33 is formed by the two columns 30 and 30 and the upper and lower horizontal bars 31a and 31b. A sliding plate 34 made of a stainless steel plate or the like for allowing the compressed material 26 to slide smoothly is fixed to the entire inner peripheral surface of the insertion space 33.
The buckling prevention member 27 formed in this manner is located at a position where the allowable buckling stress of the compression member 26 does not become smaller than the generated buckling stress at the connection point of the compression member 26. Is fixed with an anchor 35.

前記圧縮材２６のサイズの設定は、クレーン構造規格による強度計算例に基づき、次のようにして行われる。
１．降伏点又は耐力が２４５Ｎ／ｍｍ^２以下の鋼材（ＳＳ４００）を使用したものとすると、その基本許容応力σａは、鋼材の降伏点を１．５で除した次式で求められる。
σａ＝２４５／１．５＝１６３Ｎ／ｍｍ^２
許容圧縮応力σｃａは、この基本許容応力σａを１．１５で除した次式で求められる。
σｃａ＝σａ／１．１５＝１６３／１．１５＝１４２Ｎ／ｍｍ^２ The setting of the size of the compression member 26 is performed as follows based on a strength calculation example based on the crane structure standard.
1. Assuming that a steel material (SS400) having a yield point or a proof stress of 245 N / mm ² or less is used, the basic allowable stress σa is obtained by the following equation in which the yield point of the steel material is divided by 1.5.
σa = 245 / 1.5 = 163 N / mm ²
The allowable compressive stress σca is obtained by the following equation obtained by dividing the basic allowable stress σa by 1.15.
σca = σa / 1.15 = 163 / 1.15 = 142 N / mm ²

２．圧縮材の検討
圧縮材１本当たりの荷重Ｐ＝１５００ｋＮとする。
（１）発生座屈応力の検討
使用材 □Ｐ（角パイプ）３００×３００×１２ｔ
自重：ｗ１＝１０６ｋｇ／ｍ
断面積Ａ＝１３４ｃｍ^２
断面２次半径ｉ＝１１．７ｃｍ
座屈長さＬｋ＝１０００ｃｍ
細長比 λ＝１０００／１１．７＝８５．５
座屈係数 ω＝１．４３（座屈係数表による）
許容座屈応力 σｋ＝σｃａ／ω＝１４２／１．４３＝９９Ｎ／ｍｍ^２
発生座屈応力 σｃ＝Ｐ／Ａ＝１５００×１０^３／１３４
＝１１１９４Ｎ／ｃｍ^２＝１１２Ｎ／ｍｍ^２＞σｋ＝９９Ｎ／ｍｍ^２
となり、前記座屈長さＬｋ＝１０００ｃｍの使用材の許容座屈応力σｋ＝９９Ｎ／ｍｍ^２では、発生座屈応力許容σｃ＝１１２Ｎ／ｍｍ^２より小さくなり、必要な許容座屈応力が得られない。 2. Examination of compressed material Load per compressed material P = 1500 kN.
(1) Examination of generated buckling stress Material used □ P (square pipe) 300 × 300 × 12t
Own weight: w1 = 106kg / m
Cross-sectional area A = 134cm ²
Secondary radius of cross section i = 11.7cm
Buckling length Lk = 1000cm
Slenderness ratio λ = 1000 / 11.7 = 85.5
Buckling coefficient ω = 1.43 (according to buckling coefficient table)
Allowable buckling stress σk = σca / ω = 142 / 1.43 = 99 N / mm ²
Generating buckling stress σc = P / A = 1500 × 10 3/134
= 11194 N / cm ² = 112 N / mm ² > σk = 99 N / mm ²
Next, the said seat屈長of Lk = 1000 cm use material allowable buckling stress σk = 99N / mm ^2, smaller than the generated buckling stress tolerance σc = 112N / mm ^2, the required tolerance buckling stress is obtained Absent.

