JP2014222005A - Tensioning force releasing method for pc outer cable - Google Patents

Tensioning force releasing method for pc outer cable Download PDF

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JP2014222005A
JP2014222005A JP2013102425A JP2013102425A JP2014222005A JP 2014222005 A JP2014222005 A JP 2014222005A JP 2013102425 A JP2013102425 A JP 2013102425A JP 2013102425 A JP2013102425 A JP 2013102425A JP 2014222005 A JP2014222005 A JP 2014222005A
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external cable
tension
cable
external
releasing
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JP6132142B2 (en
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秀平 小野
Shuhei Ono
秀平 小野
浩 布下
Hiroshi Nunoshita
浩 布下
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Shimizu Construction Co Ltd
Shimizu Corp
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Shimizu Corp
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Abstract

PROBLEM TO BE SOLVED: To provide a tensioning force releasing method for pc outer cable that can gradually remove tensioning force operating on a PC outer cable relatively safely.SOLUTION: There is provided a method of removing tensioning force of an existing PC outer cable 18, as a tensioning material, of an outer cable type bridge 10 which has a main girder 12 pre-stressed through a fixation part 20 and a deflection part 22 of the PC outer cable 18 while the PC outer cable 18 is arranged along a bridge axial direction sectionally outside a member of the main girder 12, the method including the steps of: providing a temporary fixation part 24 for temporarily fixing the PC outer cable 18 to the deflection part 22; and tensing and temporarily fixing the PC outer cable 18 at the temporary fixation part 24 in a direction in which the tensioning force of the PC outer cable 18 arranged between the deflection part 22 and the fixation part 20 as a primary fixation part adjoining it is reduced.

Description

本発明は、構造物にプレストレスを導入するためにこの構造物の外側などに緊張状態に配設された既設のＰＣ外ケーブルの緊張力を解放する方法に関し、特に、既設の外ケーブル方式によるＰＣ箱桁橋のＰＣ外ケーブルの緊張力解放方法に関するものである。   The present invention relates to a method for releasing the tension force of an existing PC external cable disposed in a tensioned state on the outside of the structure in order to introduce prestress to the structure, and in particular, by an existing external cable system. The present invention relates to a method for releasing tension of a PC external cable of a PC box girder bridge.

従来、外ケーブル方式を用いたＰＣ箱桁橋は多数建設されており、近い将来、こうしたＰＣ箱桁橋のＰＣ外ケーブルの取替えや更新に伴う撤去工事の増加が予想される。しかしながら、既設のＰＣ外ケーブルの交換方法に関連して、その緊張力解放方法や更新時の撤去方法は確立されていないのが現状である。既設ＰＣ外ケーブルの交換方法に関連する従来の技術としては、例えば特許文献１の技術が知られている。   Conventionally, a large number of PC box girder bridges using the external cable system have been constructed, and in the near future, it is expected that the number of removal works associated with replacement and renewal of PC external cables of such PC box girder bridges will increase. However, in connection with the existing method of replacing the PC external cable, the current state is that the tension release method and the removal method at the time of renewal have not been established. As a conventional technique related to a method for replacing an existing PC external cable, for example, the technique of Patent Document 1 is known.

特許文献１のＰＣ外ケーブルの張力解放方法は、既設ＰＣケーブルの張力を解放するにあたり、加工を施す予定位置における張力伝達有効長さを推定し、この有効長さの内の一定長さの部分を、ＰＣケーブルの降伏強度が２０ｋｇ／ｍｍ２以下となる強度低下温度に一様に加熱し、この加熱部を降伏伸長させるものである。 In the method for releasing the tension of the PC external cable disclosed in Patent Document 1, the tension transmission effective length at the position to be processed is estimated when releasing the tension of the existing PC cable, and a portion of a certain length of the effective length is estimated. Is uniformly heated to a strength lowering temperature at which the yield strength of the PC cable is 20 kg / mm 2 or less, and the heating portion is yielded and elongated.

また、既設ＰＣ外ケーブルの緊張力の調整を扱った従来の技術としては、例えば特許文献２の技術が知られている。特許文献２は、プレストレストコンクリート橋梁の定着具と支圧板が密着する程度の低い張力で緊張した外ケーブルを配設したプレストレストコンクリート橋梁構造であって、外ケーブルを緊張する緊張機構と、外ケーブルの張力変動を検出する検出手段とを設け、検出手段により外ケーブルの張力変動を計測することにより、プレストレストコンクリート橋梁の耐荷力をモニタリングするものである。この技術では、検出手段が所定の張力の増加を検出した場合に上記の緊張機構によって外ケーブルを再緊張することが提案されている。   Further, as a conventional technique dealing with the adjustment of the tension force of an existing PC external cable, for example, the technique of Patent Document 2 is known. Patent Document 2 is a prestressed concrete bridge structure in which an outer cable that is tensioned at a tension low enough to allow the fixing tool of the prestressed concrete bridge and the bearing plate to be in close contact with each other. Detection means for detecting tension fluctuation is provided, and the load resistance of the prestressed concrete bridge is monitored by measuring the tension fluctuation of the outer cable by the detection means. In this technique, it is proposed that the outer cable is re-tensioned by the above-described tension mechanism when the detection unit detects an increase in a predetermined tension.

