記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

researchmap

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

J-GLOBAL

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Informa UK Limited  

DOI： 10.1080/15732479.2024.2413637

researchmap

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

researchmap

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

researchmap

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

researchmap

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：International Association for Bridge and Structural Engineering (IABSE)  

<jats:p>Orthotropic steel decks in long-span steel bridges are susceptible to fatigue cracking, especially subsurface root-deck cracks. These cracks, hard to detect visually, can cause significant damage if unnoticed. Therefore, the early detection of these subsurface cracks is crucial in preventing further deterioration and ensuring the long-term sustainability of the bridge. In this study, a novel approach for the detection of subsurface cracks in orthotropic steel decks, utilizing new signal processing techniques based on eddy current technology (ECT), as well as optimizing the configuration of the ECT probes, is proposed. Through numerical analysis, response signals obtained from subsurface crack detection using ECT in frequency domains are extracted and analyzed with the proposed method to develop advanced feature extraction techniques that enhance sensitivity and improve the depth of subsurface crack detection. Additionally, various coil-based eddy current probes are examined to identify the most suitable probe configuration that offers robust performance in detecting subsurface cracks. The findings from this study contribute to the advancement of more effective strategies for subsurface crack detection in orthotropic steel decks by integrating advanced eddy current techniques, feature extraction methods, and optimized hardware configurations.

</jats:p>

CiNii Research

researchmap

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：International Association for Bridge and Structural Engineering (IABSE)  

<jats:p>Despite Finite Element Analysis (FEA) having a strong theoretical foundation with high accuracy, its significant limitation in computational time is highlighted when a large number of FEAs is required. This study thus desires to address the issue by investigating the capabilities of Neural Networks (NNs) in being surrogate models of highly detailed FE models. The generalized processes of the NN model development and the exemplar architectures of the NN models for predicting the frequencies and mode shapes are first proposed before being applied to the task of high dimensional Finite Element Model Updating (FEMU) of a complex cable-stayed bridge. Then, the aspects of the computational time, accuracy, and challenges of the NNs in future works are discussed. Results from the FEMU that utilizes the multi-restart Genetic Algorithm (GA) emphasize the efficiency of the NNs in leading the GA toward an updated FE model that better replicates the actual dynamic responses.

</jats:p>

CiNii Research

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Informa UK Limited  

DOI： 10.1080/15732479.2023.2218351

CiNii Research

researchmap

記述言語：日本語   出版者・発行元：公益社団法人 土木学会  

本研究は，橋梁の振動応答を利用した交通環境センシングの構築を目指し，時間領域解析による特徴抽出とニューラルネットワーク（Neural Network: NN）による橋梁上と橋梁周辺の移動体の検知と識別を試みた．はじめに，加速度の振動応答から移動体通過による強制加振を自動検知してデータの抽出を行った．次に，最大振幅や実効値などの特徴量に加えて，歩行者や周辺交通（鉄道）による振動波形の周期性に着目した波群周期，モード形状に着目した加速度センサ間の波形ラグなどの特徴量を提案し，複数のアルゴリズムを用いた特徴量評価を行った．その上で，重要度が高い特徴量を入力として移動体を識別するNNを構築し，移動体が単独通過する条件のデータで検証した結果，適合率が90%以上であることを示した．

DOI： 10.11532/jsceiii.4.3_715

CiNii Research

researchmap

出版者・発行元：International Association for Bridge and Structural Engineering (IABSE)  

<jats:p>High-strength bolted joints are widely used in steel bridges. However, bolt axial force may decrease during the service life of a bridge for many reasons including relaxation, traffic load, and earthquake. Consequently, the remaining bolt axial force is considered a factor with uncertainty that is important to evaluate. In a previous study, the authors proposed an axial force evaluation method using eddy current. In this study, to apply the proposed axial force evaluation method to the actual measurements, new evaluation indices with the possibility of reducing measurement errors and simplifying measurement have been considered. The applicability of the improved method for high- strength bolts using weathering steel has also been examined. An experiment using both high- strength bolts and weathering steel high-strength bolts was conducted to investigate the possibility of evaluating the stress change due to the axial force with the new indices.

</jats:p>

DOI： 10.2749/prague.2022.1148

CiNii Research

researchmap

出版者・発行元：International Association for Bridge and Structural Engineering (IABSE)  

<jats:p>In this study, an influence line of the girder displacement of the bridge was estimated by Bridge- Weigh-In-Motion using an accelerometer. Displacement was calculated by two times of integration of the measured acceleration. The data has the problem of low sensitivity due to a single sensor, and it contains measurement noise. To compensate for these problems, two correction methods were applied to the integration result. They were the baseline correction method and the drift correction method using boundary conditions of traffic-induced vibrations. It was shown that the result of integration was improved by using these methods. A calibration process to estimate the influence line of the bridge was proposed using iterative calculation method to optimize the result using local buses. It was shown that by using this method, vehicle detection and weight estimation can be performed with high accuracy, especially for large vehicles.

</jats:p>

DOI： 10.2749/prague.2022.0407

CiNii Research

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

出版者・発行元：International Association for Bridge and Structural Engineering (IABSE)  

<jats:p>Thermoelectric energy harvesting was studied using the temperature difference in concrete bridges. A design of the heat sink unit of thermoelectric energy harvesters was parametrically analyzed using FE models. Prototype thermoelectric energy harvesters were fabricated and tested in a simple wind tunnel. The experiment was carried out on a concrete bridge. The concrete bridge accumulated thermal energy from sunlight, and the temperature difference with the air occurred. The thermal energy was harvested especially in daytimes. On the other hand, electric power was less generated at night-times than expected. The harvesting energy would be significantly improved if the problem is solved.

