Updated on 2026/03/10

写真a

 
CHIJIWA NOBUHIRO
 
Organization
School of Environment and Society Professor
Title
Professor
External link

Degree

  • 博士(工学) ( 2009.3   東京大学 )

Research Interests

  • Maintenance engineering, Concrete engineering, Material & structure integrated field

Research Areas

  • Social Infrastructure (Civil Engineering, Architecture, Disaster Prevention) / Civil engineering material, execution and construction management

Papers

  • Deterioration Mechanism of Protective Coating Materials for Anti-corrosion in Sewage Facilities Under Long-term Service Environment Reviewed

    Kenichi Fujisawa, Ryuta Imai, Nobuhiro Chijiwa, Manabu Fujii

    Concrete Research and Technology   36   61 - 69   2025.9

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    Language:Japanese   Publishing type:Research paper (scientific journal)  

    DOI: 10.3151/crt.36.61

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  • Study on Radio Wave Transparency Improvement of Concrete Focusing on Internal Water Content

    Ryo Sakamoto, Nobuhiro Chijiwa, Kentaro Saito, Kazuhide Nakayama, CheChia Kang

    Journal of Advanced Concrete Technology   Vol. 23 ( Issue 8 )   2025.8

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    DOI: 10.3151/jact.23.395

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  • MICP using calcium-rich waste solution from acetic acid treatment as a calcium source to improve the properties of recycled coarse aggregate

    Wiracha Thaue, Mitsuyasu Iwanami, Kazuhide Nakayama, Nobuhiro Chijiwa

    Construction and Building Materials   Volume 489   2025.6

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  • Study on the nucleation process of reaction products in geopolymer by in situ test using Raman microscopy

    Ryo Sakamoto, Federico P. Pederson, Hee-Jeong Kim, Nobuhiro Chijiwa

    Journal of Building Engineering   Vol. 111   2025.6

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    This study investigates the growth process of reaction products in geopolymer by in situ test using Raman microscopy and the new analysis procedure. Geopolymer is a new cementitious material which solidifies by the dehydration-polycondensation reaction of alumina-silica precursors. It has been proposed as a replacement for ordinary Portland cement as the primary construction material, and as one of the construction materials used in space. In addition, the application of geopolymer has also shown the potential to reduce radio interference caused by concrete structures. However, the reaction mechanism is not yet clear and a method for controlling its performance has not been established. This study focuses on the visualization of growth process of reaction products in order to clarify the nucleation mechanism, which is the main factor influencing the microstructure and mechanical properties of geopolymer. The system was constructed for in situ Raman microscopy while samples were cured at a high temperature to accelerate the reaction, and the same area scans were repeated for fly ash-based geopolymer up to 24 h after mixing. The Raman spectrum of reaction products was defined as the difference between the average spectrum of the first and last scans, because the Raman spectrum of reaction products of geopolymer has not been clarified due to their amorphous structure. Finally, the obtained Raman mapping images at each time step are the first visualization of the growth of reaction products in geopolymer.

    DOI: 10.1016/j.jobe.2025.113232.

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  • PC跨道橋で生じている課題たわみ発生機構の解明

    千々和伸浩, 大橋夏樹, 吉野通範, 菊地新平

    プレストレストコンクリート   2025.5

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    Language:Japanese   Publisher:公益社団法人プレストレストコンクリート工学会  

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  • Novel fiber reinforced concrete based on liquid metal technology toward resource recycling society

    Kondo Masatoshi, Kano Yuki, Chijiwa Nobuhiro, Oh Minho

    Progress in nuclear science and technology   Vol. 7   2025.3

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    DOI: 10.15669/pnst.7.243

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  • 水分状態に着目したコンクリートの電波透過性向上法の検討

    坂本 亮, 千々和 伸浩, 齋藤 健太郎, 中山 一秀, 康 哲嘉

    土木学会論文集   Vol. 81 ( No. 3 )   2025.3

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    DOI: 10.2208/jscejj.24-00070

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  • 中小河川に架かる橋梁を対象とした効率的な定期点検への取り組み

    後藤幹尚, 藤森竣平, 近藤冬東, 岩波光保, 千々和伸浩, 津野和宏

    インフラメンテナンス実践研究論文集   Vol. 4 ( No. 1 )   2025.2

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  • Deterioration Prediction and Optimal Repair Timing Assessment for RC Abutments in Tidal River Environments

    Yuto Suzuki, Nobuhiro Chijiwa, Kazuhide Nakayama, Mitsuyasu Iwanami, Amadou Sakhir Syll

    Proceedings of the Eighth International Conference on Durability of Concrete Structures   2025

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    Publishing type:Research paper (international conference proceedings)   Publisher:Purdue University  

    DOI: 10.5703/1288284318115

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  • 低弾性材料で上面増厚補強を施したRC床版の疲労寿命への水の影響に関する解析的検討

    浦島康希, 千々和伸浩, 田中大介, 上條崇

    コンクリート工学年次論文集   Vol. 46 ( No. 2 )   2024.6

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  • 深海環境におけるRCはりの原位置載荷実験と解析的検討

    石鍋直樹, 藤川理沙子, 千々和伸浩, 岩波光保

    コンクリート工学年次論文集   Vol. 46 ( No. 1 )   2024.6

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  • 実環境下におけるジオポリマーコンクリートの時間依存変形特性に関する検討

    前川虎大郎, 坂本亮, 千々和伸浩, 中山一秀

    コンクリート工学年次論文集   Vol. 46 ( No. 1 )   2024.6

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  • Multiscale analysis of shrinkage-induced performance degradation of shear wall and application to structural analysis

    Ryota Kurihara, Nobuhiro Chijiwa

    Structures   Vol. 61   2024.2

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    Shrinkage-induced cracks reduce the stiffness of concrete structures. Shear walls are more sensitive to drying shrinkage than other members because of their fully restricted condition and large surface areas exposed to air. This study examines how concrete structural performance is affected by shrinkage due to moisture loss via hydration or dissipation by applying multiscale integrated finite element analysis. First, a cyclic shear loading test on shear wall specimens subjected to drying in a previous study was reproduced. Based on the reproduction analysis model, parametric analysis was conducted, focusing on the member scale, mix proportion, and surface treatment of concrete. Shrinkage-induced cracks reduced member stiffness, and the effects of the member scale on drying speed were shown. The dominance of autogenous shrinkage in the case of high-strength concrete was also observed. The sealing of the concrete surface effectively prevented moisture dissipation, but moisture supply from ambient air was also blocked when the humidity inside the concrete was low. Thus, a proper surface protection method should be selected considering water consumption via hydration. Finally, the use of equivalent material properties for considering initial damage due to shrinkage was proposed as a simple way to account for drying effects in structural analyses.

