担当区分：筆頭著者,　責任著者   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）

DOI： 10.1201/9781003322641-155

担当区分：責任著者   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）

DOI： 10.1201/9781003322641-242

担当区分：責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

The buckling restrained bracing (BRB) is widely used to improve seismic behavior of buildings. It is employed for bridges as well, but the application is very limited. The BRB can be used also as a damper, in which case the device may be called a buckling restrained damper (BRD). Yet such application has not been explored. There are quite a few bridges designed by the old design codes in Japan. Their seismic resistance may not be satisfactory for the current seismic design codes. Against this background, the behavior of a steel truss bridge under a large seismic loading is investigated by the nonlinear dynamic finite element analysis. Some members are indeed found damaged in the earthquake. Retrofit is needed. To this end, the application of the BRD is tried in the present study: a parametric study on the seismic behavior of a steel truss bridge with BRD is conducted by changing the length and the cross-sectional area of the yielding core of the BRD. The study concludes that with the application of well-designed BRDs to appropriate locations, a steel truss bridge could go through a large earthquake without damage.

DOI： 10.14455/ISEC.2022.9(1).STR-43

Scopus

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担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

For determining an appropriate retrofitting method for a bridge structure based on economy, this work proposes an annual-expected resilience index for a bridge to simulate the resilience-considered seismic risk that is caused by multiple seismic events in a given period. Along with the direct costs, the resilience-considered indirect costs are also included in the seismic risk and benefit–cost ratio to determine an appropriate retrofitting strategy for a bridge structure. In this work, a bridge in Taipei is used as an example of the application of the proposed quantification method to determine a retrofitting method with economy based on the resilience-considered benefit–cost ratio.

DOI： 10.1080/13632469.2021.1982797

Scopus

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担当区分：最終著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）

担当区分：最終著者,　責任著者   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）

担当区分：筆頭著者,　責任著者   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）

担当区分：最終著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）

<p>耐候性鋼材の外観評価基準は必ずしも定量的ではなく，評価が容易でない場合がある．そこで本研究では，画像分類問題に使用される畳み込みニューラルネットワークを用いてさび画像分類AIを構築し，モデル構造の違いによる分類傾向の確認，複数モデルを用いた多数決によるアンサンブル法の実施によって，簡便性と実用性を有する外観評価手法の検討を行った．その結果，さび画像の分類精度はモデルにおける 畳み込み層構造の層構造パターンに比べて，pooling方法の違いによる影響を受けやすいことを明らかにした．また，複数の学習済みモデルを用いた多数決による簡易なアンサンブル法を用いることにより，誤判定の傾向をコントロールしながら分類精度の更なる向上が可能であることを示した．</p>

DOI： 10.11532/jsceiii.3.j2_594

CiNii Research

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

DOI： 10.1002/cepa.1296

担当区分：最終著者,　責任著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）

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）

The application of ductile cast iron to a bridge deck is explored. Produced by casting, the deck can be of any shape without welding and expected to have little possibility of fatigue crack. The deck would be light, about a half of the RC deck, so that it could enhance the seismic resistance of a bridge. The deck is designed following the Japanese design specifications for steel highway bridges. The design is done by 3-D FEM. Through computational simulations and actual casting trials, the ductile cast-iron deck panel with uniform material property is produced successfully. To investigate its structural behavior, the panel is loaded statically. Ductile structural behavior is observed without initiating cracks. Fatigue test is carried out. No fatigue cracks occur even when the number of the loading cycles reaches 10,000,000. The wheel load running test of the 12 deck panels was conducted, ensuring that a very good fatigue resistance．.

Scopus

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担当区分：筆頭著者,　責任著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）

担当区分：筆頭著者,　責任著者   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）

An overpass is occasionally damaged by a truck running underneath. Typical collision damage in a steel girder bridge includes the deformation of a main girder, the buckling of a transverse stiffener and the removal of a transverse stiffener from the web. The influence of the damage on the safety of the bridge needs be judged. Yet it is not always an easy task, since the load-carrying capacity of a girder damaged by collision has not been studied much. The first author has been involved in the evaluation of a highway steel girder bridge damaged by collision. Based on the data obtained from that bridge, the load-carrying capacity of the deformed girder is studied numerically in the present study. To be specific, the deformation of the main girder due to collision is reproduced by the finite element analysis and the deformed steel girder is loaded to evaluate the load-carrying capacity. The result indicates that as far as the damage is confined to the deformation of the girder, the collision does not threaten the safety of the bridge even when the deformation is quite large.

