橋梁点検時における応急塗装の腐食抑制効果に関する実験的検討
原田隆郎, 筆頭著者
土木学会構造工学論文集, 2020年03月, ［査読有り］
フラクタル次元を用いた耐候性鋼材のさび形状評価に関する研究
町田純平,原田隆郎, ラスト(シニア)オーサー
土木学会論文集F3（土木情報学）, 2020年03月, ［査読有り］
供用中の鋼製起伏堰を対象とした実用的な更新計画の検討
原田隆郎,金森豪,桑島智明, 筆頭著者
土木学会構造工学論文集, 2019年03月, ［査読有り］
生体脈波を利用した歩道橋横断時の不快感評価に関する基礎的研究原田隆郎,横山功一, 筆頭著者, It is most important to propose the evaluation technique of the unpleasantness which a human body receives due to bridge vibration. In this study, the experiment to measure physiological information was performed in order to propose evaluation technique of serviceability of pedestrian bridges. In the experiment, the vibration of both pedestrian bridges and pedestrians were measured simultaneously, and the relation of both vibration characteristic and the biological pulse wave have been investigated. As the result, it is found that the Lyapunov exponent of biological pulse wave could be used as an index for evaluating the unpleasant bridge vibration which pedestrians feel., 公益社団法人 土木学会
土木学会構造工学論文集, 2016年03月,
［査読有り］ PVDFフィルムセンサによるひび割れ検知に関する研究原田隆郎,横山功一,田名部菊次郎, 筆頭著者, Structural monitoring with various sensors has been used as a quick quantifying of damages of infrastructures. In this paper, a strain measurement using piezoelectric PVDF (polarized polyvinylidene fluoride) film is studied. First, sensing performance of the PVDF film on static measurement was compared with traditional strain gages. A PVDF film sensor for crack detection was developed. The crack progress on an aluminum specimen was monitored with the developed PVDF film sensor. Moreover, the PVDF film sensor has been used to monitor the initiation and propagation of cracks on RC specimens., 公益社団法人 土木学会
土木学会構造工学論文集, 2013年03月,
［査読有り］ 生体脈波を用いた道路の乗り心地評価に関する基礎的研究原田隆郎、横山功一, 筆頭著者, 本研究では，道路利用者の乗り心地を評価するための走行性指標を提案するため，車両走行中の運転者および同乗者の生体脈波をセンシングし，人間の感覚的な観点からの道路の乗り心地を評価する手法を提案するとともに，舗装マネジメントにおける乗り心地指標の適用可能性に関する検討を行った．走行試験によって計測された生体脈波を用いて，路面の不陸や段差が道路利用者に与える乗り心地の程度を定量評価するとともに，生体脈波のカオス解析によって得られたリアプノフ指数を利用して複数道路の乗り心地の区別化を行い，舗装マネジメントのための乗り心地評価指標を提案した．, Japan Society of Civil Engineers
土木学会論文集F4（建設マネジメント）, 2012年04月20日,
［査読有り］ 横断歩道橋の支柱に生じたき裂損傷の原因調査と対策三木千壽,小野 潔,横山功一, 原田隆郎, 地方道を跨ぐ横断歩道橋の支柱で，支柱の全周の約半分に達する大きなき裂損傷が発見された．横断歩道橋でこのような重度のき裂損傷が報告された例は著者らの知る限りない．日本の横断歩道橋は昭和40年代に飛躍的に整備されたが，標準設計を適用して設計・施工された横断歩道橋も多い．よって，今回，重度のきれつ損傷が発見された横断歩道橋の鋼管支柱と同様の構造細目を有する横断歩道橋も存在し，同様の重度の損傷が発生する危険性もあるため，その原因を解明することは，同種の損傷を未然に防ぐ意味で非常に重要である．
そこで，本論文では，破面観察，材料試験，応力測定等を行って損傷の発生原因調査，メカニズムの推測を行うとともに，き裂損傷の補強等の対策も行ったので報告するものである．, Japan Society of Civil Engineers
土木学会論文集A, 2009年,
［査読有り］ ニューラルネットワークを用いた橋脚の地震時リアルタイム損傷判定法に関する検討横山功一,原田隆郎,黒田 聡,A.K.M. Rafiquzzaman, 1995 年の阪神淡路大震災のように、人口が密集した都市で大地震が発生した場合、道路橋を含む交通システムが被災することにより、交通機能や復旧作業に大きな支障をきたすことが予想される。それゆえ橋梁構造物に関しては、地震発生直後の交通網の被災情報を提供し、被災度の軽減、被害の拡大防止、及び復旧作業の補助を行うための地震時リアルタイム損傷検知システムが必要であると考えられる。本研究では、ニューラルネットワーク (Neural Networks: NN) を用いた地震時リアルタイム損傷検知システムにおける橋脚の損傷判定法を提案した。損傷判定法では、まずNN を用いて健全時の構造システムの同定を行う。次に橋脚構造の同定が行われたNN を用いて、地震を受けた場合の出力値 (NN予測値) と橋脚の応答計測値 (実測値) の間に生じる誤差 (NN予測誤差) から損傷判定を行う。ここで、NN予測誤差の評価指標としては、実測値とNN予測値における振幅比と位相差を選定した。そして、独立行政法人土木研究所で行われたRC 単柱の加振実験のデータを用いて、提案した損傷判定法の検証を行った。その結果、振幅比と位相差の二つの評価指標が損傷程度 (固有周期変化・減衰定数変化) とよく一致することを確認した。また、提案した損傷判定法は、周波数領域の解析手法に比べてより迅速に損傷情報を提供することが可能である。, JAPAN ASSOCIATION FOR EARTHQUAKE ENGINEERING
日本地震工学論文集, 2007年07月,
［査読有り］ 構造ヘルスモニタリングにおけるひずみ測定の温度影響の補正に関する研究
町口敦志,横山功一,原田隆郎,高木優任
構造工学論文集, 2007年03月, ［査読有り］