</jats:p>

DOI： 10.2749/prague.2022.0458

DOI： 10.2208/jscejj.23-00293_references_DOI_I5lS5w3xYp0194AZeqPaxUao9Lk

CiNii Research

researchmap

出版者・発行元：Elsevier BV  

Abstract This paper presents a verification of tensile strength and failure mechanism of internal diaphragms in wide flange (WF) beam-to-box column connections with and without concrete filling. The flexural load transfer mechanism from the beam flange to column was locally evaluated based on a plate-to-box column connection with an internal diaphragm. The objective of this study is to establish an efficient design method for the internal diaphragms in WF-beam-to-box column connections. First, theoretical and experimental approaches were used to evaluate a strength equation considering the effects of the plate-to-column width and column width-to-thickness ratios and concrete filling. Finally, the cyclic performance of the WF-beam-to-box column connections was numerically assessed to validate the design and response of the internal diaphragms. The results showed that concrete filling was able to improve the connection strength by approximately 30% compared to that without concrete filling. It was also confirmed that the plate-to-column width and column width-to-thickness ratios did affect the tensile strength of the connection and must be considered in the strength equation. More importantly, the response of an internal diaphragm designed using the proposed equation in this study was validated and confirmed by both the experiment and the numerical evaluation.

DOI： 10.1016/j.jobe.2020.102037

CiNii Research

researchmap

出版者・発行元：International Association for Bridge and Structural Engineering (IABSE)  

<jats:p>The hammer test is generally used as one of the non-destructive methods for detecting defects such as voids and delamination in concrete structures like tunnels and bridges. It is necessary to eliminate human mistakes and improve quantitative analysis so that Impact Acoustics Method (IAM) was proposed and studied. IAM helps human decision of the defective concrete parts through comparing waveform and frequency distribution between healthy and defective parts which are taken from sensor or microphone. Hence, artificial intelligence (AI) is expected to replace or assist the human labor inspection by quantifying the defects. This research aims to inspect defects quickly and efficiently the only microphone through promoting a machine learning AI analysis system flow which mainly includes neural networks. Two experiments were held to achieve the purpose.

</jats:p>

DOI： 10.2749/ghent.2021.0955

CiNii Research

researchmap

J-GLOBAL

researchmap

出版者・発行元：International Association for Bridge and Structural Engineering (IABSE)  

<jats:p>Many bridges have been in service for over 40 years and face to the repapering or reinforcing period due to deterioration. Particularly, in a high-strength bolts used for joints may be loosened due to co-rotation, corrosion, or vibration caused by the vehicles. Thus, it is important to evaluate an axial force of the high-strength bolts. In this research, an axial force evaluation of high-strength bolt using eddy current that does not require measurement preparation has been investigated. The eddy current method is capable of capturing the change in permeability of steel members due to the stress change. Further, the stress distribution of the bolt head is assumed uniform without directionality. Therefore, a numerical simulation and an experiment that measures the output signal of the eddy current probe while introducing axial force to the high-strength bolt has conducted.

</jats:p>

DOI： 10.2749/christchurch.2021.0045

DOI： 10.2208/jscejseee.78.1_108_references_DOI_KdqNvwTxWX9VgSfhIHPHYlZz5ts

CiNii Research

researchmap

出版者・発行元：Informa UK Limited  

In this paper, a method called “least-work solution” was empirically simplified to evaluate shear lag stress in the steel box moment connections with internal diaphragms in order to serve for the p...

DOI： 10.1080/15376494.2019.1710004

CiNii Research

researchmap

researchmap

J-GLOBAL

researchmap

出版者・発行元：Informa UK Limited  

This paper presents determination of the stress state of steel bridges, due to stress redistribution because of corrosion or cracking, as a new important parameter in structural health monitoring f...

DOI： 10.1080/15732479.2019.1703759

DOI： 10.2208/jscejseee.78.2_231_references_DOI_3m8qk9s5M8LP3Tq2hUjkfrEkXIT

CiNii Research

researchmap

出版者・発行元：Elsevier BV  

Abstract This paper presents numerical and theoretical studies on the performance of internal diaphragm connections to box columns. The study aims to investigate the static and cyclic performances of the connections including the behavior of diaphragms. This paper contains an assessment of the numerically and theoretically parametric studies on plate-to-box column connections considering several influence parameters, such as diaphragm, plate width, and column thickness. Subsequent sections discuss the prediction and validation of strength of the connections, followed by the performance of wide flange (WF) beam-to-box column connections. The results are presented and discussed as finding that diaphragms were the key elements to enhance the performance of the connections.

DOI： 10.1016/j.tws.2019.106221

CiNii Research

researchmap

出版者・発行元：Informa UK Limited  

This article presents corrosion profile estimation as a method to determine the extent of corrosion in steel members having corroded exterior, with or without protective cover, when the only side a...

DOI： 10.1080/15732479.2019.1615961

CiNii Research

researchmap

出版者・発行元：American Society of Civil Engineers (ASCE)  

DOI： 10.1061/(asce)be.1943-5592.0001356

CiNii Research

researchmap

出版者・発行元：Springer Science and Business Media LLC  

This study aims to investigate the effects of strain rate on the low-cycle fatigue strength of steel welded joints. Load-carrying cruciform joints with different material mismatch ratios were fabricated in order to observe the effects of material mismatching. A series of displacements that generate low-cycle fatigue damage were applied to the specimens. The experiment was conducted by fast cyclic loading and displacement control, using feedback from a displacement transducer. The feedback control algorithm was found to be critical. Thus, a non-linear feedback control algorithm, i.e., PID control, was implemented in the testing machine. An experimental setup capable of fast cyclic loading was developed. Fatigue life based on the load drop curve indicated that higher strain rates caused lower fatigue life. Failure behavior regarding the strain rate effects of steel welded joints was observed.

