JP2010031568A - Aseismatic reinforcing construction method for existing foundation and aseismatic reinforcing structure of existing foundation - Google Patents

Aseismatic reinforcing construction method for existing foundation and aseismatic reinforcing structure of existing foundation Download PDF

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JP2010031568A
JP2010031568A JP2008195708A JP2008195708A JP2010031568A JP 2010031568 A JP2010031568 A JP 2010031568A JP 2008195708 A JP2008195708 A JP 2008195708A JP 2008195708 A JP2008195708 A JP 2008195708A JP 2010031568 A JP2010031568 A JP 2010031568A
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existing foundation
steel material
tensile steel
pile
foundation
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JP5207047B2 (en
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Hiroyuki Kimata
宏之 木全
Yutaka Fujita
豊 藤田
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Shimizu Construction Co Ltd
Shimizu Corp
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Abstract

<P>PROBLEM TO BE SOLVED: To provide an aseismatic reinforcing construction method for an existing foundation and an aseismatic reinforcing structure of an existing foundation, achieving good workability in a narrow work space, shortening the term of construction, lowering the construction cost, and improving earthquake-resisting performance. <P>SOLUTION: This aseismatic reinforcing construction method for the existing foundation includes: a process of drilling a hole extending into the installation ground of the existing foundation from the upper end part of the existing foundation having a concrete pile for supporting a structure; a process of filling the drilled hole with unhardened hardening material and inserting a tension steel material; a process of applying tensile force to the tension steel material after the unhardened hardening material is hardened and the lower end part of the tension steel material is fixed by the cured hardener; and a process of fixing the upper end part of the tension steel material to which the tensile force is applied to the upper end part of the existing foundation through a fixing member. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

本発明は、構造物を支持するためのコンクリート杭を有する既設基礎の耐震強度を増強するための既設基礎の耐震補強工法及び既設基礎の耐震補強構造に関する。   The present invention relates to a seismic reinforcement method for an existing foundation and a seismic reinforcement structure for an existing foundation for enhancing the seismic strength of an existing foundation having a concrete pile for supporting a structure.

大地震において発生する建築物等の構造物の傾斜や倒壊の被害は、杭基礎の耐震強度の不足に起因するものが多い。大地震時に杭基礎に発生する被害の内、杭頭部の被害は構造物の慣性力によって発生し、杭中間部の被害は、地盤の水平せん断変形によって発生する。したがって、杭基礎に求められる耐震性能は、構造物の水平慣性力及び地盤の水平せん断力に対する水平耐力と、構造物の傾斜によるモーメントや引き抜き力に対する耐力である。   The damage caused by the inclination and collapse of structures such as buildings caused by large earthquakes is often due to the lack of seismic strength of pile foundations. Of the damage that occurs on the pile foundation during a large earthquake, the damage to the pile head is caused by the inertia of the structure, and the damage to the middle part of the pile is caused by horizontal shear deformation of the ground. Therefore, the seismic performance required for the pile foundation is the horizontal strength against the horizontal inertia force of the structure and the horizontal shearing force of the ground, and the strength against the moment and pull-out force due to the inclination of the structure.

構造物を新築する場合の杭基礎の耐震補強方法としては、施工上の制約が少ないため、深層混合処理工法等による地盤改良や、杭基礎自体の水平耐力を大きくしたり、あるいは、杭頭部と構造物の基礎フーチングとの接続強度を大きくしたりするものがある。   As a seismic reinforcement method for pile foundations when constructing a new structure, there are few construction restrictions, so the ground improvement by deep mixed processing method, etc., the horizontal strength of the pile foundation itself can be increased, or the pile head Some increase the connection strength between the base footing and the structure.

既存の構造物を支持する既設の杭基礎の耐震強度を増強するための耐震補強工法として、特開2007−177531号公報には、既設の杭基礎の近傍に新たに補強杭を構築し、新たに構築した補強杭を既設の杭基礎と一体に連結する耐震補強工法が開示されている。また、特開平8−296240号公報には、既存基礎の脇から地盤改良用の竪孔を削孔し、この竪孔にパイプを挿入して硬化材を注入し、既存基礎の周囲地盤を地盤改良して既設基礎の耐震強度を増強する耐震補強工法が開示されている。
特開2007−177531号公報 特開平8−296240号公報
As a seismic reinforcement method for enhancing the seismic strength of existing pile foundations that support existing structures, JP 2007-177531A newly constructs a reinforcing pile near the existing pile foundation, A seismic reinforcement method is disclosed in which the reinforced pile constructed in 1 is connected to the existing pile foundation. JP-A-8-296240 discloses a hole for ground improvement from the side of an existing foundation, a pipe is inserted into the hole and a hardening material is injected, and the surrounding ground of the existing foundation is grounded. A seismic reinforcement method for improving the seismic strength of existing foundations has been disclosed.
JP 2007-177531 A JP-A-8-296240

しかしながら、従来の既設杭基礎の耐震補強は、施工スペースの制約も多く、施工が困難な場合があり、その場合施工コストも高価になるという問題があった。   However, conventional seismic reinforcement of existing pile foundations has a problem that construction space is often limited and construction is difficult, and in that case, construction cost is also expensive.

本発明は、上記従来技術のもつ課題を解決する、狭い作業スペースでの施工性が良く、施工期間が短縮でき、施工コストが安価で、耐震性能を向上することができる既設コンクリート杭基礎の耐震補強工法及び既設コンクリート杭基礎の耐震補強構造を提供することを目的とする。   The present invention solves the above-mentioned problems of the prior art, has good workability in a narrow work space, can shorten the construction period, has a low construction cost, and can improve earthquake resistance. The purpose is to provide a reinforcement method and seismic reinforcement structure for existing concrete pile foundations.

本発明の既設基礎の耐震補強工法は、前記課題を解決するために、構造物を支持するためのコンクリート杭を有する既設基礎の上端部から、前記既設基礎の設置地盤中に延びる孔を削孔する工程と、前記削孔された孔に未硬化の硬化材を充填し、引張鋼材を挿入する工程と、前記未硬化の硬化材が硬化し、前記引張鋼材の下端部が前記硬化した硬化材により固定された後、前記引張鋼材に引張力を付加する工程と、前記引張力を付加された前記引張鋼材の上端部を、前記既設基礎の上端部に固定部材を介して固定する工程と、を有することを特徴とする。   In order to solve the above-mentioned problem, the seismic reinforcement method for an existing foundation according to the present invention drills a hole extending from the upper end of an existing foundation having a concrete pile for supporting a structure into the installation ground of the existing foundation. A step of filling an uncured hardened material into the drilled hole and inserting a tensile steel material, and a hardening material in which the uncured hardened material is cured and the lower end portion of the tensile steel material is the hardened material. A step of applying a tensile force to the tensile steel material, and a step of fixing the upper end portion of the tensile steel material to which the tensile force is applied to the upper end portion of the existing foundation via a fixing member. It is characterized by having.

