JP2005029953A

JP2005029953A - Reinforcing method for subgrade slab

Info

Publication number: JP2005029953A
Application number: JP2003154300A
Authority: JP
Inventors: Hiroshi Kojima; 宏小島; Shigeyuki Matsui; 繁之松井; Masazumi Okada; 昌澄岡田; Hirobumi Nakano; 博文中野; Akira Kobayashi; 朗小林; Sanehiro Kube; 修弘久部; Hideaki Fukagawa; 英明深川; Yoshimitsu Fujimoto; 宜充藤本
Original assignee: METROPOLITAN EXPRESSWAY PUBLIC CORP; Nippon Steel Composite Co Ltd; Toray Industries Inc; Nippon Oil Corp; Mitsubishi Kagaku Sanshi Corp
Current assignee: METROPOLITAN EXPRESSWAY PUBLIC CORP; Toray Industries Inc; Nippon Steel Chemical and Materials Co Ltd; Mitsubishi Kagaku Sanshi Corp; Eneos Corp
Priority date: 2003-05-15
Filing date: 2003-05-30
Publication date: 2005-02-03
Anticipated expiration: 2023-05-30
Also published as: JP4004436B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reinforcing method for a subgrade slab facilitating the observation of the lower surface for maintenance control of the subgrade slab, preventing retention of permeating water, greatly decreasing the quantity of reinforcing material consumed in comparison with the conventional method while ensuring an objective reinforcing performance by adopting the result based on a fatigue test by moving wheel load in determining a reinforcement specification and capable of being efficiently executed at a low cost. <P>SOLUTION: The reinforcing method for the subgrade slab uses a grating structural body of a continuous fiber sheet made by arranging continuous reinforcing fibers in a grid structure on the under surface of the subgrade slab and impregnating it with a resin and constituting the structural body so as to have a tensile rigidity of 45 to 75 kN/mm per unit width of the slab when the body is bonded to the slab. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、道路床版の補強方法に関し、とくに、床版下面に連続補強繊維を格子状に配置するとともに樹脂を含浸して帯状連続繊維シートの格子構造体を構成、接着することにより床版を補強する道路床版の補強方法に関する。
【０００２】
【従来の技術】
連続補強繊維（たとえば、連続炭素繊維や連続アラミド繊維）と樹脂（たとえば、エポキシ樹脂）から構成される連続繊維シートを道路床版の下面に接着する道路床版の補強方法が知られている。このような連続繊維シートを用いた道路床版の補強方法としては、従来、予め設定された静荷重に対して、補強後の床版の補強筋（鉄筋）の応力が許容応力値１２０〜１４０ｋＮ／ｍｍ^２以下に納まるよう、連続繊維シートを床版下面の実質的に全面にわたって接着するようにしている。
【０００３】
このような補強方法において、上記のように鉄筋応力を許容応力値以下に抑えるためには、接着された連続繊維シートの引張剛性を１００ｋＮ／ｍｍ以上にすることが必要となる場合が多い。そのため、シート積層枚数が多くなったり、高弾性の連続繊維を多く使用したシートを全面施工する必要が生じたりし、補強繊維やそのシートの使用量が多くなるとともに、施工コストが高くなるという問題がある。
【０００４】
この問題に対し、鉄筋応力を許容応力値以下に抑えるよう設計、施工するのではなく、より実際に近い形態で、つまり、自動車が繰り返し走行する形態を想定した移動輪荷重による疲労試験から、より無駄のない、より適切な補強仕様、つまり、補強後に要求される強度をより無駄のない、より適切な強度として求める方法が最近開発された。そして実際に、この疲労試験方法から求められる補強用連続繊維シートの引張剛性を８２ｋＮ／ｍｍ程度とするよう、床版下面全面に連続繊維シートを接着する補強方法が国土交通省（旧建設省）土木研究所「コンクリート部材の補修・補強に関する共同研究報告書（ＩＩＩ）炭素繊維シート接着工法による道路橋コンクリート部材の補修・補強に関する設計・施工指針（案）」として提案されている。この提案により、鉄筋応力を許容応力値以下に抑えるよう床版下面全面に接着していた場合に比べて、補強用連続繊維シートの使用量の低減が可能となった。
【０００５】
しかし、上記提案による疲労試験に基づく補強では、床版下面全面を連続繊維シートで覆うために、補強後の鉄筋コンクリート床版の維持管理を行う上で、床版下面のコンクリートのひび割れ等を観察できない、床版上面側からの浸透水が床版下面部におけるコンクリート部分やコンクリート部分と連続繊維シートとの間に滞留し、床版の寿命を低下させるおそれがある等の問題がある。
【０００６】
一方、床版下面のひび割れ観察を目的として床版下面に連続繊維シートを格子状に接着する方法が土木学会第４９回年次学術講演会「炭素繊維接着による床版補強の検討（第３報）」により提案されている。しかし、この提案方法では、補強仕様として、連続繊維シートの補強量を、前述の鉄筋応力が許容応力値以下になるまで連続繊維シートを接着する許容応力度法に基づいて決めているため、結果としてさらに多くの連続繊維シートを積層、接着することが必要となり、他工法に比べコスト的に不利なものとなっている。
【０００７】
【発明が解決しようとする課題】
そこで本発明の課題は、床版の維持管理を行う上で床版下面のコンクリートのひび割れ等の観察を容易に行うことができ、かつ、床版上面側からの浸透水の、床版下面部におけるコンクリート部分やコンクリート部分と連続繊維シートとの間への滞留を防止できるとともに、従来の許容応力度法によらず移動輪荷重による疲労試験に基づく結果を補強仕様決定に採用することにより、目標とする補強性能を確保しつつ従来法に比べて大幅に補強材の使用量を低減することができる、安価に効率よく施工可能な道路床版の補強方法を提供することにある。
【０００８】
【課題を解決するための手段】
上記課題を解決するために、本発明に係る道路床版の補強方法は、道路床版の下面に、連続補強繊維を格子状に配置し樹脂を含浸して帯状連続繊維シートの格子構造体を構成、接着するに際し、該連続繊維シートの格子構造体を、床版の単位幅当たりの引張剛性が４５〜７５ｋＮ／ｍｍとなるように構成することを特徴とする方法からなる。
【０００９】
この方法における上記連続繊維シートの格子構造体の、床版の単位幅当たりの引張剛性は、従来の鉄筋許容応力による手法ではなく、連続繊維シート補強床版の移動輪荷重による疲労試験に基づいて決定されたものであり、補強後の床版の耐久疲労性から確認された耐久寿命が望ましい値となるように決定されたものである。これによって、現実の使用形態における十分に高い補強効果を達成しつつ、全体の補強材使用量を、許容応力による手法から導き出される量よりも大幅に低減することができる。また同時に、帯状連続繊維シートを格子状に接着することで、補強施工後にも床版のひび割れ等を容易に観察することができ、かつ、床版上面側からの雨水等の浸透水の滞留も防止することができる。
【００１０】
