担当区分：最終著者   記述言語：日本語   掲載種別：研究論文（研究会，シンポジウム資料等）

担当区分：最終著者   記述言語：日本語   掲載種別：研究論文（研究会，シンポジウム資料等）

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）

Surface roughness is an important characteristic of blast-cleaned structural steel plates. This is because the adhesion of the coating and the frictional grip of the bolted connections are related to surface roughness. Surface roughness is usually measured using a surface roughness meter. Because the roughness of blast-cleaned surfaces is not uniform, it varies from position to position. The surface roughness test results obtained from a broad area are more valuable than those obtained from a narrow area. Because the measured values contain deviations, they are measured multiple times and averaged to reduce the influence of deviations. However, to evaluate roughness, it is necessary to clarify the measurement conditions to obtain accurate results. Consider combining these sentences as follows: In this study, the surface roughness of the blast-cleaned structural steel sample was measured at multiple locations to obtain its distribution characteristics. During each sample measurement, the detection sensor of the surface roughness meter was lifted and placed on the steel sample to determine deviations from the actual results. The surface roughness distributions of five blast-cleaned samples were the same under the identical measurement conditions. This indicates that accurate results can be obtained by measuring representative samples, without the need for measuring all samples; actually, 17 measurements were adequate to obtain a mean surface roughness value with a 95% confidence level and a 5% acceptable error rate.

DOI： 10.1007/s13296-024-00907-7

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）

For the repair work of a corroded bolted connection, common practice is to use temporary bents or a bypass member over the connection. The costs of these methods are quite high and the traffic needs be regulated. The present study explores a repair method that requires no bents, no bypass member and no traffic regulation. The method is to conduct repair in an incremental fashion: the repair work proceeds gradually, part by part. Its validity is investigated by FEA. For the best accuracy, a bolt is to be modelled by 3-D solid elements, but the computational cost is very high. The employment of connector elements is therefore tried and its effectiveness is confirmed by the comparison with the results of solid element ana-lysis and experiment, using a small connection model. The proposed method is then applied to a 4×23 bolted connection. The validity is verified by FEA with connector elements.

DOI： 10.1201/9781003483755-475

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）

The tensile resistance of the main plate of a bolted connection is reduced by making bolt holes. The structures are sometimes exposed to excessive forces, such as earthquake action. The resistance and energy absorption are important performances against such forces. High energy absorption can realize a ductile structure. However, the energy absorption of the bolted con-nection needs to be clearer because the bolted connection is usually designed based on resistance. In this study, the energy absorption of bolted connections was investigated by a finite element analysis. At first, the numerical model was checked by reproduction analysis of some experiments focused on failure modes and the stress-strain model. A parametric study was conducted to clear the energy absorption. The energy absorption was evaluated and discussed, focusing on the failure modes.

DOI： 10.1201/9781003483755-477

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（研究会，シンポジウム資料等）

担当区分：責任著者   記述言語：日本語   掲載種別：研究論文（研究会，シンポジウム資料等）

担当区分：最終著者   記述言語：日本語   掲載種別：研究論文（研究会，シンポジウム資料等）

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）

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：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）

The component of bolted connection is sometimes replaced due to some reasons, which are corrosion, bolt delayed fracture and so on. The influence or mechanical behaviour of bolt replacement of bolted connection applied tensile force was already investigated in previous studies. However, that of the connection applied the bending moment is not cleared. In this study, simple and small specimens of bolted connection were prepared and bolt replacement experiments under bending were conducted to clear the behaviour and compare it and that of bolted connection applied tensile force. And, numerical analysis was carried out to investigate the influence of bolt replacement focused on the order of bolt replacement. As a result, although the centre opening stretch of the upper side and the lower side was different due to bending, the averaged opening stretch was the same as that of the connection in tensile. The order of bolt replacement affected the opening stretch, however, did not affect the elongation of bolted connection.

DOI： 10.2749/istanbul.2023.1023

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）

Recently, Japanese aged built-up members have lost their lacing bars due to corrosion. However, the remaining strength of the built-up column with vanished lacing bars has not been clarified yet. In addition, residual stress of channel-shaped steel which consists of built-up columns has not been made sufficiently clear. The authors measured the residual stress distribution of channel-shaped steel, which was removed from an aged steel truss bridge. Moreover, the authors numerically calculated the ultimate behavior of the builtup column with vanished lacing bars using the finite element method. As a result, it is found that the residual stress magnitude of the channel-shaped steel is small compared to that of the welded member, vanishment of lacing bars does not cause a significant reduction of the compression strength and column strength curve given in Japan Specifications for Highway Bridges can be used to estimate its remaining strength conservatively.