また、本発明の既設基礎の耐震補強工法は、前記コンクリート杭として、RC杭、PHC杭、PC杭、場所打RC杭のいずれかを用いることを特徴とする。   Moreover, the seismic reinforcement method for an existing foundation according to the present invention is characterized in that any one of RC pile, PHC pile, PC pile, and cast-in-place RC pile is used as the concrete pile.

また、本発明の既設基礎の耐震補強工法は、前記引張鋼材が前記コンクリート杭の内部を通して延びるように設置されることを特徴とする。   The seismic reinforcement method for an existing foundation according to the present invention is characterized in that the tensile steel material is installed so as to extend through the inside of the concrete pile.

また、本発明の既設基礎の耐震補強工法は、前記既設基礎は、複数のコンクリート杭の杭頭部を一体に連結して形成された基礎フーチングを有し、前記基礎フーチングを通して前記複数のコンクリート杭間に延びるように設置されることを特徴とする。   In the seismic reinforcement method for an existing foundation according to the present invention, the existing foundation has a foundation footing formed by integrally connecting pile heads of a plurality of concrete piles, and the plurality of concrete piles are passed through the foundation footing. It is installed so that it may extend in between.

また、本発明の既設基礎の耐震補強工法は、前記コンクリート杭の打設方向と平行に延びる引張鋼材と、前記コンクリート杭の打設方向に対して傾斜して延びる引張鋼材とを組み合わせて設置することを特徴とする。   Moreover, the seismic reinforcement method for an existing foundation according to the present invention is installed by combining a tensile steel material extending parallel to the concrete pile placing direction and a tensile steel material extending obliquely with respect to the concrete pile placing direction. It is characterized by that.

また、本発明の既設基礎の耐震補強構造は、構造物を支持するためのコンクリート杭を有する既設基礎の上端部から、前記既設基礎の設置地盤中に延びる引張鋼材を備え、前記引張鋼材の下端部が硬化材により固定され、前記引張鋼材の上端部が引張力を付加された状態で前記既設基礎上端部に固定部材を介して固定されることを特徴とする。   The seismic reinforcement structure for an existing foundation according to the present invention includes a tensile steel material that extends from an upper end portion of an existing foundation having a concrete pile for supporting a structure into an installation ground of the existing foundation, and a lower end of the tensile steel material. The portion is fixed by a hardened material, and the upper end portion of the tensile steel material is fixed to the upper end portion of the existing foundation via a fixing member in a state where a tensile force is applied.

本発明の構造物を支持するためのコンクリート杭を有する既設基礎の上端部から、前記既設基礎の設置地盤中に延びる孔を削孔する工程と、前記削孔された孔に未硬化の硬化材を充填し、引張鋼材を挿入する工程と、前記未硬化の硬化材が硬化し、前記引張鋼材の下端部が前記硬化した硬化材により固定された後、前記引張鋼材に引張力を付加する工程と、前記引張力を付加された前記引張鋼材の上端部を、前記既設基礎の上端部に固定部材を介して固定する工程と、を有する構成により、大きな作業スペースを必要としない小型の削孔機で削孔でき、施工が容易であり、施工期間も短期で済むので低コストで耐震補強ができる。さらに、圧縮力を付与されたコンクリート杭は、地震時に付加される応力により圧縮軸力が増加し、圧縮軸力の増加により曲げ耐力が増加し、耐震性能を向上することができる。   A step of drilling a hole extending into an installation ground of the existing foundation from an upper end portion of an existing foundation having a concrete pile for supporting the structure of the present invention, and an uncured hardener in the drilled hole And inserting a tensile steel material, and a step of applying a tensile force to the tensile steel material after the uncured hardened material is cured and a lower end portion of the tensile steel material is fixed by the hardened hardened material. And a step of fixing the upper end portion of the tensile steel material to which the tensile force is applied to the upper end portion of the existing foundation via a fixing member, and thus a small hole that does not require a large work space Drilling can be done with a machine, construction is easy, and the construction period is short, so earthquake-proof reinforcement can be achieved at low cost. Furthermore, the concrete pile to which the compressive force is applied increases the compressive axial force due to the stress applied at the time of the earthquake, and the flexural strength increases due to the increase of the compressive axial force, so that the seismic performance can be improved.

また、コンクリート杭として、RC杭、PHC杭、PC杭、場所打RC杭のいずれかを用いる構成により、これらの杭は圧縮力を付与することで地震時に付加される応力により断面圧縮軸力が増加し、断面圧縮軸力の増加が曲げ耐力の増加に結びつく耐力曲線を有し、本発明の耐震補強工法に適した杭である。   In addition, as a concrete pile, RC piles, PHC piles, PC piles, cast-in-place RC piles are used, and these piles have a compressive axial force due to the stress applied during an earthquake by applying a compressive force. The pile is suitable for the seismic reinforcement method of the present invention, having a yield curve in which the increase in cross-sectional compression axial force leads to an increase in flexural yield.

また、引張鋼材がコンクリート杭の内部を通して延びるように設置される構成により、それぞれのコンクリート杭に直接圧縮力を付与することができるので、各コンクリート杭毎に正確な耐震性能を付与することができる。   In addition, since the tensile steel material is installed so as to extend through the inside of the concrete pile, a compressive force can be directly applied to each concrete pile, so that an accurate seismic performance can be given to each concrete pile. .

また、既設基礎は、複数のコンクリート杭の杭頭部を一体に連結して形成された基礎フーチングを有し、前記基礎フーチングを通して前記複数のコンクリート杭間に延びるように設置される構成により、少ない引張鋼材で複数のコンクリート杭に基礎フーチングを介して効率よく圧縮力を付与することができ、複数のコンクリート杭の耐震性能を向上することができる。   In addition, the existing foundation has a foundation footing formed by integrally connecting pile heads of a plurality of concrete piles, and there are few by a configuration installed to extend between the plurality of concrete piles through the foundation footing. It is possible to efficiently apply a compressive force to the plurality of concrete piles through the foundation footing with the tensile steel material, and the seismic performance of the plurality of concrete piles can be improved.