DOI： 10.1007/s13296-018-0026-x

CiNii Research

researchmap

記述言語：日本語   出版者・発行元：公益社団法人 土木学会  

これまで筆者らは，500Hz以下の低周波渦電流により得られた検出電圧信号を用いた腐食を有する鋼部材のさび層と残存板厚を推定する腐食損傷状態分析手法を提案しているが，本研究ではさらなる精度向上と測定の簡易化を目指し，検出電圧とともに板厚情報を同時に取得可能であると考えられる位相特性を活用した腐食損傷分析手法の検討を行う．はじめに，数値シミュレーションにより損傷状態の違いを想定した低周波渦電流特性を明らかにし，その違いを捉えるために検出電圧と入力電流に対する検出電圧の位相差に着目した分析手法について検討した．そして，これらの検討結果に基づき，より高度な鋼部材の腐食損傷分析手法を構築し，実験によって提案手法の適用性について検討を行った．

DOI： 10.2208/jscejseee.74.145

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

記述言語：英語  

CiNii Research

researchmap

J-GLOBAL

researchmap

記述言語：日本語   出版者・発行元：公益社団法人 土木学会  

本研究では腐食損傷を有する鋼部材を対象として，さび層の生成や減肉等の損傷の程度を分析すべく，さび厚と残存板厚を同時に取得可能な分析手法について検討した．非破壊的に簡便な分析手法とするため渦電流試験に着目し，特に1～1000Hz程度の低周波渦電流を用い，鋼部材の表裏どちらか一方の面からの検査で腐食損傷状態を検出可能な分析手法の検討を行う．励磁波形として，一度に多くの板厚情報が取得可能なスイープ波と簡易な周波数ステップ波形を設計した．本研究では時間領域で周波数特性を把握可能なウェーブレット解析を導入し，指標として検出電圧とウェーブレット係数を用いる手法について検討した．数値シミュレーションと実験両面からの検討結果に基づいて鋼部材の腐食損傷状態分析手法を提案し提案手法の有効性について検討を行った．

DOI： 10.2208/jscejseee.73.387

researchmap

出版者・発行元：Informa UK Limited  

AbstractApplication of maintenance to ensure the safety, extend the service life and reduce the life-cycle cost of civil structures is important. In this paper, a new inspection method is proposed using a robot which can effectively approach target sections of structures, such as areas that are either too narrow or too dangerous to approach and perform both visual and detailed inspection with various devices. The small-sized self-propelled robot was initially developed. The test model can freely move on the surfaces of various types of structures. Next, the function to detect the deterioration of concrete or steel surfaces by attached cameras to the robot was examined. Moreover, a function was installed to identify the location of the robot automatically using a phase-only correlation method and to determine structural behaviours using an accelerometer. Finally, the applicability of robotic movement and all installed functions was tested on an existing bridge.

DOI： 10.1080/15732479.2016.1236132

CiNii Research

researchmap

掲載種別：研究論文（学術雑誌）   出版者・発行元：Elsevier BV  

Abstract A bridge vibration energy harvester has been proposed in this paper using a tuned dual-mass damper system, named hereafter Tuned Mass Generator (TMG). A linear electromagnetic transducer has been applied to harvest and make use of the unused reserve of energy the aforementioned damper system absorbs. The benefits of using dual-mass systems over single-mass systems for power generation have been clarified according to the theory of vibrations. TMG parameters have been determined considering multi-domain parameters, and TMG has been tuned using a newly proposed parameter design method. Theoretical analysis results have shown that for effective energy harvesting, it is essential that TMG has robustness against uncertainties in bridge vibrations and tuning errors, and the proposed parameter design method for TMG has demonstrated this feature.

DOI： 10.1016/j.jsv.2015.10.002

DOI： 10.2183/pjab.94.008_references_DOI_LJcTqyrbMlyQPgZ5QbXlkpdxLLC

CiNii Research

researchmap

J-GLOBAL

researchmap

掲載種別：研究論文（学術雑誌）   出版者・発行元：MDPI AG  

<jats:p>Polyvinylidene Flouride (PVDF) is a film-type polymer that has been used as sensors and actuators in various applications due to its mechanical toughness, flexibility, and low density. A PVDF sensor typically covers an area of the host structure over which mechanical stress/strain is averaged and converted to electrical energy. This study investigates the fundamental “stress-averaging” mechanism for dynamic strain sensing in the in-plane mode. A numerical simulation was conducted to simulate the “stress-averaging” mechanism of a PVDF sensor attached on a cantilever beam subjected to an impact loading, taking into account the contribution of piezoelectricity, the cantilever beam’s modal properties, and electronic signal conditioning. Impact tests and FEM analysis were also carried out to verify the numerical simulation results. The results of impact tests indicate the excellent capability of the attached PVDF sensor in capturing the fundamental natural frequencies of the cantilever beam. There is a good agreement between the PVDF sensor’s output voltage predicted by the numerical simulation and that obtained in the impact tests. Parametric studies were conducted to investigate the effects of sensor size and sensor position and it is shown that a larger sensor tends to generate higher output voltage than a smaller one at the same location. However, the effect of sensor location seems to be more significant for larger sensors due to the cancelling problem. Overall, PVDF sensors exhibit excellent sensing capability for in-plane dynamic strain induced by impact loading.</jats:p>

DOI： 10.3390/s16050601

PubMed

CiNii Research

researchmap

その他リンク： https://dblp.uni-trier.de/db/journals/sensors/sensors16.html#DungS16

J-GLOBAL

researchmap

記述言語：英語   出版者・発行元：Japan Society of Civil Engineers  

This study aims to investigate the effects of very high strain rate on low-cycle fatigue behavior of structural steel under large plastic strain with strain rate order of 1.0 s^-1 as expected during earthquakes. Low-cycle fatigue tests were conducted using compact-tension specimens at various strain rate levels. Fatigue life based on crack size indicated that the higher strain rate caused lower fatigue life in large plastic strain region. The energy approach was employed to clarify the low-cycle fatigue mechanism in this region. Finally, a prediction method for fatigue life regarding high strain rate effect in large plastic strain region is proposed in this study.