Cost evaluation in bridge inspection strategies by using real options methodHarada; T. and Yokoyama; K., 筆頭著者, To support expensive bridge inspection by the human being, bridge monitoring technique for damages such as crack, fatigue and corrosion has already been introduced. But, the cost evaluation of the bridge inspection strategies in consideration of the bridge monitoring has not discussed enough in current situation. In this study, the cost evaluation method for bridge inspection alternative by using Real Options method has been proposed. Then, by the proposed cost evaluation method considering the change of inspection cost in the future, the role of monitoring of bridge inspection has been discussed., TAYLOR & FRANCIS LTD
Life-Cycle Cost and Performance of Civil Infrastructure Systems, 2007年,
［査読有り］ Performance of a BOTDR optical fibre sensing technique for crack detection in concrete structuresWu; Z. S.; Xu; B.; Takahashi; T. and Harada; T, Strain distribution measurements and problematic crack detection are important issues in the damage detection and performance evaluation of concrete, or reinforced concrete, structures. In recent years, the Brillouin Optical Time Domain Reflectometry (BOTDR) based optical fibre sensing technique has attracted great attention as a distributed monitoring method. Current BOTDR instruments are suitable for strain measurements over a certain distance (termed spatial resolution), but damage such as cracks in concrete structures are local. It is crucial to find an effective method to detect local damage in concrete. In this study, two basic optical fibre installation methods, overall bonding (OB) installation and point fixation (PF) installation, are proposed. Then, several unique installation methods (one-round, one-round superposition and two-round superposition) are proposed and investigated experimentally for a reinforced concrete bending beam. The efficiency of the proposed installation methods and the effect of the length of the sensing region on the measurement accuracy are also discussed. Experimental results show that the n-round superposition installation method can effectively and correctly detect the total crack width within a relatively local region. The performance of the overall bonding and point fixation installation methods with different sensing region lengths, or gauge lengths, for local crack initiation and total crack width measurement is also discussed., TAYLOR & FRANCIS LTD
Journal of Structure and Infrastructure Engineering, 2006年11月,
［査読有り］ Electrical and Mechanical Characterization of Hybrid CFRP SheetsWu; Z.S.; Yang; C.Q.; Tobe; Y.; Ye; L.P. and Harada; T., This study brings forth the electrical and mechanical models of a new kind of hybrid carbon fiber-rein forced polymer (HCFRP) composites consisting of several types of carbon fibers with different strengths and Young's moduli. Then, an experimental program with some main variables including the carbon fiber types and their volume fractions has been carried out. Six types of specimens have been fabricated to investigate the mechanical properties and self-health monitoring function of the HCFRP sheets with different types of carbon fiber and volume fractions. The experimental results indicate that the hybridization of several types of carbon fibers is an effective method for upgrading the mechanical properties of the HCFRP sheets. The electrical resistance of the HCFRP sheets changes with the strain in a stepwise manner due to the gradual macro-fracture of different types of carbon fibers. The number of steps is related to the number of carbon fiber types. It has also been shown that the ruptured carbon fibers can still contribute to the current conduction through transverse electrical conduction. The good correlations between the mechanical and electrical behaviors reveal the self-health monitoring function of the HCFRP sheets., SAGE PUBLICATIONS LTD
