{"created":"2023-05-15T15:29:37.431661+00:00","id":19393,"links":{},"metadata":{"_buckets":{"deposit":"423e38e4-4545-45c2-b466-f4390d716fda"},"_deposit":{"created_by":15,"id":"19393","owners":[15],"pid":{"revision_id":0,"type":"depid","value":"19393"},"status":"published"},"_oai":{"id":"oai:sucra.repo.nii.ac.jp:00019393","sets":["94:429:431:432:992"]},"author_link":[],"item_113_alternative_title_1":{"attribute_name":"タイトル（別言語）","attribute_value_mlt":[{"subitem_alternative_title":"頭付きスタッドを有する鋼コンクリート混合桁の持続荷重下における長期変形挙動"}]},"item_113_biblio_info_9":{"attribute_name":"書誌情報","attribute_value_mlt":[{"bibliographicIssueDates":{"bibliographicIssueDate":"2020","bibliographicIssueDateType":"Issued"}}]},"item_113_date_35":{"attribute_name":"作成日","attribute_value_mlt":[{"subitem_date_issued_datetime":"2021-09-16","subitem_date_issued_type":"Created"}]},"item_113_date_granted_20":{"attribute_name":"学位授与年月日","attribute_value_mlt":[{"subitem_dategranted":"2020-09-23"}]},"item_113_degree_grantor_22":{"attribute_name":"学位授与機関","attribute_value_mlt":[{"subitem_degreegrantor":[{"subitem_degreegrantor_name":"埼玉大学"}],"subitem_degreegrantor_identifier":[{"subitem_degreegrantor_identifier_name":"12401","subitem_degreegrantor_identifier_scheme":"kakenhi"}]}]},"item_113_degree_name_21":{"attribute_name":"学位名","attribute_value_mlt":[{"subitem_degreename":"博士(学術)"}]},"item_113_description_13":{"attribute_name":"形態","attribute_value_mlt":[{"subitem_description":"x, 114p","subitem_description_type":"Other"}]},"item_113_description_23":{"attribute_name":"抄録","attribute_value_mlt":[{"subitem_description":"Steel-concrete composite girders have gained popularity worldwide; as combining them become more effective and beneficial with the properties of both, i.e., can double the flexural strength and stiffness, reduce its span-to-depth ratio with consequent cost savings in real structural construction. In addition, they are lighter, guarantee better quality and have easier and faster erection than concrete structures as well as environmentally friendly. Based on the concept of composite structures, a further innovative idea of hybrid steel-concrete girder system is developed that uses lighter steel girder and inexpensive concrete girder which provides an economical solution for bridge girders. In general, most composite bridge girders are girder composite and box girder composite in nature, which are efficient for longer spans. Considering the longitudinal compositions, prestressed reinforced concrete （PRC） girders instead of concrete girders are preferred because of high stiffness and durability that leads to significant cost savings. For hybrid girder, assessing the performances of the junction or overlapping part with different shear connectors is much important, since this lack determines the limited applications of this structural type. This junction part must be designed to prevent separation between them as well as to ensure resisting the shear forces to the steel-PRC interface. Performance of such girder under any static and dynamic load significantly depends on force transfer mechanism at the junction and headed stud shear connections are most commonly used for this purpose. In Japan, the existing specifications considers very limited nominal shear force for the connector than its actual capacity and assumes almost insignificant deformation. Therefore, effective uses of stud shear strength could be a way forward in perspective of a more rational and economical design for practical applications. To adopt such a design method that allows effective uses of stud strength and incorporates parameters that clarify the influence on its deformation behaviour, and mechanism are very crucial. Due to the local deformation behaviour of stud connections, how they can influence the deformation behaviour of structure as a whole are also an important issue. For hybrid girder, particularly the creep induced long-term deformation behavior of junction under sustained loading is not considered explicitly but using of enhanced stud strength in the junction part will reduce the number of shear connections; for which the time-dependent behaviour of concrete may weaken the strength of the shear connections. It is assumed that under the sustained load the stiffness of junction will be slightly reduced even though the capacity might be same. Therefore, owing to the sustained loading action, there is a possibility that the mechanical behavior of stud connections and concrete will have an influence on the overall deformation of the whole structure; and this particular area was not considered in the previous research. The type of junction that adopted for hybrid girder is designed mainly according to structural details based on the results of experimental works. The junction is considered to have greater capacity than the other parts but there is no way to verify the capacity. Therefore, to ensure a safety-side design approach; so many shear connectors are provided in junction that usually induce a problem in construction works as it becomes very congested with steel plates, reinforcements, prestressing bars, and studs within a narrow space. Thus, the main concern of this study is to reduce the number of shear connectors in junction part; aiming to improve the constructability with a consequent savings of cost.