特許第２６１３３４６号公報Japanese Patent No. 2613346 特開２０１２−１２７０５３号公報JP 2012-127053 A

ところで、一般的なＰＣ箱桁橋などで用いられるＰＣ外ケーブルでは、その延長が２００ｍ程度の場合にはその総伸び量は１２００ｍｍ程度となる。こうしたＰＣ外ケーブルが配設されたＰＣ箱桁橋などにおいては、既設ＰＣ外ケーブルの緊張力を解放するために再緊張作業を一旦行う必要があるが、定着部においてはこの再緊張作業に必要なケーブル余長は殆どないのが通常であり、この作業を行うのは難しい。また、定着部の楔部分を加熱する方法などによる通常の緊張力解放の方法では、緊張力が大きく、伸び量が大きい場合には作業時に危険を伴うおそれがあり、これをそのまま使用することはできない。したがって、ＰＣ外ケーブルに作用している緊張力を比較的安全に漸次的に解放することができる技術が望まれていた。   By the way, in the case of a PC external cable used in a general PC box girder bridge or the like, when the extension is about 200 m, the total extension amount is about 1200 mm. In such a PC box girder bridge where PC external cables are arranged, it is necessary to perform re-tensioning work once in order to release the tension of existing PC external cables. Usually, there is almost no extra cable length, and this operation is difficult. Also, in the normal tension release method such as heating the wedge part of the fixing part, there is a risk of danger when working if the tension force is large and the extension amount is large. Can not. Therefore, there has been a demand for a technique that can gradually release the tension acting on the PC external cable relatively safely.

本発明は、上記に鑑みてなされたものであって、ＰＣ外ケーブルに作用している緊張力を比較的安全に漸次的に解放することができるＰＣ外ケーブルの緊張力解放方法を提供することを目的とする。   The present invention has been made in view of the above, and provides a PC external cable tension release method that can gradually release the tension applied to the PC external cable relatively safely. With the goal.

上記した課題を解決し、目的を達成するために、本発明に係るＰＣ外ケーブルの緊張力解放方法は、主桁の部材の断面外側に橋軸方向に沿って緊張材としてのＰＣ外ケーブルが配置され、前記ＰＣ外ケーブルの定着部と偏向部を介して前記主桁にプレストレスを与える外ケーブル方式の橋梁における既設の前記ＰＣ外ケーブルの緊張力を解放する方法であって、前記偏向部に前記ＰＣ外ケーブルを仮定着するための仮定着部を設ける工程と、前記偏向部と、これと隣り合う本定着部としての前記定着部との間に配置される前記ＰＣ外ケーブルの緊張力を緩める方向に、前記仮定着部の前記ＰＣ外ケーブルを緊張して仮定着する工程とを有することを特徴とする。   In order to solve the above-described problems and achieve the object, the PC external cable tension release method according to the present invention includes a PC external cable as a tension material along the bridge axis direction outside the cross section of the main girder member. A method of releasing the tension force of an existing PC external cable in an external cable type bridge that is disposed and prestresses the main girder via a fixing unit and a deflection unit of the PC external cable, the deflection unit And a tensioning force of the PC external cable disposed between the deflection unit and the fixing unit as the main fixing unit adjacent to the deflection unit. A step of tensioning the PC external cable of the assumed attachment portion in the direction of loosening the attachment.

また、本発明に係る他のＰＣ外ケーブルの緊張力解放方法は、上述した発明において、前記仮定着部の前記ＰＣ外ケーブルを緊張して仮定着する際に、ラムチェアおよびジャッキを用いて前記ＰＣ外ケーブルを緊張することを特徴とする。   According to another aspect of the present invention, there is provided a method for releasing tension of a PC external cable. In the above-described invention, when the PC external cable of the hypothetical wearing part is tensioned and presumably worn, the PC is used by using a ram chair and a jack. It is characterized by tensioning the outer cable.

また、本発明に係る他のＰＣ外ケーブルの緊張力解放方法は、上述した発明において、前記仮定着部の前記ＰＣ外ケーブルを緊張して仮定着した後に、前記本定着部に設けられる前記ＰＣ外ケーブルを固定するための楔を加熱する工程をさらに有することを特徴とする。   According to another aspect of the present invention, there is provided a method for releasing tension of a PC external cable. In the above-described invention, the PC provided in the main fixing unit after the PC external cable of the hypothetical attaching unit is tensioned and presumed. It further has the process of heating the wedge for fixing an outer cable.

また、本発明に係る他のＰＣ外ケーブルの緊張力解放方法は、上述した発明において、前記仮定着部は、前記ＰＣ外ケーブルに外周がねじ面である半割りスリーブを固定し、固定した前記スリーブに半割りの仮支圧板およびナットを装着し、前記仮支圧板を前記偏向部に固定することにより形成されることを特徴とする。   In addition, in the above-described invention, in the above-described invention, the assumed attachment portion is formed by fixing the half-sleeve whose outer periphery is a threaded surface to the PC external cable, A halved temporary support plate and a nut are attached to the sleeve, and the temporary support plate is fixed to the deflecting portion.

また、本発明に係る他のＰＣ外ケーブルの緊張力解放方法は、上述した発明において、前記半割りスリーブの長さを、前記ＰＣ外ケーブルの所定の長さの伸びに応じた長さに設定したことを特徴とする。   According to another aspect of the present invention, there is provided a method for releasing tension of a PC external cable. In the above-described invention, the length of the half sleeve is set to a length corresponding to an extension of the predetermined length of the PC external cable. It is characterized by that.