    DOI: 10.1016/j.istruc.2024.106051

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  • Utilization of high-volume fly ash in pervious concrete mixtures for mangrove conservation

    Januarti Jaya Ekaputri, Xevna De Elshinta Arellsya Ruitan, Himawan Tri, Bayu Murti Petrus, Martin Anda, Liliek Harmianto Purbawinasta, Irwanda Laory, Davin H.E. Setiamarga, Nobuhiro Chijiwa, Chikako Fujiyama

    Resources, Conservation & Recycling Advances   2024.2

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1016/j.rcradv.2024.200204

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  • 橋のメンテナンスの区民協働に向けて実施した新たな意識付け活動の考察

    後藤朋子, 後藤理沙, 後藤浩, 後藤幹尚, 藤森俊平, 岩波光保, 千々和伸浩, 津野和宏

    インフラメンテナンス実践フォーラム   Vol. 1 ( No. 1 )   2024.2

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  • 跨線橋の定期点検における効率化の取組み

    後藤幹尚, 岩波光保, 千々和伸浩, 津野和宏

    インフラメンテナンス実践研究論文集   Vol. 3 ( No. 1 )   2024.2

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  • 防食被覆層の施工が下水道コンクリート構造物の耐久性に与える影響

    千々和伸浩

    日本下水道新聞   2023.12

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    Language:Japanese   Publisher:日本下水道新聞社  

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  • PC 技術者の化学入門 第4回 コンクリートの収縮・クリープ

    千々和伸浩

    プレストレストコンクリート   2023.11

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  • 既設濃縮余剰汚泥貯留槽の調査結果に基づく防食被覆工法の有効性の検討

    今井隆太, 千々和伸浩, 藤澤 健一, 藤井学

    コンクリート工学年次論文集   Vol. 45   2023.7

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  • 高速道路跨道橋で発生した過大なたわみの原因機構に関する解析的検討

    大橋夏樹, 千々和伸浩, 吉野通範, 菊池 新平

    コンクリート工学年次論文集   Vol. 45   2023.7

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  • 鉄筋に沿ったひび割れが鉄筋ーコンクリート間の付着劣化に及ぼす影響

    小島萌, 千々和伸浩, 栗原遼大

    コンクリート工学年次論文集   Vol. 45   2023.7

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  • The effect of non-uniform steel bar corrosion on pre-stressed RC members subjected to hysteretic load at the mid-span: experimental study and three-dimensional FEM modeling

    Rajib Kumar Biswas, Mitsuyasu Iwanami, Nobuhiro Chijiwa, Takahiro Saito

    Archives of Civil and Mechanical Engineering   23   2023.6

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1007/s43452-023-00705-8

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  • A new implicit gradient damage model based on energy limiter for brittle fracture: Theory and numerical investigation

    Hung Thanh Tran, Tinh Quoc Bui, Nobuhiro Chijiwa, Sohichi Hirose

    Computer Methods in Applied Mechanics and Engineering   Vol. 413   2023.5

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    We present a general form of the gradient-enhanced damage theory and its numerical implementation using finite element method (FEM) in modeling quasi-static brittle crack growth in one- (1D), two- (2D) and three-dimensional (3D) bodies. Coupled equations of the equilibrium and a new implicit gradient damage formulation are introduced to govern the deformation of the solid and evolution of the damage. The resulting nonlocal damage evolution equation featuring the growth of diffusive crack is integrated with a characteristic length scale to eliminate the common mesh-bias issue in FEM implementation. In contrast to the traditional gradient-enhanced damage approaches, the nonlocal damage field here is defined as the primary variable of the damage evolution equation without interpolation mismatch between the displacement and nonlocal damage fields. For derivation of the material constitutive law and local damage parameter, a novel strain energy density (SED) function based on the energy limiter theory for brittle crack growth problems under small strain regime is introduced. To further improve the performance of the developed model, an initial SED threshold, which is used for determining the critical point when damage starts to initiate in the material, is integrated into the novel energy limiter theory. For preventing nonphysical failure in compression domains, the spectral decomposition technique for the strain tensor is adopted to split the reference SED. With integrating the energy limiter into the developed theory, unlike the conventional nonlocal damage theories where the interpretation of the length scale is still ambiguous, the developed nonlocal damage model defines the length scale parameter as the problem-dependent factor. The performance and ability of the proposed model are demonstrated via a set of representative numerical examples in 1D, 2D and 3D fracture problems.

    DOI: 10.1016/j.cma.2023.116123

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  • 過剰たわみが生じた東名高速道路跨道橋の原因推定と安全性評価

    吉野 通範, 菊地 新平, 若月 健司, 千々和伸浩

    構造工学論文集 A   Vol. 69A   2023.4

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    DOI: 10.11532/structcivil.69A.734

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  • 石炭ガス化スラグ細骨材を用いた鉄筋コンクリートはりの構造性能に関する検討

    松浦 忠孝, 髙橋 恭涼, 千々和 伸浩, 岩波 光保

    構造工学論文集 A   Vol. 69A   2023.4

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    DOI: 10.11532/structcivil.69A.884

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  • メンテナンスの区民協働を通じた橋の新たな価値の創造に向けた取り組み-未来へつなぐ おおたの橋-

    後藤幹尚, 川越貴水, 浅野和香奈, 後藤朋子, 多和田俊介, 岩波光保, 千々和伸浩, 津野和宏

    インフラメンテナンス実践研究論文集   Vol. 2 ( No. 1 )   2023.2

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    Language:Japanese   Publishing type:Research paper (scientific journal)  

    DOI: 10.11532/jsceim.2.1_11

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  • 感潮河川にかかる橋梁の下部構造に対する非破壊調査の適用について

    後藤幹尚, 岩野聡史, 高鍋雅則, 影澤雅人, 三輪空司, 岩波光保, 千々和伸浩, 津野和宏

    インフラメンテナンス実践研究論文集   Vol. 2 ( No. 1 )   2023.2

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  • A simplified approach to estimate seismic fragility of corrosion damaged RC bridge piers

    R. K. Biswas, M. Iwanami, N. Chijiwa, T. Saito, C. M Chuquitaype

    Developments in the Built Environment   Vol. 12   2022.12

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  • Assessment of bond deterioration in corroded RC members incorporating cracking response and tension stiffening

    Atichon Kunawisaru, Iwanami Mitsuyasu, Chijiwa Nobuhiro, Nakayama Kazuhide

    Structure and infrastructure engineering : maintenance, management, life-cycle design and performance   2022.10

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  • Determination of Johnson–Cook Material and Failure Model Constants for HighーTensileーStrength Tendon Steel in PostーTensioned Concrete Members