Scopus

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担当区分：責任著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

DOI： 10.1002/cepa.1731

担当区分：責任著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）

担当区分：最終著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）

担当区分：責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

The shear lag effect on stress concentration in a simply-supported stiffened box girder is investigated by three-dimensional finite element analysis. In the analysis, the dependence of the stress concentration on the finite element mesh is circumvented by the multimesh extrapolation method. An extensive parametric study is conducted with respect to the geometry of the stiffened box girder including the cross-sectional area of stiffeners. The influence of the method of load application is also studied. The stress concentration due to the shear lag is sensitive to the way a concentrated load is modeled, while relatively insensitive to the way a uniformly distributed load is modeled. The estimation of the stress concentration by the formula of Eurocode 3 agrees well with the present finite element analysis results for an unstiffened box girder. However, the formula tends to overestimate the influence of the stiffener. Regression analysis is then conducted, taking three approaches. The multiple linear regression equation is the simplest approach and helps identify the degree of the influence of each parameter, yet the accuracy is low, as the mean square error is as large as 16–20%. Though a little more involved, the accuracy of the empirical formula is much higher, with the mean square error about 3%. An artificial intelligence technique, based on the regression model of the multi-layer perceptron, is also examined. The accuracy is the highest of the approaches tested: the mean square error is well below 1%.

DOI： 10.1016/j.jcsr.2021.106715

Scopus

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記述言語：日本語   掲載種別：研究論文（学術雑誌）

担当区分：責任著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）

担当区分：責任著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）

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）

The box beam composed of two face-to-face C-section beams is getting popular in the cold-formed steel construction due to its advantage in strength. However, at present, no clear design rules are available for this type of built-up box beam. In this study, the mechanical behaviour of this box beam built-up C-section is investigated both experimentally and numerically. The finite element model using ABAQUS is conducted to verify experimental results. Four connection spacings are considered for each of the five C-sections, and thus 20 built-up beams are tested.

DOI： 10.1007/978-981-15-8079-6_140

Scopus

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担当区分：筆頭著者,　責任著者   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）

A method of estimating traffic loads on a highway by the deformation of a bridge is called bridge-weigh-in-motion (BWIM). The conventional BWIM is based on the strain measurement of main girders. To obtain supplemental information, strains of transverse stiffeners are also measured. Previously, it has been shown that the estimation of the truck loads by the strains of transverse stiffeners solely was possible. The method is competitive from the viewpoint of cost-effectiveness. Involving the integration of time-history response of strain, the method is called BWIM by Integration Method with Transverse Stiffeners. The present study tries to modify it so as to estimate the axle loads, concluding that it works fine for the axle load as well. Yet it is noticed that when two trucks run side by side, accuracy may be deteriorated. The way to improve the accuracy in such a case is also presented.

DOI： 10.1201/9780429279119-560

Scopus

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担当区分：責任著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）

担当区分：責任著者   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）

担当区分：責任著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）

担当区分：筆頭著者   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）

記述言語：英語   掲載種別：研究論文（学術雑誌）

© 2020 Techno-Press, Ltd. The use of passive energy dissipation devices has been widely used in the construction industry to minimize the probability of damage occurred under intense ground motion. In this study, collapse margin ratio (CMR) and fragility curves are the main parameters in the assessment to characterize the collapse safety of the structures. The assessment is done on three types of RC frame structures, incorporating three types of dampers, viscoelastic, friction, and BRB dampers. The Incremental dynamic analyses (IDA) were performed by simulating an array of 20 strong ground motion (SGM) records considering both far-field and near-field seismic scenarios that were followed by fragility curves. With respect to far-field ground motion records, the CMR values of the selected frames indicate to be higher and reachable to safety margin more than those under near-field ground motion records that introduce a high devastating impact on the structures compared to far-field excitations. This implies that the near field impact affects the ground movements at the site by attenuation the direction and causing high-frequency filtration. Besides that, the results show that the viscoelastic damper gives better performance for the structures in terms of reducing the damages compared to the other energy dissipation devices during earthquakes.