本発明に係るＰＣ外ケーブルの緊張力解放方法によれば、主桁の部材の断面外側に橋軸方向に沿って緊張材としてのＰＣ外ケーブルが配置され、前記ＰＣ外ケーブルの定着部と偏向部を介して前記主桁にプレストレスを与える外ケーブル方式の橋梁における既設の前記ＰＣ外ケーブルの緊張力を解放する方法であって、前記偏向部に前記ＰＣ外ケーブルを仮定着するための仮定着部を設ける工程と、前記偏向部と、これと隣り合う本定着部としての前記定着部との間に配置される前記ＰＣ外ケーブルの緊張力を緩める方向に、前記仮定着部の前記ＰＣ外ケーブルを緊張して仮定着する工程とを有するので、緊張力の解放に伴って収縮するＰＣ外ケーブルにおける伸び量を、全長の伸び量に対して仮定着部と本定着部との間のより短い区間の比較的小さい伸びにすることができる。このため、従来の定着部の楔部分を加熱してケーブル全長の緊張力を解放しようとする方法などに比べて仮定着部と本定着部との間のＰＣ外ケーブルの緊張力を比較的安全に漸次的に解放することができるという効果を奏する。また、仮定着部と本定着部との間の緊張力の解放により、他の区間の緊張力の解放作業が行い易くなる。   According to the method for releasing the tension force of the PC external cable according to the present invention, the PC external cable as the tension material is arranged along the bridge axis direction outside the cross section of the main girder member, and the fixing portion and the deflection of the PC external cable are arranged. A method for releasing the tension force of the existing PC external cable in an external cable type bridge that prestresses the main girder via a section, assuming that the PC external cable is attached to the deflecting section. The PC of the hypothetical landing part in a direction of loosening the tension of the PC external cable disposed between the step of providing the landing part, the deflection part, and the fixing part as the main fixing part adjacent thereto. The outer cable is tensioned and presumed to be attached. Therefore, the extension amount of the PC outer cable that contracts with the release of the tension force is set between the assumed attachment portion and the main fixing portion with respect to the total length extension amount. Shorter interval ratio It can be target small elongation. For this reason, the tension of the cable outside the PC between the assumed wearing part and the main fixing part is relatively safer than the conventional method of heating the wedge part of the fixing part to release the tension of the entire length of the cable. The effect is that it can be gradually released. In addition, releasing the tension between the assumed wearing part and the main fixing part facilitates the work of releasing the tension in the other sections.

また、本発明に係る他のＰＣ外ケーブルの緊張力解放方法によれば、前記仮定着部の前記ＰＣ外ケーブルを緊張して仮定着する際に、ラムチェアおよびジャッキを用いて前記ＰＣ外ケーブルを緊張するので、上記の効果に加え、緊張力の解放作業を従来の方法を用いて容易に行うことができるという効果を奏する。   In addition, according to another method for releasing tension of a PC external cable according to the present invention, when the PC external cable of the assumed wearing portion is tensioned and worn, the PC external cable is attached using a ram chair and a jack. Since it is tense, in addition to the above-described effect, there is an effect that the work of releasing the tension can be easily performed using a conventional method.

また、本発明に係る他のＰＣ外ケーブルの緊張力解放方法によれば、前記仮定着部の前記ＰＣ外ケーブルを緊張して仮定着した後に、前記本定着部に設けられる前記ＰＣ外ケーブルを固定するための楔を加熱する工程をさらに有するので、仮定着部と本定着部との間のより短い区間の緊張力の解放作業を従来の方法を用いて容易に行うことができるという効果を奏する。   In addition, according to another method for releasing tension of a PC external cable according to the present invention, the PC external cable provided in the main fixing unit may be installed after the PC external cable of the hypothetical mounting part is tensioned. Since the method further includes the step of heating the wedge for fixing, it is possible to easily perform the releasing operation of the tension force in the shorter section between the assumed wearing portion and the main fixing portion using the conventional method. Play.

また、本発明に係る他のＰＣ外ケーブルの緊張力解放方法によれば、前記仮定着部は、前記ＰＣ外ケーブルに外周がねじ面である半割りスリーブを固定し、固定した前記スリーブに半割りの仮支圧板およびナットを装着し、前記仮支圧板を前記偏向部に固定することにより形成されるので、上記の効果に加え、既存のＰＣ外ケーブルに対して容易に仮定着部を設けることができるという効果を奏する。   Further, according to the other method for releasing tension of a PC external cable according to the present invention, the hypothetical attachment portion fixes a half sleeve whose outer periphery is a threaded surface to the PC external cable, and the half of the fixed sleeve is fixed to the fixed sleeve. Since it is formed by attaching a split temporary support plate and a nut and fixing the temporary support plate to the deflecting portion, in addition to the above effects, an assumed attachment portion is easily provided for an existing PC external cable. There is an effect that can be.

また、本発明に係る他のＰＣ外ケーブルの緊張力解放方法によれば、前記半割りスリーブの長さを、前記ＰＣ外ケーブルの所定の長さの伸びに応じた長さに設定したので、上記の効果に加え、例えば半割りスリーブの長さをＰＣ外ケーブルの伸びを解放できるだけ確保するようにすれば、緊張力の解放作業をより安全に行うことができるという効果を奏する。   In addition, according to the tension release method of another PC external cable according to the present invention, the length of the half sleeve is set to a length according to the extension of the predetermined length of the PC external cable. In addition to the above-described effects, for example, if the length of the half sleeve is ensured so as to release the extension of the PC external cable, the effect of releasing the tension force can be performed more safely.