    Ioannis Gkolfinopoulos, Nobuhiro Chijiwa

    Applied Sciences   Vol. 12 ( No. 15 )   2022.8

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.3390/app12157774

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  • Determination of Johnson–Cook Material and Failure Model Constants for High-Tensile-Strength Tendon Steel in Post-Tensioned Concrete Members

    Ioannis Gkolfinopoulos, Nobuhiro Chijiwa

    Applied Sciences   2022.8

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    DOI: 10.3390/app12157774

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  • 目地板引抜きにより形成した目地による覆工コンクリートのひび割れ誘発特性

    齋藤 隆弘, 浜田 元, 目黒 緑, 千々和 伸浩, 岩波 光保

    土木学会論文集F1(トンネル工学)   Vol. 78 ( No. 1 )   2022.5

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    DOI: 10.2208/jscejte.78.1_40

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  • 次世代の橋梁長寿命化修繕計画の実践-大田区での取り組み事例-

    後藤幹尚, 槇野ちひろ, 長瀬祥敬, 志村航, 岩波光保, 千々和伸浩, 津野和宏

    インフラメンテナンス実践研究論文集   Vol. 1 ( No. 1 )   2022.3

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    DOI: 10.11532/jsceim.1.1_504

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  • The Influence of Interlock Loss between Rebar and Concrete on Bond Performance of RC Member

    Ryota Kurihara, Youhei Ito, Qianghua Cai, Nobuhiro Chijiwa

    Applied Sciences   Vol. 12 ( Issue 3 )   2022.1

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    DOI: 10.3390/app12031079

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  • 災害対応時の道路ネットワーク確保を目指した橋梁耐震整備計画の検討-大田区の現状と対策-

    後藤幹尚, 長瀬祥敬, 槇野ちひろ, 井上雅志, 沼田宗純, 岩波光保, 千々和伸浩

    第12回インフラ・ライフライン減災対策シンポジウム講演論文集   2022.1

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  • The Influence of Interlock Loss between Rebar and Concrete on Bond Performance of RC Member

    Ryota Kurihara, Youhei Ito, Qianghua Cai, Nobuhiro Chijiwa

    Applied Sciences   2022.1

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    DOI: 10.3390/app12031079

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  • Structural assessment of the coupled influence of corrosion damage and seismic force on the cyclic behaviour of RC columns

    R. K. Biswas, M. Iwanami, N. Chijiwa, K. Nakayama

    Construction and Building Materials   ( No. 304 )   2021.10

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    DOI: 10.1016/j.conbuildmat.2021.124706

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  • 道路の維持管理業務に着目した包括的民間委託導入に向けた土木行政における地方自治体職員の意思決定行動の分析

    曾川 宏彬, 岩波 光保, 千々和 伸浩, 中山 一秀

    土木学会論文集F4(建設マネジメント)   Vol. 77 ( No. 1 )   2021.8

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    DOI: 10.2208/jscejcm.77.1_172

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  • Effect of rebar corrosion in concrete on interaction zone under tensile load

    A. Kunawisaru, M. Iwanami, N. Chijiwa, K. Nakayama

    Proceedings of 10th International Conference on Bridge Maintenance, Safety and Management (IABMAS 2020)   2021.4

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  • Improving Geopolymer Characteristics with Addition of Poly-Vinyl Alcohol (PVA) Fibers

    Ekaputri, J.J., Fujiyama, C., Chijiwa, N., Ho, T.D., Nguyen, H.T.

    Civil Engineering Dimension   Vol. 23 ( No. 1 )   2021.3

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    DOI: 10.9744/ced.23.1.28-34

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  • Effect of steel bar corrosion on the cyclic behaviour of RC bridge piers, Proceedings of 11th International Conference on Materials Processing and Chracterization

    R. K. Biswas, M. Iwanami, N. Chijiwa, K. Nakayama

    Proceedings of 11th International Conference on Materials Processing and Chracterization   2020.12

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  • Mitigating Bond Deterioration under Cyclic Loading and Water Exposure

    Tomohisa Saito, Nobuhiro Chijiwa, Hiroo Shinozaki, Mitsuyasu Iwanami

    ACI Structural Journal   Vol. 117 ( Issue 6 )   2020.11

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    Several cases of premature damage of wind turbine tower foundations constructed using the anchor-ring method have been reported to cause towers’ uplift. Sludge buildup (in the form of crushed concrete) was evident along the periphery of the damaged base towers and was found to originate mainly from the concrete-steel interface around the steel anchor foundation that is embedded in concrete, due to the cyclic movement of the anchor steel and the induced water pressure at the interface. This study experimentally investigated possible repair and reinforcing methods to mitigate this problem. Cyclic load tests were carried out on three steel anchor mockup specimens. In the first two specimens, the anchor steel was retrofitted with a nonshrink mortar and epoxy resin, respectively, whereas in the other specimen, the anchor steel was further restrained against uplift by additional anchorage bars. The results indicate that the non-shrink mortar was not effective in preventing water ingress into the interface and could only delay the extent of concrete damage and the progress of bond deterioration during cyclic loading. Epoxy resin was found to perform much better in this regard. In addition, the epoxy layer could also help to dissipate the induced bearing stresses under cyclic loading, thereby making it the best candidate for repair and reinforcing materials in such applications. The use of additional anchorage bars was also found to be effective, although it still requires additional measure to prevent moisture ingress.

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  • 波浪による消波ブロックのロッキング衝突現象に関する実験的研究

    昇悟志, 堀内滋人, 三井順, 久保田真一, 千々和伸浩, 岩波光保

    土木学会論文集B3   Vol. 76 ( No. 1 )   2020.8

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  • スコットランドから見た日本のインフラ維持管理

    千々和伸浩

    コンクリート工学   2020.4

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    DOI: 10.3151/coj.58.4_310

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  • Impacts from concrete microstructure and surface on the settlement of sessile organisms affecting chloride attack

    T. Chlayon, M. Iwanami, N. Chijiwa

    Construction and Building Materials   Vol. 239   2020.4

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  • Effect of non-uniform rebar corrosion on structural performance of RC structures: A numerical and experimental investigation

    Rajib Kumar Biswas, Mitsuyasu Iwanami, Nobuhiro Chijiwa, Kunihiko Uno

    CONSTRUCTION AND BUILDING MATERIALS   230   2020.1

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    DOI: 10.1016/j.conbuildmat.2019.116908

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  • Investigation on mitigation of maintenance burden of pile-supported port structures based on structural analysis

    Sumire Nakamura, Nobuhiro Chijiwa, Mitsuyasu Iwanami

    Thailand Concrete Association Journal   Vol. 6 ( No. 2 )   2018.9

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  • Preconditioning effect on SEM concrete samples and its impact on the implementation of concrete surface analysis at microscopic scale