DOI： 10.1201/9781003348443-155

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：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）

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）

Bolted connection is one of the well-used techniques to connect structural members of steel bridges. Not only load capacity but also energy absorption are important characteristics of the structure to resist seismic action. In a finite element analysis, a true stress-true strain material model is needed to obtain an accurate evaluation in case the structure is exposed to excessive forces and deformed largely, although the true stress-true strain model is almost the same as to nominal stress-strain model in the small strain part. This study proposes a simple true stress-true strain model. And, the validity of the model was confirmed by the compare the finite element analysis and steel material tensile test or tensile experiment of bolted connection. Some true stress-true strain models were investigated and discussed from the viewpoint of load capacity and energy absorption.

DOI： 10.2749/nanjing.2022.1465

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）

スペイン   バルセロナ   2022年07月11日  -  2022年07月15日

Bolted connection usually carries the load by frictional load transfer in not only pre-slip behavior but also post-slip behavior. Bolt preload is an important factor because the preload is related to slip resistance. In past experimental research, the ultimate maximum resistance of the bolted connection tightened the bolt without bolt preload was almost the same as that of the connection tightened the bolt with preload. However, the mechanism is unknown yet. In this study, finite element analysis was conducted to clear the mechanism. The bolt axial force during pre-slip and post-slip behavior is changed, and the bolt axial forces of bolted connections tightened the bolt with and without preload are almost the same in ultimate behavior even the bolt preload is different. As a result, the ultimate resistances are almost the same. This result suggests that the loss of the bolt axial force of a part of bolts reduces the slip resistance, but the influence on the ultimate resistance is small.

DOI： 10.1201/9781003322641-259

DOI： 10.1201/9781003322641-259

Scopus

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記述言語：日本語   掲載種別：研究論文（学術雑誌）

DOI： 10.11532/structcivil.68a.112

CiNii Research

記述言語：英語   掲載種別：研究論文（学術雑誌）

CiNii Research

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）

Slip resistance of slipped high strength bolted frictional joint is lower than that of un-slipped joint because the coating on the frictional surface is peeled partially by the slip. Coating thickness is one of the most important factors to estimate slip resistance. The coating thickness is usually measured by the film thickness meter. Measured thickness usually varies widely. Measurement method such as measurement position, the number of measurement times is not pre-scripted even if the target of measurement is un-slipped coating. In this study, slip experiment of bolted joint had been executed. Coating thickness on the frictional surface of not only the specimens before the experiment, but also those after the experiment is measured. The number of measurement times to satisfy an accuracy is discussed. Because the peeled degree of coating depends on the position on frictional surface, the measurement position on the frictional surface after slip is also discussed.

DOI： 10.1201/9780429279119-538

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）

In recent steel bridges, for improving productivity and constructability, members which have different dimensions are connected by high-strength bolts or welding. As for bolted joints, it's known that the difference in thickness of connected members is adjusted with loose type or tight type fillers. End of the former plate is aligned on end of splice plates, and the latter is connected to a member with additional bolts outside the joint. However, the difference of the mechanical behaviour between the joint with them isn't clarified. In this study, tensile tests and FEA of high-strength frictional bolted joints with loose and tight filler plates were conducted to investigate the difference of their load transfer mechanism and mechanical performance. From obtained results, it's found that load carrying capacity of joint such as slip coefficient, maximum load was decreased by presence of a filler plate and its connection method, and additional bolts outside splice plates can hardly contribute to the performance enhancement of the joint with a filler plate. So, loose type filler is more preferably used than tight type filler. The effect of additional bolts on the mechanical performance of joint is to equalize the load sharing ratio of splice plates. Therefore, in case that eccentric moment can't be disregarded because thickness of a filler plate is large, tight type filler may prevent failure of the splice plate which is contacted with connected plate.