図１は、本発明に係るＰＣ外ケーブルの緊張力解放方法が適用されるＰＣ箱桁橋の実施例を示す概略斜視図である。FIG. 1 is a schematic perspective view showing an embodiment of a PC box girder bridge to which the method for releasing tension of an external PC cable according to the present invention is applied. 図２−１は、本発明に係るＰＣ外ケーブルの緊張力解放方法が適用されるＰＣ箱桁橋を模式的に示す説明図である。FIGS. 2-1 is explanatory drawing which shows typically the PC box girder bridge to which the tension | tensile_strength release method of the PC external cable which concerns on this invention is applied. 図２−２は、図２−１のＰＣ箱桁橋の偏向部に対して仮定着部を設けた場合の概略図である。FIG. 2-2 is a schematic view when an assumed landing part is provided for the deflection part of the PC box girder bridge of FIG. 2-1. 図３は、本発明に係るＰＣ外ケーブルの緊張力解放方法の仮定着部で用いられる半割りスリーブからなるマンション構造の一例を示す概略斜視図である。FIG. 3 is a schematic perspective view showing an example of a condominium structure composed of a half sleeve used in a hypothetical wearing part of the tension releasing method for an external PC cable according to the present invention. 図４は、本発明に係るＰＣ外ケーブルの緊張力解放方法の工程１を模式的に示す説明図である。FIG. 4 is an explanatory view schematically showing step 1 of the PC external cable tension releasing method according to the present invention. 図５は、本発明に係るＰＣ外ケーブルの緊張力解放方法の工程２を模式的に示す説明図である。FIG. 5 is an explanatory view schematically showing step 2 of the tension releasing method for the PC external cable according to the present invention. 図６は、本発明に係るＰＣ外ケーブルの緊張力解放方法の工程３を模式的に示す説明図である。FIG. 6 is an explanatory view schematically showing step 3 of the tension releasing method for the PC external cable according to the present invention. 図７は、本発明に係るＰＣ外ケーブルの緊張力解放方法の工程４を模式的に示す説明図である。FIG. 7 is an explanatory view schematically showing Step 4 of the tension releasing method for the PC external cable according to the present invention. 図８は、ラムチェアおよびジャッキの配置例を示す概略図である。FIG. 8 is a schematic view showing an example of arrangement of the ram chair and the jack.

以下に、本発明に係るＰＣ外ケーブルの緊張力解放方法の実施の形態を図面に基づいて詳細に説明する。なお、この実施例によりこの発明が限定されるものではない。   Embodiments of a method for releasing tension of an external PC cable according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

図１および図２−１に示すように、本発明に係るＰＣ外ケーブルの緊張力解放方法が適用されるＰＣ箱桁橋１０（橋梁）は、プレストレストコンクリートからなる上床版１２と下床版１４とウェブ１６（主桁）とを有する。上床版１２の下面側には緊張されたＰＣ外ケーブル１８が配設されている。   As shown in FIGS. 1 and 2-1, a PC box girder bridge 10 (bridge) to which the PC external cable tension release method according to the present invention is applied includes an upper floor slab 12 and a lower floor slab 14 made of prestressed concrete. And web 16 (main girder). A tensioned external PC cable 18 is disposed on the lower surface side of the upper floor slab 12.

ＰＣ外ケーブル１８は、上床版１２の下面側の端部近傍に設置された定着部２０間に張り渡されるとともに、定着部２０の間の下床版１４の上面側に設けられた偏向部２２によって、ＰＣ外ケーブル１８に与えられたプレストレスの分力をＰＣ箱桁橋１０に伝達する。ここで、定着部２０は、金属製の定着具を金属あるいはコンクリート部材に固定し、挿通されたＰＣ外ケーブル１８を緊張することにより、コンクリート部材に圧縮応力を与える。また、偏向部２２は、金属あるいはコンクリート等からなる偏向具をコンクリート部材に固定し、ＰＣ外ケーブル１８に与えられた張力の分力をコンクリート部材に与える。   The PC external cable 18 is stretched between the fixing portions 20 installed in the vicinity of the end portion on the lower surface side of the upper floor slab 12 and the deflection portion 22 provided on the upper surface side of the lower floor slab 14 between the fixing portions 20. Thus, the prestress component applied to the PC external cable 18 is transmitted to the PC box girder bridge 10. Here, the fixing unit 20 applies a compressive stress to the concrete member by fixing the metal fixing tool to the metal or the concrete member and tensioning the inserted PC external cable 18. The deflecting unit 22 fixes a deflecting tool made of metal, concrete, or the like to the concrete member, and applies a component of tension applied to the PC external cable 18 to the concrete member.

本発明に係るＰＣ外ケーブルの緊張力解放方法は、図２−２に示すように、左側に位置する偏向部２２にＰＣ外ケーブル１８を仮定着するための仮定着部２４を設ける工程と、この偏向部２２と、これと隣り合う左端に位置する定着部（以下、本定着部という。）２０との間に配置されるＰＣ外ケーブル１８の緊張力を緩める方向に、仮定着部２４のＰＣ外ケーブル１８を緊張して仮定着する工程とを有するものである。   As shown in FIG. 2-2, the PC external cable tension release method according to the present invention includes a step of providing a hypothetical attachment portion 24 for presumably attaching the PC external cable 18 to the deflection portion 22 located on the left side, In the direction of loosening the tension of the external PC cable 18 disposed between the deflecting unit 22 and a fixing unit (hereinafter referred to as a main fixing unit) 20 located at the left end adjacent to the deflecting unit 22, A process of tensioning and attaching the PC external cable 18.

