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  4. Vol.27 No.100 2003.3


Vol.27 No.100 2003.3


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

【巻頭言】Prefatory note

  • リスク管理

    Risk Management


    Makoto Kitagawa

【技術論文】Technical report

  • 水中鉄筋コンクリート(水中RC)の施工性確認実験

    Experiment on Workability of Underwater Reinforced Concrete (Underwater RC)


    Kazuo Sumi


    Ultra long span bridges, which would surpass the current longest span, Akashi Kaikyo Bridge, are planned in strait-crossing projects in next generation. These ultra long span bridges will have the deepest foundations of over 100 meters in deep water, which will far excess the precedents. The experiment was carried out to establish the reasonable construction technology for the underwater RC in deep water.

  • 海峡部PC橋の長寿命化対策

    Life Elongation of Offshore PC Bridges


    Kazuhiko Tsuru, Ikuo Yamada


    Prestressed concrete structures, which are normally made of lesser water-cement ratio concrete than ordinary RC, have not been spotlighted in the viewpoint of lengthening of the life of structure. However, offshore PC structures, which are exposed in severe chloride corrosion environment, should keep their lives as designed. Therefore, the study on lengthening of PC life aiming at the duration of 200 years was carried out. The study included forecasting aging based on the analysis of current condition of the real structure on thickness of reinforcement coverage, neutralization progress, and quantity of salt in the concrete of the structure.

  • 大鳴門橋1A道路桁補修工事

    Repair Work of Ohnaruto Bridge 1A-Road Deck


    Kazuyoshi Sakai, Seiji Ishimoto


    Stirrup bars were partially exposed and corroded on the Ohnaruto Bridge 1A road deck. Therefore, investigation on concrete was carried out to forecast future deterioration, and the result indicated necessity of prompt rehabilitation. The repair work consists of recovery of cross-section area, attachment of surface protection, and arrangement of monitoring points for the measurement of natural voltage.

  • 瀬戸中央自動車道交通管理システムの更新計画

    Plan of Retrofit of the Traffic Management System in the Seto-Chuo Expressway


    Shinichi Oe, Kunio Nakashima



    The traffic management system in the Seto-chuo Expressway was in use on April 10, 1988, and has been operated to assist the management of the highway traffic. The system, however, has become outdated and requires renovation because the system troubles have increased and it associated with difficulties in repair. Also, the outdated system has not satisfied the driver's needs such as obtaining wider area traffic information beyond the Seto-Chuo Expressway.

    In this plan of renovation, drastic change is proposed of the existing traffic management system. For example, the system would equip with the IP network utilizing the cutting-edge IT. In addition, the system provides event-processor, the distributed processing components, and the integrated operation console to control the new traffic management system. The system will contribute to simplification of peripheral facilities and reduce the man power in the traffic management, which are brought about by the experience of the traffic management for fourteen years.

    This paper describes the plan of retrofit of the traffic management system and the concept of the new one.

  • 舗装変状部の調査と分析

    Investigation and Analysis on Deteriorated Pavement


    Tatsuo Okazawa


    The paper reports the investigation, analysis, and the future care in the two works on on-going rehabilitation for the pavement deterioration found on parts of the pavement, which was previously rehabilitated in a short time after opening to the traffic. In a short time after opening to the traffic, cracks and defacement of the pavement were found in the two sections. Therefore, field and laboratory tests were carried out to obtain data on quality and physical properties of asphalt mixture, and characteristics of bearing capacity. Although the deteriorations in two sections looked like quite similar to each others, one section was caused by shortness of bearing capacity of the lower bed, and the other was by the deterioration in quality of asphalt.

  • 生口橋箱桁内の腐食環境調査

    Corrosive Environment Survey on the Inside Box Girder of Ikuchi Bridge


    Kazuhiko Furuya, Hiroshi Isoe, Hiroyuki Oogushi




    Nishi-seto Expressway has eight long span bridges with steel box girders covered with interior painting excepting the Shin-Onomichi Bridge. Since irregularity was found on internal painting of Ohshima Bridge, we carried out investigation on ambient corrosion environment inside the steel box girder in 1999; the observed ambient data showed a good condition inside the deck.

    Since then, the corrosion environment investigation was repeatedly done at lkuchi Bridge in 2001 and 2002, in order to grasp the tendency of the ambient corrosion environment inside the steel box girder.

    Although inside air was good in general in the latter surveys, approximately 100 milligram of salt was adhered par year inside the deck near the opening to outside. Also, more salt adhesion was found at the some other spots of the box girder, therefore, we were anxious about worsening of corrosion environment in the future in case the counteraction would be undone.

【海外報告】Overseas report

  • 海外報告(マレーシア、橋には花が咲き乱れ)

    Overseas Report (Malaysia, Flowers are blooming beautifully on bridges)


    Yoshitaka Yoshida

  • 海外報告(フィリピン橋梁事情)

    Overseas Report (Bridges in Philippines)


    Motoi Okuda

【技術ニュース】Technical news