    Tom Chlayon, Nobuhiro Chijiwa, Mitsuyasu Iwanami

    Thailand Concrete Association Journal   Vol. 6 ( No. 2 )   2018.9

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  • 鉄筋腐食ひび割れを生じたRCはりのせん断疲労耐荷機構に及ぼすせん断補強筋の影響

    山田雄太, 千々和伸浩, 岩波光保

    土木学会論文集E2   Vol. 74 ( No. 3 )   2018.8

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    DOI: 10.2208/jscejmcs.74.176

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  • Combined protective action of barnacles and biofilm on concrete surface in intertidal areas

    Tom Chlayon, Mitsuyasu Iwanami, Nobuhiro Chijiwa

    Construction and Building Materials   Vol. 179   2018.8

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  • 周辺地盤と躯体間の相互作用変化を考慮した中柱式地中RCカルバートの損傷機構に関する検討

    米津薫, 千々和伸浩, 土屋智史

    コンクリート工学年次論文集   Vol. 40 ( No. 2 )   2018.7

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  • Application of GGBFS and Bentonite to Auto-Healing Cracks of Cement Paste

    J. J. Ekaputri, M. S. Anam, Y. Luan, C. Fujiyama, N. Chijiwa, D. H. E. Setiamarga

    Journal of Advanced Civil and Environmental Engineering   Vol. 1 ( No. 1 )   2018.4

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    DOI: 10.30659/jacee.1.1.38-48

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  • Long-Term Differential and Averaged Deformation of Box-Type Pre-stressed Concrete Exposed to Natural Environment

    Nobuhiro Chijiwa, Shuntaro Hayasaka, Koichi Maekawa

    Journal of Advanced Concrete Technology   Vol. 16 ( No. 1 )   2018.1

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    DOI: 10.3151/jact.16.1

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  • Thermo-Hygral Analysis on Long-Term Natural Frequency of RC Buildings with Different Dimensions

    Ryota Kurihara, Nobuhiro Chijiwa, Koichi Maekawa

    Journal of Advanced Concrete Technology   Vol. 15 ( No. 8 )   2017.8

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    DOI: 10.3151/jact.15.381

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  • 引張主鉄筋に沿う人工損傷の長さがせん断補強筋の無いRCはりの疲労耐荷機構に及ぼす影響

    山田雄太, 千々和伸浩, 岩波光保

    土木学会論文集E2   Vol. 73 ( No. 3 )   2017.8

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    DOI: 10.2208/jscejmcs.73.323

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  • 消波ブロック被覆堤の最下層に設置されるブロックに作用する上載荷重に関する実験的研究

    昇悟志, 久保田真一, 松本朗, 千々和伸浩, 岩波光保

    土木学会論文集B3   Vol. 73 ( No. 1 )   2017.7

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    DOI: 10.2208/jscejoe.73.43

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  • コンクリート中における電気浸透流に関する基礎的研究

    大塚邦朗, 岩波光保, 千々和伸浩

    コンクリート工学年次論文集   Vol. 39 ( No. 1 )   2017.7

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  • コンクリート工学の最新トピック

    千々和伸浩

    地質工学   2017.1

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  • 関東支部若手会21の活動

    千々和伸浩

    コンクリート工学   2017.1

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    DOI: 10.3151/coj.55.1_54

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  • Shear creep failures of reinforced concrete slender beams without shear reinforcement

    Saifullah, H.A., Nakarai, K., Piseth, V., Nobuhiro Chijiwa, Maekawa, K.

    ACI Structural Journal   Vol. 114 ( No. 6 )   2017

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    DOI: 10.14359/51700916

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  • 消波工の最下層に設置されるブロックに作用する上載荷重の特性

    昇 悟志, 久保田 真一, 松本 朗, 千々和 伸浩, 岩波 光保

    土木学会論文集B3(海洋開発)   Vol. 72 ( No. 2 )   2016.8

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    DOI: 10.2208/jscejoe.72.I_235

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  • 消波工の最下層に設置される消波ブロックの曲げ耐荷力評価に関する基礎的研究

    昇悟志, 千々和伸浩, 岩波光保

    コンクリート工学年次論文集   Vol. 38 ( No. 2 )   2016.7

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  • Mechanism of Long-Term Excessive Deformation and Delayed Shear Failure of Underground RC Box Culverts

    Maekawa, K., Zhu, X., Chijiwa, N., Tanabe, S.

    Journal of Advanced Concrete Technology   Vol. 14 ( No. 6 )   2016.5

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    DOI: 10.3151/jact.14.183

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  • 近接するLNG地下タンク群と地盤で構成されるタンクヤード全体の3次元動的応答解析

    土屋 智史, 千々和 伸浩, 原田 光男, 三島 徹也, 前川 宏一

    土木学会論文集A1(構造・地震工学)   Vol. 71 ( No. 3 )   2015.12

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    DOI: 10.2208/jscejseee.71.429

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  • Thermo-Hygral Case-Study on Full Scale RC Building under Corrosive Environment and Seismic Actions

    Nobuhiro Chijiwa, Koichi Maekawa

    Journal of Advanced Concrete Technology   Vol. 13 ( No. 10 )   2015.10

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    This paper is to apply the multi-scale thermo-hygro-mechanistic modeling to full-scale RC structural systems under combined long-term ambient and short seismic actions. The authors also aim to dissolve numerical difficulty for full-scale performance assessment of huge degree-of-freedom. First, the multi-scale modeling is experimentally checked by using corroded RC columns under high axial compression. Second, the steel corrosion is computationally reproduced to a multi-story RC building under long-term fictitious ambient conditions. The seismic ground motion is subsequently applied to the corrosion damaged mockup. Beforehand, the effect of drying shrinkage, which is inevitable for structural concrete in air, is discussed so as to clarify the pure corrosion impact to the whole structural system. The steel corrosion deteriorates the ductility of seismic resistant members, but as a global influence, steel corrosion is validated to reduce the base-shear input of floors owing to the decayed stiffness by corrosion. Through these case-studies, the authors raise the points of discussion to take into account the local and global effects of corrosion all at once for seismic performance assessment, and that the knowledge solely on the capacity of corroded RC members cannot lead to an engineering solution.