（２）上記使用材では、許容値外のため、部材サイズ（肉厚）を上げ、再検討すると、
使用材 □Ｐ（角パイプ）３００×３００×１６ｔ
自重：ｗ２＝１３８ｋｇ／ｍ
断面積Ａ＝１７５ｃｍ^２
断面２次半径ｉ＝１１．５ｃｍ
座屈長さＬｋ＝１０００ｃｍ
細長比 λ＝１０００／１１．５＝８７．０
座屈係数 ω＝１．４５（座屈係数表による）
許容座屈応力 σｋ＝σｃａ／ω＝１４２／１．４５＝９８Ｎ／ｍｍ^２
発生座屈応力 σｃ＝Ｐ／Ａ＝１５００×１０^３／１７５
＝８５７１Ｎ／ｃｍ^２＝８６Ｎ／ｍｍ^２＜σｋ＝９８Ｎ／ｍｍ^２
となり、この部材サイズ（肉厚）を上げた使用材では、発生座屈応力より大きな許容座屈応力が得られる。
ただし、重量比として１ｍ当たり、ｗ２／ｗ１＝１３８／１０６＝１．３０倍重くなるため、高価になる。 (2) For the above-mentioned materials, the member size (thickness) was raised and reconsidered because it was outside the allowable value.
Materials used □ P (square pipe) 300 × 300 × 16t
Own weight: w2 = 138 kg / m
Cross-sectional area A = 175cm ²
Secondary radius of cross section i = 11.5cm
Buckling length Lk = 1000cm
Slenderness ratio λ = 1000 / 11.5 = 87.0
Buckling coefficient ω = 1.45 (according to buckling coefficient table)
Allowable buckling stress σk = σca / ω = 142 / 1.45 = 98 N / mm ²
Generating buckling stress σc = P / A = 1500 × 10 3/175
= 8571 N / cm ² = 86 N / mm ² <σk = 98 N / mm ²
Thus, in the case of the used material having the increased member size (thickness), an allowable buckling stress larger than the generated buckling stress is obtained.
However, since w2 / w1 = 138/106 = 1.30 times as heavy as 1 m in weight ratio, it becomes expensive.

（３）部材サイズ（肉厚）を上げず、使用材の長さの半分の箇所に本発明による座屈防止材２７を設置したものとすると、
使用材 □Ｐ（角パイプ）３００×３００×１２ｔ
断面積Ａ＝１３４ｃｍ^２
断面２次半径ｉ＝１１．７ｃｍ
座屈長さＬｋ＝５００ｃｍ
細長比 λ＝５００／１１．７＝４２．７
座屈係数 ω＝１．０３（座屈係数表による）
許容座屈応力 σｋ＝σｃａ／ω＝１４２／１．０３＝１３８Ｎ／ｍｍ^２
発生座屈応力 σｃ＝Ｐ／Ａ＝１５００×１０^３／１３４
＝１１１９４Ｎ／ｃｍ^２＝１１２Ｎ／ｍｍ^２＜σｋ＝１３８Ｎ／ｍｍ^２
となり、前記座屈長さＬｋ＝５００ｃｍの使用材では、許容座屈応力σｋ＝１３８Ｎ／ｍｍ^２が発生座屈応力σｃ＝１１２Ｎ／ｍｍ^２より大きくなり、必要な許容座屈応力が得られる。 (3) Assuming that the buckling prevention member 27 according to the present invention is installed at a half of the length of the used material without increasing the member size (wall thickness),
Materials used □ P (Square pipe) 300 × 300 × 12t
Cross-sectional area A = 134cm ²
Secondary radius of cross section i = 11.7cm
Buckling length Lk = 500cm
Slenderness ratio λ = 500 / 11.7 = 42.7
Buckling coefficient ω = 1.03 (according to buckling coefficient table)
Allowable buckling stress σk = σca / ω = 142 / 1.03 = 138 N / mm ²
Generating buckling stress σc = P / A = 1500 × 10 3/134
= 11194 N / cm ² = 112 N / mm ² <σk = 138 N / mm ²
Next, the use material of the seat屈長of Lk = 500 cm, the allowable buckling stress σk = 138N / mm ² is larger than the generated buckling stress σc = 112N / mm ^2, the required permissible buckling force.