\nFor practical applicability, before reducing the number of shear connectors, it needs to investigate its impact on the structural performance of junction considering serviceability and ultimate limits. For serviceability approach, it may influence on deflection, vibration, fatigue, etc and for ultimate limit, capacity will be a major concern. Since, the junction part is a composite section with a same sized concrete cross section with steel girder section, thus, even though the number of shear connectors are reduced capacity will not be a major issue. Therefore, from the point of ultimate limit state, the number of shear connectors in junction part may possibly be reduced.\n From serviceability point of view, even though it needs to investigate other factors; under the present study, scope is focused mainly on deflection （deformation） which is governed by instantaneous stiffness （short-term deflection） and time-dependent material properties （influenced by on long-term deflection） such as creep, shrinkage and relaxation. Regarding instantaneous stiffness, the number of shear connectors may have a sensitive impact on it. Therefore, a detail investigation is needed on that impact, as to reduce the number of shear connectors. If it could lead to a solution to reduce the number of shear connectors based on instantaneous stiffness, time-dependent problem would be major issue to investigate. However, there are very few researches that investigate the time-dependent behavior of junction part. Thus, this study focused on the long-term deformation （deflection） behaviour as a very fundamental study. Since, time-dependent deformation under sustained loading is crucial for hybrid girders. investigations must be conducted for quantifying such behaviour and then its application for practical construction may be promoted for sustainable design.\n Therefore, experimental investigations have been conducted to quantify the long-term deformation of hybrid girder. Pushout tests with FEA presents the long-term deformations of stud connections that lead to a reduction of stud stiffness. Then a sensitivity analysis is also presented to clarify the impact of reduction of studs and how the instantaneous and time dependent deformations of stud connections influences the deformation of whole structure. A parametric study and an approximate simplified model is proposed to determine the long-term deformation of stud connections under this study although it has some limitations. However, this simplified prediction model could be applied for real structures to determine their long-term deformation behavior.","subitem_description_type":"Abstract"}]},"item_113_description_24":{"attribute_name":"目次","attribute_value_mlt":[{"subitem_description":"ACKNOWLEDGEMENT ..................................................................................................... i\nABSTRACT ........................................................................................................... ii\nTABLE OF CONTENTS .................................................................................................. iv\nLIST OF TABLES .................................................................................................... vii\nLIST OF FIGURES .................................................................................................. viii\n1 INTRODUTION ................................................................................................ ...... 1\n1.1 Background and Motivation ....................................................................................... 1\n1.2 Research Objectives ............................................................................................. 3\n1.3 Dissertation Outline............................................................................................. 4\n2 RESEARCH BACKGROUND AND LITERATURE REVIEW.......................................................................... 6\n2.1 Introduction .................................................................................................... 6\n2.2 Literature Review ............................................................................................... 6\n2.3 Statement of the Problem: The long-term deformation ............................................................ 13\n2.4 References ..................................................................................................... 17\n3 TIME DEPENDENT DEFORMATION OF STUD UNDER SUSTAINED SHEAR FORCE ................................................... 19\n3.1 Introduction ................................................................................................... 19\n3.2 Design of specimens............................................................................................. 19\n3.3 Specimen assemble, casting and curing .......................................................................... 20\n3.4 Material properties ............................................................................................ 21\n3.5 Experimental programme ......................................................................................... 22\n3.5.1 Sensor layout and load setup.................................................................................. 22\n3.5.2 Specimen loading scheme and history .......................................................................... 22\n3.6 Environmental conditions ....................................................................................... 