    DOI: 10.3151/jact.13.465

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  • Rapid Degradation of Concrete Anchorage Performance by Liquid Water

    Nobuhiro Chijiwa, Hong Thi Mai, Mitsuyasu Iwanami, Tomohisa Saito, Atsushi Yamaya, Hiroyuki Motegi, Hiroo Shinozaki

    Journal of Advanced Concrete Technology   Vol. 13 ( No. 10 )   2015.10

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    Sludge ejection from the foundation of a wind turbine tower fixed by the anchor-ring method and the resulting sludge buildup have been confirmed to cause the undesirable phenomenon of lifting of the tower. Using specimen that is a pirtial model of the wind turbine foundation, this study investigates the influence of liquid water, differences in W/C, and differences in loading speed, to analyze developing factors on the concrete damage . The results shows that penetration of liquid water from rainfall and snowfall produces a wedge effect, breakdown of the concrete pore skeleton structure, grinding by sludge particle, cavitation and other effects, and leads to rapid deterioration of the anchorage performance of concrete foundation. Based on the knowledge on the deterioration process, rational countermeasures on design and maintenance are proposed.

    DOI: 10.3151/jact.13.438

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  • 高水圧作用下におけるコンクリートの破壊挙動に関する基礎的研究

    堀尚 an, 千々和伸浩, 岩波光保

    土木学会論文集B3(海洋開発)   Vol. 71 ( No. 2 )   2015.9

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    DOI: 10.2208/jscejoe.71.I_179

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  • 液状水に起因した風車基礎アンカーリング周りのコンクリート損傷進展機構の解明

    Mai Thi Hong, 千々和伸浩, 岩波光保, 齊藤智久

    コンクリート工学年次論文集   Vol. 37 ( No. 2 )   2015.7

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    アンカーリング方式により定着された風車のタワー基礎において,スラッジが噴出し,噴出量が多くなるとタワーが浮き上がる現象が確認された。本研究では,風車基礎の一部をモデル化した試験体を用いて液状水の存在,水セメント
    比の違い,加力速度の違いに注目することで,コンクリート損傷の進展原因を解明する。その結果,降雨降雪に由来した。液状水が内部に浸入したことにより,くさび効果,コンクリート骨格破壊,エロージョン,キャビテーション等の作用が生じ,基礎部分におけるコンクリートを急激に損傷させることが明らかになった。

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  • せん断スパン内にひび割れを有する鉄筋コンクリートはりのせん断疲労耐荷機構に及ぼすひび割れ先端位置の影響

    山田雄太, 千々和伸浩, 岩波光保

    コンクリート工学年次論文報告集   Vol. 37 ( No. 2 )   2015.7

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    鉄筋腐食ひび割れを有する鉄筋コンクリートはりにおけるせん断疲労挙動を解明するための,基礎的理論の構築を目的とし,コンクリートのせん断力分担分をストラット幅及び角度に及ぼす影響に分離する方法を提案した。せん断スパン内に導入されたひび割れ先端位置を変化させた三次元有限要素解析を行った結果,ストラット幅及び有効圧縮強度係数は,上限荷重比の低下に伴い減少することが明らかになった。静的載荷時,耐力の増加に寄与するひび割れを有するはりは,ストラット幅の減少が支配的な影響を及ぼすことで,繰返し回数の増加に伴い,せん断疲労耐力が急激に減少することが明らかになった。

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  • 既設コンクリート構造物のドリル孔を対象とした塩化物イオンモニタリングセンサの設置方法の検討と性能検証

    篠原桂介, 千々和伸浩, 岩波光保, 佐藤達三

    コンクリート工学年次論文集   Vol. 37 ( No. 1 )   2015.7

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    効率的な劣化調査の実現のため,既設コンクリート構造物に削孔したドリル孔を活用し,塩化物イオンの浸透を検知するモニタリングセンサを孔内に設置する方法について検討を行った。実験によって,既設コンクリートとセンサの境界部における塩分浸透について,エポキシ樹脂の使用により物質移動抵抗性を付与できることを明らかにした。加えて,検討した設置方法を適用したモルタル供試体を用いて塩化物イオン浸透実験を行い,センサが塩化物イオンの浸透を深さ方向に検知できることを確認した。

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  • セメント硬化体の時間依存変形に及ぼす気象作用の影響評価

    早坂駿太郎, 千々和伸浩, 岩波光保

    コンクリート工学年次論文集   Vol. 36 ( No. 1 )   2014.7

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  • Multiscale Coupled-Hygromechanistic Approach to the Life-Cycle Performance Assessment of Structural Concrete

    K. Maekawa, T. Ishida, N. Chijiwa, C. Fujiyama

    Journal of Material in Civil Engineering   Vol. 27 ( No. 2 )   2013.12

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    DOI: 10.1061/(ASCE)MT.1943-5533.0000984

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  • Part2 Stock/第5回 構造物

    千々和伸浩

    Vol. 30   2013.3

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  • インフラの維持管理 1)構造物

    千々和伸浩

    Vol. 31   2013.3

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  • 大規模解析に向けた劣化構造物の残存構造評価手法

    千々和伸浩

    Vol. 28   2013.2

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  • 統合シミュレータにおける建物地震応答解析

    千々和伸浩, 壁谷澤寿一

    Vol. 28   2013.2

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  • Integrated Earthquake Simulation

    Nobuhiro CHIJIWA, Lalith MADDEGEDARA

    Journal of Asian Urbanism   ( No. 7 )   2012.9

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  • An Investigation into the Long-Term Excessive Deflection of PC Viaducts by Using 3D Multi-scale Integrated Analysis

    Motohiro Ohno, Nobuhiro Chijiwa, Benny Suryanto, Koichi Maekawa

    Journal of Advanced Concrete Technology   Vol. 10 ( No. 2 )   2012.2

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    DOI: 10.3151/jact.10.47

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  • コンクリート中の細孔水に起因する変形駆動力が実PC橋の長期クリープたわみに及ぼす影響

    大野元寛, 千々和伸浩, 前川宏一

    コンクリート工学年次論文集   Vol. 33   2011.7

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  • Long-term deformational simulation of PC bridges based on the thermo-hygro model of micro-pores in cementitious composites

    Koichi Maekawa, Nobuhiro Chijiwa, Tetsuya Ishida

    Cement and Concrete Research   Vol. 41 ( No. 12 )   2011.5

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    DOI: 10.1016/j.cemconres.2011.03.021

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  • 引張鉄筋定着部に腐食劣化を有するRC梁の残存耐力と未損傷領域への面的補強

    千々和伸浩, 川中勲, 前川宏一

    土木学会論文集E2(材料・コンクリート構造)   Vol. 67 ( No. 2 )   2011.4

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    DOI: 10.2208/jscejmcs.67.160

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  • コンクリートの微細空隙中の水分とPC橋の長期変位

    千々和伸浩, 石田哲也, 前川宏一

    橋梁と基礎   2011.1

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  • セメント硬化体中の微視的機構モデルに基づく実PC橋の長期時間依存変形シミュレーション

