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  4. Vol.39 No.124 2015.3


Vol.39 No.124 2015.3


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

【巻頭言】Prefatory note

  • 『挑戦』の第一歩

    The first step of challenge to realization in the bridge which can be used for more than 200 years


    Toshiya Nakao

【技術論文】Technical report

  • 重防食塗装の劣化予測の高度化

    Upgrading of deterioration prediction for heavy-duty coating


    Masahiro Otsuka, Shigeki Kusuhara



    The heavy-duty coating has been applied to the steel members of the Honshu-Shikoku Bridges, and its area is approximately 4 million m2. The preventive maintenance for coating, which is timely repainted only surface coat and middle coat is adopted, and the deterioration prediction of paint film is conducted to select the repainting period. According to the accumulated data, it was found that the weather resistance performance of paint film is higher than that of previous repainting plan, and extension of repainting cycle was expected. From a viewpoint of the preventive maintenance policy, the studies for high accuracy deterioration prediction method using the latest data of coating was carried out, in order to keep timing of the starting for repainting.

    The data of deterioration prediction for coating is influenced by the reduction rate of coat thickness and the remaining thickness of paint film, and each factor has dispersion. Therefore, the investigation method and modeling method for the dispersion of them were studied. This paper describes the high accuracy deterioration prediction method for the heavy-duty coating considering the dispersion of the characteristics of coating.

  • ケーブル気密化のための塗装仕様検討と試験施工

    Application and study of re-coating specification for corrosion protection of main cables of suspension bridges


    Akira Moriyama, Mitsukuni Kajio


    For the corrosion protection of the main cables of suspension bridges, the surface of the cables is covered by some coating materials. However, deteriorations such as cracks have been reported in the coatings of some existing bridge cables, and repair works for the deteriorations are required in order to secure the airtightness of the cables. Focusing on the flexibility of the coating materials, the deterioration trend of existing bridge cables with various types of coating materials is studied. Based on the study result, re-coating specification for main cables of suspension bridges is proposed. In this paper, the proposed re-coating specification and the result of laboratory test to check the flexibility of the coating films are presented. Also, the workability of the test painting materials and the result of the follow-up inspection for the test painting are reported.

  • 舞子トンネル防災システムの更新

    Renewal of Maiko tunnel disaster prevention system


    Toshihiro Matsuo, Osamu Nakamura, Tomoki Nishi


    The disaster prevention system of Maiko tunnel, passed 16 years after installation, was renewed in order to secure the reliability and safety, and to improve the economic efficiency of the system. The renewal work was difficult because the renewal work had to be carried out under the situation where the existing/new systems coexist keeping the function of the system. This paper reports the outline of the renewed system and the problem and technical challenges in the system switching works.

  • 土佐泊浦高架橋の耐震補強設計・施工

    Design and construction of seismic retrofit for Tosadomariura Bridge


    Hiroki Murakami, Akira Tanaka


    Seismic retrofit works for highway bridges located in some part of Kobe-Awaji-Naruto Expressway are now being carried out in order to secure the emergency route which connect the prefectural capitals of Honshu and Shikoku Islands together with national highways in case of huge earthquake in the futute. This report illustrates the outlines of the seismic performance verification, retrofitting design, and retrofitting construction works of Tosadomariura Bridge, located between Naruto-Kita IC and Naruto IC.

  • 共用アンカレイジスプレー室内の除湿効率改善

    Improvement of Dehumidification Condition for Splay Chamber of the Center Anchorage of Kita & Minami Bisan-Seto Bridges


    Takenobu Kitamura, Masahiro Takeguchi, Masaki Misaka


    The relative humidity inside of the splay chambers of the anchorages of the Honshu-Shikoku Bridges is controlled below 50%RH to protect the main cables from corrosion. Because the splay chambers of the BB4A center anchorage of Kita and Minami Bisan-Seto Bridge have the largest volume in the Honshu-Shikoku Bridges, the humidity controlled volume was minimized by covering the cable strands using dampproof sheet in order to improve the humidity condition. In particular, the BB4A anchorage, the commoditized anchorage between the Kita and Minami Bisan-Seto Bridges, has the complicated chambers which accommodate the strands of the two suspension bridges. This paper reports the measures and the results of the improvement of the dehumidification condition inside the spray chambers of the BB4A anchorage.

  • LED照明の海峡部橋梁自歩道への適用

    Application of LED lighting for the bicycle and pedestrian way of a long-span bridge


    Akihiro Ueda, Tetsuya Kobatake



    The pedestrian lightings of the Innoshima bridge, passed 32 years after the installation, were severely corroded, and almost all of the lighting fixtures were tied by fall prevention stainless steel band. However, there still remained the possibility that the corroded parts would fall down, so the renewal work of the lighting fixtures has been required. Recently, the technology of high power LED has been developed, and the LED lighting is now being widely spread in our everyday life. Also, for road and tunnel lighting devices, long life, low power consumption, and energy saving lighting equipment are developed.

    With such a background, the lightings of bicycles and pedestrian way of the Innnoshima bridge were renewed with the LED lightings. This paper reports the result of illuminance and light-leak measurements for the LED lightings.

【海外報告】Overseas report

  • 米国橋梁安全点検講習

    Safety Inspection of In-service Bridges in the United States of America


    Naoki Yanadori

【技術ニュース】Technical news