DOI： 10.12989/eas.2020.18.3.379

Scopus

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記述言語：英語   掲載種別：研究論文（学術雑誌）

The use of passive energy dissipation devices has been widely used in the construction industry to minimize the probability of damage occurred under intense ground motion. In this study, collapse margin ratio (CMR) and fragility curves are the main parameters in the assessment to characterize the collapse safety of the structures. The assessment is done on three types of RC frame structures, incorporating three types of dampers, viscoelastic, friction, and BRB dampers. The Incremental dynamic analyses (IDA) were performed by simulating an array of 20 strong ground motion (SGM) records considering both far-field and near-field seismic scenarios that were followed by fragility curves. With respect to far-field ground motion records, the CMR values of the selected frames indicate to be higher and reachable to safety margin more than those under near-field ground motion records that introduce a high devastating impact on the structures compared to far-field excitations. This implies that the near field impact affects the ground movements at the site by attenuation the direction and causing high-frequency filtration. Besides that, the results show that the viscoelastic damper gives better performance for the structures in terms of reducing the damages compared to the other energy dissipation devices during earthquakes.

DOI： 10.12989/eas.2020.18.3.391

Scopus

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担当区分：責任著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）

担当区分：責任著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）

担当区分：筆頭著者   記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）

担当区分：筆頭著者,　責任著者   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）

Copyright © 2018 by The Hong Kong Institute of Steel Construction. The application of ductile cast iron to a bridge deck was explored. Produced by casting, the deck can be of any shape without welding and expected to have little possibility of fatigue crack. The deck would be light also, about a half of the RC deck slab, so that it could enhance the seismic resistance of a bridge. The deck was designed, following the Japanese design specifications for steel highway bridges. To that end, the design analysis was done by 3-D FEM to take local stress into account, making the maximum stress smaller than the allowable value. The first challenge in this research is to produce a ductile cast-iron deck with uniform material property: difficulty arises from the fact that it is not only quite large but also thin relative to the width. Through computational simulations and actual casting trials, the ductile cast-iron deck panel has been produced successfully. To investigate its structural behavior, the panel was loaded statically at its center. Ductile structural behavior has been confirmed. Fatigue test was then carried out. No fatigue cracks occurred even when the number of the loading cycles reached 10,000,000.

DOI： 10.18057/ICASS2018.K.10

Scopus

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担当区分：責任著者   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）

The buckling restrained bracing (BRB) is widely used to improve the seismic behavior of a building. It is employed for a bridge as well, but the application is very limited. The BRB device may also be used as a damper rather than the structural component or the bracing, in which case the device is called a buckling restrained damper (BRD). Yet, such application has not been explored much. There are quite a few bridges designed according to the old seismic design codes in Japan. Their seismic resistance may not be satisfactory for the current seismic design codes. Against this background, the behavior of a steel truss bridge under a large seismic load is investigated by nonlinear dynamic finite element analysis. Some members are indeed found possibly damaged in the earthquake. Retrofitting is therefore needed. To this end, the application of the BRD is tried in the present study. A parametric study on the seismic behavior of the truss bridge with the BRD is conducted by changing the length and the cross-sectional area of the yielding core of the BRD, to this end. The FEA show that the BRD surely improves the seismic performance of the truss bridge and with some BRDs, all the members could stay intact. The points to note for the application of the BRD are also revealed.

Scopus

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記述言語：英語   掲載種別：研究論文（学術雑誌）

For a bridge, its columns or piers, which are the main seismically resistant members of the bridge, are generally retrofitted to improve seismic performance. However, retrofitting may cause unexpected damage to the non-retrofitted components/members. Therefore, a corresponding retrofitting of these components/members should be considered as part of any retrofitting method to eliminate unexpected damage. This work is to develop an estimating procedure of the seismic reliability of the system for a bridge considering the seismic reliability of each specified component/member. Additionally, the damage state of bridge for the system reliability analysis is built based on the engineering judgement. For the convenience of the calculation, the seven-point estimation method and the Nataf transformation method are combined to calculate the first four moment values of a specified limit state function in the moment-based system reliability analysis. For determining the retrofitting strategy, this work also presents a method for calculating the relationship between the resilience in functionality and seismic intensity that is achieved using a particular retrofitting method. Moreover, the system reliability and recovery time of each damaged component/member are considered in a resilience analysis. Finally, a bridge is selected as an example to demonstrate the application of this work.