    千々和伸浩, 杉田恵, 石田 哲也, 前川宏一

    コンクリート工学年次論文集   Vol. 32   2010.7

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  • 未損傷部への選択的な鉄筋配置が定着部損傷を有するRC部材の耐荷機構に及ぼす影響

    千々和伸浩, 川中勲, 前川宏一

    土木学会論文集E   Vol. 66 ( No. 2 )   2010.5

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    DOI: 10.2208/jsceje.66.179

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  • 無損傷領域に繊維シート材料を配置した予防的先行補強の効果

    川中勲, 千々和伸浩, 前川宏一

    コンクリート工学年次論文集   Vol. 31 ( No. 2 )   2009.7

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  • 定着部に損傷を有するRC部材の残存構造性能評価と補強に関する研究

    千々和伸浩

    2009.3

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  • 定着部に損傷を有するRC部材に対する予防的先行補強

    千々和伸浩, 川中勲, 前川宏一

    コンクリート工学年次論文報告集   Vol. 31 ( No. 2 )   2009

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  • Shear Fatigue Simulation of RC Beams Subjected to Fixed Pulsating and Moving Loads

    Esayas Gebreyouhannes, Nobuhiro Chijiwa, Chikako Fujiyama, Koichi Maekawa

    Jornal of Advanced Concrete Technology   Vol. 6 ( No. 1 )   2008.3

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    DOI: 10.3151/jact.6.215

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  • 移動荷重と水分の影響を同時に受けるRC部材の疲労破壊特性

    藤山知加子, 千々和伸浩, 川中勲, 前川宏一

    コンクリート工学年次論文集   Vol. 30   2008

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  • 定着部に損傷を有するRC梁への限定的補強の効果に関する研究

    千々和伸浩, 川中勲, 商峰, 前川宏一

    コンクリート工学年次論文集   Vol. 30   2008

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  • 移動荷重下の床版疲労寿命に影響を及ぼす各種要因の数値解析に基づく分析

    藤山知加子, GEBREYOUHANNES Esayas, 千々和伸浩, 前川宏一

    コンクリート工学年次論文集   Vol. 29   2007.7

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  • 定着部に損傷を有するRC梁のせん断耐荷機構

    千々和伸浩, GEBREYOUHANNES Esayas, 藤山知加子, 前川宏一

    コンクリート工学年次論文集   Vol. 29 ( No. 3 )   2007.7

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  • Fatigue Behavior of RC Beams under Fixed Pulsating and Moving Loads

    千々和 伸浩

    コンクリート工学年次論文集   Vol. 29   2007.7

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  • 遺伝子組み換え微生物を用いたコンクリート解体法の開発

    千々和伸浩

    2006.3

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  • 画像処理を用いたケーブル動的挙動の計測

    千々和伸浩

    2004.3

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▼display all

MISC

  • EVALUATION OF RESIDUAL STRUCTURAL PERFORMANCE OF STEEL PIPE PILED PIER WITH LOCAL STEEL BAR CORROSION

    UNO Kunihiko, CHIJIWA Nobuhiro, IWANAMI Mitsuyasu, MIYOSHI Toshiyasu, OGASAWARA Tetsuya

    Journal of Japan Society of Civil Engineers, Ser. B3 (Ocean Engineering)   73 ( 2 )   I_408 - I_413   2017

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    Steel pipe piled piers are exposed to severe corroding salty environment and they should be more appropriately maintained. However, few researches have been conducted on the residual structural and seismic performance of corroded piers. The objective of this study is to clarify the effect of corroded steel bar at the RC superstructure and the junction area between superstructure and the steel pipe on the structural performance of the entire pile-supported structure. This study has been developed through the laboratory loading tests and numerical analyses. From the experiment and analysis, it is confirmed that corrosion on the superstructure has impact on the residual structural performance. However, corrosion on the reinforcement bar in haunch has minor impact on the whole behavior.

    DOI: 10.2208/jscejoe.73.i_408

    CiNii Research

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  • EVALUATION OF SEISMIC PERFORMANCE OF PILE-SUPPORTED STRUCTURE WITH LOCAL STEEL BAR CORROSION AND PROPOSAL OF ITS MAINTENANCE METHOD

    NOMURA Sanami, CHIJIWA Nobuhiro, IWANAMI Mitsuyasu, MIYOSHI Toshiyasu, OGASAWARA Tetsuya, UNO Kunihiko

    Journal of Japan Society of Civil Engineers, Ser. B3 (Ocean Engineering)   71 ( 2 )   I_173 - I_178   2015

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    The objective of this study is to analytically clarify the effect of steel bar corrosion on the seismic performance of the entire pile-supported structure, and to then propose an appropriate maintenance method for pile-supported structures with steel bar corrosion, based on the analytical results.<br> First, a steel corrosion model using RC beams was proposed and verified. Then, the structural performance of the corroded RC beams was analyzed. Concurrently, loading experiments of the RC beams were conducted to verify the analyses. After confirming the validity of the analysis, the constitutive law of RC beams with various corrosion patterns was calculated by cyclic loading analysis. The seismic performance of the pile-supported structure with several combinations of this constitutive law was analyzed to clarify the relationship between local steel bar corrosion and the seismic performance of the whole structure. Finally, an appropriate maintenance method was proposed based on the analytical results.

    DOI: 10.2208/jscejoe.71.i_173

    CiNii Research

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Research Projects

  • 持続可能社会実現に貢献する縮重合反応を基本とする新しいアルカリ活性材料の開発

    Grant number:22H00230  2022.4 - 2026.3

    日本学術振興会  科学研究費助成事業  基盤研究(A)

    一宮 一夫, 佐川 康貴, 山本 武志, 藤山 知加子, 千々和 伸浩

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    Grant amount:\43420000 ( Direct Cost: \33400000 、 Indirect Cost:\10020000 )

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  • 石灰石骨材コンクリートにおける微細ひび割れの発生制御と高性能化

    Grant number:22H01565  2022.4 - 2026.3

    日本学術振興会  科学研究費助成事業  基盤研究(B)

    半井 健一郎, 小川 由布子, 千々和 伸浩, 佐川 孝広

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    Grant amount:\17290000 ( Direct Cost: \13300000 、 Indirect Cost:\3990000 )

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  • 石灰石骨材コンクリートにおける微細ひび割れの発生制御と高性能化

    Grant number:23K22835  2022.4 - 2026.3

    日本学術振興会  科学研究費助成事業  基盤研究(B)

    半井 健一郎, 小川 由布子, 千々和 伸浩, 佐川 孝広

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    Grant amount:\17290000 ( Direct Cost: \13300000 、 Indirect Cost:\3990000 )