Journal of Composite Materials, 2006年02月,
［査読有り］ Structural health monitoring in a tunnel management systemHarada; T.; Miyazawa; S. and Wu; Z.S., 筆頭著者, The concrete block falling accident in the railway tunnel made the maintenance of tunnel structures an emergency problem in Japan. The present work of tunnel management cannot meet the needs for management of tunnel structures because of lack of systematizing. On the other hand, the development of decentralized management of data, utilization of advanced sensing technology like optical fiber, and improvement in network technology make it possible to update the present work of tunnel management. In this paper, a Tunnel Management System (TMS) is proposed with the support of these advanced technologies. And, this study developed a seamlessly real network and designed a remote monitoring system in TMS with advanced functions., SOUTHEAST UNIV PRESS
Proc. of International Symposium on Innovation & Sustainability of Structures in Civil Engineering - Including Seismic Engineering, 2005年11月,
［査読有り］ An Experimental Study on the Measuring Characteristic of BOTDR for Structure Health Monitoring
Wu, Z.S; Shi, B; Harada, T; Ishii, T; Xu, B
China Civil Engineering Journal, 2005年08月, ［査読有り］
Self-diagnosis of structures strengthened with hybrid carbon-fiber-reinforced polymer sheetsWu; Z.S.; Yang; C.Q.; Harada; T. and Ye; L.P., The correlation of mechanical and electrical properties of concrete beams strengthened with hybrid carbon-fiber-reinforced polymer (HCFRP) sheets is studied in this paper. Two types of concrete beams, with and without reinforcing bars, are strengthened with externally bonded HCFRP sheets, which have a self-structural health monitoring function due to the electrical conduction and piezoresistivity of carbon fibers. Parameters investigated include the volume fractions and types of carbon fibers. According to the investigation, it is found that the hybridization of uniaxial HCFRP sheets with several different types of carbon fibers is a viable method for enhancing the mechanical properties and obtaining a built-in damage detection function for concrete structures. The changes in electrical resistance during low strain ranges before the rupture of carbon fibers are generally smaller than 1%. Nevertheless, after the gradual ruptures of carbon fibers, the electrical resistance increases remarkably with the strain in a step-wise manner. For the specimens without reinforcing bars, the electrical behaviors are not stable, especially during the low strain ranges. However, the electrical behaviors of the specimens with reinforcing bars are relatively stable, and the whole range of self-sensing function of the HCFRP-strengthened RC structures has realized the conceptual design of the HCFRP sensing models and is confirmed by the experimental investigations. The relationships between the strain/load and the change in electrical resistance show the potential self-monitoring capacity of HCFRP reinforcements used for strengthening concrete structures., IOP PUBLISHING LTD
Smart Materials and Structure, 2005年06月,