ここで、図３に示すように、仮定着部２４は、ＰＣ外ケーブル１８に外周がねじ面２６である半割りスリーブ２８を固定し、固定したスリーブ２８に半割りの仮支圧板３０および半割りのナット３２を装着した、既存のグランドアンカーなどに使用されているいわゆるマンション構造において、仮支圧板３０を図示しない偏向部２２にコンクリート等を介して固定することにより形成することができる。仮定着部２４をこのようなマンション構造を用いて構成することで、既存のＰＣ外ケーブル１８に対して容易に仮定着部２４を設けることができる。   Here, as shown in FIG. 3, the assumed attachment portion 24 fixes a half sleeve 28 whose outer periphery is a threaded surface 26 to the PC outer cable 18, and the half-supported temporary supporting pressure plate 30 and the half sleeve 28 are fixed to the fixed sleeve 28. In a so-called condominium structure used for an existing ground anchor or the like equipped with a split nut 32, the temporary support plate 30 can be formed by fixing it to a deflecting portion 22 (not shown) via concrete or the like. By configuring the assumed landing part 24 using such an apartment structure, the assumed wearing part 24 can be easily provided to the existing PC external cable 18.

次に、本発明に係るＰＣ外ケーブルの緊張力解放方法の具体的な作業手順について図４〜図７を参照しながら説明する。図４は作業直前の状態を表したものである。   Next, a specific work procedure of the PC external cable tension releasing method according to the present invention will be described with reference to FIGS. FIG. 4 shows a state immediately before the work.

まず、図４および図５に示すように、偏向部２２の左端面２２ａ側に延在するＰＣ外ケーブル１８に半割りスリーブ２８を装着する。半割りスリーブ２８はエポキシ樹脂などを介してＰＣ外ケーブル１８の外周に固定する。   First, as shown in FIGS. 4 and 5, the half sleeve 28 is attached to the PC external cable 18 extending to the left end face 22 a side of the deflecting portion 22. The half sleeve 28 is fixed to the outer periphery of the PC external cable 18 via an epoxy resin or the like.

次に、図６に示すように、半割りスリーブ２８に半割りの仮支圧板３０およびナット３２を装着する。続いて、偏向部２２に隣接した半割りスリーブ２８の周囲に仮支圧板３０を固定するための仮定着部２４として機能する仮定着用コンクリート３４を打設する。ここで、半割りスリーブ２８は仮定着用コンクリート３４からの摩擦を受けず左右方向に移動自在なように仮定着用コンクリート３４内部に設けた貫通穴３４ａの内部に配置する。なお、コンクリートを打設する代わりに偏向部２２に鋼板等を設け、これに仮支圧板３０を固定してもよい。   Next, as shown in FIG. 6, a half temporary support plate 30 and a nut 32 are attached to the half sleeve 28. Subsequently, a hypothetical wearing concrete 34 that functions as a hypothetical wearing portion 24 for fixing the temporary support plate 30 around the half sleeve 28 adjacent to the deflecting portion 22 is placed. Here, the half sleeve 28 is disposed inside a through hole 34 a provided in the assumed wearing concrete 34 so as to be movable in the left-right direction without receiving friction from the assumed wearing concrete 34. Instead of placing concrete, a steel plate or the like may be provided on the deflecting portion 22 and the temporary support plate 30 may be fixed thereto.

次に、図７に示すように、半割りスリーブ２８の左端側にジャッキ３６、半割りのラムチェア３８を配置する。ここで、ジャッキ３６は、図８に示すように、ＰＣ外ケーブル１８の周囲に複数個（例えば２〜４個程度）配置するものとし、これらジャッキ３６の中心にＰＣ外ケーブル１８が位置するように組み立てる。続いて、ジャッキ３６のロッド３６ａに設けた係合部材３６ｂを半割りスリーブ２８のねじ面に螺合して左方向に牽引する。ナット３２を締め付けることで、半割りスリーブ２８からなるマンション構造を左方向に移動させる。このように、ＰＣ外ケーブル１８を緊張して仮定着用コンクリート３４の左端面３４ｂに仮定着する際に、ラムチェアおよびジャッキを用いてＰＣ外ケーブルを漸次的に緊張することができる。ここで、半割りスリーブ２８を介して既設のＰＣ外ケーブル１８が左方向に変位することで、本定着部２０の付近、つまり仮定着部２４と本定着部２０との間のＰＣ外ケーブル１８の緊張力が漸次的に解放される。   Next, as shown in FIG. 7, the jack 36 and the half ram chair 38 are arranged on the left end side of the half sleeve 28. Here, as shown in FIG. 8, as shown in FIG. 8, a plurality of jacks 36 (for example, about 2 to 4) are arranged around the PC external cable 18, and the PC external cable 18 is positioned at the center of the jack 36. Assemble. Subsequently, the engaging member 36b provided on the rod 36a of the jack 36 is screwed with the thread surface of the half sleeve 28 and pulled leftward. By tightening the nut 32, the apartment structure composed of the half sleeve 28 is moved in the left direction. In this way, when the PC external cable 18 is tensioned and is supposedly attached to the left end surface 34b of the assumed wearing concrete 34, the PC external cable can be gradually tensioned using the ram chair and the jack. Here, the existing PC external cable 18 is displaced in the left direction via the half sleeve 28, so that the PC external cable 18 in the vicinity of the main fixing unit 20, that is, between the assumed attachment unit 24 and the main fixing unit 20. The tension of is gradually released.