    本研究の目的は,微細ひび割れを構造と材料の複合問題としてとらえ,その発生機構を明らかにしたうえで,コンクリート構造物としての性能への影響を定量的かつ体系的に分析することで,性能向上のために微細ひび割れを積極的に導入する手法を確立することである.これにより,せん断耐力の低下によって構造安全性を低下させるという,石灰石骨材を用いたコンクリート構造物の課題を解決するとともに,材料設計と構造物の性能評価を直結させるものである.
    本年度は,まず,材料物性の化学反応の観点からの評価として,材齢初期からの膨張材の反応とそれに伴う拘束膨張ひずみの発現に関する分析結果について精査し,地球化学モデルを用いたエトリンガイト生成量との関係性について検討を行った.次に,膨張材の添加量を変化させた膨張コンクリートに関して,透気性の観点から,微細ひび割れと耐久性の関係を分析した.特に,鉄筋の配置による膨張の拘束方向の違いに加え,養生温度に着目した検討を行った.さらに,石灰石骨材膨張材コンクリートを用いたRCはり試験体を用い,過膨張によって生じた微細ひび割れが石灰石骨材によるせん断強度の低下・回復に及ぼす影響を,繰り返し載荷試験を用いて議論した.その結果,微細ひび割れの存在によって耐疲労抵抗性が向上する傾向の結果が得られた.また,静的載荷試験で得られるせん断耐力を破壊エネルギーの観点から評価する簡易手法についても検討を進めた.

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  • Durability Mechanics of Cementitious Composites and Structural Performance under Broadband Environments

    Grant number:20H00260  2020.4 - 2023.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (A)

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    Grant amount:\37960000 ( Direct Cost: \29200000 、 Indirect Cost:\8760000 )

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  • Analysis of micro-cracking of concrete and its applications

    Grant number:18H01512  2018.4 - 2021.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (B)

    Nakarai Kenichiro

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    Grant amount:\15210000 ( Direct Cost: \11700000 、 Indirect Cost:\3510000 )

    This study focused on micro-cracking in concrete and examined its effects on the material and structural performance. At the material level, experimental results varying the curing conditions and the used materials such as limestone aggregate, expansion material, and blast furnace slag cement showed that the concrete material properties can be explained by the reaction rate of each mineral, the amounts of reacted water and hydrates. At the structural level, loading tests were conducted on RC beams, and it was shown that limestone aggregate concrete subjected to an initial high-temperature history could develop micro-cracks, which could resolve the reduction in shear strength.

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  • Fracture progress mechanism of concrete under high water pressure considering water movement in microstructure

    Grant number:18H01508  2018.4 - 2021.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (B)

    Iwanami Mitsuyasu

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    Grant amount:\17030000 ( Direct Cost: \13100000 、 Indirect Cost:\3930000 )

    This study consisted of experimental investigation with high pressure loading apparatus and numerical investigation based on FEM. In the experiment, loading tests on concrete specimens with various shapes and materials were conducted using the high pressure loading apparatus. By changing the maximum water pressure, loading rate, repeated cycles, the strains in the specimen and its surface appearance were examined in order to make clear the fracture process of concrete under high water pressure. In the numerical investigation, utilizing the FEM analytical platform where the water transportation can be simulated in the micro-pore scale, the micro fracture process was examined to compensate the experimental approach.

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  • Research on the influence of liquid water on fatigue deterioration of embedded joint in corrugated steel web PC bridge and development of effective countermeasures

    Grant number:16H06096  2016.4 - 2019.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Young Scientists (A)

    Chijiwa Nobuhiro, IWANAMI Mitsuyasu, SASAKI Eiichi, TAMURA Hiroshi, SHINOZAKI Hiroo, SAITO Tomohisa, MAEKAWA Koichi

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    Grant amount:\25350000 ( Direct Cost: \19500000 、 Indirect Cost:\5850000 )

    This research aims to examine the possibility of rapid deterioration of anchorage performance of steel web embedded in the concrete flanges in steel corrugate web PC bridge due to the liquid state water, and propose some effective countermeasures for the problem. As a result of the research, it is confirmed that the risk of concerning problem is small. This is because the interface opening is confined by the pre-stressing force, and the water pressure of the interface is limited in low level due to the crack penetration through thin concrete flanges. It is also confirmed that the effectiveness of a new countermeasure with a special treatment on the interface between steel and concrete by suppressing local water pressure.

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  • Development of simple evaluation method of residual pre-stressing force in PC structure by using concrete expansion with water absorption

    Grant number:16K14289  2016.4 - 2018.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Challenging Exploratory Research

    CHIJIWA Nobuhiro

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    Grant amount:\3770000 ( Direct Cost: \2900000 、 Indirect Cost:\870000 )

    Dried concrete expands by absorbing water, and this volumetric change of concrete can be confined by external pre-stressing force. We tried to develop simple evaluation method of residual pre-stressing force in PC structure by using this character.
    For small scale test specimens, it is confirmed that the volumetric change can be confined by external force in experiment and numerical analysis. However, in the experiment with the real scale test specimen, such a tendency can not be observed, though numerical analysis gives similar trends with small scale test. This difference may be caused by uneven water contents and microcracks in real scale test specimen.
    Applicability of image analysis to measure the volumetric change is also examined. It is found that quantity of light is important to get precise result.

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  • Development of biochemical demolishing method for concrete with genetically engineered microorganisms

    Grant number:24656268  2012.4 - 2015.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Challenging Exploratory Research

    CHIJIWA Nobuhiro, WATANABE Manabu

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    Grant amount:\4030000 ( Direct Cost: \3100000 、 Indirect Cost:\930000 )

    This research aims to develop new concrete demolishing method with the genetically engineered microorganisms which produces special chemicals to dissolve cement hydrate. Two independent demolishing systems with microorganisms are designed; one is based on hydrochloric acid and the other is based on nitric acid. The acid producing performance of genetically engineered microorganisms are checked, but the results show that the pH of each culture media does not decrease against expectations in each systems. It is found that the organ to carry the produced chemicals out of the microorganism body and the tolerance property to the produced chemical are requested for the genetically modified microorganisms.