DOI： 10.2208/journalofjsce.4.1_118

CiNii Research

researchmap

出版者・発行元：Springer Science and Business Media LLC  

There are a number of existing steel railway bridges which has problems regarding structure-borne noise under train passage. Authors have proposed a performance improvement method of existing steel railway bridges by installing concrete deck. By this method, the vibration of the girder and the structure-borne noise are expected to be reduced. Generally, it is known that concrete deck can reduce the vibration and the noise. However, the noise reduction effect has not been clarified. In this study, impact hammer tests were carried out to figure out the reduction effect of the concrete deck on the vibration and the noise. Through the test, it was found that the response acceleration of the steel girder web was reduced by installing the concrete deck, as a result of reducing the propagation of on-girder vibration into the steel girder.

DOI： 10.1007/s13296-015-3015-3

CiNii Research

researchmap

出版者・発行元：Springer Science and Business Media LLC  

DOI： 10.1007/s13296-015-3018-0

DOI： 10.2208/jscejseee.74.145_references_DOI_BAvI0SXsXcvCUE81eK6IP2TKKcZ

CiNii Research

researchmap

その他リンク： http://link.springer.com/article/10.1007/s13296-015-3018-0/fulltext.html

記述言語：日本語   出版者・発行元：Japan Society of Civil Engineers  

地震時の鋼部材溶接止端部においては，ごく浅い表面亀裂を起点として脆性破壊が誘発される場合があると考えられる．その際の発生条件には溶接部形状が大きく関与するため，既存の手法では破壊発生限界の評価は困難となり，危険側の予測を与える可能性を残している．本研究では，鋼材内部におけるマイクロクラックの発生・進展過程を考慮した修正ワイブル応力に基づき，低温破壊実験と数値解析によって地震時脆性破壊を想定した破壊発生限界の評価を行った．その結果，修正ワイブル応力の限界値が止端半径，初期亀裂深さ，温度等に依存しない材料固有の特性値とみなせ，これを用いることで一般性の高い破壊予測が可能となることが示された．その上で，実構造物への適用例として鋼製橋脚隅角部の破壊限界評価を試み，破壊確率を定量的に扱う手法を示した．

DOI： 10.2208/jscejseee.71.173

researchmap

出版者・発行元：International Association for Bridge and Structural Engineering (IABSE)  

DOI： 10.2749/222137815815622915

DOI： 10.3151/coj.60.1_134_references_DOI_XoQjS65rkgXGSqoMdCfUUSxRtPx

CiNii Research

researchmap

出版者・発行元：International Association for Bridge and Structural Engineering (IABSE)  

<jats:p>Bridge Structural Health Monitoring (SHM) system could provide the assessment of the bridge structure condition immediately after the occurrence of a major seismic event, potentially enhancing safety and reducing the time needed for evaluating the bridge state before bridge is being returned to service.

The bridge wireless SHM sensor node operates on batteries and records data intermittently, when triggered. The sensors located on the bridge records both seismic events and various traffic induced vibrations. An independent triggering algorithm of each sensor node using the acceleration data recorded on the bridge has been adopted. Several trigger algorithms are being compared for enhancing detection of seismic events in the presence of the traffic and wind induced vibration. The preliminary analysis of the data at the bridge sensor setup location is being used for the validation of the proposed triggering algorithm. An in-memory event classification algorithm is being used to determine seismic events triggers and traffic induced triggers. Trigger detection with simulated earthquake records data was conducted to evaluate the effectiveness of trigger detection algorithm.

</jats:p>

DOI： 10.2749/222137815815775781

DOI： 10.2183/pjab.94.008_references_DOI_XQBFsIK9ig7QePwE16iwfnTG2KA

CiNii Research

researchmap

出版者・発行元：Springer Science and Business Media LLC  

A common practice for the manufacture of orthotropic steel decks in Japan is to use 75% partial joint penetration welds between closed ribs and deck plates. To evaluate the effectiveness of the proposed 100% penetration on improving the fatigue strength of rib-to-deck welded joints in orthotropic steel bridge decks, four full-scale orthotropic deck specimens were subjected to laboratory testing. Specimens, consisting of a 12-mm-thick deck plate and 6-mm-thick rib, with one closed rib, were fabricated with 75% and 100% penetration. Fatigue test results showed that fatigue cracks initiated from the weld toe inside the rib in the 100% penetration specimens, but from weld root inside the rib in the 75% penetration specimens. To investigate this fatigue behavior, strain measurements were taken at 5 mm from the rib-to-deck weld line. Results of finite element analysis using the effective notch stress method indicate that a deeper partial penetration results in a slightly higher effective notch stress at the weld root of the partial penetration weld. The effective notch stress at the crack initiation location with 100% penetration is lower than that obtained with partial penetration. The open angle appears to have a significant effect on the effective notch stress at the upper weld toe when using 100% penetration. Therefore, the proposed 100% penetration appeared to have a positive effect on enhancing the fatigue resistance of rib-to-deck welded joints.

DOI： 10.1007/s13296-014-1103-4

DOI： 10.2208/jscejseee.72.393_references_DOI_N2NdX9JxKW5ORFyf8E1zKGAClNU

CiNii Research

researchmap

その他リンク： http://link.springer.com/article/10.1007/s13296-014-1103-4/fulltext.html

出版者・発行元：Springer Science and Business Media LLC  

The present study deals with the effect of uniform and non-uniform local corrosion damages at the bearing stiffener and nearby web on the bearing capacity of plate girder. Five plate girder ends simulated with different uniform and non-uniform types of corrosion damage, at the base of the bearing stiffener are used in the experimental program. The experimental results are modeled and verified on a Finite Element (FE) software ABAQUS, considering shell-solid coupling elements formulation. The study is further extended to various damage cases i.e., stiffener damage, stiffer plus web damages etc. considering different damage heights and residual thicknesses. The study concludes that minimum thickness within any damage height may be used to simulate the corrosion damage in a FE analysis. At the end, some empirical relationships are also proposed to estimate the bearing strength of the plate girder affected by the local corrosion damage at plate girder end.