上記移動輪荷重による疲労試験の結果からは、床版の単位幅当たりの引張剛性が従来の標準補強量である８２ｋＮ／ｍｍより少ない４５〜７５ｋＮ／ｍｍで十分であることが判明した。引張剛性がこの４５〜７５ｋＮ／ｍｍの範囲内となるようにするには、たとえば、幅１５〜３５ｃｍの所定の剛性の連続繊維シートを、５〜２０ｃｍの間隔をあけて、床版の下面に、主筋方向および配力筋方向に各々１層ずつ接着することで十分な寿命が予測され、所望の補強性能が得られることが判明した。
【００１１】
より適切な補強仕様としては、床版の厚みに応じて決定することが可能である。たとえば、厚みが１０ｃｍ以上１８ｃｍ未満の床版に対しては、連続繊維シートの格子構造体を、床版の単位幅当たりの引張剛性が６２〜７５ｋＮ／ｍｍとなるように構成することが好ましい。この場合、幅１５〜３５ｃｍの連続繊維シートを８〜１３ｃｍの間隔をあけて格子状に接着することが好ましい。
【００１２】
また、厚みが１８ｃｍ以上２５ｃｍ以下の床版に対しては、連続繊維シートの格子構造体を、床版の単位幅当たりの引張剛性が４５〜６２ｋＮ／ｍｍとなるように構成することが好ましい。この場合、幅１５〜３５ｃｍの連続繊維シートを１３〜２０ｃｍの間隔をあけて格子状に接着することが好ましい。
【００１３】
また、連続繊維シート自体としても、望ましい特性を有することが好ましい。たとえば、連続繊維シート自体の単位幅当たりの引張剛性としては８５〜１０５ｋＮ／ｍｍの範囲内にあることが好ましい。補強繊維としては、代表的にはたとえば炭素繊維やアラミド繊維を使用できるが、炭素繊維を使用する場合、たとえば、ヤング係数が３５０〜６５０ｋＮ／ｍｍ^２の炭素繊維を繊維目付量２７０〜５５０ｇ／ｍ^２にて含む連続繊維シートを用いることが好ましい。また、アラミド繊維を使用する場合、たとえば、ヤング係数が７０〜１３０ｋＮ／ｍｍ^２、好ましくは１１０〜１２５ｋＮ／ｍｍ^２のアラミド繊維を繊維目付量８００〜２０００ｇ／ｍ^２にて含む連続繊維シートを用いることが好ましい。
【００１４】
なお、本発明における上記ヤング係数は補強繊維単体の数値であるが、ＦＲＰ化した状態での測定値であり、ＪＳＣＥ−Ｅ５４１−２０００に準拠して測定するものとする。また、繊維目付量は補強繊維単体の数値であり、織物タイプおよび編物タイプではＪＩＳＲ７６０２に準拠して、プリプレグタイプではＪＩＳＫ７０７１に準拠して測定するものとする。また、前記引張剛性は、補強繊維単体の数値であるがＦＲＰ化した状態での測定値であり、ヤング係数×単位施工幅当たりの繊維断面積で表される。
【００１５】
さらに、上記連続繊維として炭素繊維を使用する場合の数値の根拠は、後述の如く試験によって求められたものであるが、アラミド繊維を使用する場合の数値は、炭素繊維の場合から割り出した予測値である。
【００１６】
【発明の実施の形態】
以下に、本発明の望ましい実施の形態について、図面を参照して説明する。
図１は、本発明の一実施態様に係る方法により補強した道路床版の下面側を示している。図１に示すように、道路床版１の下面に、連続補強繊維２を格子状に配置し、それに樹脂を含浸してたとえば図２に配置例を示すような帯状連続繊維シート３の格子構造体４を構成するとともに接着する。図２に示す図示例では、幅２５ｃｍ（２５０ｍｍ）の帯状連続繊維シート３が間隔１００ｍｍにて格子状に配置されており、帯状連続繊維シート３自体を繋ぐ場合には、重ね継手ラップ長１０ｃｍで繋ぎ合わされている。このような連続繊維シート３の格子構造体４を構成、接着するに際して、床版１の単位幅当たりの引張剛性が４５〜７５ｋＮ／ｍｍとなるように構成する。
【００１７】
連続補強繊維２としては、たとえば炭素繊維、アラミド繊維、ＰＢＯ（ポリパラフェニレンベンズビスオキサゾール）繊維、ガラス繊維等の使用が可能であり、このうち特に、炭素繊維、アラミド繊維の使用が好ましい。連続繊維シート３を構成するために連続補強繊維２に含浸する樹脂としては、たとえばエポキシ樹脂、メチルメタクリレート樹脂、ビニルエステル系樹脂、不飽和ポリエステル樹脂またはポリウレタン樹脂等の使用が可能であり、このうち特にエポキシ樹脂の使用が好ましい。
【００１８】
上記実施態様では、帯状連続繊維シート３は各々１層ずつ、床版１の主筋方向（長手方向）および配力筋方向（長手方向と直交する方向）に各々接着される。この補強は、たとえば、図３に示すように行われる。まず、下地である床版１の下面のケレンを行う。このとき、たとえば、施工範囲の割付け、墨出しや、洗浄、乾燥、さらには劣化層の除去・研磨を行う。次に、その下地にプライマーを塗布する。格子部の墨出しマスキングを行い、プライマーを調製してそれを刷毛塗り等で塗布し、硬化させる。次いで、不陸修正を行い、凸部の削り取り、ハンチ入隅の平滑化、凹部のエポキシパテ埋め等を行う。この上に、１層目連続繊維シート（たとえば、炭素繊維シート）を貼り付ける。たとえば、１層目墨出しマスキングを行い、樹脂を調製してローラー刷毛塗り（下塗り）を行った後、その上に繊維シートを貼り付けてしごき含浸・脱泡を行い、その上にさらにローラー刷毛塗り（上塗り）を行った後しごき含浸・脱泡を行い、１層目マスキングを除去する。次いで、２層目連続繊維シート（たとえば、炭素繊維シート）を貼り付ける。たとえば、２層目墨出しマスキングを行い、樹脂を調製してローラー刷毛塗り（下塗り）を行った後、その上に繊維シートを貼り付けてしごき含浸・脱泡を行い、その上にさらにローラー刷毛塗り（上塗り）を行った後しごき含浸・脱泡を行い、２層目マスキングを除去する。格子状に１層目、２層目連続繊維シートを接着した後、養生する。
【００１９】
本発明において、上記のように構成される帯状連続繊維シート３の格子構造体４により補強された床版１の補強効果は、自動車が実際に繰り返し走行する形態を想定した移動輪荷重による疲労試験によって検証される。そして、この疲労試験による結果から、十分な耐久性を得るための補強仕様が判断され、それに基づいて本発明における、目標とする補強性能を得るための連続繊維シートの格子構造体の、床版の単位幅当たりの引張剛性４５〜７５ｋＮ／ｍｍの範囲が規定された。この範囲内とすることにより、無駄な補強材を使用することなく効率よく、要求された補強性能が達成され、かつ、格子構造とすることにより、維持管理のための下方からの観察が可能になる。また、格子構造により下地が露出する部分にはプライマー、エポキシパテ、樹脂が塗布されないように墨出しマスキングを行うことにより、雨水等の上方からの浸透水は露出する部分より排出され、滞留が防止されることになる。なお、露出する部分のコンクリートが劣化により剥落する危険がある場合は、剥落防止用ネット材を床版下面に配し、ネット材と格子構造体を接着することにより脱落を防止することが可能であり、この場合も維持管理のための下方からの観察が可能であるとともに雨水等の上方からの浸透水の滞留も防止される。
【００２０】
上記移動輪荷重による疲労試験は、たとえば図４に示すような輪荷重走行試験機１１を用いて行われる。この輪荷重走行試験機１１は、所定厚みを有する床版の供試体１２を支持桁１３上に固定し、供試体１２上の軌道１４上に、車輪１５を往復動させる。車輪１５には、油圧ジャッキ１６により各種荷重が加えられており、その状態にて、モータ１７によって駆動されるクランク機構１８により、車輪１５が設定回数に到達するまで往復動される。試験に用いた輪荷重走行試験機１１では、クランク機構１８の回転半径が１００ｃｍ、車輪１５の移動ストロークが２００ｃｍ（床版中央から±１００ｃｍ）、支持桁１３の最大スパンが３００ｃｍである。載荷能力が１００〜３００ｋＮ、車輪走行速度が１１２ｍ／分（２８往復／分）、車輪の径が５０ｃｍ、幅が３０ｃｍである。この仕様の輪荷重走行試験機１１は、大阪大学が保有しており、以下の試験にもその輪荷重走行試験機１１を使用した。
【００２１】
試験には、連続繊維シートとして炭素繊維シートを使用した。試験に使用した床版は長さ（橋軸方向）３０００ｍｍ×幅（橋軸直角方向）２０００ｍｍで、床版支間は１８００ｍｍに統一した。床版厚は１５ｃｍ、１８ｃｍ、２２ｃｍの３通りに設定し、それぞれ３体（Ｎｏ．２〜４）、２体（Ｎｏ．５、Ｎｏ．６）、１体（Ｎｏ．１）製作した。これらのうち、床版厚２２ｃｍのものと、床版厚１５ｃｍ厚のもののうち一体については炭素繊維補強を実施せず、無補強時の比較用のデータの収集のみを行った。供試体の配筋は表１に示すように設定した。１５ｃｍ厚の床版はＳ３９（昭和３９年）鋼道路橋設計示方書で規定される床版、１８ｃｍ厚の床版はＳ４３（昭和４３年）鋼道路橋の床版設計に関する暫定基準で規定される床版、２２ｃｍ厚の床版はＨ８（平成８年）道路橋示方書で規定される床版を想定している。使用した鉄筋は、床版厚１５ｃｍ、１８ｃｍ厚のものではＳＤ２９５Ａ、床版厚２２ｃｍのものではＳＤ３４５とした。設計上の鉄筋かぶりは圧縮側、引張側で同じとし、床版厚２２ｃｍの床版で４５ｍｍ、それ以外の床版で３０ｍｍとした。また、試験時に測定したコンクリートの圧縮強度、弾性係数はそれぞれ３５．６Ｎ／ｍｍ^２、２６．６ｋＮ／ｍｍ^２（床版厚１５ｃｍ、２２ｃｍ）、３６．２Ｎ／ｍｍ^２、２８．６ｋＮ／ｍｍ^２（床版厚１８ｃｍ）であった。
【００２２】
【表１】

