SATO, Yasuhiko

写真a

Affiliation

Faculty of Science and Engineering, School of Creative Science and Engineering

Job title

Professor

Homepage URL

https://kaken.nii.ac.jp/d/r/60261327.ja.html

Concurrent Post 【 display / non-display

  • Faculty of Science and Engineering   Graduate School of Creative Science and Engineering

Research Institute 【 display / non-display

  • 2020
    -
    2022

    理工学術院総合研究所   兼任研究員

Degree 【 display / non-display

  • 北海道大学   博士(工学)

Research Experience 【 display / non-display

  • 2018.04
    -
    Now

    Waseda University

  • 2018.04
    -
    2020.03

    北海道大学大学院   客員教授

  • 2007.04
    -
    2018.03

    Hokkaido University

  • 2005.04
    -
    2007.03

    北海道大学大学院   助教授

  • 1997.04
    -
    2005.03

    北海道大学大学院   助手

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Professional Memberships 【 display / non-display

  •  
     
     

    aci

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    fib

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    資源素材学会

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    コンクリート工学会

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    PC工学会

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Research Areas 【 display / non-display

  • Civil engineering material, execution and construction management

  • Structure engineering and earthquake engineering

  • Safety engineering

  • Social systems engineering

Research Interests 【 display / non-display

  • design

  • concrete

Papers 【 display / non-display

  • Experimental and numerical study of structural effects of anisotropic frost damage on reinforced concrete beams

    Takeru Kanazawa, Yasuhiko Sato, Ryosuke Takahashi

    Journal of Advanced Concrete Technology   19 ( 1 ) 14 - 25  2021

     View Summary

    Unlike plain concrete, frost damaged reinforced concrete (RC) exhibits anisotropy because of the presence of reinforcing bars. The resultant mechanical responses are influenced strongly by the loading direction. Therefore, to ascertain the mechanical behavior up to failure of RC beams subjected to freeze-thaw action and subsequent mechanical loading, anisotropic damage models of frost-damaged RC elements were assessed in this study using three-dimensional nonlinear finite element analysis (3D-NLFEA), which revealed that the anisotropic damage affected load-deflection responses and played a key role in failure modes that differed from those of an undamaged RC beam. This paper is the English translation from the authors' previous work [Kanazawa, T., Sato, Y. and Takahashi, R., (2019). "Frost damage of reinforced concrete beams and analytical evaluation of its static failure behavior." Journal of Japan Society of Civil Engineers. Ser. E2 (Materials and Concrete Structures), 75(4), 293-307. (in Japanese)].

    DOI

  • Fatigue behavior of air-entrained high strength concrete with blast furnace slag fine aggregates under freezing and thawing

    M. A. Farooq, Y. Sato, K. Niitani, H. Yokota

    Lecture Notes in Civil Engineering   101   2025 - 2035  2021

     View Summary

    This experimental study investigates the compressive fatigue behavior of air-entrained (AE) concrete with blast furnace slag (BFS) fine aggregates subjected to freeze-thaw cycles (FTC). The fatigue tests were carried out on cylindrical specimens of intact and frost-damaged AEBFS concrete and the results are compared with those of AE high strength (HS) normal concrete using crushed sand. The strain measurements are used to discuss the damage progress under fatigue loading. The results reveal that although the static compressive strength of AEBFS concrete is slightly less than AEHSN concrete, the fatigue life of AEBFS concrete is longer than that of AEHSN concrete. No significant effect of FTC is found on the fatigue behavior of each concrete due to very low frost damage. Moreover, it is found that overall the fatigue life of AEHS concrete is longer than that of non-AE high strength concrete from literature and this difference is pronounced with the reduction in maximum stress level.

    DOI

  • Experimental investigation of monotonic behavior and stress-strain models of AE and non-AE high strength concrete with BFS fine aggregates under freezing and thawing

    Muhammad Aboubakar Farooq, Yasuhiko Sato, Kyoji Niitani

    Construction and Building Materials   249  2020.07

     View Summary

    This study is attempted to investigate the change in mechanical properties and to formulate the stress-strain models of air-entrained (AE) and non-air entrained high strength concrete with blast furnace slag (BFS) sand as fine aggregates under freezing and thawing. The freeze-thaw (FT) test was carried out on the concrete specimens followed by static compression tests and the results are compared with those of AE normal strength normal (AENSN) and AE high strength normal (AEHSN) concrete using crushed sand. The experimental results disclose that overall the rate of plastic strain development due to freezing and thawing in non-AE high strength concrete is higher than that of AE high strength concrete, but less than that of companion normal strength concrete. Consequently, the mechanical properties of non-AE concrete deteriorate at higher rate in comparison with AE concrete under freezing and thawing. However, no significant reduction in mechanical properties of AEBFS and AEHSN concrete is observed compared to AENSN concrete. Moreover, it is found that the Young's modulus of frost-damaged concrete degrades rapidly than the compressive strength. Thereafter, the stress-strain relationships for AE and non-AE high strength concrete under monotonic loading are formulated based on elasto-plastic and fracture concept. Based on the experimental data, the relationships for fracture parameter and plastic strain development of high strength concrete under monotonic loading are developed. The stres-strain relationships calculated by the proposed model are compared with the experimental ones.