DOI： 10.1007/s13296-014-3023-8

DOI： 10.2208/jscejseee.73.443_references_DOI_KSXODRsniO93rkCtNU8SuHjQjFV

CiNii Research

researchmap

その他リンク： http://link.springer.com/article/10.1007/s13296-014-3023-8/fulltext.html

出版者・発行元：Elsevier BV  

Abstract Load carrying cruciform joints with incomplete penetration generally have two fatigue cracking points which are the weld root and toe. The crack initiation point in high cycle fatigue region depends mainly on weld leg size and incomplete penetration ratio, while the material mismatching between the base and weld metal becomes significant in the low cycle fatigue region. Elasto-plastic analysis was performed on load carrying cruciform joints with difference in size of weld leg, incomplete penetration and material mismatching. The effective notch was assigned at the weld root and toe, and the strains around both notches were compared. It was demonstrated that the cracking points estimated from the analysis agreed with the experimental results.

DOI： 10.1016/j.ijfatigue.2013.09.002

CiNii Research

researchmap

J-GLOBAL

researchmap

出版者・発行元：Springer Science and Business Media LLC  

This study discusses the effect of local corrosion damages nearby the bearing region including the bearing stiffener and adjacent web damage on the ultimate shear and post-buckling strength of steel plate girder bridges. A computer package ABAQUS is utilized for the verification and extension of the numerical study. Various corrosion damage cases, specifically the bearing stiffener are studied considering different damage thickness and damage heights. The study concludes that local damage on bearing stiffener damage is more fatal than the local web damage for the shear resistance of the plate girder. Further, some empirical relationships are also derived to assess the residual shear capacity of the locally corroded plate girder at the bearing region.

DOI： 10.1007/s13296-013-4004-z

DOI： 10.2208/jscejseee.74.145_references_DOI_vjWEkYs4FAh8wxzRtx1UmvV3La

CiNii Research

researchmap

その他リンク： http://link.springer.com/article/10.1007/s13296-013-4004-z/fulltext.html

出版者・発行元：Springer Science and Business Media LLC  

Steel railway bridges which exceed their design lifetime are increasing in Japan, and some of them have problems such as corrosion and fatigue. In this study, we proposed a method to improve the performance, such as the load-carrying capacity, of the existing steel railway bridges by installation of concrete decks. To figure out the applicability of the proposed method, we discussed the applicable range of span and the effect of stress reduction. Considering application into actual bridges, we proposed an installation method using pre-cast concrete decks and girder-deck connection with filler mortar and steel fasteners. Finally, we carried out loading tests of the connection with fasteners and bending tests of the applied girders. As a result, we found that the girder-deck connections have enough static capacity for lateral force and train loads, under the condition that the studs are installed and the gaps between the pre-cast decks are filled with mortar.

DOI： 10.1007/s13296-013-3007-0

CiNii Research

researchmap

記述言語：日本語   出版者・発行元：公益社団法人 土木学会  

暴露試験結果の分析により，腐食パラメータB_sは局所腐食環境指数のZ値と強い相関があると判明した．しかし，Z値はその算出に多数の計測が要求されるためコストが問題となっている．そこで，Z値に代わるものとして，環境の腐食性をACM型腐食環境センサで計測し，その結果を耐候性鋼材腐食量推定へ適用する方法について検討を行った．センサ特性を把握し，評価方法の検討・検証を行った上で，暴露試験結果データを用いて腐食量推定式の構築を試みた．その結果，ACM型腐食環境センサへの気温の影響は小さく，気温が及ぼす効果は別途考慮する必要があること，年間ACM電気量の対数とB_sの相関が高いことが判明した．得られた知見をもとに，ACM型腐食環境センサを利用した腐食環境計測データから耐候性鋼材の腐食速度を推定する手法を提案した．

DOI： 10.2208/jscejseee.69.275

DOI： 10.2208/jscejam.72.i_731_references_DOI_7tUr5tztd0nDczgls2ZZdjl83Rv

CiNii Research

researchmap

J-GLOBAL

researchmap

出版者・発行元：Springer Science and Business Media LLC  

This study examined the effects of inherent defects due to plate assembling and material mismatched condition between base and weld metal on the fatigue strength of beam-to-column connections. Low cycle fatigue tests were carried out on specimens with different plate assembling systems and material mismatched conditions. The test results revealed that the global load-displacement relationships from specimens with different plate assembling systems and material mismatched conditions are similar, meaning these effects involve only local behavior of specimens. However, the fatigue strength of the specimens strongly depends on the location of defects resulting from plate assembling and mismatched conditions. The specimen with the undermatched conditions and the existing defect located closer to the corner of beam-to-column connection tends to have lower fatigue strength. The fracture surfaces indicated that failure patterns of specimen are different regarding mismatched conditions. While the crack propagated through the weld metal for the undermatched condition, it propagated towards the boundary between base and weld metal for overmatched condition. Elasto-plastic shell analysis was performed under the same condition as the experiments. And it is found that when evaluating fatigue strength of beam-to-column connections, the effects of plate assembling system and material mismatched condition should be considered.

DOI： 10.1007/s13296-012-3005-7

DOI： 10.2208/journalofjsce.4.1_118_references_DOI_7ilEraUsa3IyqyiFtReqlOlNPFK

CiNii Research

researchmap

その他リンク： http://link.springer.com/article/10.1007/s13296-012-3005-7/fulltext.html

出版者・発行元：Informa UK Limited  

Many field surveys depict that steel plate girder ends tend to corrode due to the leakage of water from construction joints and/or detention of rain water near bearing regions. In many cases, buckling failures of plate girders were observed due to the excessive loss of material at the bottom portion of bearing stiffeners. In this study, the effect on the buckling strength of steel plate girder due to the corrosion damage at bearing stiffeners was investigated. Full-scale experimental tests were performed on two plate girder ends to determine the bearing capacity. Bearing capacity and failure modes were also verified by numerical analyses. Initial imperfections and welding residual stresses were also taken into account in analytical models. The simulation of the model was extended to the various corrosion damages, considering different damaged heights and thicknesses of the bearing stiffener near weld seam. All results were plotted in terms of remaining bearing capacity versus damage thickness ratio keeping the damage height of the stiffener constant. In this study, a damage parameter Reduced Thickness Ratio was used to assess the ultimate capacity and buckling of steel plate girder end with various corrosion levels.