25\n3.7 Test results and discussions.................................................................................... 28\n3.7.1 Time dependent shear force-slip displacement curve ........................................................... 28\n3.7.2 Slip displacement over time .................................................................................. 28\n3.7.3 Skeleton curve and residual displacement ..................................................................... 32\n3.8 Failure load and patterns ...................................................................................... 34\n3.9 Summary and conclusion ......................................................................................... 36\n3.10 References .................................................................................................... 37\n4 FE ANALYSIS ON TIME DEPENDENT DEFORMATION OF STUD UNDER SUSTAINED SHEAR FORCE .................................... 39\n4.1 Introduction ................................................................................................... 39\n4.2 Construction of non-linear FEM program ......................................................................... 39\n4.3 Modeling for Concrete .......................................................................................... 40\n4.4 Method of Modeling.............................................................................................. 42\n4.4.1 Material Constitutive Laws and Characteristic Value .......................................................... 43\n4.4.2 Concrete tension softening behaviour ......................................................................... 43\n4.4.3 Concrete compressive softening behaviour ..................................................................... 44\n4.4.4 Creep deformation model ...................................................................................... 45\n4.5 Modeling of pushout specimen ................................................................................... 47\n4.5.1 Model Description ............................................................................................ 47\n4.5.2 Analysis Procedure ........................................................................................... 48\n4.5.3 Loading Method ............................................................................................... 49\n4.6 FE analysis result ............................................................................................. 49\n4.6.1 Shear force - slip displacement relationship ................................................................. 50\n4.6.2 Long-term slip displacement: FEA and experimental results .................................................... 52\n4.7 Internal stress- strain state under sustained shear force ...................................................... 54\n4.8 Parametric study: Factors that influence long-term displacement ................................................ 55\n4.8.1 Compressive strength of concrete ............................................................................. 55\n4.8.2 Height to diameter (h/d) ratio of stud ....................................................................... 56\n4.8.3 Headed stud yield strength ................................................................................... 57\n4.8.4 Level of shear force (SF) .................................................................................... 58\n4.9 Parametric study: Factors that influence initial slip displacement ............................................. 59\n4.10 Formulation of a simplified model for long-term deformation behaviour ......................................... 60\n4.11 Comparison of FEA and prediction model by proposed formulation ................................................ 61\n4.12 Summary and conclusion ........................................................................................ 62\n4.13 References .................................................................................................... 64\n5 LONG-TERM DEFLECTION OF HYBRID GIRDER ............................................................................ 65\n5.1 Introduction ................................................................................................... 65\n5.2 Design of specimen and connections ............................................................................. 65\n5.2.1 Design of composite girder part .............................................................................. 66\n5.2.2 Design of PRC girder ......................................................................................... 69\n5.3 Specimen assemble, casting and curing .......................................................................... 70\n5.4 Material Properties ............................................................................................ 71\n5.5 Experimental Programme ......................................................................................... 71\n5.5.1 Sensor layout and load setup.................................................................................. 71\n5.5.2 Specimens loading scheme and history ......................................................................... 73\n5.6 Environmental conditions ....................................................................................... 