【００２３】
本試験では、炭素繊維シートを格子状に配置したときの補強効果について確認するため、炭素繊維シートの配置として図２に示したような格子配置を採用した。つまり、炭素繊維シートの幅を２５０ｍｍとし、シート間の設置間隔は１００ｍｍ（床版厚１５ｃｍ）又は１５０ｍｍ（床版厚１８ｃｍ）に設定した。また、炭素繊維の種類は中弾性タイプ（ヤング係数Ｅ＝４．４×１０^５Ｎ／ｍｍ^２）のものを使用した。炭素繊維の目付け量は４００ｇ／ｍ^２（繊維シート厚ｔ＝０．２２０ｍｍ）、４７０ｇ／ｍ^２（ｔ＝０．２５９ｍｍ）とし、目付け量の違いによる挙動の変化についても確認することにした（表３参照）。
【００２４】
今回の試験は、上述の大阪大学保有の輪荷重走行試験機を用いて実施した。床版の支持条件は、床版長辺（支持桁直上）を単純支持、床版短辺を端横桁による弾性支持とした。炭素繊維で補強を行う床版についは表２に示すような予備載荷を実施し、事前に損傷を与えた後に補強を行い、輪荷重走行試験を実施することにした。輪荷重走行試験時の荷重載荷プログラムを表３に示す。なお、Ｎｏ．３については予備載荷１、予備載荷２の２回の予備載荷を実施した。今回の試験では、床版の耐力に応じて載荷荷重の大きさと往復回数を決定し、試験を実施した。補強に用いた各供試体床版における格子構造体の、設計上の床版単位幅当たりの引張剛性ＥＡは、供試体Ｎｏ．３が８０ｋＮ／ｍｍ、Ｎｏ．４が６８ｋＮ／ｍｍ、Ｎｏ．５が７０ｋＮ／ｍｍ、Ｎｏ．６が６０ｋＮ／ｍｍであった。
【００２５】
【表２】