［査読有り］ A soft post-earthquake damage identification methodology using vibration time seriesXu; B.; Wu; Z.S.; Yokoyama; K. and Harada; T., A neural-network-based post-earthquake damage identification methodology for smart structures with the direct use of vibration measurements is developed. Two neural networks are constructed to facilitate the process of post-earthquake damage identification. The rationality of the proposed methodology is explained and the theory basis for the construction of an emulator neural network (ENN) and a parametric evaluation neural network (PENN) are described according to the discrete time solution of the structural state space equation. An evaluation index called the root mean square of the prediction difference vector (RMSPDV) is presented to evaluate the condition of different associated structures. Based on the trained ENN, which is a non-parametric model of the object structure in a healthy state, and the PENN that describes the relation between structural parameters and the components of the corresponding RMSPDVs, the inter-storey stiffness of the damaged object structure is identified. The accuracy, sensibility and efficacy of the proposed strategy for different ground excitations are also examined using a multi-storey shear building structure by numerical simulations. Since the methodology does not require the extraction of structural dynamic characteristics such as frequencies and mode shapes from measurements, it has the potential of being a practical tool for health monitoring of smart engineering structures., IOP PUBLISHING LTD
Smart Materials and Structure, 2005年06月,
［査読有り］ Optimization of maintenance strategies for road pavement by considering flexibility of alternativesHarada, T; Yokoyama, K, 筆頭著者, 道路舗装の維持管理においては,限られた予算の中で道路利用者や周辺住民に対するサービス水準を維持するための効果的な補修計画を立てる必要がある.一方,将来が不確実な状況下で計画案の持つフレキシビリティの価値を評価する手法としてリアルオプションの導入が注目されている.本研究では,計画案を導出するための最適化手法として遺伝的アルゴリズムを利用し,フレキシビリティを考慮した道路舗装の維持管理計画を策定する最適化システムの開発を行った.そして,このシステムを利用して実路線のデータによる数値シミュレーションを行った結果,計画案のフレキシビリティを考慮しない硬直的な評価手法よりも効果の高い計画案が得られることを確認でき,開発したシステムの有用性が確認できた., Japan Society of Civil Engineers
Proc. of 4th International Workshop on Life-Cycle Cost Analysis and Design of Civil Infrastructure Systems, 2005年05月,
［査読有り］ 計画案のフレキシビリティを考慮した道路舗装の維持管理計画策定システムの開発原田隆郎,吉田勘平,横山功一, 筆頭著者, 道路舗装の維持管理においては,限られた予算の中で道路利用者や周辺住民に対するサービス水準を維持するための効果的な補修計画を立てる必要がある.一方,将来が不確実な状況下で計画案の持つフレキシビリティの価値を評価する手法としてリアルオプションの導入が注目されている.本研究では,計画案を導出するための最適化手法として遺伝的アルゴリズムを利用し,フレキシビリティを考慮した道路舗装の維持管理計画を策定する最適化システムの開発を行った.そして,このシステムを利用して実路線のデータによる数値シミュレーションを行った結果,計画案のフレキシビリティを考慮しない硬直的な評価手法よりも効果の高い計画案が得られることを確認でき,開発したシステムの有用性が確認できた., Japan Society of Civil Engineers
土木学会舗装工学論文集, 2004年12月,
［査読有り］ Applying Moving Vehicle Load to Structural Identification and Health Monitoring of Bridges
Rafiquzzaman; A.K.M; Yokoyama, K; Yoshizawa, E; Harada, T
Second International Workshop on Structural Health Monitoring of Innovative Civil Engineering Structures, 2004年09月, ［査読有り］
鋼合成桁の温度分布に影響を及ぼす環境要因に関する実験的研究
高木優任,横山功一,原田隆郎
構造工学論文集, 2004年03月, ［査読有り］
In-situ damage detection of concrete beams strengthened with hybrid CFRP sheets by DC electrical resistanceWu; Z.S.; Yang; C.Q.; Harada; T. and Tobe; Y., In this paper, the mechanical and electrical behaviors of strengthened concrete beams with a new kind of hybrid carbon fiber reinforced polymers (HCFRP) sheets of several kinds of carbon fibers are investigated. The main purpose is to find out the self-health monitoring function of concrete beams externally strengthened with HCFRP through DC electrical resistance measurement. An experimental program with