また、コンクリート杭の打設方向と平行に延びる引張鋼材と、コンクリート杭の打設方向に対して傾斜して延びる引張鋼材とを組み合わせて設置する構成により、地震時の方向が異なる応力に対して耐震性能を向上することができる。   In addition, by installing a combination of tensile steel material that extends parallel to the concrete pile placement direction and tensile steel material that extends at an angle with respect to the concrete pile placement direction, it can be applied to stresses with different directions during an earthquake. Seismic performance can be improved.

また、構造物を支持するためのコンクリート杭を有する既設基礎の上端部から、前記既設基礎の設置地盤中に延びる引張鋼材を備え、前記引張鋼材の下端部が硬化材により固定され、前記引張鋼材の上端部が引張力を付加された状態で前記既設基礎上端部に固定部材を介して固定される構成により、圧縮力を付与された既設基礎は、地震時に付加される応力により圧縮軸力が増加し、圧縮軸力の増加により曲げ耐力が増加し、耐震性能を向上することができる。   Moreover, it has the tensile steel material extended in the installation ground of the said existing foundation from the upper end part of the existing foundation which has a concrete pile for supporting a structure, The lower end part of the said tensile steel material is fixed by the hardening material, The said tensile steel material With the structure in which the upper end of the base is fixed to the upper end of the existing foundation via a fixing member in a state where a tensile force is applied, the existing foundation to which the compressive force is applied has a compressive axial force due to the stress applied during an earthquake. The bending strength increases by increasing the compression axial force, and the seismic performance can be improved.

本発明の実施の形態を図により説明する。図1は、本発明の既設基礎の耐震補強工法の第1実施形態を示す図である。   Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a first embodiment of the seismic reinforcement method for an existing foundation according to the present invention.

コンクリート杭を有する既設基礎1は、既存の建築物等の上部構造物を支持している。既設基礎1は、表層地盤2から支持地盤3まで延びるように設置された複数のコンクリート杭4、4’と、複数のコンクリート杭4、4’の杭頭部を一体に連結する基礎フーチング5とからなる。基礎フーチング5上に建築物等の上部構造が構築される。   The existing foundation 1 having a concrete pile supports an upper structure such as an existing building. The existing foundation 1 includes a plurality of concrete piles 4, 4 ′ installed so as to extend from the surface ground 2 to the support ground 3, and a foundation footing 5 that integrally connects the pile heads of the plurality of concrete piles 4, 4 ′. Consists of. An upper structure such as a building is constructed on the foundation footing 5.

本発明の耐震補強工法は、コンクリート杭4、4’として、RC杭(遠心力成形鉄筋コンクリート杭)、PHC杭(遠心力成形高強度プレストレストコンクリート杭)、PC杭(遠心力成形プレストレスト杭)、場所打RC杭(場所打鉄筋コンクリート杭)のいずれかを用いる。   The seismic reinforcement method of the present invention includes RC piles (centrifugal force formed reinforced concrete piles), PHC piles (centrifugal force formed high strength prestressed concrete piles), PC piles (centrifugal force prestressed piles), place Use one of the cast RC piles (placed reinforced concrete piles).

これらの杭は、断面圧縮軸力の増加が曲げ耐力の向上につながる耐力曲線(M−N interaction curve)を有するので本発明の耐震補強工法に適している。これに対して、鋼管杭は、断面圧縮軸力が0の時に曲げ耐力が最大となる耐力曲線を有するので、本発明の耐震補強工法に鋼管杭は適用しない。   These piles are suitable for the seismic reinforcement method of the present invention because they have a proof curve (MN interaction curve) in which an increase in cross-sectional compression axial force leads to an improvement in bending strength. On the other hand, since a steel pipe pile has a yield strength curve in which the bending strength becomes maximum when the cross-sectional compression axial force is zero, the steel pipe pile is not applied to the seismic reinforcement method of the present invention.

既設基礎1の耐震性能を向上するため、先ず、基礎フーチング5からコンクリート杭の杭頭部、コンクリート杭4、4’の内部を通して、支持地盤3の所定深さまで延びる小口径孔6を小型穿孔機を用いて穿孔する。第1実施形態では、小口径孔6は、コンクリート杭4、4’の打設方向と平行に穿孔される。   In order to improve the seismic performance of the existing foundation 1, first, a small-diameter drilling machine is provided with a small-diameter hole 6 extending from the foundation footing 5 through the pile head of the concrete pile and the concrete piles 4 and 4 'to a predetermined depth of the supporting ground 3. Use to drill. In the first embodiment, the small-diameter hole 6 is drilled in parallel to the placing direction of the concrete piles 4, 4 '.

小型穿孔機による小口径孔6の穿孔は、基礎フーチング5、杭頭部内はコンクリート中の穿孔になる。基礎フーチング5には補強鉄筋が配筋されているので、穿孔の際、補強鉄筋を切断しないように穿孔位置を設定する。コンクリート杭4、4’の内部は、場所打ちRC杭以外は、杭内部は中空又は中空部に土砂等が充填されているだけであり、杭下端部には根固めコンクリートが充填される程度であるので、穿孔作業は比較的容易である。通常、支持地盤は岩盤又は硬質地盤であるので、穿孔された小口径孔6の孔壁の崩落の発生が比較的少ない。   The drilling of the small-diameter hole 6 by the small drilling machine is performed in the foundation footing 5 and the pile head in the concrete. Since the reinforcing reinforcing bars are arranged in the foundation footing 5, the drilling position is set so that the reinforcing reinforcing bars are not cut during drilling. The inside of the concrete piles 4 and 4 ′ except for the cast-in-place RC pile, the inside of the pile is only hollow or the hollow portion is filled with earth and sand, etc. As a result, the drilling operation is relatively easy. Usually, since the supporting ground is a rock or a hard ground, the occurrence of collapse of the hole wall of the small-diameter hole 6 drilled is relatively small.

支持地盤3中の穿孔の長さは、後述する引張鋼材8が硬化材7により固定された後、ジャッキにより引張力を付加する際に、その引張力に耐える十分な定着力を有するように設定される。引張鋼材8の外周に凸凹を形成すると、硬化材7との定着性が向上する。   The length of the perforations in the support ground 3 is set so as to have a sufficient fixing force to withstand the tensile force when a tensile force is applied by a jack after the tensile steel material 8 described later is fixed by the hardened material 7. Is done. When unevenness is formed on the outer periphery of the tensile steel material 8, the fixing property with the hardened material 7 is improved.