【００２６】
【表３】

【００２７】
今回実施した一連の輪荷重走行試験では、床版厚２２ｃｍのＮｏ．１は荷重走行１，０００，０００回に到達しても破壊しなかったものの、他の供試体は全て破壊した。床版厚１５ｃｍの供試体では補強されていない供試体であるＮｏ．２が４１０，０００回（荷重１１７．６ｋＮ）、補強を施した供試体Ｎｏ．３、Ｎｏ．４がそれぞれ３４２，０００回（荷重１４７ｋＮ）、４３６，０００回（荷重１４７ｋＮ）で押し抜きせん断破壊を生じ、床版厚１８ｃｍの供試体では、Ｎｏ．５が９４１，６００回（荷重２０５．８ｋＮ）、Ｎｏ．６が８８４，０００回（荷重２０５．８ｋＮ）で押し抜きせん断破壊により破壊した。
【００２８】
各供試体で載荷荷重が異なること、一つの供試体についても荷重を階段状に変化させていることから、破壊までの載荷回数で直接疲労耐久性を比較することは困難である。そこで、各供試体の疲労耐久性を比較、検討するために、松井らによって「道路橋ＲＣ床版のひび割れ損傷と耐久性」（阪神高速道路公団／阪神高速道路管理技術センター、平成３年１２月）等で提案されている大阪大学の輪荷重走行試験機における実験式とマイナー則を用いて、基準荷重Ｐ_０を１５ｔｆとした場合の換算走行回数と、実荷重（Ｐ_０）と耐力（Ｐｓｘ）との比である無次元荷重Ｐ_０／Ｐｓｘとの関係を、図５に示す。
【００２９】
図５から分かるように、平成８年（Ｈ８）道路橋示方書に準じて製作した床版厚２２ｃｍの供試体Ｎｏ．１は、１５ｔｆ一定載荷に換算すると２１００万回以上の破壊寿命であったのに対し、昭和３９年（Ｓ３９）道路橋示方書に準じて製作した床版厚１５ｃｍの無補強供試体Ｎｏ．２は、１５ｔｆ一定載荷では約１．８万回であった。つまり、供試体Ｎｏ．１は無補強供試体Ｎｏ．２に比べ同じ輪荷重が作用すると実に１０００倍以上の寿命を持つことになる。床版厚１５ｃｍの無補強床版が実橋で約４０年供用されていることを考慮すると、平成８年（Ｈ８）道路橋示方書に準じた床版は、移動荷重に対する疲労寿命は、実用上充分であると言える。
【００３０】
上記１５ｃｍ厚の床版の補強効果についてみるに、炭素繊維シートを格子状に接着して補強したＮｏ．３（目付量４７０ｇ／ｍ^２、格子間隔１００ｍｍ、引張剛性ＥＡ８０ｋＮ／ｍｍ）、Ｎｏ．４（目付量４００ｇ／ｍ^２、格子間隔１００ｍｍ、引張剛性ＥＡ６８ｋＮ／ｍｍ）の１５ｔｆ一定載荷の換算破壊回数はそれぞれ１４．８万回、２０．６万回となり、無補強供試体Ｎｏ．２に比べそれぞれ８倍、１３倍の寿命を示した。無補強のＮｏ．２と同じ諸元のＲＣ床版が実橋で約４０年供用されていることを考慮すると、Ｎｏ．３、Ｎｏ．４いずれも補強後１００年を超える疲労耐久性を有することになり、十分な補強効果が得られていることが分かる。なお、Ｎｏ．３とＮｏ．４が引張荷重の大小関係にもかかわらず寿命が逆転したのは、初期損傷度の違い等が影響したものと考えられる。このような違いを考えても、寿命延長効果から、本発明で規定した、連続繊維シートの格子構造体の、床版の単位幅当たりの引張剛性は７５ｋＮ／ｍｍあれば十分と考えられる。
【００３１】
初期損傷を与えた１８ｃｍ厚の床版の補強効果についてみるに、炭素繊維シートを格子状に接着して補強したＮｏ．５（目付量４７０ｇ／ｍ^２、格子間隔１５０ｍｍ、引張荷重ＥＡ７０ｋＮ／ｍｍ）、Ｎｏ．６（目付量４００ｇ／ｍ^２、格子間隔１５０ｍｍ、引張荷重ＥＡ６０ｋＮ／ｍｍ）の１５ｔｆ一定載荷の換算破壊回数はそれぞれ約１７６３万回、約１７２０万回となり、推定で算出した無補強供試体に比べそれぞれ約２７倍、約２６倍の十分に長い寿命を示した。
【００３２】
これらの結果から、本発明で規定した、連続繊維シートの格子構造体の、床版の単位幅当たりの引張剛性は４５〜７５ｋＮ／ｍｍあれば十分と考えられる。また、Ｎｏ．４の結果から、厚みが１０ｃｍ以上１８ｃｍ未満の床版に対しては、幅１５〜３５ｃｍの連続繊維シートを５〜２０ｃｍの間隔をあけて格子状に接着し、連続繊維シートの格子構造体を、床版の単位幅当たりの引張剛性が６２〜７５ｋＮ／ｍｍとなるように構成すればよいことが分かる。また、Ｎｏ．６の結果から、厚みが１８ｃｍ以上２５ｃｍ以下の床版に対しては、幅１５〜３５ｃｍの連続繊維シートを８〜１３ｃｍの間隔をあけて格子状に接着し、連続繊維シートの格子構造体を、床版の単位幅当たりの引張剛性が４５〜６２ｋＮ／ｍｍとなるように構成すればよいことが分かる。
【００３３】
また、図５には併せて、１８ｃｍ厚の床版について従来の全面接着の場合も示してある。図中の供試体「３００×２ｔ１８Ｓ４３ＥＡ８２全面」は、ヤング係数２４５００Ｎ／ｍｍ^２、繊維目付量３００ｇ／ｍ^２の高強度型炭素繊維シートを床版全面に主筋方向２層、配力筋方向２層合計４層接着して補強したものであり、供試体「６００×１ｔ１８Ｓ４３ＥＡ８２全面」はヤング係数２４５００Ｎ／ｍｍ^２、繊維目付量６００ｇ／ｍ^２の高強度型炭素繊維シートを床版全面に主筋方向１層、配力筋方向１層合計２層接着して補強したものであり、補強材の床版単位幅あたりの引張剛性はいずれもＥＡ＝８２ｋＮ／ｍｍとなる。また、図５中の「計算ｔ１８Ｓ４３無補強」は、〔００２８〕段落で述べた大阪大学の輪荷重走行試験における実験式を用いて算定した、１８ｃｍ厚の無補強のＲＣ床版の計算上のＰ_０／Ｐｓｘと寿命を示したものである。図５に示すように供試体Ｎｏ．５、Ｎｏ．６は、引張剛性ＥＡ＝８２ｋＮ／ｍｍとなるように従来工法により全面接着した供試体「３００×２ｔ１８Ｓ４３ＥＡ８２全面」および「６００×１ｔ１８Ｓ４３ＥＡ８２全面」とほぼ同等の補強効果を発揮した。したがって、Ｎｏ．５、Ｎｏ．６では補強材が大幅に低減でき、かつ、格子構造による効果が確実に得られていることがわかる。
【００３４】
【発明の効果】
以上説明したように、本発明に係る道路床版の補強方法によれば、従来よりも少量の補強用連続繊維シートの使用量で十分な補強効果を得ることができ、かつ、格子状に補強構造体を構成することにより、ひび割れ観察を容易に行えるようになるとともに浸透水の滞留を防止することもできるようになる。したがって、低施工コストにて、望ましい形態で道路床版の補強を行うことができるようになる。
【図面の簡単な説明】
【図１】本発明の一実施態様に係る道路床版の補強方法を示す床版下面側の斜視図である。
【図２】本発明における連続繊維シートの格子構造体の一例を示す床版の底面図である。
【図３】本発明の一実施態様に係る道路床版の補強方法における作業順序を示す工程フロー図である。
【図４】本発明における評価に用いた輪荷重走行試験機の正面図である。
【図５】本発明による補強効果を示す特性図である。
【符号の説明】
１道路床版
２連続補強繊維
３帯状連続繊維シート
４格子構造体
１１輪荷重走行試験機
１２床版の供試体
１３支持桁
１４軌道
１５車輪
１６油圧ジャッキ
１７モータ
１８クランク機構[0001]
BACKGROUND OF THE INVENTION
TECHNICAL FIELD The present invention relates to a method for reinforcing a road slab, and in particular, a floor slab by arranging and reinforcing continuous reinforcing fibers in a lattice shape on the lower surface of the floor slab and impregnating a resin to form and adhere a lattice structure of strip-like continuous fiber sheets. The present invention relates to a method for reinforcing a road slab that reinforces the floor.
[0002]
[Prior art]
There is known a method for reinforcing a road floor slab in which a continuous fiber sheet composed of continuous reinforcing fibers (for example, continuous carbon fiber or continuous aramid fiber) and a resin (for example, epoxy resin) is bonded to the lower surface of the road floor slab. As a method for reinforcing a road floor slab using such a continuous fiber sheet, conventionally, a stress of a reinforcing member (rebar) of a slab after reinforcement is an allowable stress value of 120 to 140 kN with respect to a preset static load. / Mm ² so that the continuous fiber sheet is bonded over substantially the entire lower surface of the floor slab so as to be within ² mm / mm ² .
[0003]
In such a reinforcing method, in order to keep the reinforcing bar stress below the allowable stress value as described above, it is often necessary to set the tensile stiffness of the bonded continuous fiber sheet to 100 kN / mm or more. Therefore, the number of sheets laminated increases, and it becomes necessary to apply the entire sheet using a large amount of high-elastic continuous fibers, which increases the amount of reinforcing fibers and sheets used and increases the construction cost. There is.
[0004]
In response to this problem, rather than designing and constructing the rebar stress below the allowable stress value, it is more realistic, that is, from a fatigue test with a moving wheel load assuming a form in which the car repeatedly runs, Recently, there has been developed a more appropriate reinforcement specification without waste, that is, a method for obtaining the strength required after reinforcement as a more appropriate strength without waste. In fact, the Ministry of Land, Infrastructure, Transport and Tourism (former Ministry of Construction) is a reinforcing method in which the continuous fiber sheet is bonded to the entire lower surface of the floor slab so that the tensile stiffness of the continuous fiber sheet for reinforcement required from this fatigue test method is about 82 kN / mm. Public Works Research Institute “Joint Research Report on Repair and Reinforcement of Concrete Member (III) Design and Construction Guidelines (Draft) on Repair and Reinforcement of Road Bridge Concrete Member by Carbon Fiber Sheet Bonding Method” is proposed. This proposal made it possible to reduce the amount of reinforcing continuous fiber sheet used compared to the case where the reinforcing plate was bonded to the entire lower surface of the floor slab so as to keep the rebar stress below the allowable stress value.
[0005]
However, in the reinforcement based on the fatigue test based on the above proposal, since the entire bottom surface of the floor slab is covered with a continuous fiber sheet, it is impossible to observe cracks in the concrete on the bottom surface of the floor slab when performing maintenance management of the reinforced concrete floor slab after reinforcement. There is a problem that the permeated water from the upper surface side of the floor slab may stay between the concrete portion on the lower surface portion of the floor slab or between the concrete portion and the continuous fiber sheet, thereby reducing the life of the floor slab.
[0006]
