AKIYAMA, Mitsuyoshi

写真a

Affiliation

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

Job title

Professor

Homepage URL

http://www.f.waseda.jp/akiyama617/

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Concurrent Post 【 display / non-display 】

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

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Research Institute 【 display / non-display 】

  • 2020
    -
    2022

    理工学術院総合研究所   兼任研究員

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Education 【 display / non-display 】

  • 　
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    1997

    Tohoku University   Graduate School, Division of Engineering   Department of Civil and Environmental Engineering  

  • 　
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    1995

    Tohoku University   Faculty of Engineering  

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Degree 【 display / non-display 】

  • Tohoku University   Dr. Eng.

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Research Experience 【 display / non-display 】

  • 2011.04
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    早稲田大学教授

  • 2007.04
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    東北大学准教授

  • 2004.04
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    東北大学助教授

  • 2001.10
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    東北大学講師

  • 1998.04
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    東北大学助手

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Professional Memberships 【 display / non-display 】

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    American Concrete Institute

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    (社)日本コンクリート工学協会

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    日本地震工学会

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    IABSE

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    IALCCE

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Research Areas 【 display / non-display 】

  • Structure engineering and earthquake engineering

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Research Interests 【 display / non-display 】

  • earthquake-resistant structure, life-cycle analysis, reliability analysis

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Papers 【 display / non-display 】

  • Effect of the interaction of corrosion pits among multiple tensile rebars on the reliability of RC structures: Experimental and numerical investigation

    Supasit Srivaranun, Mitsuyoshi Akiyama, Paolo Bocchini, Vasileios Christou, Dan M. Frangopol, Hiroyuki Fukushima, Keisuke Masuda

    Structural Safety   93  2021.11

    　View Summary

    The deterioration of reinforced concrete (RC) structures due to chloride-induced corrosion is not spatially uniform because of the spatial variability related to material properties and environmental stressors. This variation has a substantial effect on the reliability of RC structures. However, few experimental studies have focused on the effect of the interaction of corrosion pits among tensile rebars on the reliability of RC structures. Therefore, in this paper, an experimental procedure that incorporates X-ray and digital image processing techniques was conducted on RC slab specimens subjected to accelerated corrosion. Using the experimental results, the parameter of the transverse correlation function of steel weight loss distributions was estimated to investigate how the corrosion pits in corroded rebars are correlated. Based on the experimentally obtained model parameters, the spatial steel weight loss distributions were simulated by spectral representation method. A three-dimensional (3D) nonlinear finite element (FE) analysis of RC structures with simulated steel weight loss distributions was conducted to obtain the ultimate bending capacity of RC structures. In an illustrative example, the effect of the transverse correlation among steel weight loss distributions of multiple tensile rebars on the failure probability of RC girders was quantified.

    DOI

  • Modelling method of fibre distribution in steel fibre reinforced concrete based on X-ray image recognition

    Yue Li, Xin Ruan, Mitsuyoshi Akiyama, Mingyang Zhang, Jiyu Xin, Sopokhem Lim

    Composites Part B: Engineering   223  2021.10

    　View Summary

    The accurate and efficient simulation of steel fibre reinforced concrete (SFRC) is of great significance for its further application in civil engineering. Problems of existing modelling methods can be recognized as two points; (1) the integral model only simplified fibre contribution into the unified post-peak ductility in concrete element but cannot reflect the material variation caused by real fibre distribution, and (2) the separate model built the concrete matrix and fibre inclusions respectively, but the directly random fibre distributions still need to be refined based on the actual material. In this paper, based on the X-ray image recognition results from real SFRC material, a mathematical model of fibre distribution and orientation is proposed for SFRC simulation, and the detailed value distributions of geometrical parameters are optimized for convenience and accuracy of material modelling. In the geometrical extraction of near 4000 fibres from X-ray images, the whole comprehensive procedure of image processing, enhancement and recognition is presented with technologies like pixel semantic classification and Hough transform. With the proposed geometrical mathematical model, the modelling method that consists of multiple refined sampling is illustrated with mechanical applications. After the model verification by experimental comparison, the detailed contribution of steel fibre and the effect of fibre distribution refinement are discussed as well.