このため、本発明によれば、緊張力の解放に伴って収縮するＰＣ外ケーブル１８における伸び量を、ケーブル全長の伸び量に対して仮定着部２４と本定着部２０との間のより短い区間の比較的小さい伸びにすることができる。このため、従来の定着部２０の図示しない楔部分を加熱してケーブル全長の緊張力を解放しようとする方法などに比べて仮定着部２４と本定着部２０との間のＰＣ外ケーブル１８の緊張力を比較的安全に漸次的に解放することができる。また、仮定着部２４と本定着部２０との間の緊張力の解放により、他の区間の緊張力の解放作業が行い易くなる。   For this reason, according to the present invention, the extension amount of the PC external cable 18 that contracts with the release of the tension is shorter than the extension amount of the total length of the cable, between the assumed attachment portion 24 and the main fixing portion 20. A relatively small elongation of the section can be achieved. For this reason, as compared with the conventional method of heating the wedge portion (not shown) of the fixing unit 20 to release the tension of the entire length of the cable, the cable of the external PC cable 18 between the assumed mounting portion 24 and the main fixing unit 20 is used. The tension can be gradually released relatively safely. Further, by releasing the tension between the assumed wearing part 24 and the main fixing part 20, it becomes easier to perform the releasing work of the tension in the other sections.

なお、仮定着部２４と本定着部２０との間のＰＣ外ケーブル１８の緊張力を解放するために、図６に示すような状態において、従来の楔を加熱する方法を適用し、本定着部２０に設けられるＰＣ外ケーブル１８を固定するための図示しない楔を加熱してもよい。本定着部２０と仮定着部２４との間隔が短く、この区間のＰＣ外ケーブル１８の伸び量はケーブル全長に比べて小さいので、従来の楔を加熱する方法で比較的安全にこの区間の緊張力を解放することができる。   In order to release the tension of the external PC cable 18 between the assumed attachment portion 24 and the main fixing portion 20, a conventional method of heating a wedge in the state shown in FIG. A wedge (not shown) for fixing the PC external cable 18 provided in the section 20 may be heated. Since the interval between the fixing portion 20 and the assumed attachment portion 24 is short and the extension amount of the PC external cable 18 in this section is smaller than the total length of the cable, the tension in this section can be relatively safely secured by the conventional method of heating the wedge. You can release power.

また、上記の実施の形態において、半割りスリーブ２８の長さ、つまり、上記の短い区間でＰＣ外ケーブル１８が変位可能な距離を、ＰＣ外ケーブル１８の所定の長さの伸びに応じた長さに設定してもよい。例えば半割りスリーブ２８の長さをＰＣ外ケーブル１８の伸びを解放できるだけ確保するようにすれば、ラムチェア３８とジャッキ３６により安全に解放作業が行える。   In the above embodiment, the length of the half sleeve 28, that is, the distance that the PC external cable 18 can be displaced in the short section is set to a length corresponding to the predetermined length of the PC external cable 18. You may set it. For example, if the length of the half sleeve 28 is set to ensure that the extension of the PC external cable 18 can be released, the release operation can be safely performed by the ram chair 38 and the jack 36.

また、上記の実施の形態において、仮定着部２４を偏向部２２に固定する場合について説明したが、これに限るものではない。すなわち、本定着部２０と仮定着部２４との間の距離が短いほど、この区間のＰＣ外ケーブル１８の伸び量が小さくなるので、本定着部２０と仮定着部２４との間ができるだけ短くなるように仮定着部２４の位置を設定して、本定着部２０付近における緊張力をより安全に解放することが好ましい。   In the above-described embodiment, the case where the assumed landing portion 24 is fixed to the deflection portion 22 has been described. However, the present invention is not limited to this. That is, as the distance between the main fixing unit 20 and the assumed wearing part 24 is shorter, the extension amount of the PC external cable 18 in this section becomes smaller. Therefore, the distance between the main fixing part 20 and the assumed wearing part 24 is as short as possible. It is preferable to set the position of the assumed wearing part 24 so that the tension in the vicinity of the main fixing part 20 is released more safely.

以上説明したように、本発明に係るＰＣ外ケーブルの緊張力解放方法によれば、主桁の部材の断面外側に橋軸方向に沿って緊張材としてのＰＣ外ケーブルが配置され、前記ＰＣ外ケーブルの定着部と偏向部を介して前記主桁にプレストレスを与える外ケーブル方式の橋梁における既設の前記ＰＣ外ケーブルの緊張力を解放する方法であって、前記偏向部に前記ＰＣ外ケーブルを仮定着するための仮定着部を設ける工程と、前記偏向部と、これと隣り合う本定着部としての前記定着部との間に配置される前記ＰＣ外ケーブルの緊張力を緩める方向に、前記仮定着部の前記ＰＣ外ケーブルを緊張して仮定着する工程とを有するので、緊張力の解放に伴って収縮するＰＣ外ケーブルにおける伸び量を、全長の伸び量に対して仮定着部と本定着部との間のより短い区間の比較的小さい伸びにすることができる。このため、従来の定着部の楔部分を加熱してケーブル全長の緊張力を解放しようとする方法などに比べて仮定着部と本定着部との間のＰＣ外ケーブルの緊張力を比較的安全に漸次的に解放することができるという効果を奏する。また、仮定着部と本定着部との間の緊張力の解放により、他の区間の緊張力の解放作業が行い易くなる。   As described above, according to the tension release method of the PC external cable according to the present invention, the PC external cable as the tension material is disposed along the bridge axis direction outside the cross section of the main girder member, A method of releasing the tension of the existing PC external cable in an external cable type bridge that prestresses the main girder via a cable fixing unit and a deflection unit, wherein the PC external cable is connected to the deflection unit. In the direction of loosening the tension of the external PC cable arranged between the step of providing an assumed attachment portion for assumed attachment, the deflection portion, and the fixing portion as the main fixing portion adjacent to the deflection portion, A step of tensioning the PC outer cable of the assumed wearing portion, and assuming that the extension amount of the PC outer cable that contracts as the tension is released is set to With fixing section It can be made relatively small elongation of shorter sections than the. For this reason, the tension of the cable outside the PC between the assumed wearing part and the main fixing part is relatively safer than the conventional method of heating the wedge part of the fixing part to release the tension of the entire length of the cable. The effect is that it can be gradually released. In addition, releasing the tension between the assumed wearing part and the main fixing part facilitates the work of releasing the tension in the other sections.