小型穿孔機による支持地盤3中への所定深さの小口径孔6の穿孔作業が終了すると、支持地盤3に形成された小口径孔6への未硬化の硬化材の充填工程となる。小型穿孔機のドリルパイプを通してグラウト材等の未硬化の硬化材7を供給可能な小型穿孔機の場合、小型穿孔機の掘削流体供給口にグラウト材注入管を接続し、ドリルパイプを引き上げながら、支持地盤3中の小口径孔6にグラウト等の未硬化の硬化材7を充填する。   When the drilling operation of the small-diameter hole 6 having a predetermined depth into the support ground 3 by the small drilling machine is completed, the process is a filling process of the uncured hardened material into the small-diameter hole 6 formed in the support ground 3. In the case of a small drilling machine capable of supplying uncured hardened material 7 such as grout material through the drill pipe of the small drilling machine, while connecting the grout material injection pipe to the drilling fluid supply port of the small drilling machine and pulling up the drill pipe, A small-diameter hole 6 in the support ground 3 is filled with an uncured hardener 7 such as grout.

グラウト注入ができない小型穿孔機の場合は、ドリルパイプを引き上げ後、グラウト供給管から未硬化の硬化材7を支持地盤3中の小口径孔6に充填する。未硬化の硬化材7が充填された支持地盤3中の小口径孔6に、未硬化の硬化材7が硬化する前に、基礎フーチング5に穿孔された小口径孔、杭頭部に穿孔された小口径孔及び既設コンクリート杭4、4’の内部を通して引張鋼材8を挿入する。引張鋼材8としては、PC鋼線、PC撚り線、PC鋼棒等を用いる。引張鋼材8を支持地盤3中の小口径孔6に挿入した後、未硬化の硬化材6を支持地盤3中の6に充填しても良いし、引張鋼材8の小口径孔6、6’、6’’への挿入工程と、未硬化の硬化材7の充填工程を同時に実施しても良い。   In the case of a small drilling machine that cannot inject grout, the uncured hardened material 7 is filled into the small-diameter hole 6 in the support ground 3 from the grout supply pipe after the drill pipe is pulled up. Before the uncured cured material 7 is cured, the small diameter hole 6 drilled in the foundation footing 5 is drilled in the pile head before the uncured cured material 7 is cured in the small diameter hole 6 in the support ground 3 filled with the uncured cured material 7. The tensile steel material 8 is inserted through the inside of the small-diameter hole and the existing concrete piles 4, 4 ′. As the tensile steel material 8, a PC steel wire, a PC stranded wire, a PC steel rod or the like is used. After the tensile steel material 8 is inserted into the small-diameter hole 6 in the support ground 3, the uncured hardened material 6 may be filled into 6 in the support ground 3, or the small-diameter holes 6, 6 ′ of the tensile steel material 8 may be filled. , 6 ″ and the filling step of the uncured hardener 7 may be performed simultaneously.

支持地盤3中の小口径孔6中の未硬化の硬化材7が硬化し、引張鋼材8の下端部が支持地盤3中の小口径孔6にしっかりと定着された後、引張鋼材8の上端部に、引張鋼材8を挿入する孔を形成した台座9を基礎フーチング5上に設置する。   After the uncured hardened material 7 in the small-diameter hole 6 in the support ground 3 is hardened and the lower end portion of the tensile steel material 8 is firmly fixed in the small-diameter hole 6 in the support ground 3, the upper end of the tensile steel material 8. A pedestal 9 in which a hole for inserting the tensile steel material 8 is formed on the base footing 5.

台座9にジャッキを設置し、台座9を反力受けとしてジャッキにより引張鋼材8に引張力を付加する。引張鋼材8に引張力を付加することにより、コンクリート杭4、4’に反力として圧縮力が付加される。引張鋼材8に付加される引張力は、コンクリート杭4、4’に所望の耐震性能を発揮可能な圧縮力が付加されるように設定する。   A jack is installed on the pedestal 9, and a tensile force is applied to the tensile steel member 8 by the jack using the pedestal 9 as a reaction force receiver. By applying a tensile force to the tensile steel member 8, a compressive force is applied as a reaction force to the concrete piles 4, 4 '. The tensile force applied to the tensile steel material 8 is set so that a compressive force capable of exhibiting a desired seismic performance is applied to the concrete piles 4, 4 ′.

引張鋼材8に引張力を付加した状態で、引張鋼材8の上端部と台座9とをナット等の固定手段10で固定する。固定手段10として、溶接等の他の固定手段を用いても良い。   In a state where a tensile force is applied to the tensile steel material 8, the upper end portion of the tensile steel material 8 and the base 9 are fixed by a fixing means 10 such as a nut. Other fixing means such as welding may be used as the fixing means 10.

第1実施形態の既設基礎1の耐震補強工法は、コンクリート杭4、4’の内部を通して引張鋼材8が設置されて、その引張鋼材8に引張力が付加されるので、各コンクリート杭4、4’に直接圧縮力が付加されるので、設定された耐震性能を発揮できる圧縮力を正確に付加することができる。   In the seismic reinforcement method for the existing foundation 1 of the first embodiment, the tensile steel material 8 is installed through the concrete piles 4, 4 ′, and a tensile force is applied to the tensile steel material 8. Since the compressive force is directly added to ', the compressive force that can exhibit the set seismic performance can be added accurately.

図1では、コンクリート杭4、4’が支持地盤3上に支持される杭を例として、小口径孔6を杭下端の支持地盤3中まで延びるように穿孔したものを示したが、コンクリート杭4、4’を支持地盤3上で支持するものでなく周辺地盤との摩擦力で支持する摩擦杭の場合、孔6の穿孔は、支持地盤3まで延ばさなくても良い。   In FIG. 1, a concrete pile 4, 4 ′ is shown as an example of a pile supported on the support ground 3, and a small-diameter hole 6 is drilled so as to extend into the support ground 3 at the lower end of the pile. In the case of a friction pile that does not support 4, 4 ′ on the supporting ground 3 but by a frictional force with the surrounding ground, the drilling of the holes 6 may not extend to the supporting ground 3.

図2は、本発明の既設基礎1の耐震補強工法の第2実施形態を示す図である。   FIG. 2 is a diagram showing a second embodiment of the seismic reinforcement method for the existing foundation 1 according to the present invention.