以上のような構成において、鋼材支持材２２と鋼材固定材２３との間に必要な本数のＰＣ鋼材１３を配置し、それぞれの定着部２１で固着する。前記鋼材支持材２２とジャッキ受け台２８との間に据え付けたジャッキ２０のピストンを押し出すと、鋼材支持材２２が図１（ｃ）の鎖線で示すように摺動し、前記ＰＣ鋼材１３に所定の緊張力が付加される。このとき、ジャッキ受け台２８に受けた反力が両側の圧縮材２６で受け、この圧縮材２６が収縮し、緊張用フレーム２４とジャッキ受け台２８が摺動案内板４８の上で鎖線のようにわずかに移動する。
ここで、圧縮材２６が２．（１）で検討した３００×３００×１２ｔで座屈長さＬｋ＝１０００ｃｍのパイプであるものとすると、固有の許容座屈応力σｋ＝９９Ｎ／ｍｍ^２では、発生座屈応力許容σｃ＝１１２Ｎ／ｍｍ^２より小さくなり、必要な許容座屈応力が得られない。 In the above-described configuration, a necessary number of PC steel materials 13 are arranged between the steel material support member 22 and the steel material fixing member 23, and fixed at the respective fixing portions 21. When the piston of the jack 20 installed between the steel support member 22 and the jack cradle 28 is pushed out, the steel support member 22 slides as shown by a chain line in FIG. Is applied. At this time, the reaction force received by the jack receiving stand 28 is received by the compression members 26 on both sides, and the compression member 26 contracts, and the tension frame 24 and the jack receiving stand 28 are arranged on the sliding guide plate 48 as shown by a chain line. To move slightly.
Here, the compressed material 26 is 2. Assuming that the pipe is a 300 × 300 × 12 t and buckling length Lk = 1000 cm studied in (1), the inherent allowable buckling stress σk = 99 N / mm ^{2 and} the allowable buckling stress σc = 112 N / smaller than mm ^2, the allowable buckling stress is not obtained required.

しかし、圧縮材２６が２．（３）で検討した３００×３００×１２ｔで座屈長さＬｋ＝５００ｃｍのパイプであるものとすると、固有の許容座屈応力σｋ＝１３８Ｎ／ｍｍ^２であるから、発生座屈応力許容σｃ＝１１２Ｎ／ｍｍ^２より大きくなり、必要な許容座屈応力が得られる。
そこで、部材サイズを元の３００×３００×１２ｔで、座屈長さＬｋ＝５００ｃｍのパイプを順次連結して用いても座屈の発生を防止するため、固有の許容座屈応力σｋが発生座屈応力許容σｃより大きくなる位置、例えば、連結した５００ｃｍの位置に順次座屈防止材２７を据え付ける。これらの座屈防止材２７は、地盤１１にアンカー３５で固定し、上部の横桟３１ａを外して圧縮材２６のジャッキ受け台２８から５００ｃｍ部分を上から摺動自在に嵌め込み、横桟３１ａを被せる。この座屈防止材２７の据え付け位置は、固有の許容座屈応力σｋが発生座屈応力許容σｃより大きくなる位置であれば、５００ｃｍ以上でも、以下でもよい。また、連結位置に限られない。
このように、２．（３）で検討した３００×３００×１２ｔで座屈長さＬｋ＝５００ｃｍの各パイプであって、発生座屈応力σｃ＝１１２Ｎ／ｍｍ^２であるとしても、順次座屈防止材２７を配置することにより、許容座屈応力σｋ＝１３８Ｎ／ｍｍ^２が得られ、圧縮材２６の断面積を増やすことなく制限なく伸ばすことができる。
前記ＰＣ鋼材１３に緊張力を付加することにより圧縮材２６が伸縮すると、挿通空間３３に設けた摺動板３４に接しながら円滑に摺動する。 However, when the compression member 26 is 2. Assuming that the pipe is a 300 × 300 × 12 t and buckling length Lk = 500 cm studied in (3), the inherent allowable buckling stress σk = 138 N / mm ² , and thus the allowable buckling stress σc = It is larger than 112 N / mm ² , and the required allowable buckling stress is obtained.
Therefore, in order to prevent the occurrence of buckling even when pipes having the original member size of 300 × 300 × 12 t and buckling length Lk = 500 cm are sequentially connected, the inherent allowable buckling stress σk is generated. The buckling prevention members 27 are sequentially installed at a position larger than the allowable bending stress σc, for example, at a connected position of 500 cm. These buckling prevention members 27 are fixed to the ground 11 with the anchor 35, the upper horizontal rail 31a is removed, and a 500 cm portion from the jack cradle 28 of the compression material 26 is slidably fitted from above, and the horizontal rail 31a is attached. Put on. The installation position of the buckling prevention member 27 may be 500 cm or more or less as long as the inherent allowable buckling stress σk is larger than the generated buckling stress allowable σc. Further, the position is not limited to the connection position.
Thus, 2. Each of the pipes of 300 × 300 × 12 t and buckling length Lk = 500 cm studied in (3), and even if the generated buckling stress σc = 112 N / mm ² , the buckling prevention members 27 are sequentially arranged. As a result, the allowable buckling stress σk = 138 N / mm ² is obtained, and the compression member 26 can be extended without limitation without increasing the cross-sectional area.
When the compressive material 26 expands and contracts by applying a tension to the PC steel 13, it slides smoothly while being in contact with the sliding plate 34 provided in the insertion space 33.