On the other hand, for the purpose of observing cracks on the bottom surface of the floor slab, a continuous fiber sheet is bonded to the bottom surface of the floor slab in a lattice pattern. ) ”. However, in this proposed method, as the reinforcement specification, the amount of reinforcement of the continuous fiber sheet is determined based on the allowable stress degree method in which the continuous fiber sheet is bonded until the above-described rebar stress is equal to or lower than the allowable stress value. Therefore, it is necessary to laminate and bond more continuous fiber sheets, which is disadvantageous in terms of cost compared to other methods.
[0007]
[Problems to be solved by the invention]
Therefore, an object of the present invention is to easily observe cracks and the like of the concrete on the bottom surface of the floor slab when maintaining and managing the floor slab, and to permeate water from the top surface side of the floor slab. By using the results based on the fatigue test by moving wheel load for determining the reinforcement specifications, regardless of the conventional allowable stress method, it is possible to prevent the stagnation between the concrete part and the concrete part and the continuous fiber sheet. It is an object of the present invention to provide a method for reinforcing a road slab that can be constructed efficiently at low cost, which can significantly reduce the amount of the reinforcing material used as compared with the conventional method while ensuring the reinforcing performance.
[0008]
[Means for Solving the Problems]
In order to solve the above-described problems, a road floor slab reinforcement method according to the present invention includes a strip-like continuous fiber sheet lattice structure in which continuous reinforcing fibers are arranged in a lattice shape on a lower surface of a road floor slab and impregnated with a resin. In the construction and bonding, the lattice structure of the continuous fiber sheet is constructed such that the tensile rigidity per unit width of the floor slab is 45 to 75 kN / mm.
[0009]
The tensile stiffness per unit width of the floor slab of the continuous fiber sheet lattice structure in this method is based on a fatigue test by a moving wheel load of the continuous fiber sheet reinforced floor slab instead of the conventional method using allowable stress of reinforcing bars. It was determined so that the durability life confirmed from the durability fatigue of the slab after reinforcement would be a desirable value. This makes it possible to significantly reduce the total amount of use of the reinforcing material, compared with the amount derived from the technique based on the allowable stress, while achieving a sufficiently high reinforcing effect in an actual usage pattern. At the same time, by bonding the belt-like continuous fiber sheet in a lattice shape, it is possible to easily observe cracks and the like of the slab even after reinforcement work, and there is also retention of permeated water such as rain water from the top side of the slab Can be prevented.
[0010]
From the result of the fatigue test using the moving wheel load, it was found that 45 to 75 kN / mm, which is less than the conventional standard reinforcement amount of 82 kN / mm, is sufficient as the tensile rigidity per unit width of the floor slab. In order to set the tensile rigidity within the range of 45 to 75 kN / mm, for example, continuous fiber sheets having a predetermined rigidity of 15 to 35 cm in width are provided on the lower surface of the floor slab with an interval of 5 to 20 cm. It has been found that a sufficient life can be predicted and a desired reinforcing performance can be obtained by adhering one layer each in the main muscle direction and the distribution bar direction.
[0011]
More appropriate reinforcement specifications can be determined according to the thickness of the floor slab. For example, for a floor slab having a thickness of 10 cm or more and less than 18 cm, the lattice structure of the continuous fiber sheet is preferably configured such that the tensile rigidity per unit width of the floor slab is 62 to 75 kN / mm. In this case, it is preferable to adhere a continuous fiber sheet having a width of 15 to 35 cm in a lattice shape with an interval of 8 to 13 cm.
[0012]
For floor slabs having a thickness of 18 cm or more and 25 cm or less, the lattice structure of the continuous fiber sheet is preferably configured such that the tensile rigidity per unit width of the floor slab is 45 to 62 kN / mm. In this case, it is preferable to adhere a continuous fiber sheet having a width of 15 to 35 cm in a lattice shape with an interval of 13 to 20 cm.
[0013]
Also, the continuous fiber sheet itself preferably has desirable characteristics. For example, the tensile stiffness per unit width of the continuous fiber sheet itself is preferably in the range of 85 to 105 kN / mm. Typically, for example, carbon fiber or aramid fiber can be used as the reinforcing fiber. However, when carbon fiber is used, for example, carbon fiber having a Young's modulus of 350 to 650 kN / mm ² is used for a fiber basis weight of 270 to 550 g / m. It is preferable to use the continuous fiber sheet contained in ² . When an aramid fiber is used, for example, a continuous fiber sheet containing an aramid fiber having a Young's modulus of 70 to 130 kN / mm ² , preferably 110 to 125 kN / mm ^{2 in} a fiber basis weight of 800 to 2000 g / m ² is used. It is preferable.
[0014]
In addition, although the said Young's modulus in this invention is a numerical value of a reinforcing fiber single-piece | unit, it is a measured value in the state made into FRP, and shall be measured based on JSCE-E541-2000. The fiber basis weight is a numerical value of the reinforcing fiber alone, and is measured according to JIS R7602 for the woven fabric type and the knitted fabric type, and according to JIS K7071 for the prepreg type. The tensile rigidity is a numerical value of the reinforcing fiber itself, but is a measured value in the FRP state, and is expressed by Young's modulus × fiber cross-sectional area per unit construction width.
[0015]
Furthermore, the basis for the numerical value when using carbon fiber as the continuous fiber is obtained by testing as described later, but the numerical value when using aramid fiber is the predicted value calculated from the case of carbon fiber. It is.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows the lower surface side of a road slab reinforced by a method according to an embodiment of the present invention. As shown in FIG. 1, a continuous reinforcing fiber 2 is arranged in a lattice shape on the lower surface of a road floor slab 1 and is impregnated with a resin, for example, a lattice structure of a strip-like continuous fiber sheet 3 as shown in FIG. The body 4 is constructed and bonded. In the illustrated example shown in FIG. 2, the strip-shaped continuous fiber sheets 3 having a width of 25 cm (250 mm) are arranged in a grid pattern with an interval of 100 mm, and when the strip-shaped continuous fiber sheets 3 themselves are connected, the lap joint wrap length is 10 cm. It is connected. When the lattice structure 4 of the continuous fiber sheet 3 is configured and bonded, the tensile rigidity per unit width of the floor slab 1 is set to 45 to 75 kN / mm.
