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  4. Vol.45 No.135 2020.9


Vol.45 No.135 2020.9


* By clicking ▸ on the title of Technical Reports, abstract will be indicated.

【巻頭言】Prefatory note

  • 現場の重要性

    Importance of Work in the Field

    新 一真

    Kazumasa Atarashi

【技術論文】Technical report

  • 技術開発計画(H29-R1)の成果

    Outcomes of Technological Development Project between 2017 and 2019


    Katsuya Ogihara, Kazunori Yamaguchi, Naoki Toyama


    Three-year technological development project was worked on to practice preventive maintenance for long-span bridges between 2017 and 2019. This paper reports outcomes from the three-year project. The following three-year project that started in 2020 is explained as well.

  • 大三島橋の耐震補強設計

    Seismic retrofit design of Ohmishima Bridge


    Kazunori Yamaguchi, Hiroyuki Ogushi


    Ohmishima Bridge is located in area where the probability of the occurrence of large earthquakes with a seismic intensity level of Lower 6 or higher in coming 30 years is 26 percent or higher. Therefore the seismic retrofit of the bridges is conducted and planned to be by 2022. As the result of seismic performance verification of the bridge, it was found that the strength of road girder (side tie) and the shear strength of abutment would be exceed the allowable range. On this account, seismic retrofit design was conducted using stiffening plate for the road girder (side tie) and fiber sheet reinforcement for the abutment. This paper presents the seismic retrofit design of the Ohmishima Bridge.

  • ASRにより劣化したPC構造物の調査と対策

    Survey and countermeasure for alkali-silica reaction occurred in prestressed concrete structure


    Yasuaki Kaneda, Yoshiaki Yano, Ryu Hashimoto




    It was confirmed that alligator cracks and white precipitates were generated on the side surface of cable fixing part of PC girder at Ikuchi Bridge (Composite box girder cable stayed bridge with three continuous spans). It was presumed that the cracks were originally from Alkali-silica reaction, because numerous cracks on the longitudinal direction of the bridge were confirmed when a part of the concrete deck top surface pavement was removed.

    The bridge had been confirmed harmless through Alkali silica reactivity test when the bridge was constructed. For the above reasons, in order to identify the cause of deterioration, a detailed survey was conducted from the perspective of Alkali-silica reaction. As a result of the survey, it was identified that the deterioration was originally from the late expansive alkali-silica reaction that is linked to the reactive aggregate containing microcrystalline.

    Crack injection, surface coating, and surface impregnation were conducted since the basic policy for the repairmen was prevention of the water infiltration. This thesis reports the results of various surveys and the repairment methods for the relevant deteriorations.

  • 瀬戸大橋長大橋(吊橋・斜張橋・トラス橋)の耐震補強工事

    Seismic retrofit of Seto-Ohashi Bridges (suspension, cable-stayed and truss bridges)


    Hiroki Murakami, Yasuyuki Hirayama


    Seismic retrofit work of the Seto-Ohashi Bridges and approach viaducts started in 2014. It will be finished by the end of FY2020. This paper describes the seismic retrofit work of three suspension bridges, two cable-stayed bridges, and four truss bridges in the Seto-Ohashi Bridges. According to the result of seismic performance verification and retrofit design, seismic retrofit of these bridges was designed to minimize the volume of reinforcement work of truss members over railway tracks and of the whole bridges. Road deck bearings were reinforced in the seimic retrofit work of the suspension bridges. And, the buckling strength of the lower chords was improved for the cable-stayed bridges, and the truss bridges were retrofitted by reinforcing truss members, road deck bearings, and so on.

  • 大鳴門橋補剛桁アプローチ率向上に向けた橋梁点検補修用作業車改造の取組

    Improvement of maintenance vehicles to improve approach rate of Ohnaruto Bridge


    Toshihiro Matsuo, Kazuhiro Kiyohara, Masato Matsuba


    In Ohnaruto Bridge, the access to the stiffening girder was examined the access method at the stage of construction, and maintenance vehicles and maintenance walkways were installed to the bridge structure. However, the accessible area of the Ohnaruto Bridge which was constructed in the early stage in the history of the Honshu-Shikoku Bridge construction projects, is extremely limited compared to those of other bridges. On the other hand, in recent years, local corrosions were confirmed in the bearings of steel deck, etc., and close visual inspection to each member of the girder was required every five years due to the revision of Road Act. Therefore, improvement of the approach rate became an urgent problem. To solve the problem, the existing maintenance vehicles were efficiently and economically modified. In this paper, efforts for the remodeling of the maintenance vehicle to improve the approach rate are reported.

【技術開発年次報告】Annual report of technology development

  • 防食分科会 塗装(鋼)WGの取組

    Report of Working Group for Metal Coating System, Anticorrosion Subcommittee


    Masahiro Takeguchi, Yukio Usuda, Akira Yamane

  • 防食分科会 コンクリート保護工WGの取組

    Report of Working Group for concrete coating system, Anticorrosion Subcommittee


    Hirotaka Oga, Masahiro Takeguchi

  • 疲労分科会の取組

    Report of Fatigue Subcommittee


    Masahiro Hayashi, Noriyasu Arima

  • 耐震分科会の取組

    Report of Seismic Subcommittee


    Kazunori Yamaguchi, Hiroyuki Ogushi

  • 舗装分科会の取組

    Report of Pavement Subcommittee


    Mitsukuni Kajio, Yoshio Nakayama

  • 点検分科会 点検技術WGの取組

    Report of Working Group for Inspection Technology, Inspection Subcommittee


    Masahiro Hayashi, Noriyasu Arima

  • 耐風分科会の取組

    Report of Wind-Resistance Subcommittee


    Masahiro Takeguchi, Naoki Toyama

【技術ニュース】Technical news

  • 土木学会田中賞作品部門(改築)受賞

    2019 JSCE Tanaka Award (Excellence in Bridge Design and Construction)


    Yukio Usuda

  • 塗膜劣化検出方法特許取得

    A Patent for “Evaluation method for deterioration of paint coating” was approved


    Kazuo Kuramori