要するに、圧縮材２６の途中の、この圧縮材２６の持つ固有の許容座屈応力が発生座屈応力より小さくならない位置に座屈防止材２７を順次設置し、この座屈防止材２７に形成した挿通空間３３に前記圧縮材２６を摺動可能に遊嵌することにより、アンカー３５が反力を受けることなく、かつ、圧縮材２６の許容座屈応力は、発生座屈応力と等しいか大きくなり、必要な座屈応力が得られる。 In short, the buckling prevention members 27 are sequentially installed at positions in the middle of the compression member 26 where the inherent allowable buckling stress of the compression member 26 does not become smaller than the generated buckling stress, and the buckling prevention members 27 are formed. By slidably fitting the compression member 26 into the insertion space 33 so that the anchor 35 does not receive a reaction force, the allowable buckling stress of the compression member 26 becomes equal to or larger than the generated buckling stress. The required buckling stress is obtained.

前記実施例では、座屈防止材２７の挿通空間３３に圧縮材２６を摺動自在に遊嵌して座屈防止をするようにした。
しかし、これに限られるものではなく、座屈防止材２７は、図６〜図９に示すように、圧縮材２６の一部に長孔４１を穿設し、この長孔４１に座屈防止材２７に設けたピン４２を貫通して圧縮材２６が長さ方向に移動自在に構成してもよい。更に詳しくは、圧縮材２６の連結部分には、無垢材の連結材３９を連結し、端部のフランジ３６をボルト３８で連結する。また、連結材３９の長孔４１に望ませて座金４４を固着し、台座２９の上部に挿通空間３３をもって２枚の挟持材４０を固着する。そして、挿通空間３３に連結材３９を遊嵌し、摺動板３４を介在してボルトからなるピン４２をガイドパイプ４３とともに摺動自在に挿入し固定する。
このような構成において、圧縮材２６に圧縮力がかかり、縮小しようとすると長孔４１で許容される。 In the above embodiment, the compression member 26 is slidably and loosely fitted into the insertion space 33 of the buckling prevention member 27 to prevent buckling.
However, the present invention is not limited to this. For the buckling prevention member 27, as shown in FIGS. The compression member 26 may be configured to be movable in the length direction through the pin 42 provided on the member 27. More specifically, a connecting member 39 made of solid wood is connected to a connecting portion of the compressed material 26, and a flange 36 at an end is connected by a bolt 38. A washer 44 is fixed to the long hole 41 of the connecting member 39 as desired, and two holding members 40 are fixed to the upper part of the pedestal 29 with the insertion space 33. Then, the connecting member 39 is loosely fitted in the insertion space 33, and the pin 42 made of a bolt is slidably inserted and fixed together with the guide pipe 43 via the sliding plate 34.
In such a configuration, a compression force is applied to the compression member 26, and an attempt to reduce the compression member 26 is permitted by the elongated hole 41.