[0017]
As the continuous reinforcing fiber 2, for example, carbon fiber, aramid fiber, PBO (polyparaphenylene benzbisoxazole) fiber, glass fiber or the like can be used. Of these, carbon fiber and aramid fiber are particularly preferable. As the resin impregnated in the continuous reinforcing fiber 2 for constituting the continuous fiber sheet 3, for example, an epoxy resin, a methyl methacrylate resin, a vinyl ester resin, an unsaturated polyester resin or a polyurethane resin can be used. The use of an epoxy resin is particularly preferable.
[0018]
In the said embodiment, the strip | belt-shaped continuous fiber sheet 3 is each adhere | attached on the main reinforcement direction (longitudinal direction) and the distribution line direction (direction orthogonal to a longitudinal direction) of the floor slab 1 respectively. This reinforcement is performed, for example, as shown in FIG. First, cleansing is performed on the lower surface of the floor slab 1 as a base. At this time, for example, the construction range is assigned, inking, cleaning, drying, and removal / polishing of the deteriorated layer are performed. Next, a primer is applied to the base. Masking of the lattice part is performed, and a primer is prepared and applied by brushing or the like to be cured. Next, unevenness correction is performed, and the convex portion is cut off, the corner of the haunch is smoothed, and the epoxy putty is filled in the concave portion. On this, a 1st-layer continuous fiber sheet (for example, carbon fiber sheet) is affixed. For example, the first layer of ink masking is performed, a resin is prepared and a roller brush is applied (undercoating), and then a fiber sheet is pasted thereon to perform ironing impregnation and defoaming. After coating (top coating), ironing impregnation and defoaming are performed to remove the first layer masking. Next, a second-layer continuous fiber sheet (for example, a carbon fiber sheet) is attached. For example, after masking the second layer of ink, preparing a resin and applying a roller brush (undercoating), a fiber sheet is pasted on it to perform ironing impregnation and defoaming. After coating (top coating), ironing impregnation and defoaming are performed to remove the second layer masking. After the first and second continuous fiber sheets are bonded in a lattice shape, they are cured.
[0019]
In the present invention, the reinforcing effect of the floor slab 1 reinforced by the lattice structure 4 of the strip-shaped continuous fiber sheet 3 configured as described above is a fatigue test by a moving wheel load on the assumption that an automobile actually travels repeatedly. Verified by And, from the results of this fatigue test, the reinforcement specifications for obtaining sufficient durability are judged, and based on this, the floor slab of the lattice structure of the continuous fiber sheet for obtaining the target reinforcement performance in the present invention The range of tensile rigidity per unit width of 45 to 75 kN / mm was defined. By making it within this range, the required reinforcement performance can be achieved efficiently without using useless reinforcements, and the lattice structure enables observation from below for maintenance management. Become. In addition, by performing ink masking so that primer, epoxy putty, and resin are not applied to the part where the ground is exposed due to the lattice structure, the permeated water from above such as rainwater is discharged from the exposed part, preventing stagnation. Will be. If there is a risk that the exposed concrete will fall off due to deterioration, it is possible to prevent dropping by placing a net material for preventing peeling on the bottom of the floor slab and bonding the net material and the lattice structure. In this case as well, observation from below for maintenance is possible and retention of permeated water from above such as rain water is prevented.
[0020]
The fatigue test by the moving wheel load is performed using, for example, a wheel load running test machine 11 as shown in FIG. The wheel load running test machine 11 fixes a floor slab specimen 12 having a predetermined thickness on a support beam 13 and reciprocates a wheel 15 on a track 14 on the specimen 12. Various loads are applied to the wheel 15 by the hydraulic jack 16, and in this state, the crank mechanism 18 driven by the motor 17 reciprocates until the wheel 15 reaches the set number of times. In the wheel load running test machine 11 used for the test, the turning radius of the crank mechanism 18 is 100 cm, the moving stroke of the wheel 15 is 200 cm (± 100 cm from the center of the floor slab), and the maximum span of the support beam 13 is 300 cm. The loading capacity is 100 to 300 kN, the wheel traveling speed is 112 m / min (28 reciprocations / min), the wheel diameter is 50 cm, and the width is 30 cm. The wheel load running tester 11 having this specification is owned by Osaka University, and the wheel load running tester 11 was used for the following tests.
[0021]
In the test, a carbon fiber sheet was used as a continuous fiber sheet. The floor slab used for the test had a length (bridge axis direction) of 3000 mm × width (bridge axis perpendicular direction) of 2000 mm, and the floor slab support was unified to 1800 mm. The floor slab thickness was set to three types of 15 cm, 18 cm, and 22 cm, and three bodies (No. 2 to 4), two bodies (No. 5, No. 6), and one body (No. 1) were manufactured. Of these, carbon fiber reinforcement was not carried out for the one with a floor slab thickness of 22 cm and the one with a floor slab thickness of 15 cm, and only the data for comparison was collected without reinforcement. The bar arrangement of the specimen was set as shown in Table 1. The 15cm-thick floor slab is specified by the S39 (Showa 39) steel road bridge design specification, and the 18cm-thick floor slab is specified by the provisional standard on the S43 (Showa 43) steel road bridge floor slab design. The floor slabs of 22cm thickness are assumed to be those specified in the H8 (1996) Road Bridge Specification. The reinforcing bars used were SD295A for floor slab thicknesses of 15 cm and 18 cm, and SD345 for floor slab thickness of 22 cm. The designed rebar cover was the same on the compression side and the tension side, 45 mm for the floor slab with a floor slab thickness of 22 cm, and 30 mm for the other slabs. The compressive strength of the concrete were measured during the test, each of the elastic modulus ^{35.6N / mm 2, 26.6kN / mm} 2 ( slab thickness ^{15cm, 22cm), 36.2N / mm} 2, 28.6kN / mm 2 The floor slab thickness was 18 cm.
[0022]
[Table 1]