既設基礎1の耐震性能を向上するため、先ず、基礎フーチング5からコンクリート杭4、4’、4’’の杭間を通して、支持地盤3の所定深さまで延びる小口径孔6を小型穿孔機を用いて穿孔する。第2実施形態では、小口径孔6は、コンクリート杭4、4’ 、4’’の打設方向と平行に穿孔される。基礎フーチング5には補強鉄筋が配筋されているので、穿孔の際、補強鉄筋を切断しないように穿孔位置を設定する。   In order to improve the seismic performance of the existing foundation 1, first, a small drilling machine is used to make a small-diameter hole 6 extending from the foundation footing 5 to the predetermined depth of the supporting ground 3 through the piles of the concrete piles 4, 4 ′, 4 ″. And drill. In the second embodiment, the small-diameter hole 6 is drilled in parallel with the placing direction of the concrete piles 4, 4 ', 4 ". Since the reinforcing reinforcing bars are arranged in the foundation footing 5, the drilling position is set so that the reinforcing reinforcing bars are not cut during drilling.

小型穿孔機による小口径孔6の穿孔は、基礎フーチング5、表層地盤2、支持地盤3中に形成される。支持地盤3中の穿孔の長さは、引張鋼材8が硬化材7により固定された後、ジャッキにより引張力を付加する際に、その引張力に耐える十分な定着力を有するように設定される。引張鋼材8の外周に凸凹を形成すると、硬化材7との定着性が向上する。   The small-diameter hole 6 is drilled in the foundation footing 5, the surface ground 2, and the support ground 3 by a small drilling machine. The length of the perforations in the supporting ground 3 is set so as to have a sufficient fixing force to withstand the tensile force when a tensile force is applied by a jack after the tensile steel material 8 is fixed by the hardened material 7. . When unevenness is formed on the outer periphery of the tensile steel material 8, the fixing property with the hardened material 7 is improved.

小型穿孔機による支持地盤3中への所定深さの小口径孔6の穿孔作業が終了すると、支持地盤3に形成された小口径孔6への未硬化の硬化材の充填工程となる。小型穿孔機のドリルパイプを通してグラウト材等の未硬化の硬化材7を供給可能な小型穿孔機の場合、小型穿孔機の掘削流体供給口にグラウト材注入管を接続し、ドリルパイプを引き上げながら、支持地盤3中の小口径孔6にグラウト等の未硬化の硬化材7を充填する。   When the drilling operation of the small-diameter hole 6 having a predetermined depth into the support ground 3 by the small drilling machine is completed, the process is a filling process of the uncured hardened material into the small-diameter hole 6 formed in the support ground 3. In the case of a small drilling machine capable of supplying uncured hardened material 7 such as grout material through the drill pipe of the small drilling machine, while connecting the grout material injection pipe to the drilling fluid supply port of the small drilling machine and pulling up the drill pipe, A small-diameter hole 6 in the support ground 3 is filled with an uncured hardener 7 such as grout.

グラウト注入ができない小型穿孔機の場合は、ドリルパイプを引き上げ後、グラウト供給管から未硬化の硬化材7を支持地盤3中の小口径孔6に充填する。未硬化の硬化材7が充填された支持地盤3中の小口径孔6に、未硬化の硬化材7が硬化する前に、引張鋼材8を挿入する。引張鋼材8としては、PC鋼線、PC撚り線、PC鋼棒等を用いる。引張鋼材8を支持地盤3中の小口径孔6に挿入した後、未硬化の硬化材6を支持地盤3中の小口径孔6に充填しても良いし、引張鋼材8の小口径孔6、6’、6’’への挿入工程と、未硬化の硬化材7の充填工程を同時に実施しても良い。   In the case of a small drilling machine that cannot inject grout, the uncured hardened material 7 is filled into the small-diameter hole 6 in the support ground 3 from the grout supply pipe after the drill pipe is pulled up. The tensile steel material 8 is inserted into the small-diameter hole 6 in the supporting ground 3 filled with the uncured hardened material 7 before the uncured hardened material 7 is hardened. As the tensile steel material 8, a PC steel wire, a PC stranded wire, a PC steel rod or the like is used. After inserting the tensile steel material 8 into the small-diameter hole 6 in the support ground 3, the uncured hardened material 6 may be filled into the small-diameter hole 6 in the support ground 3, or the small-diameter hole 6 of the tensile steel material 8. , 6 ′, 6 ″ and the filling process of the uncured hardener 7 may be performed simultaneously.

支持地盤3中の孔6中の未硬化の硬化材7が硬化し、引張鋼材8の下端部が支持地盤3中の小口径孔6にしっかりと定着された後、引張鋼材8の上端部に、引張鋼材8を挿入する孔を形成した台座9を基礎フーチング5上に設置する。   After the uncured hardened material 7 in the hole 6 in the support ground 3 is hardened and the lower end portion of the tensile steel material 8 is firmly fixed in the small-diameter hole 6 in the support ground 3, the upper end portion of the tensile steel material 8 is fixed. The base 9 having a hole for inserting the tensile steel material 8 is installed on the basic footing 5.

台座9にジャッキを設置し、台座9を反力受けとしてジャッキにより引張鋼材8に引張力を付加する。引張鋼材8に引張力を付加することにより、既設コンクリート杭4、4’、4’’に反力として圧縮力が付加される。引張鋼材8に付加される引張力は、既設コンクリート杭4、4’、4’’に所望の耐震性能を発揮可能な圧縮力が付加されるように設定する。   A jack is installed on the pedestal 9, and a tensile force is applied to the tensile steel member 8 by the jack using the pedestal 9 as a reaction force receiver. By applying a tensile force to the tensile steel material 8, a compressive force is applied as a reaction force to the existing concrete piles 4, 4 ′, 4 ″. The tensile force applied to the tensile steel material 8 is set so that a compressive force capable of exhibiting a desired seismic performance is applied to the existing concrete piles 4, 4 ′, 4 ″.

引張鋼材8に引張力を付加した状態で、引張鋼材8の上端部と台座9とをナット等の固定手段10で固定する。固定手段10として、溶接等の他の固定手段を用いても良い。   In a state where a tensile force is applied to the tensile steel material 8, the upper end portion of the tensile steel material 8 and the base 9 are fixed by a fixing means 10 such as a nut. Other fixing means such as welding may be used as the fixing means 10.