前記実施例１を示す図１では、ＰＣ鋼材１３を定着した鋼材支持材２２をジャッキ２０で押し出すようにしてＰＣ鋼材１３にテンションをかけるようにした。
しかし、これに限られるものではなく、ジャッキ受け台２８にジャッキ２０を取り付けてＰＣ鋼材１３を定着した鋼材支持材２２をテンションロッド１９で引き込むようにしてＰＣ鋼材１３にテンションを掛けるものであってもよい。さらに詳しくは、ジャッキ受け台２８の１側面にラムチェア５２を介してジャッキ２０を取り付ける。このジャッキ受け台２８の他側面には、支柱５３で支持された圧縮材２６を固定する。また、ジャッキ受け台２８の他側面に位置してＰＣ鋼材１３を定着する鋼材支持材２２を設け、この鋼材支持材２２にテンションロッド１９の端部を固着し、このテンションロッド１９の先端部は、ジャッキ受け台２８とラムチェア５２を貫通してジャッキ２０に固着する。テンションロッド１９は、ラムチェア５２内のナット５１にて位置保持する。圧縮材２６には、図１と同様に所定間隔で座屈防止材２７が設けられる。前記支柱５３には、ピン４２と長孔４１で圧縮材２６の圧縮時の移動に対応する。 In FIG. 1 showing the first embodiment, a tension is applied to the PC steel 13 by pushing out the steel support 22 to which the PC steel 13 is fixed with a jack 20.
However, the present invention is not limited to this. The tension is applied to the PC steel 13 by attaching the jack 20 to the jack receiving stand 28 and pulling in the steel support 22 to which the PC steel 13 is fixed with the tension rod 19. Is also good. More specifically, the jack 20 is attached to one side of the jack receiving stand 28 via the ram chair 52. The compression member 26 supported by the support pillar 53 is fixed to the other side surface of the jack cradle 28. Further, a steel support member 22 for fixing the PC steel 13 is provided on the other side surface of the jack receiving stand 28, and an end of the tension rod 19 is fixed to the steel support member 22, and the tip of the tension rod 19 is , Penetrates the jack rest 28 and the ram chair 52 and is fixed to the jack 20. The tension rod 19 is held in position by a nut 51 in a ram chair 52. The compression member 26 is provided with buckling prevention members 27 at predetermined intervals as in FIG. The pin 53 and the elongated hole 41 correspond to the movement of the compression member 26 when the compression member 26 is compressed.

このような構成において、鋼材支持材２２にＰＣ鋼材１３を定着し、この鋼材支持材２２をジャッキ２０でテンションロッド１９を介して引き込むと、ＰＣ鋼材１３にテンションが掛けられる。このとき、圧縮材２６に発生する圧縮力による収縮は、長孔４１とピン４２で逃げられる。ジャッキ２０でテンションロッド１９が引き込まれて移動すると、ナット５１を締め付けてジャッキ２０の開放したときのテンションロッド１９の戻りを遮断する。
圧縮材２６の座屈防止機能、コンクリート１２の打設は、前述と同様である。 In such a configuration, when the PC steel 13 is fixed to the steel support 22 and the steel support 22 is pulled in by the jack 20 via the tension rod 19, tension is applied to the PC steel 13. At this time, the contraction due to the compression force generated in the compression member 26 is escaped by the elongated hole 41 and the pin 42. When the tension rod 19 is pulled and moved by the jack 20, the nut 51 is tightened to block the return of the tension rod 19 when the jack 20 is opened.
The buckling prevention function of the compression member 26 and the placement of the concrete 12 are the same as those described above.

