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  4. Vol.17 No.67 1993.7


Vol.17 No.67 1993.7


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

【巻頭言】Prefatory note

  • 役割分担

    Role Sharing


    Hiroshi Niino

【技術論文】Technical report

  • 明石海峡大橋大型風洞試験(一様流試験結果)

    Full Aeroelastic Model Wind Tunnel Tests of the Akashi Kaikyo Bridge in Smooth Flow


    Masahiko Yasuda, Shuichi Suzuki, Hiroshi Katsuchi


    Wind tunnel tests were carried out in the boundary layer wind tunnel laboratory of HSBA with a 1/100-scaled full model to investigate aerodynamic stability of the Akashi Kaikyo Bridge in high precision. It is one of the most important subjects to attain superior aerodynamic stability because the Akashi Kaikyo Bridge will have a center span of 1990m surpassing existing the longest span suspension bridge. Therefore, in addition to conventional wind tunnel tests with a sectional model, full aeroelastic model wind tunnel tests were carried out with an elaborate model to examine aerodynamic properties in higher precision. This paper shows a part of test results including properties on static deformation and flutter.

  • 明石海峡大橋主塔の景観設計

    Aethetic Design on the Tower of Akashi Kaikyo Bridge


    Masahiko Yasuda, Yoshitaka Yoshida


    Many studies and discussions on aesthetic design had been held on the structure and configuration of the Akashi Kaikyo Bridge. One of the most important themes was the configuration of bracing member of the tower. After creating designs for many types of figures, we selected two types : the truss type and plate type with elliptic hollows.Finally, we adopted former one to the tower's figure, after the extensive evaluation on the fabrication and erection. The paper outlines the basic idea of aesthetic design on the tower of the suspension bridge, including characteristics of respective types and the process to the conclusion of configuration.

  • ピン定着ケーブルバンドの構造特性

    Structural characteristics of a pin-connected cable band


    Harukazu Ohashi


    The application of a pin-connected cable band for box-type stiffening girder has many advantages in simplifying the anchoring details. Although a few examples exist in long-span suspension bridges, the structural characteristics of this type of cable band have not been cleared, therefore for its adaption, the design method has to be established. So full scale experiments were carried out and the results were compared with elasto-plastic finite element analysis.

    From this study, following results were obtained:

    1. Under the hanger loading, band bolts behaves as a tension-type bolt. The additional axial force is approximately 10 to 20% of the applied load.

    2. At about three times of the design hanger load, the stresses at band reach a yielding point by bending, but the ultimate strength is proved to be even higher.

    3. Effect of hanger loading on slip resistance of cable band is small. The friction coefficient of more than 0.15 is assured.

    4. An elasto-plastic finite element analysis using contact elements at the interface between cable and band, could simulate contact/separation phenomena. Deformations and stresses caused by fastening and tightening the bolts or under hanger loading are also well described by this analysis.

  • デッキとスティフナの溶接部の疲労実験

    Fatigue Test on Welding of the vertical stiffener and the deck plate Floor-Stiffener Connection


    Tsuyoshi Matsumoto, Kazuo Endo


    Recent years, fatigue damages have been found on the welding beads of the deck plate and the web plate or the deck plate and the vertical stiffeners of the web plate.

    These fatigue cracks are found on the box welding of the upper end of the vertical stiffeners and on the both toes, deck plate side and the stiffener side.The cause and the fatigue strength have not been clarified yet. This test, composed of static loading and fatigue test of the above welding, was conducted to obtain basic data on relationships between the stress range and the fatigue strength (S - N Curve)for such a welding.

  • 来島大橋建設工事用海底ケーブルの敷設

    Installation of Submarine Power Cable for Construction of Kurushima Bridge


    Kunio Nakashlma, Minoru Yano



    Electric power must be supplied to construction machinery used for the kurushima Bridge because they are mostly powered by electricity.

    For such areas as Ohshima (1A, 2P), Umashima(6P, 7A, 8P), and Itoyama(9P, 10A), supply was relatively easy since commercial electric lines had been provided near the construction site. However, since Mushijima area(3P, 4A, 5P) was located offshore, how to supply should be investigated. The investigation was carried out during 1990 - 1991, and installation work of submarine power line was performed in 1992 on the seabed between the point Hinaibana and thd offshore foundation of 4A.

  • 新たな機構の碍子活線洗浄装置の開発

    Development of a New Cleaning System for Ceramic Insulator


    Toru Inoue, Syoji Hirota


    Ten years have passed since the cleaner for insulator was first installed at Ohmishima Bridge, which was developed by HSBA in cooperation of a manufacture of insulator. This type of cleaner was installed at Innoshima and Ohnaruto bridge, and Tozaki viaduct as well. Recently, HSBA developed a full - automatic, intermittently - operated cleaning system for insulator, which adopted many innovative functions and could be applicable to all of bridge maintenance/repair vehicles on Seto Chuo Express way. The new system is lighter and smaller than conventional one, and has shown more excellent performance in cleaning operation test. The system will enhance applicability of itself to the work site that cannot be supplied with water and electricity, and has no room for installation of the conventional cleaning system.

【海外報告】Overseas report

  • ニカラグアを訪ねて

    Visiting Nicaragua


    Takashi Yamanaka

【技術ニュース】Technical news