第2実施形態の既設基礎1の耐震補強工法は、引張鋼材8がコンクリート杭4、4’、4’’の杭間に配置されるので、杭内部に引張鋼材8を配置する第1実施形態に比べて、引張鋼材8の設計配置の自由度が大きく、引張鋼材8に付加された引張力は基礎フーチング5を介した反力である圧縮力として既成コンクリート杭4、4’、4’’に付加される。   In the seismic reinforcement method for the existing foundation 1 according to the second embodiment, since the tensile steel material 8 is arranged between the piles of the concrete piles 4, 4 ′, 4 ″, the first embodiment in which the tensile steel material 8 is arranged inside the pile. Compared to the above, the degree of freedom in design and arrangement of the tensile steel material 8 is large, and the tensile force applied to the tensile steel material 8 is a precast concrete pile 4, 4 ′, 4 ″ as a compressive force that is a reaction force via the foundation footing 5. To be added.

図2では、コンクリート杭が支持地盤3上に支持される杭を例として、小口径孔6を杭下端よりも下方の支持地盤3中まで延びるように穿孔したものを示したが、支持地盤3の上方に引張鋼材8を定着するのに十分な強度を備えた地盤が存在する場合、小口径孔6の穿孔は、コンクリート杭の下端部より下まで延ばさなくても良く、コンクリート杭の下端部と同じ位置か上方位置としても良い。また、杭基礎形式は、摩擦杭基礎であっても良い。   In FIG. 2, as an example of a pile in which the concrete pile is supported on the support ground 3, a small-diameter hole 6 is drilled so as to extend into the support ground 3 below the lower end of the pile. If there is a ground with sufficient strength to fix the tensile steel material 8 above the bottom of the concrete pile, the small-diameter hole 6 does not need to extend below the lower end of the concrete pile. It may be the same position or an upper position. The pile foundation type may be a friction pile foundation.

図3は、本発明の既設基礎1の耐震補強工法の第3実施形態を示す図である。   FIG. 3 is a diagram showing a third embodiment of the seismic reinforcement method for the existing foundation 1 of the present invention.

既設基礎1の耐震性能を向上するため、先ず、基礎フーチング5からコンクリート杭4、4’、4’’の杭間を通して、支持地盤3の所定深さまで延びる小口径孔6を小型穿孔機を用いて穿孔する。第3実施形態では、コンクリート杭4、4’、4’’の打設方向と平行に穿孔される小口径孔6と、コンクリート杭4、4’、4’’の打設方向に対して傾斜して穿孔される小口径孔6’、6’’を穿孔する。基礎フーチング5には補強鉄筋が配筋されているので、穿孔の際、補強鉄筋を切断しないように穿孔位置を設定する。   In order to improve the seismic performance of the existing foundation 1, first, a small drilling machine is used to make a small-diameter hole 6 extending from the foundation footing 5 to the predetermined depth of the supporting ground 3 through the piles of the concrete piles 4, 4 ′, 4 ″. And drill. In the third embodiment, the small-diameter hole 6 drilled parallel to the placement direction of the concrete piles 4, 4 ′, 4 ″ and the inclination with respect to the placement direction of the concrete piles 4, 4 ′, 4 ″ Then, small-diameter holes 6 'and 6' 'to be drilled are drilled. Since the reinforcing reinforcing bars are arranged in the foundation footing 5, the drilling position is set so that the reinforcing reinforcing bars are not cut during drilling.

小型穿孔機による小口径孔6、6’、6’’の穿孔は、基礎フーチング5、表層地盤2、支持地盤3中に形成される。支持地盤3中の穿孔の長さは、引張鋼材8が硬化材7により固定された後、ジャッキにより引張力を付加する際に、その引張力に耐える十分な定着力を有するように設定される。引張鋼材8の外周に凸凹を形成すると、硬化材7との定着性が向上する。   Drilling of small-diameter holes 6, 6 ′, 6 ″ by a small drilling machine is formed in the foundation footing 5, the surface layer ground 2, and the support ground 3. The length of the perforations in the supporting ground 3 is set so as to have a sufficient fixing force to withstand the tensile force when a tensile force is applied by a jack after the tensile steel material 8 is fixed by the hardened material 7. . When unevenness is formed on the outer periphery of the tensile steel material 8, the fixing property with the hardened material 7 is improved.

小型穿孔機による支持地盤3中への所定深さの小口径孔6、6’、6’’の穿孔作業が終了すると、支持地盤3に形成された小口径孔6、6’、6’’への未硬化の硬化材の充填工程となる。小型穿孔機のドリルパイプを通してグラウト材等の未硬化の硬化材7を供給可能な小型穿孔機の場合、小型穿孔機の掘削流体供給口にグラウト材注入管を接続し、ドリルパイプを引き上げながら、支持地盤3中の小口径孔6、6’、6’’にグラウト等の未硬化の硬化材7を充填する。   When the drilling operation of the small-diameter holes 6, 6 ′, 6 ″ having a predetermined depth into the support ground 3 by the small drilling machine is completed, the small-diameter holes 6, 6 ′, 6 ″ formed in the support ground 3 are completed. It becomes a filling process of the uncured hardened material. In the case of a small drilling machine capable of supplying uncured hardened material 7 such as grout material through the drill pipe of the small drilling machine, while connecting the grout material injection pipe to the drilling fluid supply port of the small drilling machine and pulling up the drill pipe, The small diameter holes 6, 6 ′, 6 ″ in the support ground 3 are filled with uncured hardened material 7 such as grout.

グラウト注入ができない小型穿孔機の場合は、ドリルパイプを引き上げ後、グラウト供給管から未硬化の硬化材7を支持地盤3中の小口径孔6、6’、6’’に充填する。未硬化の硬化材7が充填された支持地盤3中の小口径孔6、6’、6’’に、未硬化の硬化材7が硬化する前に、引張鋼材8を挿入する。引張鋼材8としては、PC鋼線、PC撚り線、PC鋼棒等を用いる。引張鋼材8を支持地盤3中の小口径孔6に挿入した後、未硬化の硬化材6を支持地盤3中の小口径孔6に充填しても良いし、引張鋼材8の小口径孔6、6’、6’’への挿入工程と、未硬化の硬化材7の充填工程を同時に実施しても良い。   In the case of a small drilling machine incapable of grout injection, after pulling up the drill pipe, the uncured hardened material 7 is filled into the small-diameter holes 6, 6 ′, 6 ″ in the support ground 3 from the grout supply pipe. The tensile steel material 8 is inserted into the small-diameter holes 6, 6 ′, 6 ″ in the support ground 3 filled with the uncured hardened material 7 before the uncured hardened material 7 is hardened. As the tensile steel material 8, a PC steel wire, a PC stranded wire, a PC steel rod or the like is used. After inserting the tensile steel material 8 into the small-diameter hole 6 in the support ground 3, the uncured hardened material 6 may be filled into the small-diameter hole 6 in the support ground 3, or the small-diameter hole 6 of the tensile steel material 8. , 6 ′, 6 ″ and the filling process of the uncured hardener 7 may be performed simultaneously.