前記実施例では、圧縮材２６の断面積と長さを具体的な数値で例示したが、これに限られるものではなく、圧縮材２６の持つ固有の許容座屈応力が発生座屈応力より小さくならないように座屈防止材２７の設置数を的確に設定することにより、圧縮材２６の断面積と座屈長さを最小限に設定できる。 In the above-described embodiment, the cross-sectional area and the length of the compression member 26 are exemplified by specific numerical values. However, the present invention is not limited to this, and the inherent allowable buckling stress of the compression member 26 is smaller than the generated buckling stress. By properly setting the number of the buckling prevention members 27 so as not to be reduced, the sectional area and the buckling length of the compression member 26 can be set to the minimum.

前記実施例では、圧縮材２６は、適宜の長さのものを連結し、この連結部分に座屈防止材２７を配置したが、これに限られるものではなく、連結していない長い圧縮材２６を用いて、その途中の座屈長さの位置に座屈防止材２７を配置してもよい。逆に、短い又は長さの異なる圧縮材２６を連結して連結位置に係わりなく座屈長さに応じて座屈防止材２７を設置することもできる。 In the above-described embodiment, the compression member 26 is connected to a member having an appropriate length, and the buckling prevention member 27 is disposed at the connection portion. However, the present invention is not limited to this. The buckling prevention member 27 may be arranged at the position of the buckling length in the middle of the buckling. Conversely, the compression members 26 having different lengths or different lengths may be connected to each other, and the buckling prevention member 27 may be provided according to the buckling length regardless of the connection position.

既存のプレテンション付与装置を拡張する場合には、既存の圧縮材２６と同様の圧縮材２６を順次連結し、座屈長さに応じて座屈防止材２７を設置することができる。例えば、図１１に示すように、既存の装置に更に圧縮材２６を連結し、かつ、座屈防止材２７を設置することにより、複数枚のプレストレストコンクリート１２を製造するプレテンション付与装置に改良することができる。 When expanding the existing pretensioning device, the same compression member 26 as the existing compression member 26 is sequentially connected, and the buckling prevention member 27 can be installed according to the buckling length. For example, as shown in FIG. 11, by connecting a compression member 26 to an existing device and installing a buckling prevention member 27, the pretensioning device for manufacturing a plurality of prestressed concrete 12 is improved. be able to.

前記実施例では、平板状のコンクリート１２や柱状のコンクリート１２を製造する例を示したが、図１２（ａ）に示すように、左右に１本ずつの圧縮材２６を配置して断面Ｌ字形のコンクリート１２の製造する例、図１２（ｂ）に示すように、左右に２本ずつ、中央に１本の圧縮材２６を配置して断面コ字形のコンクリート１２の製造する例、図１２（ｃ）に示すように、左右に２本ずつの圧縮材２６を配置して断面Ｔ字形のコンクリート１２の製造する例とすることもできる。これらの場合にも、発生座屈応力が許容座屈応力より大きい場合には、許容座屈応力が発生座屈応力より小さくならないように座屈防止材２７を設置することはもちろんである。 In the above-described embodiment, an example of manufacturing the plate-shaped concrete 12 and the column-shaped concrete 12 has been described. However, as shown in FIG. FIG. 12B shows an example of manufacturing concrete 12 having a U-shaped cross section by arranging two compressive members 26 at the center, two on the left and right sides, as shown in FIG. As shown in c), an example of manufacturing the concrete 12 having a T-shaped cross section by arranging two compression members 26 on the left and right sides may be used. Also in these cases, if the generated buckling stress is larger than the allowable buckling stress, the buckling prevention member 27 is of course installed so that the allowable buckling stress does not become smaller than the generated buckling stress.