    DOI

  • A novel casting procedure for SFRC piles without shear reinforcement using the centrifugal forming technique to manipulate the fiber orientation and distribution

    Ramiz Ahmed Raju, Mitsuyoshi Akiyama, Sopokhem Lim, Tatsuya Kakegawa, Yuka Hosono

    Construction and Building Materials   303  2021.10

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    The structural performance of steel fiber-reinforced concrete (SFRC) members primarily depends on the distribution and orientation of the fibers. Previous experimental studies revealed that the distribution and orientation of fibers are random and hardly controlled during the fabrication process. The centrifugal forming technique may improve the orientation and distribution of steel fibers in hollow circular SFRC piles and increase the shear strength of the piles. Accomplishing this task can lead to the possible replacement of shear reinforcements with steel fibers in piles, thereby improving the demanding productivity that is desired in the pile construction industry by saving considerable time and labor. This paper presents a novel experimental program to (a) develop the casting procedure for SFRC piles and (b) investigate the shear strength of SFRC piles without shear reinforcement compared to that of conventional reinforced concrete (RC) piles with shear reinforcement. With the aid of X-ray technology, different mix proportions and casting methods were investigated to determine the optimum procedure, which produced fiber distributions and orientations in SFRC piles superior to those of RC piles. The centrifugal forming method influenced the orientation of the fibers so that they were oriented in the shear stress direction (i.e., circumferential direction). The loading test demonstrated that the steel fibers effectively worked as shear reinforcement and that the shear capacity increased with the steel fiber content. Moreover, the SFRC piles exhibited stable crack propagation and improved post-cracking stiffness without severe concrete damage compared to that of the RC piles.

    DOI

  • Risk estimation of the disaster waste generated by both ground motion and tsunami due to the anticipated Nankai Trough earthquake

    Hiroki Ishibashi, Mitsuyoshi Akiyama, Takayuki Kojima, Koki Aoki, Shunichi Koshimura, Dan M. Frangopol

    Earthquake Engineering and Structural Dynamics   50 ( 8 ) 2134 - 2155  2021.07

    　View Summary

    The amount of disaster waste is one of the most important performance indicators in quantifying the resilience of a community. In fact, disaster waste can have significant negative impacts on the environment in affected regions and hinder the postdisaster recovery process. Appropriate disaster waste management should be developed in Japan before the occurrence of the Nankai Trough earthquake. It is expected that the seismic and tsunami intensities caused by the anticipated Nankai Trough earthquake will be substantially larger than those caused by the 2011 Great East Japan earthquake. In this paper, a risk-based methodology is presented for estimating the amount of disaster waste generated by both the ground motions and the tsunami due to the anticipated Nankai Trough earthquake. First, Monte Carlo simulation-based probabilistic hazard analyses are performed to obtain seismic and tsunami hazard curves considering the uncertainty associated with fault movement along the Nankai Trough. Structural damage data associated with past earthquakes are used to develop seismic and tsunami fragility curves. The amount of disaster waste generated from a single structure is defined as the generation unit and is determined based on past disasters. Finally, with the aid of a geographic information system, the risk of disaster waste can be estimated using the hazard and fragility curves and the generation units. As an illustrative example, the risk curves and expected values associated with disaster waste in Mie Prefecture, Japan, are estimated based on the proposed framework.