支持地盤3の小口径孔6、6’、6’’中の未硬化の硬化材7が硬化し、引張鋼材8の下端部が支持地盤3中の小口径孔6、6’、6’’にしっかりと定着された後、引張鋼材8の上端部に、引張鋼材8を挿入する孔を形成した台座9を基礎フーチング5上に設置する。既成コンクリート杭4、4’、4’’の打設方向に対して傾斜した小口径孔6’、6’’に配置された引張鋼材8に対応する台座9は、その表面が引張鋼材8の引張方向と直角になるような楔形状とする。   The uncured hardened material 7 in the small-diameter holes 6, 6 ′, 6 ″ of the support ground 3 is hardened, and the lower end portion of the tensile steel material 8 is the small-diameter holes 6, 6 ′, 6 ″ in the support ground 3. Then, a base 9 having a hole for inserting the tensile steel material 8 is installed on the base footing 5 at the upper end of the tensile steel material 8. The surface of the pedestal 9 corresponding to the tensile steel material 8 disposed in the small-diameter holes 6 ′, 6 ″ inclined with respect to the direction of placing the precast concrete piles 4, 4 ′, 4 ″ is the surface of the tensile steel material 8 The wedge shape is perpendicular to the tensile direction.

台座9にジャッキを設置し、台座9を反力受けとしてジャッキにより引張鋼材8に引張力を付加する。引張鋼材8に引張力を付加することにより、既設コンクリート杭4、4’、4’’に反力として圧縮力が付加される。引張鋼材8に付加される引張力は、既設コンクリート杭4、4’、4’’に所望の耐震性能を発揮可能な圧縮力が付加されるように設定する。   A jack is installed on the pedestal 9, and a tensile force is applied to the tensile steel member 8 by the jack using the pedestal 9 as a reaction force receiver. By applying a tensile force to the tensile steel material 8, a compressive force is applied as a reaction force to the existing concrete piles 4, 4 ′, 4 ″. The tensile force applied to the tensile steel material 8 is set so that a compressive force capable of exhibiting a desired seismic performance is applied to the existing concrete piles 4, 4 ′, 4 ″.

引張鋼材8に引張力を付加した状態で、引張鋼材8の上端部と台座9とをナット等の固定手段10で固定する。固定手段10として、溶接等の他の固定手段を用いても良い。   In a state where a tensile force is applied to the tensile steel material 8, the upper end portion of the tensile steel material 8 and the base 9 are fixed by a fixing means 10 such as a nut. Other fixing means such as welding may be used as the fixing means 10.

第3実施形態の既設基礎1の耐震補強工法は、コンクリート杭4、4’、4’’の打設方向に対して平行に延びる引張鋼材8と、コンクリート杭4、4’、4’’の打設方向に対して傾斜して延びる引張鋼材8とを組み合わせて配置することで、地震時の多方向の応力に対して対応できる。図3では、杭間に引張鋼材8を配置するものを示したが、既設コンクリート杭4、4’、4’’が大径で、複数の引張鋼材の配置が可能であれば、第3実施形態のものを図1に示される第1実施形態に適用可能である。   The seismic reinforcement method for the existing foundation 1 of the third embodiment is that the tensile steel material 8 extending in parallel to the placing direction of the concrete piles 4, 4 ′, 4 ″ and the concrete piles 4, 4 ′, 4 ″. By arranging in combination with the tensile steel material 8 extending inclined with respect to the placing direction, it is possible to cope with multi-directional stresses during an earthquake. In FIG. 3, the tensile steel material 8 is arranged between the piles. However, if the existing concrete piles 4, 4 ′, 4 ″ have a large diameter and a plurality of tensile steel materials can be arranged, the third implementation is performed. The embodiment can be applied to the first embodiment shown in FIG.

また、第1〜第3実施形態の既設コンクリート杭基礎の耐震補強工法を組み合わせて適用しても良い。   Moreover, you may apply combining the earthquake-proof reinforcement construction method of the existing concrete pile foundation of 1st-3rd embodiment.

図3では、コンクリート杭が支持地盤3上に支持される杭を例として、小口径孔6を杭下端よりも下方の支持地盤3中まで延びるように穿孔したものを示したが、支持地盤3の上方に引張鋼材8を定着するのに十分な強度を備えた地盤が存在する場合、小口径孔6の穿孔は、コンクリート杭の下端部より下まで延ばさなくても良く、コンクリート杭の下端部と同じ位置か上方位置としても良い。また、杭基礎形式は、摩擦杭基礎であっても良い。   In FIG. 3, as an example of a pile in which a concrete pile is supported on the support ground 3, a small-diameter hole 6 is drilled so as to extend into the support ground 3 below the lower end of the pile. If there is a ground with sufficient strength to fix the tensile steel material 8 above the bottom of the concrete pile, the small-diameter hole 6 does not need to extend below the lower end of the concrete pile. It may be the same position or an upper position. The pile foundation type may be a friction pile foundation.

図4は、本発明の既設基礎1の耐震補強工法の作用を説明するための図である。   FIG. 4 is a diagram for explaining the operation of the seismic reinforcement method for the existing foundation 1 of the present invention.