[0023]
In this test, in order to confirm the reinforcing effect when the carbon fiber sheets are arranged in a lattice shape, the lattice arrangement as shown in FIG. That is, the width of the carbon fiber sheet was 250 mm, and the installation interval between the sheets was set to 100 mm (floor slab thickness 15 cm) or 150 mm (floor slab thickness 18 cm). Moreover, the type of carbon fiber used was a medium elastic type (Young's modulus E = 4.4 × 10 ⁵ N / mm ² ). The basis weight of the carbon fiber was 400 g / m ² (fiber sheet thickness t = 0.220 mm) and 470 g / m ² (t = 0.259 mm), and the behavior change due to the difference in basis weight was also confirmed ( (See Table 3).
[0024]
This test was conducted using the above-mentioned wheel load running tester possessed by Osaka University. The floor slab support conditions were simple support for the long side of the floor slab (immediately above the support girder) and elastic support for the side of the floor slab with the end cross girder. For floor slabs reinforced with carbon fiber, preliminary loading as shown in Table 2 was performed, and after damaging in advance, reinforcement was performed and a wheel load running test was performed. Table 3 shows the load loading program during the wheel load running test. In addition, No. For No. 3, preliminary loading 1 and preliminary loading 2 were performed twice. In this test, the magnitude of the loaded load and the number of reciprocations were determined according to the slab strength, and the test was conducted. The tensile stiffness EA per floor slab unit width of the lattice structure in each specimen floor slab used for reinforcement is the specimen number. 3 is 80 kN / mm. 4 is 68 kN / mm. 5 is 70 kN / mm. 6 was 60 kN / mm.
[0025]
[Table 2]