DOI： 10.1080/15732479.2012.697904

DOI： 10.2208/jscejseee.74.145_references_DOI_MRV4eNpvtiWaLfyYg0H9AUuDoSD

CiNii Research

researchmap

出版者・発行元：SAGE Publications  

<jats:p> This article proposes the degree of nonlinearity as a feature for damage detection on large civil structures due to earthquakes. The degree of nonlinearity, which is a numerical value, represents how nonlinear structures behave during earthquakes. The degree of nonlinearity is computed directly from the data of the ground motion and vibration of the structure. The computation of the degree of nonlinearity uses a Hilbert transform and does not require any other nonlinear structural or mathematical models. Therefore, the damage detection process is very fast. Thus, an immediate decision about the condition of structures after strong earthquakes is possible. This article shows theoretically that a plot between the degree of nonlinearity against the magnitude of the ground motion represents the behavior of a structure. This plot is considered the signature of that structure. A structure that is healthy will have its specific healthy signature. If a new earthquake strikes and the new degree of nonlinearity deviates from its healthy signature, the structure may be damaged by that earthquake. To verify the validity of the degree of nonlinearity, numerical studies of nonlinear systems are presented. Although the application of degree of nonlinearity on a real civil structure is still not totally conclusive due to the limitation of data, the results from currently available data are encouraging. With more investigation, the degree of nonlinearity could be an additional or alternative feature for vibration-based structural health monitoring. </jats:p>

DOI： 10.1177/1475921712437182

CiNii Research

researchmap

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：公益社団法人 土木学会  

兵庫県南部地震の際に，鋼製橋脚隅角部に想定外の脆性破壊が発生した．その発生要因に関して，これまでひずみ履歴や応力多軸性の影響が検討されてきたが，塑性変形に伴う局部温度上昇の影響を含めた動的負荷の影響評価には至っていない．本研究では，破壊発生橋脚を対象とした熱弾塑性解析によって地震時の温度上昇を再現し，ひずみ速度による延性-脆性遷移温度移行量と併せて動的負荷が鋼材に与えた影響を推定した．その結果，破壊起点ではひずみ速度による遷移温度移行量を上回る大きな温度上昇が生じており，動的負荷は脆性破壊の発生を抑制する効果を及ぼしていた可能性が示された．また，ひずみ履歴による遷移温度移行量は大きく，動的負荷下においても脆性破壊が発生し得た可能性を示す結果が得られた．

DOI： 10.2208/jscejseee.68.226

DOI： 10.2208/journalofjsce.4.1_118_references_DOI_2J7k2iUt1AwQpo1cFIyuU9YeV4f

CiNii Research

researchmap

その他リンク： https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-22760340/

記述言語：日本語   出版者・発行元：公益社団法人 土木学会  

JIS耐候性鋼材より性能を強化された新耐候性鋼材が開発されている．新耐候性鋼材の能力は合金元素の含有量に関連し，価格にも反映される．したがって，対象環境に適した耐候性鋼材の選定がライフサイクルコスト低減のために重要となる．本研究では，様々な環境下で新旧を含めた複数の耐候性鋼材暴露試験を実施し，鋼材と環境の指標として提案されているV値，Z値と腐食速度パラメータA_s, B_sとの関係を調査した．その結果，腐食速度パラメータA_sはV値，Z値と線形の関係にあり，B_sはほぼZ値に依存することがわかり，V値，Z値から板厚減少量を推定できた．以上の知見をもとに，対象とする環境条件(Z値)と設計寿命・許容板厚減少量から推定したV値の要求値以上のV値を有する耐候性鋼材を選択する手法を提案した．

DOI： 10.2208/jscejseee.68.610

CiNii Research

researchmap

出版者・発行元：公益社団法人 土木学会  

DOI： 10.11532/structcivil.57a.629

CiNii Research

researchmap

J-GLOBAL

researchmap

記述言語：日本語   出版者・発行元：Japan Society of Civil Engineers  

本研究では，実際に被災した鋼製橋脚を対象に，地震時脆性破壊の発生要因を破壊起点の応力三軸度に着目し検討した．本研究では特に，破壊起点となった溶接部の形状が破壊起点の応力三軸度分布に及ぼす影響について検討するため，実際の破壊起点の溶接部形状の他にも複数の形状を対象とし，弾塑性FEM解析による解析的検討を行った．その結果，溶接部に発生する応力三軸度は止端半径や等脚・不等脚といった溶接部形状の影響を受けることが明らかとなった．特に，対象橋脚の破壊起点となった止端半径が小さく不等脚の溶接部では，地震時に高い応力三軸度が発生し脆性破壊発生のリスクが高まっていたことがわかり，破壊起点の溶接部形状が破壊発生要因の一つとなった可能性が示された．

DOI： 10.2208/jsceja.66.420

researchmap

J-GLOBAL

researchmap

記述言語：日本語   出版者・発行元：一般社団法人 日本風力エネルギー学会  

DOI： 10.11333/jweasympo.32.0_199

researchmap

記述言語：英語   出版者・発行元：公益社団法人 土木学会  

This paper proposes a practical method for input-output vibration-based health monitoring. The method using degree of nonlinearity (DON), which overcomes the limitation of linear models, is proposed. Derived from the Hilbert transform of the frequency response function, the DON can measure how much the nonlinearity is present in the vibration response. The results in this paper show that the DON of a structure has a specific relationship with the magnitude of the excitation. When computed from the structure that is still healthy, this relationship can be used as a baseline for the health monitoring. If the structure is not healthy, the new computed DON will deviate from this baseline.

