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  4. Vol.26 No.99 2002.9


Vol.26 No.99 2002.9


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

【巻頭言】Prefatory note

  • 最適管理水準

    A Proper Management of Bridges


    Mitsuru Hosino

【技術論文】Technical report

  • 第3回国際吊橋管理者会議報告

    Report on the 3rd International Suspension Bridge Operators' Conference


    Shozo Yoshikawa, Shuichi Suzuki, Toyoaki Ito



    The 3rd International Suspension Bridge Operators' Conference (ISBOC) was held at the Hyogo Prefectural Awaji Yumebutai International Conference Center on May 16 and 17, 2002, organized by the Honshu-Shikoku Bridge Authority (HSBA) and the New York State Bridge Authority (NYSBA) .

    260 bridge engineers including 38 international participants from overseas, such as the United States, Denmark, Norway, China, and so forth, participated the conference. Topics on the maintenance works of suspension bridges were reported by 23 presenters from 6 countries at the conference. Since maintenance of the main cables has been concerned deeply with the operators of suspension bridges, discussion of the meeting was focused on assessing the strength, the rehabilitation and the monitoring method of corroded cable wires, and the long-term corrosion protection of the cables. Also reported were of the original maintenance methods derived from the circumferential peculiarities of the bridges.

  • 門崎高架橋(3径間部)の耐風安定性の再評価

    The Reevaluation of the Aerodynamic Stability of the Tozaki Viaduct (Three Span Continuous Bridge Section)


    Shigeki Kusuhara

    門崎高架橋は、基本風速(V10=50m/s) での設計に加え、急峻な地形を有する岬に並行して建設されることから、建設当初よりその耐風安定性に関する検討が実施されており、耐風安定化部材として、4径間部には下部スカートとダブルフラップが、3径間部にはダブルフラップが設置されている。


    The Tozaki Viaduct was constructed in the region of severe wind condition where the design wind velocity was 50 m/s. Therefore, the various investigation on aerodynamic stability were conducted during design and construction stages, and some devices for the aerodynamic stability were worked out. As for the devices to the aerodynamic stability, the lower skirt and the double flap system was installed along with the 4-span continuous bridge section, and the double flap system was installed along with the 3-span continuous bridge section. Because the devices were exposed themselves to the severe corrosive environment for more than 20 years corrosion on the devices gradually became problematic, and thus, the repair work would be considered unavoidable.

    Recently, the reduction of the maintenance cost has been focused on, and the necessity of the devices from the viewpoint of aerodynamic stability should be re-evaluated based on the characteristics of the bridge and the wind condition that was obtained in the field experiment and the accumulated field data observed for years after completion of the bridge. The wind tunnel tests on the 3- span section were also conducted with the data on the ambient conditions newly obtained, and finally, it was confirmed that the double flap on the cape side was no longer needed.

  • 海峡部橋梁箱桁用塗装装置の開発

    Development of Painting Robot for Box Deck of Offshore Bridges


    Mitsushige Sakamoto, Shoji Hirota



    The Honshu-Shikoku offshore bridges have been coated with the long-term anti-rusting paint layers, which were composed of 6 layers, since the bridges would be exposed in a severe rusting environment with marine salt particles. The coating needs repainting with an interval of about 15 years because the paint layers are deteriorated by the ultraviolet lay and the other harmful ambient gradient. The repainting operation with mechanical assistance would be desired because of the difficult task under the tight work environment, such as unnatural work position with high latitude, cold wind, and hot temperature. Reduction of painting cost was important as well since the total painting area would be more than 4 million square meters. Therefore, the painting machine was developed aiming at labor and cost saving after extensive feasibility study. This paper introduces basic concept of mechanization of repainting work, development of peripheral technologies in blasting and painting works, and the effectiveness of mechanized operation resulted in experimental works on real bridges.

  • 芸予地震における海峡部橋梁の被災復旧状況及び橋体の挙動

    The report on Disaster Restoration of the Offshore Bridges after and the Reaction of Bridges in the Geiyo Earthquake


    Kazuhiko Furuya, Hiroshi Isoe, Yukio Mori


    This paper refers the outline of damage and restoration of the structure of Nishiseto expressway, which were damaged by an earthquake. In addition to the verification on the observed earthquake motion by the field observation system, the dynamic analysis that simulated the earthquake motion as the input data was implemented by the structural analysis computer program, which was developed by the HSBA. As a result of the above verification, it was confirmed the breakage of the center-stay rod of First Kurushima Kaikyo Bridge was theoretical along with the design.

【技術ニュース】Technical news