DOI： 10.1080/15732479.2020.1767658

Scopus

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担当区分：筆頭著者   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）

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）

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（大学，研究機関等紀要）

担当区分：筆頭著者   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）

担当区分：責任著者   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）

記述言語：日本語   掲載種別：研究論文（学術雑誌）

担当区分：責任著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）

記述言語：日本語   掲載種別：研究論文（学術雑誌）

記述言語：英語   掲載種別：研究論文（学術雑誌）

© 2019 Elsevier Ltd In this study, the effect of para rubber insertion sheet on impact behavior of multilayer bulletproof panel made of steel fiber reinforced concrete was investigated. The objective of inserting rubber sheet into the middle layer was to act as a trapping layer to prevent bullets from ricocheting off the panel. Two test series were carried out: (1)investigation on energy absorption of each materials and (2)investigation on impact behavior of multilayer panel. The results from the 1st test series were used in the design of multilayer panels used in the 2nd series. The target impact energy of the bullet was 607 J. The multilayer panels were designed to have energy level ranging from 450 to 750 J. The panels were subjected impact by 9 mm caliber bullet with velocity of about 398 m/s. Results showed that the panels with impact energy absorption (IEA)level lower than the kinetic energy of the bullet (607 J.)failed by perforation. The panels with IEA level equal to or higher than 607 J. exhibited penetration failure mode with circular spalling at the back surface. There was no bullet ricocheting that occurred beyond this IEA level. At the level of IEA higher than 672 J, the failure mode shifted to penetration without visible damage at the back surface.

DOI： 10.1016/j.conbuildmat.2019.04.243

Scopus

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記述言語：英語   掲載種別：研究論文（学術雑誌）

担当区分：責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

© 2019, Emerald Publishing Limited. Purpose: This study aims to predict the types of thermally induced dynamics (TID) that can occur on deployable solar panels of a small form factor satellite, CubeSat which flies in low Earth orbit (LEO). The TID effect on the CubeSat body is examined. Design/methodology/approach: A 3U CubeSat with four short-edge deployable solar panels is considered. Time historic temperature of the solar panels throughout the orbit is obtained using a thermal analysis software. The results are used in numerical simulation to find the structural response of the solar panel. Subsequently, the effect of solar panel motion on pointing the direction of the satellite is examined using inertia relief method. Findings: The thermal snap motion could occur during eclipse transitions due to rapid temperature changes in solar panels’ cross-sections. In the case of asymmetric solar panel configuration, noticeable displacement in the pointing direction can be observed during the eclipse transitions. Research limitations/implications: This work only examines an LEO mission where the solar cells of the solar panels point to the Sun throughout the daylight period and point to the Earth while in shadow. Simplification is made to the CubeSat structure and some parameters in the space environment. Practical implications: The results from this work reveal several practical applications worthy of simplifying the study of TID on satellite appendages. Originality/value: This work presents a computational method that fully uses finite element software to analyze TID phenomenon that can occur in LEO on a CubeSat which has commonly used deployable solar panels structure.

DOI： 10.1108/AEAT-07-2018-0185

Scopus

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担当区分：責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

© 2019 by the authors. Buckling Restrained Bracings (BRBs) are widely used to improve the seismic behavior of buildings. They are employed for bridges as well, but their application in this respect is limited. BRBs can also be used as a function of the individual damper rather than the structural component or the bracing, in which case the device may be called a Buckling Restrained Damper (BRD). Yet, such application has not been explored much. There are quite a few bridges designed according to the old design codes in Japan. Their seismic resistance may not be satisfactory for the current seismic design codes. Against this background, the behavior of a steel truss bridge under a large seismic load was investigated by nonlinear dynamic finite element analysis. Some members were indeed found to be damaged in the earthquake. Retrofitting is needed. To this end, the application of BRD was tried in the present study: a parametric study on the seismic behavior of the truss bridge with BRD was conducted by changing the length, the cross-sectional area, the location and the inclination of BRD. The effectiveness of BRD was then discussed based on the numerical results thus obtained. In all the analyses, ABAQUS was used.