the main parameters including the volume fractions of high modulus (HM) carbon fibers and fiber types has been performed. According to the experimental results, it is revealed that the hybridization of unidirectional HCFRP with different kinds of carbon fibers is a viable method of upgrading mechanical properties and obtaining a built-in in-situ damage detection functions for concrete structures. In a small strain range, the resistance becomes more and more negative as cyclic loading progresses for the specimens with more amount of HM; however, the electrical resistance keeps almost constant for the specimens with less amount of HM. In a high strain ranges, the resistance changes in a step-wise manner, and the sudden steps are attributed to the bundle rupture of HM. Good corresponding relationship between load and the change in resistance reveal the potential damage detection feasibility of FCFRP strengthened beams. In addition, it is shown that the ultimate failure modes change from CFRP debonding to concrete rupture with the increase of C7., A A BALKEMA PUBLISHERS
First International Conference on Structural Health Monitoring and Intelligent Infrastructure (SHMII-1'2003), 2003年11月,
［査読有り］ 外部環境の変化がインテグラル複合ラーメン橋の挙動に及ぼす影響に関する検討
高木優任,横山功一,原田隆郎
鋼構造論文集, 2003年06月, ［査読有り］
橋梁の補修履歴データによる補修率曲線の同定原田隆郎,横山功一, 筆頭著者, 橋梁台帳に記録されている補修歴は過去の補修実績を記録したものであるが, データの蓄積が十分に行われていないなどの問題からマネジメントシステムにおいて有効に使われていない. しかしながら, 補修歴は地域ごとの維持管理方針が反映されており, 長期的な維持管理策定のためには有益な情報となる. 本研究では, 維持管理計画の策定を支援する長期供用性予測手法を開発することを目的とし, 補修歴をもとに過去の補修実績に基づく補修の必要度を表現する曲線を提案した. 各橋梁の補修履歴データを分析し, 各地域, 各部材, 各対策の補修実績の傾向を把握するとともに, 累積大型車交通量と補修件数の関係より補修率曲線を同定した. そして, 補修率曲線を用いた長期的な維持管理計画の策定手法を提案した., 公益社団法人 土木学会
土木学会論文集, 2003年06月,
［査読有り］ 遺伝的アルゴリズムの階層化による橋梁の維持管理計画モデルの開発原田隆郎,富田義紀,横山功一, 筆頭著者, 道路構造物に対する維持管理費の増大に伴い, 近年, 橋梁や舗装, トンネルなどに対する経済的かつ予防保全的な維持管理の重要性が高まっている.本研究では, 遺伝的アルゴリズム (GA) を階層化させることにより, 複数橋梁の中・長期的な維持管理計画を策定する最適化モデルを開発した.数値シミュレーションの結果, 階層型GA最適化モデルでは局所解からの回避が実現できたとともに, 複数橋の維持管理計画の策定に関して有効であることを見出せた., Japan Society of Civil Engineers
土木情報システム論文集, 2001年10月
Decentralized Control of a Cable-stayed Bridge Using Multi-layer Neural NetworksXu, B; Wu; Z. S; Yokoyama, K; Harada, T, The structural identification and dynamic control of a cable-stayed bridge are considered to be difficult due to the structural complicacy and system uncertainties. In this paper, based on the concept of decentralized information structures, a decentralized non-parametric identification and control method is proposed with neural networks for the purpose of suppressing the vibration of a well-studied and documented two-cable-stayed bridge induced by earthquake excitations. The control strategy proposed here uses the stay cables as active tendons to provide control forces through appropriate actuators. Each individual actuator is controlled by a decentralized neuro-controller that only uses local velocity and relative displacement information. The feature of decentralized control simplifies the implementation of the control algorithms and makes decentralized control easy to practice and cost effective. The effectiveness of the decentralized identification and control algorithm is evaluated through numerical simulations. The performance of the decentralized control is compared with that of the linear decentralized control method. And the adaptability of the decentralized neuro-controllers for different kinds of earthquake excitations is demonstrated via simulations., 日本計算工学会
Transactions of JSCES, 2001年05月,
［査読有り］ 固有振動数の変化による大型構造システムの局所劣化同定法の提案