また、本発明に係る他のＰＣ外ケーブルの緊張力解放方法によれば、前記仮定着部の前記ＰＣ外ケーブルを緊張して仮定着する際に、ラムチェアおよびジャッキを用いて前記ＰＣ外ケーブルを緊張するので、上記の効果に加え、緊張力の解放作業を従来の方法を用いて容易に行うことができる。   In addition, according to another method for releasing tension of a PC external cable according to the present invention, when the PC external cable of the assumed wearing portion is tensioned and worn, the PC external cable is attached using a ram chair and a jack. Since it is tense, in addition to the above effects, the work of releasing the tension can be easily performed using a conventional method.

また、本発明に係る他のＰＣ外ケーブルの緊張力解放方法によれば、前記仮定着部の前記ＰＣ外ケーブルを緊張して仮定着した後に、前記本定着部に設けられる前記ＰＣ外ケーブルを固定するための楔を加熱する工程をさらに有するので、仮定着部と本定着部との間のより短い区間の緊張力の解放作業を従来の方法を用いて容易に行うことができる。   In addition, according to another method for releasing tension of a PC external cable according to the present invention, the PC external cable provided in the main fixing unit may be installed after the PC external cable of the hypothetical mounting part is tensioned. Since the method further includes the step of heating the wedge for fixing, the work of releasing the tension force in the shorter section between the assumed attachment portion and the main fixing portion can be easily performed using a conventional method.

また、本発明に係る他のＰＣ外ケーブルの緊張力解放方法によれば、前記仮定着部は、前記ＰＣ外ケーブルに外周がねじ面である半割りスリーブを固定し、固定した前記スリーブに半割りの仮支圧板およびナットを装着し、前記仮支圧板を前記偏向部に固定することにより形成されるので、上記の効果に加え、既存のＰＣ外ケーブルに対して容易に仮定着部を設けることができる。   Further, according to the other method for releasing tension of a PC external cable according to the present invention, the hypothetical attachment portion fixes a half sleeve whose outer periphery is a threaded surface to the PC external cable, and the half of the fixed sleeve is fixed to the fixed sleeve. Since it is formed by attaching a split temporary support plate and a nut and fixing the temporary support plate to the deflecting portion, in addition to the above effects, an assumed attachment portion is easily provided for an existing PC external cable. be able to.

また、本発明に係る他のＰＣ外ケーブルの緊張力解放方法によれば、前記半割りスリーブの長さを、前記ＰＣ外ケーブルの所定の長さの伸びに応じた長さに設定したので、上記の効果に加え、例えば半割りスリーブの長さをＰＣ外ケーブルの伸びを解放できるだけ確保するようにすれば、緊張力の解放作業をより安全に行うことができる。   In addition, according to the tension release method of another PC external cable according to the present invention, the length of the half sleeve is set to a length according to the extension of the predetermined length of the PC external cable. In addition to the above-described effects, for example, if the length of the half sleeve is secured so as to release the extension of the PC external cable, the work of releasing the tension can be performed more safely.

以上のように、本発明に係るＰＣ外ケーブルの緊張力解放方法は、構造物にプレストレスを導入するためにこの構造物の外側などに緊張状態に配設された既設のＰＣ外ケーブルの緊張力を解放するのに有用であり、特に、既設の外ケーブル方式によるＰＣ箱桁橋のＰＣ外ケーブルの緊張力解放に適している。   As described above, the method for releasing the tension of the PC external cable according to the present invention is the tension of the existing PC external cable disposed in a tension state on the outside of the structure in order to introduce prestress to the structure. It is useful for releasing the force, and is particularly suitable for releasing the tension of the PC external cable of the PC box girder bridge by the existing external cable system.