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  • damage mechanism of bridge structures by huge tsunami and the proposal of countermeasures

    Grant number:24246079  2012.4 - 2015.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (A)

    MARUYAMA Kyuichi, ARIKAWA Taro, MIZUTANI Norimi, HAYASHI Kazuhiko, TANAKA Yasushi, WATANABE Ken, FUJIMA Koji, HOSODA Akira, CHIJIWA Nobuhiro, SHIGIHARA Yoshinori

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    Grant amount:\46280000 ( Direct Cost: \35600000 、 Indirect Cost:\10680000 )

    Acting force on bridge structures due to huge tsunami was studied through large scale hydraulic test, 3D computational fluid dynamics and tsunami wave propagation analysis. In addition to lift by staircase wave and solitary wave, hydrodynamic force both in steady and unsteady flow is evaluated quantitatively. Evaluation equation was verified with data set of bridge structures attacked by the 2011 off the Pacific coast of Tohoku Earthquak tsunami. Limitation of evaluation equation was also recognized.
    Computational fluid dynamic program which is able to simulate the movement of bridge structures was developed with use of coupling technique between solid, gas, and liquid phase. The effect of strengthening method is able to be evaluated by the AEM software which deals with fracture and large deformation of structures.

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  • Long-Term Dynamic Simulation of Large-Scale RC-PC Infrastructures Based on Quasi Thermo-hygral Modeling

    Grant number:23226011  2011.4 - 2016.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (S)

    MAEKAWA KOICHI, ISHIDA Tetsuya, ISHIHARA Takeshi, MISHIMA Tetsuya, ISHIBASHI Tadayoshi, TANABE Shigeru, SAKATA Noboru

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    Grant amount:\224640000 ( Direct Cost: \172800000 、 Indirect Cost:\51840000 )

    By coupling micro-pore networks with nano-channel hydraulics, the hygral-mechanical model on thermodynamic equilibrium of moisture and momentum is upgraded. Rapid adsorption of rain and following evaporation can be accurately reproduced and the model is verified by the continuous monitoring of internal moisture and curvature of the box PC mockups exposed to natural environment. Long-term varying natural frequency of tall buildings and nuclear facilities is successfully simulated by the thermo-hygral model. Delayed shear failure of underground RC culverts was also simulated by the on-site existing facilities, and the remaining risk of failure can be estimated. A unified poro-mechanics with ASR silica & corrosion gels and condensed-ice is established with strong full coupling. Based upon the simulation platform as mention above, the complex deterioration of RC bridge decks under fatigue loads and ASR & freeze/thawing cycles is investigated and the strong coupling is fairly predicted.

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  • コンクリート系床版に内在する凝縮水の動態による早期疲労限界状態

    Grant number:23246083  2011

    日本学術振興会  科学研究費助成事業  基盤研究(A)

    前川 宏一, 内村 太郎, 長井 宏平, 長山 智則, 千々和 伸浩

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    Grant amount:\25350000 ( Direct Cost: \19500000 、 Indirect Cost:\5850000 )

    水が浸透したコンクリート系橋梁床板の早期疲労劣化問題を解明するため、コンクリート構造物のひび割れや接合界面などに介在する凝結水の動態と、コンクリート構造の変形応答・破壊進展に現れる速度依存性に着目し、地盤分野で多くの成果を挙げているBiotの固液二相理論を既往のコンクリートの非線形有限要素解析プログラムに組み込んだプロトタイプモデルを作成した。これにより、多方向分散ひび割れ構成則と対数時間積分法に基づく全履歴追跡型の疲労解析法と水の動態を、ひとつの数値計算システムで解くことが可能となった。作成した数値解析モデルの感度解析を実施するとともに、検証実験の詳細設計を行った。意図的にひび割れを生じさせた鉄筋コンクリート試験体で、載荷速度をパラメータとし、ひび割れ内部の水圧変動、試験体の変形(変位)、鉄筋のひずみおよび荷重の動的測定を行い、凝縮水の圧力変動と構造物の応答変化に関するデータを得ようとするものである。また、ひび割れを有するコンクリートとひび割れ内に貯留される凝縮水に着目し、既往の研究(ひび割れを有するコンクリートの透水係数同定実験)のデータに基づき、本研究で提案する数値モデルによる異方性透水係数の検証方法を策定した。
    本研究は3年間の研究期間を想定していたが、期間途中で申請者の基盤研究Sが採用されたため、重複制限により研究廃止措置となった。よって、平成23年5月末日までの2カ月に行った研究について報告するものである。

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  • Enhancement of multi-scale integrated analysis for real concrete structure

    Grant number:22760327  2010 - 2011

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Young Scientists (B)

    CHIJIWA Nobuhiro

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    Grant amount:\4420000 ( Direct Cost: \3400000 、 Indirect Cost:\1020000 )

    In order to simulate real concrete structures in full scale by the multi-scale integrated analysis, the analytical platform is enhanced. The excessive deflection of PC viaducts are reproduced successfully by this analytical platform. The analytical results show that the difference of time-dependent volumetric change caused by steel confinement and thermo-dynamical state between upper and bottom flange is the key of excessive deflection. Based on this fact, new design concept that giving different concrete property between upper and bottom flange to control the time dependent deflection is proposed, and its validity is confirmed. The change of structural performance with corrosion is also simulated by the system. The result shows that the degradation of structural performance with time is faster than expected because of the failure mode shift with deterioration.

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  • 遺伝子組み換え微生物を用いた,コンクリート構造物の生化学的解体法の開発

    Grant number:22656099  2010

    日本学術振興会  科学研究費助成事業  挑戦的萌芽研究

    石田 哲也, 千々和 伸浩, 渡邊 学

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    Grant amount:\3530000 ( Direct Cost: \3200000 、 Indirect Cost:\330000 )

    本研究は、限定的状況下において,セメント硬化体の分解に適した化学物質を無尽蔵に生み出す遺伝子組み換え微生物を作成し、「生化学的解体法」という新たなコンクリート解体法の構築を試みるものである。
    22年度は、セメント系材料の解体に適していると考えられる化学物質を産生するための連鎖化学反応機構の解明、反応に必要な遺伝子群の特定、特定された遺伝子群を有する生物の培養及び遺伝子抽出,得られた一部遺伝子のコンピテントセルへの組み込みを行った。
    セメント系材料の解体に適していると考えられる化学物質の前駆となる物質は、自然界では複数の生命体の共生関係の上で合成されているものである。生化学的解体法の実現には、まずこの前駆物質の合成において、共生関係を必要としない単一の生命体内で完了させる必要がある。そこで、この前駆物質の合成に必要な物質と環境条件を精緻に分析し、その条件を満たすために必要な遺伝子群を特定した。これらの遺伝子群をコンピテントセルに組み込むことよって、一つの生命体内において目的とする前駆物質を合成させることに成功した。
    前駆物質からさらに目的とする物質を合成するには酸化酵素を作用させる必要があり、また効率的に物質を産生させるために、合成した物質を組み換え微生物の体外に排出する機構を追加する必要がある。これらに必要な遺伝子の配列は既に特定済みであり、今後はこれらの遺伝子の組み込みを完了し、セメント系材料の解体性能試験へと進む予定である。

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