DOI： 10.3390/app9142791

Scopus

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担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

© 2019 by the authors. Nanosatellites, like CubeSat, have begun completing advanced missions that require high power that can be obtained using deployable solar panels. However, a larger solar array area facing the Sun increases the solar radiation torque on the satellite. In this study, we investigated solar radiation torque characteristics resulting from the increased area of solar panels on board the CubeSats. Three common deployable solar panel configurations that are commercially available were introduced and their reference missions were established for the purpose of comparison. The software algorithms used to simulate a variety of orbit scenarios are described in detail and some concerns are highlighted based on the results obtained. The solar power generation of the respective configurations is provided. The findings are useful for nanosatellite developers in predicting the characteristics of solar radiation torques and solar power generation that will be encountered when using various deployable solar panels, thus helping with the selection of a suitable configuration for their design.

DOI： 10.3390/AEROSPACE6050050

Scopus

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担当区分：責任著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）

担当区分：筆頭著者,　責任著者   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）

© SDSS 2019 - International Colloquium on Stability and Ductility of Steel Structures. An accident that a truck running underneath collides against an overpass bridge happens occasionally. The influence of the damage on the safety of the bridge must be judged right away. Yet it is not always an easy task, since the load-carrying capacity of a damaged girder has not been studied much. The first author has been involved in the evaluation of a steel girder overpass bridge damaged by collision. Based on the data obtained from this bridge, the load-carrying capacity of the deformed girder is investigated numerically in the present study. To be specific, the deformation of the main girder due to collision is reproduced by the finite element analysis and the deformed steel girder is loaded to evaluate the load-carrying capacity. The result indicates that as far as the damage is confined to the deformation of the girder, the collision does not threaten the safety of the bridge even when the deformation is quite large.

Scopus

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担当区分：筆頭著者   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）

An accident that a truck running underneath collides against an overpass bridge happens occasionally. The influence of the damage on the safety of the bridge must be judged right away. Yet it is not always an easy task, since the load-carrying capacity of a damaged girder has not been studied much. The first author has been involved in the evaluation of a steel girder overpass bridge damaged by collision. Based on the data obtained from this bridge, the loadcarrying capacity of the deformed girder is investigated numerically in the present study. To be specific, the deformation of the main girder due to collision is reproduced by the finite element analysis and the deformed steel girder is loaded to evaluate the load-carrying capacity. The result indicates that as far as the damage is confined to the deformation of the girder, the collision does not threaten the safety of the bridge even when the deformation is quite large.

DOI： 10.4172/2165-784X-C1-010

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担当区分：責任著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）

記述言語：日本語   掲載種別：研究論文（学術雑誌）

記述言語：日本語   掲載種別：研究論文（学術雑誌）

担当区分：責任著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）

担当区分：責任著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）

担当区分：責任著者   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）

© 2018 KASHYAP. This study predicts thermal distortion that can occur on deployable solar panels of a CubeSat in low earth orbit during eclipse transition of night-day. A 3U CubeSat with four short edge deployable solar panels that point to the Sun is considered. There are three steps of modeling involved. Firstly, the time historic temperature of the solar panel is characterized. Secondly, the results obtained are used in general stress analysis using a finite element software to obtain deformation of the solar panel. Finally, the effect of solar panel motion on the attitude displacement of the satellite is examined using inertia relief method. Results show that quasi-static deformation appears due to the difference in crosssection temperature of the solar panel. Brief thermal snap disturbances are likely to take place during eclipse transitions as well. As a result, the pointing direction of the CubeSat could be disturbed in the case when the solar panels are in asymmetric configuration.

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担当区分：責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

<p>The application of spheroidal graphite cast iron to a bridge deck slab is explored. The deck slab is expected to have a good seismic resistance with little possibility of fatigue crack occurrence. Through a casting process, the spheroidal graphite cast iron deck slab was produced. Various material properties were tested and satisfactory results were obtained. The slab was then loaded statically. In order to ascertain the plastic deformation capacity, a large load of 941kN was applied to the deck slab. A static load-displacement curve of the deck slab was obtained. Furthermore, magnetic particle testing was carried out. There were no micro cracks. In addition, the results of the static load test were in good agreement with the results of the FEM analysis.</p>

DOI： 10.11532/structcivil.64A.109

CiNii Article

CiNii Research

その他リンク： https://ci.nii.ac.jp/naid/130007675690

担当区分：責任著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

© 2016 Elsevier B.V. A severely corroded end cross-girder is found occasionally, while the girder is expected to play an important role under seismic loading. The prevention of the end cross-girder against corrosion is therefore crucial in the bridge maintenance. To this end, the present research aims at improving its inspectability by installing inspection holes in the end cross-girder. The influences of the holes on the load-carrying capacity are then studied, to be specific. It is revealed that the inspection holes would reduce the load-carrying capacity considerably; the degree of the influence varies with the shape, the position and the size of the hole. Six reinforcement methods are therefore considered. Full recovery of the capacity turns out to be possible if the inspection hole is the same size as that of the standard opening (manhole) in a steel bridge structure, while it is not an easy task when the inspection hole is larger.