    DOI

  • Probabilistic estimation of flexural loading capacity of existing RC structures based on observational corrosion-induced crack width distribution using machine learning

    Mingyang Zhang, Mitsuyoshi Akiyama, Mina Shintani, Jiyu Xin, Dan M. Frangopol

    Structural Safety   91  2021.07

    　View Summary

    Corrosion-induced crack width can provide effective information on the deterioration level of in situ corroded reinforced concrete (RC) structures. However, the uncertainty associated with the relationship between corrosion-induced crack width and steel corrosion in RC structures is quite large. In this study, a probabilistic framework for estimating the structural capacity of corroded RC structures using the observational corrosion-induced crack width distribution and machine learning is proposed. Based on the experimental results of corroded RC beams, random field theory, and finite element (FE) analysis, artificial samples composed of corrosion-induced crack width and steel weight loss distributions over the RC beams are generated. Two machine learning-based models are then developed using these samples to estimate the steel weight loss distribution from the observational corrosion-induced crack distribution. Finally, a Monte Carlo-based FE analysis with the estimated steel weight loss distribution as the input data is conducted to obtain the probability density function (PDF) of the structural capacity of corroded RC beams. For illustrative purposes, the effect of observational corrosion-induced crack width distribution on the PDF of flexural capacity of an existing RC beam is investigated using the proposed framework. The results show that the proposed framework using a machine learning-based model is a reliable and computationally efficient approach for estimating the structural capacity of corroded RC members and demonstrates the potential for assessing the deterioration condition of existing RC structures based on the corrosion-induced crack width distribution.

    DOI

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Books and Other Publications 【 display / non-display 】

  • Structural Deterioration Mechanisms

    Akiyama, M, Soliman, M, Biondini, F, Frangopol, D.M( Part： Joint author)

    American Society of Civil Engineers  2019

  • 南海トラフ地震 その防災と減災を考える

    秋山 充良( Part： Joint author)

    早稲田大学出版部  2019

  • Reliability-based durability design and service life assessment of concrete structures in an aggressive environment

    Akiyama, M, Frangopol, D.M, Matsuzaki, H

    CRC Press/Balkema  2014

  • Computational Methods in Earthquake Engineering

    Dan M. Frangopol, M. Akiyama

    Springer  2010

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Misc 【 display / non-display 】

  • Life-cycle reliability-based design and reliability updating of reinforced concrete shield tunnels in coastal regions

    Zheng Shu He, Srivaranun Supasit, Mitsuyoshi Akiyama, Dan M. Frangopol

    Structure and Infrastructure Engineering   16 ( 4 ) 726 - 737  2020.04  [Refereed]

    　View Summary

    In this paper, a novel approach for life-cycle reliability-based design and reliability updating of reinforced concrete (RC) shield tunnels in coastal regions has been developed. For new shield tunnels, a reliability-based durability design criterion to determine the concrete cover and concrete quality for preventing the deterioration of structural performance during the structural service life is proposed. For existing shield tunnels, an approach to update structural reliability is established based on Sequential Monte Carlo Simulation. Epistemic uncertainty associated with the structural performance prediction of existing shield tunnels can be reduced compared with that of new shield tunnels. In illustrative examples, durability design factors and maximum water to cement ratio for designing RC segment satisfying the target durability reliability are investigated. For existing RC shield tunnels, the effect of the observational deformation of segmental lining on the time-dependent failure probability is discussed.

    DOI

  • コンクリート構造物の安全確保のためのシステムに関する研究小委員会成果報告書

    鎌田敏郎, 国枝稔, 秋山充良, 浅本晋吾, 大島義信, 服部晋一, 三木朋広, 山村正人, 石田雅博, 今井卓也, 稲葉尚文, 岩波光保, 笠井尚哉, 小林薫, 佐藤靖彦, 竹田宣典, 長縄卓夫, 福永靖雄, 堀倫裕, 松田浩, 森雅司

