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  4. Vol.30 No.106 2006.3


Vol.30 No.106 2006.3


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

【巻頭言】Prefatory note

  • 本四技報に期待する

    Expectations for the Honshi Technical Report


    Tamiyoshi Horikiri

【技術論文】Technical report

  • 大鳴門橋管理20年

    Maintenance works for the Ohnaruto Bridge in the two decades


    Akimitsu Sato, Kazuo Sumi



    The Ohnaruto Bridge has passed twenty years in June, 2005 since its opening. The Ohnaruto Bridge is well-known for its severe environmental conditions such as strong wind, waves due to the fact that it is the only bridge that is exposed to the Pacific oceans of Honshu-Shikoku Bridges.

    Therefore, we found many impacts caused by severe conditions. For the last two decades, many strangeness such as corrosion of steel structures, deterioration of coating films, cracks and peeling of concrete structures.

    We have implemented a lot of maintenance works such as repair works for the substructure, repainting works for the superstructure, installation of dry air injection system for main cables, corrosion protection work for the multi-column foundations as reinforcement and so forth.

    This paper reports outline of inspection and maintenance works for the Ohnaruto Bridge in the last two decades since its opening.

  • ローリングリーフ横移動吸収板の想定外変位と固定ピンの破断

    Unexpected Displacement of a Pendulum Plate and Breaking of a coupling rod of a Rolling Leaf type expansion joint


    Gohei Tokunaga


    We found that breaking of a coupling rod that connects a Pendulum Plate and an Adjusting Plate had occurred at 2 points on each Rolling Leaf type expansion joints. A coupling rod can follow displacement of the plates caused by wind and so on by having a hemisphere washer. The breaking was unexpected matter for us, bridge engineers. We report the cause of troubles and repair methods of the joint which were detected and researched on.

  • 瀬戸大橋の塗膜評価

    Coating film assessment of the Seto Ohashi Bridge


    Yukio Nagao



    Soundness of the coating film is evaluated on basic inspection, coating film assessment and precise inspection. This time, coating film assessment was implemented at every panel of Seto Ohashi Bridges to understand degradation level of the coating film in detail. This paper reports on soundness evaluation of the coating film of Seto Ohashi Bridges utilizing the coating film assessment and existing data.

  • 機械設備の障害事例ネットワークの評価と改善

    Evaluation and improvement of the obstacle example network


    Mitsushige Sakamoto, Yoshihiro Asakura, Osamu Nakamura




    We have established an obstacle example network in order to streamline the maintenance networks for mechanical equipment. In this system, an engineer encountered some difficulty in his work sends the substance, cause, measure, needed time and cost, and after condition to all engineers on this network. In addition, the engineers received the 4 difficulty report prevent the outbreak of the same difficulty by inspection and refinement. In other words, this is a knowledge management by sharing of experiences.

    This system has worked from 1999, as the number of difficulties amounted to 500 affairs, we instituted a questionnaire and analyzed the condition of difficulties.

    In this report, we describe a proposal for the important point of the maintenance work, a validity estimation and improvement of this system based on the questionnaire.

  • 防災における強風予測と対応について

    Prediction of strong winds and response action under disaster prevention


    Kunio Fujitani, Yukihiro Fujisawa


    The Ohnaruto Bridge crossing the Naruto Strait locates in the severest environmental condition of the three routes of the Honshu-Shikoku Bridges.

    The Kobe-Awaji-Naruto expressway, mainly between Awajishima-minami IC and Naruto IC is often closed when typhoons get close or land in western Japan.

    In the fiscal year of 2004, the Naruto operation center closed its operating section nine times due to typhoons and low-pressures. It was very unusual compared to recent years. This paper reports prediction method of strong winds by typhoons and so forth, and facts to be improved through our experiences on traffic closing as response action under disasters.

  • 因島大橋ケーブルバンドボルトの再締め付けにおける軸力管理

    Axial force control and management for retightening of cable-band bolts of the Innoshima Bridge


    Tomiharu Iwagaki, Kazuo Kuramori



    It is supposed to evaluate axial force of cable-band bolts of the Innoshima Bridge using "the method accumulated original length" that is considered their residual expansion in the early stage. We confirmed that this residual expansion is different from the expansion that we predicted.

    This paper reports the process of control points of axial force management in the retightening of cable-band bolts based on the results of verification of the mechanism of residual expansion.

【海外報告】Overseas report

  • 海外報告(トルコ事情)

    Overseas Report (The situation on Republic of Turkey)


    Tsuyoshi Matsumoto

【技術ニュース】Technical news