74\n5.7 Test results and discussions on hybrid girder................................................................... 75\n5.7.1 Long-term deflection of girder................................................................................ 75\n5.7.2 Long-term slip displacement................................................................................... 80\n5.7.3 Strain behaviour with respect to loading and time ............................................................ 81\n5.8 Load-deflection, crack, and failure patterns ................................................................... 85\n5.9 Long-term stud shear forces at junction: an FE evaluation ...................................................... 90\n5.9.1 Conceptual forces on junction of hybrid girder ............................................................... 90\n5.9.2 Calculation of shear forces on stud connections: FE approach ................................................. 91\n5.10 Evaluated long-term stud shear forces at junction under sustained loading ..................................... 96\n5.11 Confirmation of shear strength of stud connections............................................................ 101\n5.12 Comparative sensitivity analysis for hybrid girder ........................................................... 103\n5.12.1 Analysis approach and results .............................................................................. 103\n5.13 Summary and conclusions ...................................................................................... 107\n5.14 References ................................................................................................... 110\n6 CONCLUSIONS AND RECOMMENDATIONS ................................................................................. 111\n6.1 Conclusions ................................................................................................... 111\n6.2 Suggestions and recommendations for future investigations ..................................................... 114","subitem_description_type":"Other"}]},"item_113_description_25":{"attribute_name":"注記","attribute_value_mlt":[{"subitem_description":"指導教員 : 牧剛史","subitem_description_type":"Other"}]},"item_113_description_33":{"attribute_name":"資源タイプ","attribute_value_mlt":[{"subitem_description":"text","subitem_description_type":"Other"}]},"item_113_description_34":{"attribute_name":"フォーマット","attribute_value_mlt":[{"subitem_description":"application/pdf","subitem_description_type":"Other"}]},"item_113_dissertation_number_19":{"attribute_name":"学位授与番号","attribute_value_mlt":[{"subitem_dissertationnumber":"甲第1184号"}]},"item_113_identifier_registration":{"attribute_name":"ID登録","attribute_value_mlt":[{"subitem_identifier_reg_text":"10.24561/00019362","subitem_identifier_reg_type":"JaLC"}]},"item_113_publisher_11":{"attribute_name":"出版者名","attribute_value_mlt":[{"subitem_publisher":"埼玉大学大学院理工学研究科"}]},"item_113_publisher_12":{"attribute_name":"出版者名（別言語）","attribute_value_mlt":[{"subitem_publisher":"Graduate School of Science and Engineering, Saitama University"}]},"item_113_record_name_8":{"attribute_name":"書誌","attribute_value_mlt":[{"subitem_record_name":"博士論文（埼玉大学大学院理工学研究科（博士後期課程））"}]},"item_113_text_31":{"attribute_name":"版","attribute_value_mlt":[{"subitem_text_value":"[出版社版]"}]},"item_113_text_36":{"attribute_name":"アイテムID","attribute_value_mlt":[{"subitem_text_value":"GD0001274"}]},"item_113_text_4":{"attribute_name":"著者 所属","attribute_value_mlt":[{"subitem_text_value":"埼玉大学大学院理工学研究科（博士後期課程）理工学専攻"}]},"item_113_text_5":{"attribute_name":"著者 所属（別言語）","attribute_value_mlt":[{"subitem_text_value":"Graduate School of Science and Engineering, Saitama University"}]},"item_113_version_type_32":{"attribute_name":"著者版フラグ","attribute_value_mlt":[{"subitem_version_resource":"http://purl.org/coar/version/c_970fb48d4fbd8a85","subitem_version_type":"VoR"}]},"item_access_right":{"attribute_name":"アクセス権","attribute_value_mlt":[{"subitem_access_right":"open 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MB"}],"format":"application/pdf","licensetype":"license_note","mimetype":"application/pdf","url":{"label":"GD0001274.pdf","objectType":"fulltext","url":"https://sucra.repo.nii.ac.jp/record/19393/files/GD0001274.pdf"},"version_id":"b550a595-b206-4a68-affb-0573af929614"}]},"item_language":{"attribute_name":"言語","attribute_value_mlt":[{"subitem_language":"eng"}]},"item_resource_type":{"attribute_name":"資源タイプ","attribute_value_mlt":[{"resourcetype":"doctoral thesis","resourceuri":"http://purl.org/coar/resource_type/c_db06"}]},"item_title":"LONG-TERM DEFORMATION BEHAVIOR OF HYBRID GIRDER WITH HEADED STUD SHEAR CONNECTIONS UNDER SUSTAINED LOADING","item_titles":{"attribute_name":"タイトル","attribute_value_mlt":[{"subitem_title":"LONG-TERM DEFORMATION BEHAVIOR OF HYBRID GIRDER WITH HEADED STUD SHEAR CONNECTIONS UNDER SUSTAINED LOADING","subitem_title_language":"en"}]},"item_type_id":"113","owner":"15","path":["992"],"pubdate":{"attribute_name":"PubDate","attribute_value":"2021-09-16"},"publish_date":"2021-09-16","publish_status":"0","recid":"19393","relation_version_is_last":true,"title":["LONG-TERM DEFORMATION BEHAVIOR OF HYBRID GIRDER WITH HEADED STUD SHEAR CONNECTIONS UNDER SUSTAINED LOADING"],"weko_creator_id":"15","weko_shared_id":-1},"updated":"2023-06-23T09:01:43.492440+00:00"}