DOI： 10.11532/structcivil.55A.809

CiNii Research

researchmap

記述言語：日本語   出版者・発行元：土木学会  

CiNii Books

researchmap

researchmap

researchmap

researchmap

researchmap

記述言語：英語   掲載種別：研究発表ペーパー・要旨（全国大会，その他学術会議）  

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

記述言語：日本語   出版者・発行元：東京 : 日本建設機械施工協会  

資料形態 : テキストデータ プレーンテキスト
コレクション : 国立国会図書館デジタルコレクション > デジタル化資料 > 雑誌

CiNii Books

CiNii Research

researchmap

その他リンク： https://ndlsearch.ndl.go.jp/books/R000000004-I026618037

J-GLOBAL

researchmap

記述言語：日本語   出版者・発行元：公益社団法人 土木学会  

橋梁振動を対象とした同調質量系発電デバイスを提案するとともに，その基本特性について検討した．同調質量系発電デバイスは，従来橋梁の制振のために設置される同調質量ダンパー（TMD）を応用し，ダンパーが吸収する振動エネルギーをもとにEnergy Harvesterとして活用するものである．本研究では，橋梁振動を対象とした同調質量系発電デバイスの有利な装置構成と設計に関する検討を行うため，単質点系と二質点系の同調質量系発電デバイスを提案し，解析を行った．その結果，二質点系は発電装置の減衰比に対する鋭敏性が小さく，蓄電において有利であることを導いた．微変動する橋梁の固有振動数に対しても，二質点系はパラメータ設計によって柔軟に対応できることを示した．

DOI： 10.2208/jscejseee.71.267

DOI： 10.2208/journalofjsce.8.1_103_references_DOI_U4sPfqJId0hvhlnrEnbtDxY8Q3e

CiNii Research

researchmap

その他リンク： https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-15J06103/

J-GLOBAL

researchmap

記述言語：日本語   出版者・発行元：日本鋼構造協会  

researchmap

記述言語：日本語   出版者・発行元：東京 : 土木技術社  

CiNii Books

CiNii Research

researchmap

その他リンク： https://ndlsearch.ndl.go.jp/books/R000000004-I024065145

記述言語：日本語   出版者・発行元：東京 : 日本計算数理工学会  

CiNii Research

researchmap

その他リンク： https://ndlsearch.ndl.go.jp/books/R000000004-I024216997

記述言語：日本語  

CiNii Books

researchmap

CiNii Research

researchmap

CiNii Research

researchmap

CiNii Research

researchmap

記述言語：日本語   出版者・発行元：東京 : 建設図書  

CiNii Books

CiNii Research

researchmap

その他リンク： https://ndlsearch.ndl.go.jp/books/R000000004-I9639553

DOI： 10.11532/structcivil.54A.582

researchmap

researchmap

記述言語：英語   出版者・発行元：Japan Society of Civil Engineers  

In this paper, time-domain modeling of bridge deck flutter is first developed. The frequency dependent self-excited forces acting on a bridge deck are approximated in the Laplace transform domain by rational functions. The least-square matrix formulation of the rational function approximation is applied to flutter derivatives of the Akashi Kaikyo Bridge and airfoil. Besides, numerical analyses of the wind-induced response of the Akashi Kaikyo Bridge were conducted to facilitate the discussion. After that, the vertical deflection and torsion at the span center of the Akashi Kaikyo Bridge caused by buffeting and self-excited forces using the results of approximated flutter derivatives are examined to investigate the sensitivity of the approximation to the wind-induced response.

DOI： 10.11532/structcivil.54a.420

CiNii Research

researchmap

researchmap

DOI： 10.2208/journalam.11.997

researchmap

記述言語：英語   出版者・発行元：東京大学  

日本では, 高度成長期に建設した多くの橋梁の劣化が進行する中, 適切な維持管理を行うための技術が必須であるが, その実現のためには科学的な手法に基づいて収集した定量的な橋梁挙動基礎データの必要性が認識され始めてきている．本稿では, 筆者らがこの基礎データを効率的かつ高精度に収集すべく重量車両の交通量が著しく多い首都高渋谷3号線に構築した最新のセンサシステムをベースとした遠隔モニタリングシステムについて述べる．［本要旨はPDFには含まれない］

DOI： 10.11188/seisankenkyu.60.230

CiNii Books

researchmap

その他リンク： https://jlc.jst.go.jp/DN/JALC/00314451321?from=CiNii

記述言語：英語   出版者・発行元：Japan Society of Civil Engineers  

The static and dynamic wind-induced instability analyses of super long-span cable-stayed bridges with main span length of 1200～1800m are presented in this paper. Firstly, the static aeroelastic behaviors of bridges against displacement-dependent wind load are investigated by three-dimension geometrical nonlinear analysis. Secondly, the free vibration and flutter analyses are carried out. The comparisons of structural dynamic properties between cable-stayed and suspension bridges are discussed and the impact of the cable vibration effect on the dynamic characteristics and the flutter behavior is studied. The analytical results show that static instability controls the dimension of the girder and the safety against both static and dynamic instabilities can be ensured even with main span length of 1800m.

DOI： 10.11532/structcivil.53A.650

CiNii Research

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

researchmap

researchmap

researchmap

researchmap

researchmap

記述言語：日本語  

DOI： 10.2208/jsceja.62.950

CiNii Books

researchmap

researchmap

記述言語：日本語   出版者・発行元：建設図書  

CiNii Books

researchmap

researchmap

researchmap

researchmap

researchmap

記述言語：日本語   出版者・発行元：土木学会  

DOI： 10.2208/jscej.2005.801_97

CiNii Books

researchmap

researchmap

記述言語：日本語   出版者・発行元：公益社団法人 土木学会  

都市内高速道路の鋼製ラーメン橋脚隅角部に疲労き裂が発見され, その早急な補修補強が必要とされている. 発生した疲労き裂の主要因の1つは, ラーメン橋脚隅角部の柱・梁フランジ交差部端部近傍に発生する高い応力集中であることが指摘されている. 本研究では, 鋼製ラーメン橋脚隅角部の疲労強度向上法として, 応力集中軽減を目的とした三角リブの隅角部への溶接による取付を考え, 解析および大型試験体を用いた疲労試験により検討を行った. その結果, 三角リブ取付により隅角部の疲労強度は大幅に向上することが確認され, その有効性が示された.