１０ ＰＣ箱桁橋（橋梁）
１２ 上床版
１４ 下床版
１６ ウェブ（主桁）
１８ ＰＣ外ケーブル
２０ 定着部
２２ 偏向部
２２ａ 偏向部の左端面
２４ 仮定着部
２６ ねじ面
２８ 半割りスリーブ
３０ 仮支圧板
３２ ナット
３４ 仮定着用コンクリート
３４ａ 貫通穴
３４ｂ 仮定着用コンクリートの左端面
３６ ジャッキ
３８ ラムチェア 10 PC box girder bridge (bridge)
12 Upper floor version 14 Lower floor version 16 Web (main girder)
DESCRIPTION OF SYMBOLS 18 PC outside cable 20 Fixing part 22 Deflection part 22a Left end surface of deflection part 24 Assumed attachment part 26 Thread surface 28 Half split sleeve 30 Temporary bearing plate 32 Nut 34 Assumed wearing concrete 34a Through hole 34b Left end face of assumed wearing concrete 36 Jack 38 Lamb chair

Claims (5)

主桁の部材の断面外側に橋軸方向に沿って緊張材としてのＰＣ外ケーブルが配置され、前記ＰＣ外ケーブルの定着部と偏向部を介して前記主桁にプレストレスを与える外ケーブル方式の橋梁における既設の前記ＰＣ外ケーブルの緊張力を解放する方法であって、
前記偏向部に前記ＰＣ外ケーブルを仮定着するための仮定着部を設ける工程と、
前記偏向部と、これと隣り合う本定着部としての前記定着部との間に配置される前記ＰＣ外ケーブルの緊張力を緩める方向に、前記仮定着部の前記ＰＣ外ケーブルを緊張して仮定着する工程とを有することを特徴とするＰＣ外ケーブルの緊張力解放方法。 An external cable system in which a PC external cable as a tension material is arranged along the bridge axis direction on the outer side of the cross section of the main girder member, and prestresses the main girder via a fixing portion and a deflection portion of the PC external cable. A method for releasing the tension of the existing PC external cable in a bridge,
Providing a hypothetical attachment part for presumably attaching the PC external cable to the deflection part;
It is assumed that the PC external cable of the hypothetical wearing part is tensioned in the direction of loosening the tension of the PC external cable arranged between the deflection part and the fixing part as the main fixing part adjacent thereto. And a method for releasing tension of the external PC cable. 前記仮定着部の前記ＰＣ外ケーブルを緊張して仮定着する際に、ラムチェアおよびジャッキを用いて前記ＰＣ外ケーブルを緊張することを特徴とする請求項１に記載のＰＣ外ケーブルの緊張力解放方法。   2. The release force of the PC external cable according to claim 1, wherein the PC external cable is tensioned using a ram chair and a jack when the PC external cable of the hypothetical wearing portion is tensioned and put on. Method. 前記仮定着部の前記ＰＣ外ケーブルを緊張して仮定着した後に、前記本定着部に設けられる前記ＰＣ外ケーブルを固定するための楔を加熱する工程をさらに有することを特徴とする請求項１に記載のＰＣ外ケーブルの緊張力解放方法。   2. The method according to claim 1, further comprising a step of heating a wedge for fixing the PC external cable provided in the main fixing portion after the PC external cable of the assumed attachment portion is tensioned and assumed. 2. A method for releasing tension of the external cable of PC. 前記仮定着部は、前記ＰＣ外ケーブルに外周がねじ面である半割りスリーブを固定し、固定した前記スリーブに半割りの仮支圧板およびナットを装着し、前記仮支圧板を前記偏向部に固定することにより形成されることを特徴とする請求項１〜３のいずれか一つに記載のＰＣ外ケーブルの緊張力解放方法。   The hypothetical attachment portion fixes a half sleeve whose outer periphery is a threaded surface to the PC outer cable, and a half provisional pressure plate and a nut are attached to the fixed sleeve, and the temporary pressure plate is attached to the deflection portion. It forms by fixing, The tension | tensile_strength release method of the PC external cable as described in any one of Claims 1-3 characterized by the above-mentioned. 前記半割りスリーブの長さを、前記ＰＣ外ケーブルの所定の長さの伸びに応じた長さに設定したことを特徴とする請求項４に記載のＰＣ外ケーブルの緊張力解放方法。   5. The method of releasing tension of a PC external cable according to claim 4, wherein the length of the half sleeve is set to a length corresponding to an extension of the predetermined length of the PC external cable.
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Cited By (5)

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JP2017193899A (en) * 2016-04-21 2017-10-26 首都高速道路株式会社 Widening structure of existing PC floor slab
JP2018076654A (en) * 2016-11-07 2018-05-17 三井住友建設株式会社 Floor slab repair method and intermediate anchoring tool
CN108824221A (en) * 2018-06-22 2018-11-16 长沙理工大学 Concrete continuous girder bridge web replacing and reinforcing method based on corrugated sheet steel
CN108914760A (en) * 2018-09-25 2018-11-30 郑州大学 Consider the box beam and its prestress strengthening method of external prestressing strengthening
CN113089495A (en) * 2021-04-30 2021-07-09 太原科技大学 Effective prestress detection method under prestressed concrete simply supported bridge anchor

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2017193899A (en) * 2016-04-21 2017-10-26 首都高速道路株式会社 Widening structure of existing PC floor slab
JP2018076654A (en) * 2016-11-07 2018-05-17 三井住友建設株式会社 Floor slab repair method and intermediate anchoring tool
CN108824221A (en) * 2018-06-22 2018-11-16 长沙理工大学 Concrete continuous girder bridge web replacing and reinforcing method based on corrugated sheet steel
CN108914760A (en) * 2018-09-25 2018-11-30 郑州大学 Consider the box beam and its prestress strengthening method of external prestressing strengthening
CN113089495A (en) * 2021-04-30 2021-07-09 太原科技大学 Effective prestress detection method under prestressed concrete simply supported bridge anchor
CN113089495B (en) * 2021-04-30 2022-06-28 太原科技大学 Method for detecting effective prestress under prestressed concrete simply supported bridge anchor

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