RC杭(遠心力成形鉄筋コンクリート杭)、PHC杭(遠心力成形高強度プレストレストコンクリート杭)、PC杭(遠心力成形プレストレスト杭)、場所打RC杭は、図4に示されるような耐力曲線(M−N interaction curve)を有する。これらの杭は、地震時に発生する断面曲げモーメントM、断面圧縮軸力Nが三角形の耐力曲線内であれば、地震時の負荷に耐えることができる。既設コンクリート杭の耐力曲線に対して、地震時に発生する断面曲げモーメントMo,断面圧縮軸力Noとすると、MoとNoは、三角形の耐力曲線外に位置し、耐震補強をしないと既設コンクリート杭は、地震時の負荷に耐えることができない。   RC piles (centrifugal force-formed reinforced concrete piles), PHC piles (centrifugal force-formed high-strength prestressed concrete piles), PC piles (centrifugal force-formed prestressed piles), and cast-in-place RC piles have proof stress curves (M -N interaction curve). These piles can withstand the load at the time of earthquake if the cross-sectional bending moment M and the cross-sectional compressive axial force N generated during the earthquake are within the triangular yield curve. If the cross-sectional bending moment Mo generated during an earthquake and the cross-section compression axial force No are set against the strength curve of the existing concrete pile, Mo and No are located outside the triangular strength curve. Inability to withstand the load of an earthquake.

従来の増杭や地盤改良による耐震補強は、図4に示されるように、地震時に発生する断面曲げモーメントM0を三角形の耐力曲線内のM1にするものである。一方、本発明の既設コンクリート杭基礎の耐震補強は、既設コンクリート杭に予め圧縮力を付加することにより、断面圧縮軸力N0を曲げ耐力が耐力曲線内で最大値M2(Mmax)となるN2に増加するものである。地震時に断面圧縮軸力をN2とすることで、地震時の断面曲げモーメントMoを耐力曲線内として地震時の応力による既設コンクリート杭の破壊を防止するものである。   As shown in FIG. 4, the conventional seismic reinforcement by increasing piles or improving the ground is to change the sectional bending moment M0 generated at the time of the earthquake to M1 within the triangular yield curve. On the other hand, in the seismic reinforcement of the existing concrete pile foundation of the present invention, by applying a compressive force to the existing concrete pile in advance, the sectional compressive axial force N0 is changed to N2 where the bending strength becomes the maximum value M2 (Mmax) in the yield strength curve. It will increase. By setting the sectional compressive axial force to N2 at the time of the earthquake, the bending moment Mo at the time of the earthquake is within the proof curve, and the destruction of the existing concrete pile due to the stress at the time of the earthquake is prevented.

本発明の実施形態を示す図である。It is a figure which shows embodiment of this invention. 本発明の実施形態を示す図である。It is a figure which shows embodiment of this invention. 本発明の実施形態を示す図である。It is a figure which shows embodiment of this invention. 本発明の実施形態を示す図である。It is a figure which shows embodiment of this invention.

符号の説明Explanation of symbols

1:既設基礎、2:表層地盤、3:支持地盤、4、4’、4’’:コンクリート杭、5:基礎フーチング、6、6’、6’’:小口径孔、7:硬化材、8:引張鋼材、9:台座、10:固定手段   1: Existing foundation, 2: Surface ground, 3: Support ground, 4, 4 ′, 4 ″: Concrete pile, 5: Foundation footing, 6, 6 ′, 6 ″: Small-diameter hole, 7: Hardened material, 8: Tensile steel, 9: Pedestal, 10: Fixing means

Claims (6)

構造物を支持するためのコンクリート杭を有する既設基礎の上端部から、前記既設基礎の設置地盤中に延びる孔を削孔する工程と、
前記削孔された孔に未硬化の硬化材を充填し、引張鋼材を挿入する工程と、
前記未硬化の硬化材が硬化し、前記引張鋼材の下端部が前記硬化した硬化材により固定された後、前記引張鋼材に引張力を付加する工程と、
前記引張力を付加された前記引張鋼材の上端部を、前記既設基礎の上端部に固定部材を介して固定する工程と、
を有することを特徴とする既設基礎の耐震補強工法。
A step of drilling a hole extending into an installation ground of the existing foundation from an upper end portion of the existing foundation having a concrete pile for supporting a structure;
Filling the unbored hardened material into the drilled hole and inserting a tensile steel material;
A step of applying a tensile force to the tensile steel material after the uncured hardened material is cured and a lower end portion of the tensile steel material is fixed by the cured hardened material;
Fixing the upper end of the tensile steel to which the tensile force is applied to the upper end of the existing foundation via a fixing member;
Seismic reinforcement method for existing foundation, characterized by having
前記コンクリート杭として、RC杭、PHC杭、PC杭、場所打RC杭のいずれかを用いることを特徴とする請求項1に記載の既設基礎の耐震補強工法。 The seismic reinforcement method for an existing foundation according to claim 1, wherein any one of RC pile, PHC pile, PC pile, and cast-in-place RC pile is used as the concrete pile. 前記引張鋼材が前記コンクリート杭の内部を通して延びるように設置されることを特徴とする請求項1または2に記載の既設基礎の耐震補強工法。 The seismic reinforcement method for an existing foundation according to claim 1 or 2, wherein the tensile steel material is installed so as to extend through the inside of the concrete pile. 前記既設基礎は、複数のコンクリート杭の杭頭部を一体に連結して形成された基礎フーチングを有し、前記基礎フーチングを通して前記複数のコンクリート杭間に延びるように設置されることを特徴とする請求項1または2に記載の既設基礎の耐震補強工法。 The existing foundation has a foundation footing formed by integrally connecting pile heads of a plurality of concrete piles, and is installed to extend between the plurality of concrete piles through the foundation footing. The earthquake-proof reinforcement method of the existing foundation of Claim 1 or 2. 前記コンクリート杭の打設方向と平行に延びる引張鋼材と、前記コンクリート杭の打設方向に対して傾斜して延びる引張鋼材とを組み合わせて設置することを特徴とする請求項1〜4のいずれか1項に記載の既設コンクリート杭基礎の耐震補強工法。 The tensile steel material extending in parallel with the direction of placing the concrete pile and the tensile steel material extending inclining with respect to the direction of placing the concrete pile are installed in combination. Seismic reinforcement method for existing concrete pile foundation described in item 1. 構造物を支持するためのコンクリート杭を有する既設基礎の上端部から、前記既設基礎の設置地盤中に延びる引張鋼材を備え、前記引張鋼材の下端部が硬化材により固定され、前記引張鋼材の上端部が引張力を付加された状態で前記既設基礎上端部に固定部材を介して固定されることを特徴とする既設基礎の耐震補強構造。 A tensile steel material extending from the upper end of an existing foundation having a concrete pile for supporting a structure to the ground where the existing foundation is installed, the lower end of the tensile steel being fixed by a hardened material, and the upper end of the tensile steel A seismic reinforcement structure for an existing foundation, wherein the section is fixed to the upper end of the existing foundation via a fixing member in a state where a tensile force is applied.
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