DOI： 10.1016/j.istruc.2016.12.006

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担当区分：責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

<p>The application of spheroidal graphite cast iron to a bridge deck slab is explored. The deck slab is expected to have a good seismic resistance with little possibility of fatigue crack. The dimensions of the deck slab are determined by the 3-D FEM analysis to satisfy the design requirements. Through a careful casting process, the spheroidal graphite cast iron deck slab is produced. Various material properties are tested and satisfactory results are obtained. The slab is then loaded statically. The results are in good agreement with the finite element predictions. Furthermore, the fatigue durability test is carried out. No fatigue cracks are initiated even though the number of loading cycles reaches 10,000,000.</p>

DOI： 10.11273/jssc.24.95_13

CiNii Article

CiNii Research

その他リンク： https://ci.nii.ac.jp/naid/130007490597

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）

© 2015 Taylor & Francis Group, London. Good maintenance of a bridge requires the information on traffic loads. A method of estimating the traffic loads is bridge-weigh-in-motion (BWIM).The conventional BWIMis based on the strains of main girders. To obtain supplemental information of truck velocity, the strains of transverse stiffeners are measured additionally. Our previous research has shown that truck loads could be estimated solely by the strains of transverse stiffeners, provided that the transverse stiffeners were chosen carefully. The method is superior, since the strain measurements of main girders are no longer necessary. The method involves the integration of time-history response of strain and is called BWIM by Integration Method with Transverse Stiffeners (BWIM-IT). In the present study, BWIM-IT is extended to the estimation of axle loads. Good results are obtained if the influence of the truck in the adjacent lane is removed from the strain data.

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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）

© 2015, International Society for Structural Health Monitoring of Intelligent Infrastructure, ISHMII. All rights reserved. For constructing a good maintenance scheme of an existing bridge, it is essential to know traffic loads acting upon it. A method of estimating the loads on a highway by the deformation of a bridge is called bridge-weigh-in-motion (BWIM). The conventional BWIM is based on the strain measurement of main girders. To obtain supplemental yet vital information such as truck velocity, extra measurements are required. Strains of transverse stiffeners are usually measured, to that end. Previously, an effort was made to estimate truck loads solely by the strains of transverse stiffeners. It has been shown to be possible indeed to estimate truck loads with good accuracy through the strains of transverse stiffeners only, provided that the transverse stiffeners are chosen carefully. The method is superior, since the strain measurements of main girders are no longer necessary, reducing the cost. The method involves the integration of time-history response of strain and is called BWIM by Integration Method with Transverse Stiffeners (BWIM-IT). In the present study, BWIM-IT is extended to the estimation of axle loads which have considerable influence on the durability of the floor slab of a bridge. The study concludes that BWIM-IT can give a good estimation of axle loads as well. Yet it is noted that when two trucks run side by side, the truck in the adjacent lane influences the strains of transverse stiffeners and the accuracy deteriorates. The way to remove the influence is also presented so as to achieve a good accuracy even in such a case.

Scopus

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記述言語：日本語   掲載種別：研究論文（学術雑誌）

Weathering steel is generating precise rust on the surface, and has the character which controls progress of corrosion. However, protection rust may not generate depending on the placed environment. Therefore, the weathering steel bridge needs to perform check after construction, and needs to evaluate the state of rust. The basic method is to evaluate in five steps from rust appearance of the particle diameters. This is a standard evaluation method used for a long time, but even an expert may hesitate about a judgment because it is not necessarily given a standard quantitative enough. In order to improve these problems, we propose the appearance evaluation method using the image analysis in this study.