[0026]
[Table 3]

[0027]
In a series of wheel load running tests conducted this time, No. 22 with a floor slab thickness of 22 cm was used. Although 1 did not break even when the load traveled 1,000,000 times, all other specimens were destroyed. In the specimen having a floor slab thickness of 15 cm, No. No. 2 was 410,000 times (load 117.6 kN), and specimen No. 2 was reinforced. 3, no. No. 4 caused 34,000 times (load 147 kN) and 436,000 times (load 147 kN), respectively. 5 is 941,600 times (load 205.8 kN). 6 was broken by punching shear fracture at 884,000 times (load 205.8 kN).
[0028]
It is difficult to compare the fatigue durability directly with the number of loadings until failure because the loading load is different for each specimen and the load is also changed stepwise for one specimen. Therefore, in order to compare and examine the fatigue durability of each specimen, Matsui et al. “Crack Damage and Durability of Road Bridge RC Slab” (Hanshin Expressway Public Corporation / Hanshin Expressway Management Technology Center, 1991 12) Using the empirical formula and minor rule in the wheel load test machine of Osaka University proposed in (Moon), etc., the number of conversion runs when the reference load P ₀ is 15 tf, the actual load (P ₀ ), and the proof stress ( The relationship with the dimensionless load P ₀ / Psx, which is a ratio to (Psx), is shown in FIG.
[0029]
As can be seen from FIG. 5, the test specimen No. 22 with a floor slab thickness of 22 cm manufactured according to the 1996 (H8) Road Bridge Specification. No. 1 had a fracture life of 21 million times or more when converted to a constant load of 15 tf, whereas the unreinforced specimen No. 1 with a floor slab thickness of 15 cm manufactured according to the road bridge specifications in 1964 (S39). 2 was about 18,000 times with a constant load of 15 tf. That is, the specimen No. 1 is an unreinforced specimen No. 1; If the same wheel load is applied as compared to 2, it will have a life of 1000 times or more. Considering that unreinforced slabs with a floor slab thickness of 15 cm have been in service for about 40 years on actual bridges, the floor slabs conforming to the 1996 H8 Road Bridge Specification have practical fatigue life against moving loads. It can be said that it is sufficient.
[0030]
As for the reinforcing effect of the 15 cm-thick floor slab, No. 1 was reinforced by adhering a carbon fiber sheet in a lattice shape. 3 (weight per unit area 470 g / m ² , lattice spacing 100 mm, tensile rigidity EA 80 kN / mm), No. 3 4 (weight per unit area: 400 g / m ² , lattice spacing: 100 mm, tensile rigidity: EA 68 kN / mm), the number of converted fractures for a constant load of 15 tf was 1480,000 and 206,000, respectively. The lifetime was 8 times and 13 times that of 2, respectively. Unreinforced No. Considering that the RC floor slabs with the same specifications as No. 2 have been in service for about 40 years on actual bridges, 3, no. 4 all have fatigue durability exceeding 100 years after reinforcement, and it turns out that sufficient reinforcement effect is acquired. In addition, No. 3 and no. The reason why the life was reversed despite the fact that No. 4 was related to the magnitude of the tensile load is thought to be due to the difference in the initial damage level. Considering such a difference, it is considered that the tensile rigidity per unit width of the floor slab of the lattice structure of the continuous fiber sheet defined in the present invention is 75 kN / mm because of the life extension effect.
[0031]
As for the reinforcing effect of the 18 cm thick floor slab which gave initial damage, No. 1 was reinforced by adhering carbon fiber sheets in a lattice shape. 5 (weight per unit area 470 g / m ² , lattice spacing 150 mm, tensile load EA 70 kN / mm), No. 5 6 (weight per unit area 400 g / m ² , lattice spacing 150 mm, tensile load EA 60 kN / mm) 15tf constant load conversion failure times were about 176.3 million times and about 17.2 million times, respectively, compared to the unreinforced specimen calculated by estimation The lifetime was sufficiently long, about 27 times and about 26 times, respectively.
[0032]
From these results, it is considered that it is sufficient that the tensile stiffness per unit width of the floor slab of the continuous fiber sheet lattice structure defined in the present invention is 45 to 75 kN / mm. No. From the result of 4, for the floor slab having a thickness of 10 cm or more and less than 18 cm, a continuous fiber sheet having a width of 15 to 35 cm is bonded in a lattice form with an interval of 5 to 20 cm, and a lattice structure of the continuous fiber sheet is obtained. It can be seen that the tensile rigidity per unit width of the floor slab may be 62 to 75 kN / mm. No. From the result of 6, for the floor slab having a thickness of 18 cm or more and 25 cm or less, a continuous fiber sheet having a width of 15 to 35 cm is bonded in a lattice form with an interval of 8 to 13 cm, and a lattice structure of the continuous fiber sheet is obtained. It can be seen that the tensile rigidity per unit width of the floor slab may be 45 to 62 kN / mm.
[0033]
In addition, FIG. 5 also shows the case of conventional full-surface adhesion for an 18 cm-thick floor slab. The specimen “300 × 2t18S43EA82 entire surface” in the figure is composed of a high-strength carbon fiber sheet having a Young's modulus of 24500 N / mm ² and a fiber basis weight of 300 g / m ^{2 on} the entire surface of the floor slab. A total of four layers were bonded and reinforced. The specimen “600 × 1t18S43EA82 entire surface” was a high-strength carbon fiber sheet with a Young's modulus of 24500 N / mm ² and a fiber basis weight of 600 g / m ^{2 on} the entire surface of the floor slab. Each layer has a total of two layers bonded and reinforced, and the tensile rigidity per unit slab width of the reinforcing material is EA = 82 kN / mm. In addition, “calculated t18S43 unreinforced” in FIG. 5 is calculated based on the calculation of the reinforced RC floor slab of 18 cm thickness calculated using the empirical formula in the wheel load running test of Osaka University described in the paragraph [0028]. It shows P ₀ / Psx and life. As shown in FIG. 5, no. No. 6 exhibited substantially the same reinforcing effect as the specimens “300 × 2t18S43EA82 entire surface” and “600 × 1t18S43EA82 entire surface” which were bonded together by the conventional method so that the tensile stiffness EA = 82 kN / mm. Therefore, no. 5, no. 6, it can be seen that the reinforcing material can be greatly reduced, and that the effect of the lattice structure is reliably obtained.
[0034]
【The invention's effect】
As described above, according to the method for reinforcing a road floor slab according to the present invention, a sufficient reinforcing effect can be obtained with a smaller amount of reinforcing continuous fiber sheet used than in the past, and reinforcement in a lattice shape is possible. By constituting the structure, it becomes possible to easily observe cracks and to prevent the permeated water from staying. Therefore, the road deck can be reinforced in a desirable form at a low construction cost.
[Brief description of the drawings]
FIG. 1 is a perspective view of a floor slab lower surface side showing a method for reinforcing a road slab according to an embodiment of the present invention.
FIG. 2 is a bottom view of a floor slab showing an example of a lattice structure of continuous fiber sheets in the present invention.
FIG. 3 is a process flow diagram showing a work sequence in a method for reinforcing a road floor slab according to an embodiment of the present invention.
FIG. 4 is a front view of a wheel load running test machine used for evaluation in the present invention.
FIG. 5 is a characteristic diagram showing a reinforcing effect according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Road floor slab 2 Continuous reinforcement fiber 3 Strip | belt-shaped continuous fiber sheet | seat 4 Lattice structure 11 Wheel load running test machine 12 Specimen 13 of floor slab 13 Supporting girder 14 Track 15 Wheel 16 Hydraulic jack 17 Motor 18 Crank mechanism

Claims

On the lower surface of the road floor slab, continuous reinforcing fibers are arranged in a lattice form and impregnated with a resin to form and bond the lattice structure of the belt-like continuous fiber sheet. A method for reinforcing a road floor slab, characterized by comprising a tensile rigidity per width of 45 to 75 kN / mm.

The method for reinforcing a road floor slab according to claim 1, wherein the continuous fiber sheet is bonded to each of the main reinforcement direction and the distribution reinforcement direction of the floor slab.

The method for reinforcing a road floor slab according to claim 1 or 2, wherein a continuous fiber sheet having a width of 15 to 35 cm is bonded in a lattice pattern with an interval of 5 to 20 cm.

The lattice structure of the continuous fiber sheet is configured so that the tensile rigidity per unit width of the floor slab is 62 to 75 kN / mm with respect to the floor slab having a thickness of 10 cm or more and less than 18 cm. A method for reinforcing a road deck according to any one of the above.

The method for reinforcing a road floor slab according to claim 4, wherein continuous fiber sheets having a width of 15 to 35 cm are bonded in a lattice pattern with an interval of 8 to 13 cm.

The lattice structure of the continuous fiber sheet is configured so that the tensile rigidity per unit width of the floor slab is 45 to 62 kN / mm with respect to the floor slab having a thickness of 18 cm or more and 25 cm or less. A method for reinforcing a road deck according to any one of the above.

The method for reinforcing a road floor slab according to claim 6, wherein a continuous fiber sheet having a width of 15 to 35 cm is bonded in a lattice pattern with an interval of 13 to 20 cm.

The method for reinforcing a road floor slab according to any one of claims 1 to 7, wherein the tensile stiffness per unit width of the continuous fiber sheet itself is in the range of 85 to 105 kN / mm.

The method for reinforcing a road floor slab according to claim 8, wherein a continuous fiber sheet containing carbon fibers having a Young's modulus of 350 to 650 kN / mm ^{2 at} a fiber basis weight of 270 to 550 g / m ² is used.

The method for reinforcing a road floor slab according to claim 8, wherein a continuous fiber sheet containing an aramid fiber having a Young's modulus of 70 to 130 kN / mm ^{2 at} a fiber basis weight of 800 to 2000 g / m ² is used.