    DOI

  • Effects of bond configurations on flexural response of RC beams externally strengthened with CFRP sheets

    Jianguo Dai, Keisuke Sumiyoshi, Tamon Ueda, Hiroshi Yokota, Yasuhiko Sato

    Composites in Civil Engineering, CICE 2006     39 - 42  2020

     View Summary

    This paper investigates experimentally how various bond configurations influence the flexural response of FRP-strengthened RC beams. A total of seven beams(200×200×2200mm) were tested. One was the reference without strengthening. Two were strengthened with CFRP sheets using hard and soft adhesive bonding, respectively, along the whole test span. The remaining four were applied a combination of hard and soft adhesives but in two different ways. One way is to use the soft adhesive at the flexure-dominating zone only and another is to use it for the shear-dominating zone only. Pair tests were conducted for these four specimens under both normal and low temperature (- 10°C). It is revealed that a sole use of soft adhesive improves the ultimate member strength and ductility but leads to a loss of stiffness. Using the soft adhesive at the flexure-dominating zone can not improve the member strength but improve the member ductility only. However, use of hard adhesive at the flexure-dominating zone and the soft one for the remaining parts can improve the member strength and ductility while avoiding loss of member stiffness. This test program provides an in-depth understanding of the debonding mechanisms in the FRP-strengthened RC beams. In addition, it is verified that that a low temperature of -10°C does not influence the global flexural response of FRP strengthened beams using the combined bonding system.

  • Basic bond characteristics of frp strand sheet-concrete interface with polyurea resin

    Mitsuhiko Ozaki, Akira Kobayashi, Yasuhiko Sato, Masaki Arazoe, Akihiro Tateishi, Atsuya Komori

    Journal of Advanced Concrete Technology   18 ( 9 ) 505 - 520  2020

     View Summary

    Aiming at improving bond strengths between FRP sheet and concrete, the FRP sheet bonding method using high elongation elastic resin as a buffer layer was developed. In this study, bonding tests was conducted to clarify the basic bond characteristics of FRP strand sheet-concrete interface with a polyurea resin. As a result of the bonding tests, it was found that the use of the polyurea resin as a buffer layer significantly improved the bond strength and the interfacial fracture energy between FRP sheets and concrete. In addition, bond stress-slip relationships with a polyurea resin were proposed. Finally, numerical analyses of bonding CFRP strand sheets and concrete were conducted so as to verify validity of the proposed bond stress-slip relationships. This paper is an extended version in English from the authors' previous work [Kobayashi, A., Ozaki, M., Sato, Y., Arazoe, M., Tateishi, A. and Komori, A., (2020). “Study on bonding behavior of FRP sheets and concrete bonded with high elongation elastic resin.” Journal of Structural Engineering, JSCE, 66A, 855-867. (in Japanese)].

    DOI

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Misc 【 display / non-display

  • 隅角部補強ユニットを利用したL形隅角部の耐荷性能に関する実験的検討

    渡部孝彦, 村田裕志, 武田均, 佐藤靖彦

    コンクリート工学年次論文集(CD-ROM)   42  2020

    J-GLOBAL

  • 荷重履歴に着目したせん断補強筋を持たないRCはりの変形性状に関する検討

    竹田京子, 佐藤靖彦

    コンクリート工学年次論文集(CD-ROM)   42  2020

    J-GLOBAL

  • RC隅角部の配筋省力化技術の開発

    渡部孝彦, 村田裕志, 武田均, 佐藤靖彦

    大成建設技術センター報(CD-ROM)   ( 53 )  2020

    J-GLOBAL

  • Study on bonding behavior of FRP sheets and concrete bonded with high elongation elastic resin

    小林朗, 尾崎允彦, 佐藤靖彦, 荒添正棋, 立石晶洋, 小森篤也

    構造工学論文集 A(Web)   66A  2020

    J-GLOBAL

  • Quantitative evaluation of fatigue life for connection with rebar joint between precast PC slabs under wheel-type loads

    竹田京子, 佐藤靖彦

    構造工学論文集 A(Web)   66A  2020

    J-GLOBAL

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Industrial Property Rights 【 display / non-display

  • コンクリート構造物の補強方法

    特許第4194894号

    小林 朗, 佐藤 靖彦

    Patent

    J-GLOBAL

Awards 【 display / non-display

  • 構造工学論文集Vol.66A論文賞

    2020.06   土木学会  

  • 吉田賞

    2020.06   土木学会  

  • セメント協会論文賞

    2013.05   セメント協会  

  • Best Basic Research Paper

    2005.06   アメリカ土木学会 Journal of composites for construction  

  • 吉田賞

    2003.06   土木学会  

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Research Projects 【 display / non-display

  • 道路橋RCおよびPC床版の荷重推定と寿命予測法の開発

    基盤研究(B)

    Project Year :