呉 智深,原田隆郎,三宅博之
構造工学論文集, 2000年03月
遺伝的アルゴリズムによる大規模既存道路橋の耐震補強計画支援モデルの構築
呉 智深,原田隆郎,横山功一
構造工学論文集, 1998年03月, ［査読有り］
Genetic Algorithms-based reinforcement strategies for large scale deteriorating road bridgesWu; Z. S.; Harada; T. and Sato; F., In this paper. to establish a rational strengthening strategy for large-scale old and weak earthquake-resistant existing structures, a conceptual framework for evaluating the importance factor is developed. Then, based on the importance analysis, a general framework of strengthening strategies for large-scale bridge structures is formulated as a constrained, nonlinear optimum problem in which the total strengthening efficacy for different bridge and its different component level receive maximum within the total budget. The Genetic Algorithms are introduced to solve the optimization problem. Some efforts are made for investigating the performances and adaptabilities of different kind of Genetic Algorithms. To assess the performance of the estimator, some numerical simulations and a real investigation on existing road bridges within the area of Ibaraki prefecture are carried out. Finally, a computerized prioritization algorithm to assign a quantified ranking for retrofit and budget distribution is suggested., TECHNO-PRESS
Proc. of 7th Int. Conf. on Computing in Civil and Building Engineering, 1997年08月,
［査読有り］ Optimum modeling for maintenance planning of road pavements using Hopfield Neural NetworkWu; Z. S.; Yoshida; N.; Harada; T. and Iwamatsu, To design an optimum maintenance program, in this paper, a methodology combined with the analysis both in space and in time scales is proposed based on optimization methods. In the optimum modeling, an objective function that takes into account the total value of assembly of existing road pavements during a projected service period is used, by keeping the damage levels of ail units of road pavements at or below an established target value (a threshold value of damage). The Hopfield neural network is used to search for the solution as a minimizator in the optimization procedure. As an illustration, the methodology is applied to some road pavement systems that are designed for simulation. Finally, a real road pavement system located in Niigata prefecture is also investigated. In detail we discussed about optimum maintenance distance as a unit and maintenance-cycle., TECHNO-PRESS
Proc. of 7th Int. Conf. on Computing in Civil and Building Engineering, 1997年08月,
［査読有り］ Computational modeling on parameter estimation of large scale structures from static responses
Wu, Z. S; Iwamatsu, S; Harada, T
Proceedings of the 3rd Asian-Pacific Conference on Computational Mechanics, 1996年09月, ［査読有り］
フラクタル次元・１／ｆゆらぎを応用した橋梁の景観性評価支援システム吉岡正泰,岩松幸雄,原田隆郎,阿久澤孝之, 近年、橋梁の設計においては、周辺環境と調和し人間に "うるおい" や "やすらぎ" を与えるような景観設計が重要視されている。しかしながら、景観性については人によって感じ方が異なることから、それを定量的に評価できる指標が整備されていないのが現状である。
そこで本研究では、橋梁形式選定のためにファジィ推論による景観性評価支援システムを構築し、そのシステムにおける景観性評価指標としてフラクタル次元と1/fゆらぎの概念を導入した。そして、実際に架けられている橋梁を用いてシステムの検証をした結果、フラクタル次元と1/fゆらぎ*概念が景観性を定量化する指標の一つとして適用できることがわかった。, Japan Society of Civil Engineers
土木情報システム論文集, 1993年10月,
［査読有り］ 橋梁の比較設計支援エキスパートシステムに関する研究岩松幸雄,早川裕史,原田隆郎, 近年, 土木設計におけるコンピュータ利用はCADのみならず, エキスパートシステムにも適用されてきた. しかし, それらは橋梁全体を対象にして複数の評価要素を考慮する比較設計のような, 設計者の総合的な知識経験を必要とするものではなかった. 本研究では橋梁の上部工, 下部工, そして基礎工を対象に, 経済性, 施工性, 環境適合性等の複数の評価要素を組み込んだエキスパートシステムを提案した. そして, 過去に実施された比較設計と比較することによって本システムの有効性を検証した., 公益社団法人 土木学会
土木学会論文集, 1992年09月,
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