１０…固定式コンクリートアバット、１１…地盤、１２…コンクリート、１３…ＰＣ鋼材、１４…底面壁、１５…端部壁、１７…定着用ブロック、１８…受け梁、１９…テンションロッド、２０…ジャッキ、２１…定着部、２２…鋼材支持材、２３…鋼材固定材、２４…緊張用フレーム、２６…圧縮材、２７…座屈防止材、２８…ジャッキ受け台、２９…台座、３０…支柱、３１…横桟、３２…連結桟、３３…挿通空間、３４…摺動板、３５…アンカー、３６…フランジ、３７…補強片、３８…ボルト、３９…連結材、４０…挟持材、４１…長孔、４２…ピン、４３…ガイドパイプ、４４…座金、４５…コンクリートアバット、４６…鋼製ポスト、４７…スペーサ、４８…摺動案内板、４９…摺動支持具、５１…ナット、５２…ラムチェア、５３…支柱、５４…台座。 Reference Signs List 10: fixed concrete abutment, 11: ground, 12: concrete, 13: PC steel, 14: bottom wall, 15: end wall, 17: fixing block, 18: receiving beam, 19: tension rod, 20: jack , 21 ... Fixing part, 22 ... Steel support, 23 ... Steel fixing, 24 ... Tension frame, 26 ... Compression, 27 ... Anti-buckling, 28 ... Jack pedestal, 29 ... Pedestal, 30 ... Post, 31 ... horizontal beam, 32 ... connecting beam, 33 ... insertion space, 34 ... sliding plate, 35 ... anchor, 36 ... flange, 37 ... reinforcing piece, 38 ... bolt, 39 ... connecting member, 40 ... pinching member, 41 ... Long holes, 42 pins, 43 guide pipes, 44 washers, 45 concrete abutments, 46 steel posts, 47 spacers, 48 sliding guide plates, 49 sliding supports, 51 nuts, 52 ... lamb chair, 3 ... struts, 54 ... pedestal.

Claims

A PC steel material for the production of prestressed concrete is stretched between a steel support material and a steel material fixing material, a tension is applied to the PC steel material by a jack provided on a jack cradle, and the reaction force of the jack cradle is measured by the jack. In the pretensioning device to be received by the compressed material provided between the cradle and the steel fixing material,
The steel fixing material is fixedly attached to the ground with an anchor ,
The steel support material is slidably attached to the tension frame,
This tension frame is slidably provided on a sliding guide plate fixed to the ground with an anchor ,
In the middle of the compressed material, a buckling prevention material is installed at a position where the inherent allowable buckling stress of the compressed material does not become smaller than the generated buckling stress,
The buckling prevention member is formed on a column attached to the pedestal, and has an insertion space in which the compression member is loosely fitted and slides,
The installation of the buckling prevention material is performed by fixing the pedestal to the ground with an anchor .

The pretensioning device according to claim 1, wherein the insertion space of the buckling prevention member is built in a cross-girder shape with a column attached to a pedestal and a horizontal bar attached to the column.

The compressed material was slidably provided by a support, connected to a jack support, a jack was attached to the jack support, and a steel support material having PC steel fixed thereto was pulled into the jack via a tension rod. The pretensioning device according to claim 1, wherein:

The compression member is formed by connecting one or a plurality of members, and when the allowable buckling stress of a predetermined buckling length is smaller than the generated buckling stress, the installation position of the buckling prevention member is determined by the specific position of the compression member. 4. The pretensioning device according to claim 1, wherein the allowable buckling stress is not smaller than the generated buckling stress.

The buckling prevention member is fixed to the pedestal so as to have an insertion space in which the compression member is loosely fitted with two holding members, and a pin is attached to one of the compression member and the holding member at this loose fitting position, 2. The pretensioning device according to claim 1, wherein an elongated hole through which the pin slides is provided in one of the other.

The compression members are sequentially connected by a connecting member provided at a position having a length at which a permissible buckling stress inherent to the compression member is greater than the generated buckling stress, and the buckling preventing member is installed at a connection position by the connecting member. The pretensioning device according to claim 1 or 5, wherein:

7. The pretensioning device according to claim 1, wherein a sliding plate for assisting sliding of the compression member is provided in the insertion space of the buckling prevention member.