    コンクリート技術シリーズ   ( 108 )  2015

    J-GLOBAL

  • 示方書連絡調整小委員会報告書-次世代の「コンクリート標準示方書」に向けて-

    佐藤靖彦, 秋山充良, 石田哲也, 伊代田岳史, 加藤佳孝, 斉藤成彦, 牧剛史, 山本貴士, 浅田尚, 浅本晋吾, 阿波稔, 岩波光保, 上田隆雄, 上田尚史, 上田洋, 臼井達哉, 大島正記, 片健一, 加藤絵万, 国枝稔, 蔵重勲, 古賀裕久, 小林孝一, 齋藤隆, 坂井吾郎, 坂口淳一, 佐川康貴, 桜井邦昭, 塩畑英俊, 田所敏弥, 田中博一, 田中泰司, 千々和伸浩, 築嶋大輔, 土屋智史, 長井宏平, 半井健一郎, 西田孝弘, 日比野誠, HENRY Michael

    コンクリート技術シリーズ   ( 107 )  2015

    J-GLOBAL

  • Damage of Bridges during 2011 Great East Japan Earthquake

    KAWASHIMA Kazuhiko, KOSA Kenji, TAKAHASHI Yoshikazu, AKIYAMA Mitsuyoshi, NISHIOKA Tsutomu, WATANABE Gakuho, KOGA Hirohisa, MATSUZAKI Hiroshi

    Proc Jt Meet U S Jpn Panel Wind Seism Eff UJNR   43rd   165 - 178  2012

    J-GLOBAL

  • Size effect on compressive fracture behavior of RC column with high-strength materials

    Satoshi Abe, Mitsuyoshi Akiyama, Motoyuki Suzuki

    Journal of Structural Engineering   57A   386 - 394  2011

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Works 【 display / non-display 】

  • 点検・検査の結果を利用した劣化構造物のライフタイム評価に対する確率論的アプローチ

    2008
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    2009

  • 点検・検査の結果を利用した劣化構造物のライフタイム評価に対する確率論的アプローチ

    2008
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    2009

  • 地震リスク最小化を可能にする鋼コンクリート複合構造形式の検討

    2007
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    2009

  • 地震リスク最小化を可能にする鋼コンクリート複合構造形式の検討

    2007
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    2009

  • コンクリート充填鋼管杭を橋脚に利用した乗用車専用道路の開発

    2006
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    2007

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Awards 【 display / non-display 】

  • Junior Research Prize

    2016.06   IABMAS  

    Winner： AKIYAMA, Mitsuyoshi

  • 第56回構造工学シンポジウム論文賞

    2010.06  

  • 平成21年度土木学会吉田賞(論文部門)

    2010.05  

  • 科学技術分野の文部科学大臣表彰 若手科学者賞

    2008.05  

  • 平成18年度土木学会論文奨励賞

    2007.05  

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Research Projects 【 display / non-display 】

  • レジリエンス強化のための備災マネジメントと南海トラフ地震・津波の影響地域への適用

    Project Year :

    2019.04
    -
    2023.03
     

  • 将来の設計地震力増大に対応できるメタボリズム耐震橋脚構造の開発

    Project Year :

    2018.04
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    2022.03
     

  • 「危機耐性」の概念に基づく耐震設計体系の確立と実現のための要素技術の開発

    Project Year :

    2016.04
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    2020.03
     

    　View Summary

    危機耐性の設計概念を整理した．これまでの検討に基づき，ストレステストのための仮想的外力としての地震動や，コミュニティと技術者の情報共有を促す体系の重要性について整理した．また，共有情報のマネジメントとしてリスクガバナンスが重要であること等を示した．強震動地震動のシミュレーションのためのモデル化について特性震源化モデルを対象として検討するとともに，断層変位に対して危機耐性を確保する方策に関する調査研究を実施するための産学官の専門家による検討会を発足させた．耐震構造については，まず，摩擦振子型免震機構を有するRC橋脚について，H28の震動実験結果を受け，改良を試みた．まず，滑り面形状の工夫による滑り性能の改善，および，表面強化材の塗布による滑り面の耐摩耗性の向上を図り，水平二方向震動実験によりその効果を確認した．特に，3Dプリンターを活用した臼型滑り面と，エポキシ樹脂製コンクリート補修材を使用すること