DOI： 10.2208/jscej.2004.773_137

researchmap

記述言語：日本語   出版者・発行元：土木学会  

DOI： 10.2208/jscej.2004.766_233

CiNii Books

researchmap

researchmap

researchmap

researchmap

記述言語：日本語   出版者・発行元：社団法人溶接学会  

CiNii Books

researchmap

researchmap

出版者・発行元：Wiley  

<jats:title>Abstract</jats:title><jats:p>Seit kurzer Zeit ist ein Kommunikationssystem mit optischen Fasern entlang des nationalen Straßennetzes in Japan installiert. Die Kapazität dieses Systems ist sehr groß, und es gibt praktisch keine Maximalbelegung. Bei diesem System werden Meßdaten von speziell ausgewählten Brücken zur Berechnung in ein Labor geleitet und für verschiedene Zwecke verwendet. Dieser Beitrag stellt die Ergebnisse der Messung mit optischen Fasern beispielhaft bei einer Brücke vor.</jats:p>

DOI： 10.1002/stab.200301150

CiNii Research

researchmap

researchmap

researchmap

researchmap

記述言語：日本語   出版者・発行元：土木学会  

DOI： 10.2208/journalam.6.1009

CiNii Books

researchmap

記述言語：日本語   出版者・発行元：公益社団法人 土木学会  

兵庫県南部地震では, 幾つかの鋼製橋脚に脆性き裂が発生した. その後の調査から, 脆性き裂発生の支配的な要因は, 地震時の塑性ひずみ履歴による鋼材の脆化と考えられる. そのため, 鋼製橋脚における地震時脆性破壊防止のためには, 塑性ひずみ履歴を受けた後も十分な破壊靭性を有する鋼材を使用する必要がある. 本研究では, 脆性破壊のシナリオを想定することにより, 考慮すべきひずみ履歴パターンを示した上で, 試験体へのひずみ導入方法の開発により, 折返しのパターンを含めた様々な塑性ひずみ履歴による鋼材の破壊靭性劣化の程度を明らかにした. さらに, その結果とこれまでの研究成果をもとに, 鋼製橋脚における地震時脆性破壊防止のために鋼材に必要とされる破壊靭性について検討した.

DOI： 10.2208/jscej.2003.731_93

CiNii Books

researchmap

researchmap

記述言語：英語  

CiNii Books

CiNii Research

researchmap

その他リンク： https://ndlsearch.ndl.go.jp/books/R000000004-I6395840

researchmap

researchmap

researchmap

記述言語：日本語   出版者・発行元：土木学会  

DOI： 10.2208/jscej.2002.710_141

CiNii Books

researchmap

researchmap

researchmap

researchmap

researchmap

DOI： 10.2208/jscej.2001.689_201

CiNii Books

researchmap

researchmap

researchmap

記述言語：日本語   出版者・発行元：公益社団法人 土木学会  

本研究では, 各種鋼材を対象に, 地震時に想定される10%を超える引張あるいは圧縮の塑性歪みを考慮し, CTOD試験により, 塑性歪み導入による破壊靭性の劣化について検討した. その結果, 塑性歪みにより全く脆化しない鋼材の存在が確認される一方で, それ以外の全ての種類の鋼材で, 歪み時効脆化する以前に, 塑性歪みそのものによって著しく脆化することが明らかとなった. その際, 塑性歪みによる脆化の程度は, 鋼材の種類によって大きく異なった. また, 圧縮予歪みの方が引張予歪みよりも鋼材をより脆化させる傾向があることが確認されたことから, その要因について, 材料特性面から検討を加えた.

DOI： 10.2208/jscej.2000.640_165

CiNii Books

researchmap

researchmap

researchmap

researchmap

J-GLOBAL

researchmap

出願人：国立大学法人東京工業大学

出願番号：特願2015-024381  出願日：2015年2月

公開番号：特開2016-148549  公開日：2016年8月

特許番号/登録番号：特許第6473008号  登録日：2019年2月 

J-GLOBAL

researchmap

出願人：国立大学法人東京工業大学

出願番号：特願2015-024381  出願日：2015年2月

公開番号：特開2016-148549  公開日：2016年8月

J-GLOBAL

researchmap

出願人：オムロン株式会社, 国立大学法人東京工業大学

出願番号：特願2012-123487  出願日：2012年5月

公開番号：特開2013-250088  公開日：2013年12月

J-GLOBAL

researchmap

出願人：国立大学法人横浜国立大学

出願番号：特願2009-177238  出願日：2009年7月

公開番号：特開2011-032651  公開日：2011年2月

特許番号/登録番号：特許第5388318号  登録日：2013年10月 

J-GLOBAL

researchmap

出願人：国立大学法人東京工業大学, 国立大学法人横浜国立大学, 首都高速道路株式会社, 株式会社エヌ・ティ・ティ・データ

出願番号：特願2009-043124  出願日：2009年2月

公開番号：特開2010-197249  公開日：2010年9月

特許番号/登録番号：特許第5327796号  登録日：2013年8月 

J-GLOBAL

researchmap

出願人：株式会社エヌ・ティ・ティ・データ, 国立大学法人横浜国立大学

出願番号：特願2008-081687  出願日：2008年3月

公開番号：特開2009-237805  公開日：2009年10月

特許番号/登録番号：特許第5164100号  登録日：2012年12月 

J-GLOBAL

researchmap