    2020.04
    -
    2023.03
     

    佐藤 靖彦, 高橋 良輔

  • Disaster management of structures and infrastructures affected by the anticipated Nankai Trough earthquake for resilience enhancement

    Grant-in-Aid for Scientific Research (A)

    Project Year :

    2019.04
    -
    2023.03
     

  • Deterioration of interfacial bond property under combined effects and prediction of performance of members after intervenion

    Grant-in-Aid for Scientific Research (A)

    Project Year :

    2014.04
    -
    2017.03
     

    UEDA Tamon, ZHANG Dawei, KOMORI Atsuya, TAKAHASHI Jun, FUJIMA Seiji

     View Summary

    This study discloses that interfacial bond strength of FRP external bonding as strengthening of concrete structures slightly reduces or slightly increases after 18-months immersion of water, and that bond strengths of overlaying reduces with increase in temperature up to 60 degree but recovers partially after lowering temperature. Prediction formula for bond properties were proposed based on the test results. As technologies for enhancement of structural performance after strengthening, analytical methods of FRP external bonding with inserted polyurea resin layer, prediction model of strengthening effect by anchor bar for overlaying and prediction model for enhanced fatigue strength by resin injection into cracks were presented.
    For frost attack effects, prediction models for concrete damage under combined effect with fatigue and for accelerated frost damage under combined effect with salt attack were presented together with measuring method of frost damage distribution.

  • Performance recovery and life extension of deteriorated reinforced concrete members by repeated applications of repair

    Grant-in-Aid for Challenging Exploratory Research

    Project Year :

    2014.04
    -
    2017.03
     

    YOKOTA Hiroshi, SATO Yasuhiko

     View Summary

    This research focused on the performance recovery and life extension of deteriorated concrete members with repeated applications of electrochemical chloride extraction or section repair using fiber reinforced polymer cement mortar. These repair techniques are applicable for performance recovery, but may simultaneously provide detrimental effects on the micro structure of cement hydrate products. It was found from this experimental study that the repeated applications are beneficial for performance recovery and the detrimental effects are not so severely significant as those provided by the single application. Accordingly, it was concluded that the multiple applications of repair may have some limitations to realize the life extension because they accumulate local damages in cement hydration products.

  • Determinaion of damage index on long un-reinforced concrete structures relating to disaster prevention

    Grant-in-Aid for Scientific Research (B)

    Project Year :

    2012.04
    -
    2015.03
     

    YOKOTA Hiroshi, WATANABE Yasunori, SATO Yasuhiko, KATO Ema, HASHIMOTO Katsufumi

     View Summary

    This research focused on how the comprehensive damage grading system is established for a long un-reinforced concrete structure along coastlines from the viewpoints of structural performance and functions of disaster prevention. Major damage induced in this type of structure is concrete cracking due to shrinkage of concrete and differential settlement of the structural body; accordingly, crack width, depth and position are categorized and modeled into the structural analysis tool. Moreover, shear transfer behavior between the crack surfaces was experimentally made clear. Finally, structural analysis taking into account the above behavior was carried out to quantify remaining structural performance of damaged structures. In conclusion, new criteria for damage evaluation have been proposed to access the function and performance of cracked un-reinforced concrete structures. These results may contribute to realize more effective and objective maintenance work.

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Specific Research 【 display / non-display

  • コンクリート系床版の疲労寿命予測法の開発

    2019   竹田京子

     View Summary

     本研究では,輪荷重走行試験の実験結果に基づき,せん断耐力式とS-N曲線式によるRCおよびPC床版の疲労寿命予測法を開発するとともに,接合部を有するプレキャストPC床版の疲労耐久性評価に関する検討を行った.開発した疲労寿命予測式(提案式)は,RCおよびPC床版の疲労寿命を精度良く予測できることを実験結果との比較から示した.さらに,接合部の疲労寿命予測においては,継手鉄筋の引張力によりコンクリート内部に導入される圧縮力が主鉄筋の拘束を高め,付着力が向上することで静的な耐力が向上する機構を見出し,この耐力向上効果を提案式に考慮することで,接合部の疲労寿命の予測精度が向上することを示した.

  • 移動輪荷重を受ける道路橋RC床版の疲労設計法

    2018   竹田京子

     View Summary

     道路橋の鉄筋コンクリート床版(RC床版)は,交通荷重,すなわち移動輪荷重を繰返し受けるため,疲労に対する設計が欠かせない.しかし,その合理的な疲労設計法は存在しない.そこで,過去に複数の研究機関において行われた輪荷重走行試験結果を活用し,せん断抵抗機構および破壊機構に基づいたRC床版の疲労寿命予測式を開発した.しかし,その式はその適用範囲が限定されており,適切に評価できない実験結果が存在する. そこで本研究では,過去に開発したRC床版の疲労寿命予測式を拡張し,載荷速度と支持条件が疲労寿命に及ぼす影響を明らかにするとともに,階段状に変化する移動輪荷重下におけるRC床版の疲労寿命予測を可能とした.

 

Syllabus 【 display / non-display

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