  • 材料劣化の空間変動の確率・統計的表現とその既存構造物の性能照査への応用

    Project Year :

    2016.04
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    2020.03
     

    　View Summary

    既存鉄筋コンクリート（RC）構造物では，コンクリートの品質，あるいはかぶり不足などが原因となり，中性化や塩害による鉄筋腐食が生じている場合がある．このような鉄筋腐食が生じたRC構造物の曲げ耐力やせん断耐力，あるいは靭性能評価を行う際には，構造物の各位置で空間的に変動する鉄筋腐食の影響を考慮する必要がある．X線装置を用いて鉄筋腐食の成長過程を連続的に撮影した昨年の研究成果を見る限り，鉄筋腐食の空間変動性はランダムな現象ながらも，確率場のパラメータを適切に定めることにより，確率統計的に再現可能である．つまり，例えば，平均質量減少率が10%のRC部材の曲げ耐力を予測する場合，部材内に生じ得る鉄筋腐食分布は，ある規則に従っており，その規則を満足する平均質量減少率10%の鉄筋腐食分布を多数作成することにより，このRC部材が発現し得る曲げ耐力分布（確率密度分布）を算定できると期待される．一方，現状では，鉄筋腐食の空間変動

  • 材料劣化の空間変動の確率・統計的表現とその既存構造物の性能照査への応用

    基盤研究（B)（一般）

    Project Year :

    2016.04
    -
    2020.03
     

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Presentations 【 display / non-display 】

  • Risk and resilience of civil infrastructure systems under extreme events

    AKIYAMA, Mitsuyoshi  [Invited]

    IABSE Symposium 2019 

    Presentation date： 2019.03

  • Life-cycle reliability of bridges under independent and interacting hazards

    Mitsuyoshi Akiyama  [Invited]

    9th International Conference on Bridge Maintenance, Safety and Management (IABMAS2018)  (Melbourne, Australia) 

    Presentation date： 2018

  • Lessons from recent major earthquakes in Japan: Emphasis on reliability assessment of structures under multiple hazards

    Mitsuyoshi Akiyama  [Invited]

    18th ASEP International Convention  (Quezon, Philippine) 

    Presentation date： 2017

  • Reliability-based assessment of structures for extreme events

    Mitsuyoshi Akiyama  [Invited]

    IABSE Summit 2016  (Helsinki, Finland) 

    Presentation date： 2016

  • Probabilistic approach for road network retrofitting prioritization under seismic and tsunami hazards

    Mitsuyohis Akiyama  [Invited]

    5th International Symposium on Reliability Engineering and Risk Management (ISRERM2016)  (Seoul, Korea) 

    Presentation date： 2016

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Specific Research 【 display / non-display 】

  • 摩擦振子型免震機構付き橋脚に用いる滑り面形状の最適化と寸法効果に関する実験的研究

    2020  

    　View Summary

    　ダメージフリー橋梁の開発を目指し，摩擦振子型免震機構を有するRC橋脚を提案するとともに，その震動実験を行ってきた．提案構造は，橋脚中間部に滑り面を設けることで橋脚下部に伝達される地震時慣性力を大幅に低減することができる．特徴は3Dプリンターで製作したコンクリート型枠を用いることで，複雑な形状を有する滑り面を安価に製作できる点にある．本研究では，過去に用いた橋梁模型を大型化し，提案構造の地震応答に及ぼす寸法効果の影響を検討するための震動実験を実施し，提案構造で生じる応答加速度の低減効果や残留変位の大きさが供試体寸法に依存しないことを確認した．