DOI： 10.11532/structcivil.61A.429

CiNii Article

その他リンク： https://ci.nii.ac.jp/naid/130005439072

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）

In the 2004 Mid Niigata Prefecture Earthquake, the damage of a bridge pier was found mitigated by the collision between the abutment and the girder. In the seismic response analysis of a bridge, it is thus important to include the influence of collision. A simple and practical method of simulating the collision in finite element analysis is the introduction of a spring where the collision occurs. However, the constant of such a collision spring is yet to be formulated well. In this study, an appropriate collision-spring constant is investigated for simulating the collisions between adjacent girders and between an abutment and a girder. A small collision-spring constant tends to cause the large overlap of colliding bodies while a large collision-spring constant tends to cause many repetitive short collisions during the real collision. Various girder-girder collision models and abutment-girder collision models are constructed and analyzed, based on the results of which the formulas for the collision-spring constants are proposed. The validity of the formulas is confirmed by applying them to a cantilever girder bridge.

Scopus

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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）

The maximum width-to-thickness ratios for compact I-shaped sections are first studied for three girders: the SM490Y girder, the SBHS500 girder and the hybrid girder. SM490Y is a conventional steel and SBHS500 is a highperformance steel specifically for bridge construction. Both steel grades are registered in Japanese Industrial Standards. The hybrid girder consists of a SM490Y web and SBHS500 flanges. The maximum width-to-thickness ratio thus obtained is quite different from that of AASHTO. A cause is investigated, and the difference is found attributable to analysis conditions. The three girders with compact sections are then designed for a given plastic moment. The result shows that the SBHS500 girder is the lightest: 19% lighter than the heaviest girder, the SM490Y girder. The price varies from steel to steel. From the viewpoint of cost, the optimum girder is looked for as well. The result shows that the hybrid girder is the most competitive at the current steel price.

Scopus

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記述言語：英語   掲載種別：研究論文（学術雑誌）

© 2014 by Taylor & Francis Group, LLC. With the advancement of computer technology and commercial package, the finite element method (FEM) is now used exclusively for the analysis of structures including bridges. However, it should be well-understood that FEM is a numerical method and provides an approximate solution. The quality of the solution could vary from engineer to engineer responsible for the analysis. To conduct a good finite element analysis (FEA), the engineer should have a certain amount of knowledge of FEM, even though it is possible to get results with little knowledge of FEM itself from an FEM package.

DOI： 10.1201/b15616

Scopus

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記述言語：日本語   掲載種別：研究論文（学術雑誌）

An end cross girder plays an important role when the steel girder bridge is subjected to seismic loading. But located near the girder end, it is often found corroded, which could degrade the load-carrying capacity. Therefore, it is of a practical significance to investigate the seismic performance of a corroded end cross girder. To this end, the present study conducts nonlinear finite element analysis of end cross girders with various corrosions under horizontal load. It is observed that the corrosion area and the plate-thickness loss influence the load-carrying capacity, and their influence depends on the corrosion type. It is also pointed out whether or not the lower flange is connected to the main girder makes a large difference in the load-carrying capacity: the connection between the lower flange and the main girder is therefore very important for seismic performance.

DOI： 10.11532/structcivil.60A.105

CiNii Article

その他リンク： https://ci.nii.ac.jp/naid/130005438899

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）

One of the crucial factors that could terminate the service life of a steel bridge is corrosion. Since many of the corrosion problems are found in the girder end, it is quite essential to know the load-carrying capacity of the girder end for efficient maintenance. To this end, the present study investigates the influence of corrosion at a girder end. Steel I-section girders with various corrosion models are constructed, and placing a vertical load at the upper flange right above the support, the girders are analyzed by nonlinear FEM. The degradation of the load-carrying capacity of a steel girder due to corrosion at its end is thus evaluated numerically. It is found that different corrosion patterns at a girder end can lead to significantly different degradations of the load-carrying capacity.

Scopus

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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）

One of the crucial factors that could terminate the service life of a steel bridge is corrosion. Since many of the corrosion problems are found in the girder end, it is quite essential to know the load-carrying capacity of the girder end for efficient maintenance. To this end, the present study investigates the influence of corrosion at a girder end. Steel I-section girders with various corrosion models are constructed, and placing a vertical load at the upper flange right above the bearing, the girders are analyzed by nonlinear FEM. The degradation of the load-carrying capacity of a steel girder due to corrosion at its end is thus evaluated numerically. It is found that a different corrosion pattern at a girder end can lead to a significantly different degradation of the load-carrying capacity.