DOI： 10.1007/978-981-15-8079-6_134

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）

Welded joints is adopted rather than bolted joints for megastructure's connections because the former can carry large force. However, the former has several problems, such as quality control of welding in situ, which the latter can solve. By contrast, as the load transfer ratio of each bolt becomes uneven proportionally to the number of bolts, local slip around extreme bolts occurs before the whole slip. Extreme bolts to which a large shear force is applied will break before other bolts. For utilizing the strength of all bolts, the problem is solved by improving shear deformation capacity in faying surface with novel surface treatment. Here, the treatment concepts were explored, and the coating's effectiveness was evaluated through friction tests. The deformation capacity can be twice or more than that of conventional treatment, and the slip coefficient doesn't depend on contact pressure. These features have the advantage to give stable slip behaviour.

Scopus

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記述言語：英語   掲載種別：研究論文（学術雑誌）

CiNii Research

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）

This study focuses on fabrication tolerance of high strength bolted friction type joint. The investigation of past researches and experimental and FEM analytical results provides statistical characteristics of fabrication variation related to strength of the joint. The characteristic value shows that the variation of the thickness of coating hardly affects the slip strength of the joint. Furthermore, the influence of other variations is evaluated by the FEM analysis. This paper cleared predominant factors of fabrication tolerances affects slip strength of the joint.

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）

High strength bolted friction type joints are commonly used to join members of steel bridge structures. Recently, such joints have become larger, because members of bridges tend to be large to seek structural simplicity. Since large members consist of extremely thick plates, large size joints are needed with many bolts in a line, containing thick plates including splice plates. It is of concern that many bolts and thick plates affect the slip behaviour of such large size joints. So, FEA focused on joints with many bolts and thick plates is carried out. Based on the results, it is clear that a non-uniform distribution of friction force exists. And, it is also shown that a certain combination of thicknesses of connected plates and splice plates has the large capacity of slip resistance. It is concluded that such results can be explained by the influence of the additional bending moment due to thick plates.

Scopus

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開催期間： 2025年03月08日   記述言語：日本語  

開催期間： 2025年03月08日   記述言語：日本語  

開催期間： 2024年11月14日 - 2024年11月15日   記述言語：英語  

開催期間： 2024年11月14日 - 2024年11月15日   記述言語：英語  

開催期間： 2024年03月09日   記述言語：日本語  

開催期間： 2024年03月09日   記述言語：日本語  

開催期間： 2024年03月09日   記述言語：日本語  

開催期間： 2024年03月09日   記述言語：日本語  

開催期間： 2024年03月09日   記述言語：日本語  

開催期間： 2023年09月14日 - 2023年09月15日   記述言語：日本語  

開催期間： 2023年09月14日 - 2023年09月15日   記述言語：日本語  

開催期間： 2023年09月14日 - 2023年09月15日   記述言語：日本語  

開催期間： 2023年03月04日   記述言語：日本語  

開催期間： 2023年03月04日   記述言語：日本語  

開催期間： 2023年03月04日   記述言語：日本語  

開催期間： 2023年03月04日   記述言語：日本語  

開催期間： 2023年03月04日   記述言語：日本語  

開催期間： 2022年12月12日 - 2022年12月14日   記述言語：英語  

開催期間： 2022年09月15日 - 2022年09月16日   記述言語：日本語   開催地：京都大学   国名：日本国  

開催期間： 2022年09月15日 - 2022年09月16日   記述言語：日本語   開催地：京都大学   国名：日本国  

開催期間： 2022年03月05日   記述言語：日本語  

開催期間： 2022年03月05日   記述言語：日本語  

開催期間： 2022年03月05日   記述言語：日本語  

開催期間： 2021年09月09日 - 2021年09月10日   記述言語：日本語  

開催期間： 2021年09月09日 - 2021年09月10日   記述言語：日本語  

開催期間： 2021年03月06日   記述言語：日本語  

開催期間： 2021年03月06日   記述言語：日本語  

開催期間： 2021年03月06日   記述言語：日本語  

開催期間： 2021年03月06日   記述言語：日本語  

開催期間： 2020年09月09日 - 2020年09月11日   記述言語：日本語  

開催期間： 2020年09月09日 - 2020年09月11日   記述言語：日本語  

開催期間： 2020年09月09日 - 2020年09月11日   記述言語：日本語  

開催期間： 2020年03月07日   記述言語：日本語  

開催期間： 2020年03月07日   記述言語：日本語  

開催期間： 2019年05月25日   記述言語：日本語  

開催期間： 2019年03月02日   記述言語：日本語  

開催期間： 2019年03月02日   記述言語：日本語