  • 鉄筋腐食の空間変動性を考慮したRC部材の構造性能評価

    2019  

    　View Summary

    　鉄筋コンクリート（RC）部材に生じる鉄筋腐食などの材料劣化は，場所ごとに腐食程度が大きく異なり，空間的に変動している．劣化RC部材の3D-X線撮影により得られる鉄筋腐食分布からその空間変動を確率・統計的に表現するためのパラメータを同定するとともに，鉄筋腐食の不均一な分布がRC部材の耐力や変形能に及ぼす影響を実験的・解析的に検討した．また，既存RC構造物から得られる数点の点検・検査結果からデータ同化手法を用いることで，RC構造物内に生じている鉄筋腐食量の空間的な変動を同定し，数値解析によりその耐力や変形能を算定した．これと残存供用期間に応じて求められる作用荷重との比較を行うことで，既存構造物の合理的な性能照査やライフサイクル解析が可能となった．

  • 2次元非ガウス確率場の拡張と点検・検査結果への同化による鉄筋腐食分布の推定

    2018  

    　View Summary

    本研究では，まず，RC部材の電食実験と，そのX線撮影・ディジタル画像処理により，RC構造物内の鉄筋腐食分布がどのように進展・成長するのかを理解した．X線撮影には，比較的規模の大きいRC部材をそのまま収容できる装置（早稲田大学所有）を使用した． 次に，鉄筋腐食分布の連続的な変化を2次元非ガウス確率場にてモデル化した．Lehigh大学のProf. Bocchiniの研究グループにおいて開発が進められている行列型非ガウス確率場を応用した．本モデルは，離散的に配置された鉄筋の腐食分布の表現に適しており，計算式で必要となるパラメータを前述の実験結果に基づき決定した．最後に，既存RC構造物から得られる数点の鉄筋腐食量に応じて，鉄筋腐食分布の絞込みを行った．鉄筋腐食量の測定位置とその鉄筋腐食量の測定結果を与え，更新理論を介することにより，点検・検査結果に応じた鉄筋腐食量の分布を同定した．数点の鉄筋腐食量の点検・検査結果から，大規模なRC構造物全体に拡がっている鉄筋腐食分布を出力できるようにしたのが本研究の成果である．

  • 南海トラフ地震による強震動と津波の影響を受けるインフラ構造物のリスク評価

    2018  

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    単一の地震ハザードに対する信頼性の確保から，それを起因として引き起こされる，異なるマルチハザードを想定し，構造物の信頼性に影響する支配的なハザードの抽出などを行う必要がある．本研究では，マルチハザードを受ける構造物の信頼性評価に関する基礎研究として，南海トラフ地震により引き起こされる強震動および津波を想定した．信頼性のアプローチを南海トラフ地震の影響地域にある構造物に適用することで，その破壊可能性を支配するハザードの抽出や異種構造物（橋梁・盛土）の安全性の大小などを比較した．これらの情報は，対策を優先的に施していく地域や構造物の同定に活用される．

  • 構造形態の工夫によるRC柱のダメージフリー化と震動実験による性能確認

    2017  

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    本研究では，これまでの既存研究の知見を基に二方向入力を受ける場合を想定して摩擦振子型免震機構付き柱を設計し，震動実験によりその地震時挙動を確認した．一方向入力の場合と異なり，滑り曲面上を斜め方向に摩擦振子が滑る場合の滑り性能の確保，あるいはそれに適した滑り曲面形状や橋脚の配置方法などが問題となった．また，骨組解析モデルを用いた非線形動的解析も行い，提案構造の地震時挙動を数値解析的に評価するための基礎検討も行った．なお，これまでに観測されている範囲の鉛直地震動の大きさでは，本構造の地震時挙動に鉛直地震動が及ぼす影響は極めて限定的であることから，本実験では，鉛直方向成分の入力は行わなかった．

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Committee Memberships 【 display / non-display 】

  • 2019
    -
    Now

    Managing Editor of Structure and Infrastructure Engineering

  • 2017
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    Now

    IABSE  Vice Chair of Commission 6 - Sustainability, IABSE

  • 2016
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    Now

    Editorial Board Member of Structural Safety

  • 2016
    -
    Now

    Associate Editor of the ASCE Journal of Bridge Engineering

  • 2015
    -
    Now

    Editorial Board Member of International Journal of Earthquake and Impact Engineering

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