Scopus

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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）

The application of the weathering steel to a bridge increases in Japan in recent years. A study is reviewed to give some idea about the performance of the weathering steel in bridges, revealing some bridges have developed abnormal rust and that the durability design is not practiced well even though most of the weathering steel bridges are in good shape. JSSC set up the working group to improve the situation. The working group came up with two technical reports entitled "Potentials and New Technologies of Weathering Steel Bridges" and "Applicability Assessment and Prevention of Corrosion of Weathering Steel in Bridges", respectively. The basis and the framework of the durability design of weathering steel bridges thus established in the JSSC activity are outlined in this paper, showing the new methods for assessing atmospheric corrosiveness in the light of the applicability of the weathering steel to the bridge and the practical applicability-assessment procedure. © 2010 Taylor & Francis Group, London.

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記述言語：英語   掲載種別：研究論文（学術雑誌）

In this paper, three-dimensional finite element analysis of composite steel-concrete bridges is performed to simulate the actual bridge behavior. The accuracy of the model is verified against the results acquired from a field test. Thai trucks are loaded at possible locations of the bridge in order to obtain the maximum stresses on the bridge. The influences of concrete barriers, the displacement of bridge piers, and the Young's modulus of concrete are then discussed, to reveal the actual behavior of the steel-concrete composite bridge. The reactions at the bearings on the bridge piers are also evaluated and discussed in this conjunction. Good agreement is obtained between the models and loading tests to show that the finite element model can aid engineers in design practices.

Scopus

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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）

2003年04月  -  2003年04月

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）

2003年04月  -  2003年04月

記述言語：英語   掲載種別：研究論文（学術雑誌）

記述言語：英語   掲載種別：研究論文（学術雑誌）

記述言語：日本語   掲載種別：研究論文（学術雑誌）

記述言語：日本語   掲載種別：研究論文（学術雑誌）

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）

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）

2002年04月  -  2002年04月

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）

2002年04月  -  2002年04月

記述言語：英語   掲載種別：研究論文（学術雑誌）

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）

記述言語：日本語   掲載種別：研究論文（学術雑誌）

記述言語：日本語   掲載種別：研究論文（学術雑誌）

記述言語：日本語   掲載種別：研究論文（学術雑誌）

記述言語：日本語   掲載種別：研究論文（学術雑誌）

記述言語：日本語   掲載種別：研究論文（学術雑誌）

記述言語：英語   掲載種別：研究論文（その他学術会議資料等）

2001年04月  -  2001年04月

記述言語：英語   掲載種別：研究論文（その他学術会議資料等）

2001年04月  -  2001年04月

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）

2001年04月  -  2001年04月

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）

2001年04月  -  2001年04月

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）

2001年04月  -  2001年04月

記述言語：日本語   掲載種別：研究論文（学術雑誌）

記述言語：日本語   掲載種別：研究論文（学術雑誌）

記述言語：日本語   掲載種別：研究論文（学術雑誌）

記述言語：日本語   掲載種別：研究論文（学術雑誌）

記述言語：日本語   掲載種別：研究論文（学術雑誌）

記述言語：日本語   掲載種別：研究論文（学術雑誌）

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）

記述言語：英語   掲載種別：研究論文（学術雑誌）

記述言語：日本語   掲載種別：研究論文（学術雑誌）

記述言語：日本語   掲載種別：研究論文（学術雑誌）

記述言語：日本語   掲載種別：研究論文（学術雑誌）

記述言語：英語   掲載種別：研究論文（その他学術会議資料等）

1999年04月  -  1999年04月

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）

記述言語：日本語   掲載種別：研究論文（学術雑誌）

記述言語：英語   掲載種別：研究論文（学術雑誌）

記述言語：英語   掲載種別：研究論文（学術雑誌）

記述言語：英語   掲載種別：研究論文（学術雑誌）

記述言語：日本語   掲載種別：研究論文（学術雑誌）

記述言語：日本語   掲載種別：研究論文（学術雑誌）

記述言語：英語   掲載種別：研究論文（学術雑誌）

記述言語：日本語   掲載種別：研究論文（学術雑誌）

記述言語：英語   掲載種別：研究論文（学術雑誌）

記述言語：日本語   掲載種別：研究論文（学術雑誌）

記述言語：日本語   掲載種別：研究論文（学術雑誌）

記述言語：日本語   掲載種別：研究論文（学術雑誌）

記述言語：日本語   掲載種別：研究論文（学術雑誌）

記述言語：英語   掲載種別：研究論文（学術雑誌）

記述言語：日本語   掲載種別：研究論文（学術雑誌）