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  4. Vol.37 No.120 2013.3


Vol.37 No.120 2013.3


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

【巻頭言】Prefatory note

  • 千三百年の心構え

    Attitude toward 1300 Years


    Toru Adachi

【技術論文】Technical report

  • 岩黒島橋の鋼床版垂直補剛材のひずみ計測と疲労評価

    Strain measurement and fatigue evaluation of vertical stiffener at steel deck


    Sunao Kawabata


    Some cracks have occurred on vertical stiffener at intersection of stringer and crossgirder in steel deck of Hitsuishi-jima Bridge and Iwakuro-jima bridge. These cracks had some similarities in their situation, and were suspected to be the fatigue cracks. So, we measured strain of crack spot in operating condition, and examined the stress range and its frequency distribution at there. From this examination, it became clear that not only the heavy vehicles which pass through the road but the trains which run the lower deck railway as well cause high stresses at there. And the occurrence of the large stress range was comparatively high. So, this part is in hard fatigue environment, and it is thought that these cracks were caused by fatigue.

  • 舞子トンネル換気用排風機の維持管理

    Maintenance of Exhaust Fans in Maiko Tunnel


    Yoshihiro Asakura, Yoshiji Oura


    Many large-sized exhaust fans are installed for the Maiko Tunnel ventilation system and they shall be maintained based on Condition Based Maintenance policy. This policy is required to grasp the accurate deterioration of the fans in order to make a decision of the overhaul time. This paper reports results of the detail inspection from simple diagnosis and overhaul of the exhaust fans, and also the maintenance policy for the exhaust fans.

  • 瀬戸大橋スプレー室除湿設備の改善と効果

    Improvement and Effect of Dehumidification system for spray chamber of the Seto-Ohashi Bridges


    Akira Kagawa


    In order to prevent the main cables from corrosion, the dehumidification system for spray chamber of anchorage was installed to the suspension bridge of the Seto-Ohashi Bridges. And the target of this syatem is keeping the humidity of chamber less than the control criterion. Since the system was installed at the end of construction, there were insufficient knowledge of the chamber dehumidification. Therefore, it was difficult to keep the humidity less than control criterion of 50%RH (relative humidity). While some approach for improvement of humidity was carried out, it was impossible to attain the control criterion throughout the year. Thus, the problem of this system was analysed and the nessesary improvement (air-sealing, increase of equipment) was applied. As a result, the system could keep good humidity condition throughout the year. This paper describes the improvement, effect and save electricity of the dehumidification system for spray chamber.

  • コンクリート構造物の現況と評価

    Current condition and Evaluation of Concrete Structures


    Kazuyoshi Sakai, Tokihide Oto, Toshihiro Kagoike



    As for the concrete structures of Honshu-Shikoku Expressways, the non-destructive test was started in order to grasp soundness from 1999. The non-destructive testing manual (draft) was created in March 2001, and the test is carried out based on this manual. Since the 1st time of the non-destructive test of concrete structures was completed in 2011, the measurement result was summarized. As a result, as for carbonation it was understood that there is a tendency for advance to be early and the influence of sunshine or rain water is seen. As for chloride ion concentration, it was understood that internal chloride ion concentration is differing before and behind chloride regulation of total emission and surface chloride ion concentration are greatly related to the horizontal distance from the seashore etc.

    Moreover, as for the superstructures of specific PC bridges, measurement of carbonation and chloride ion concentration is carried out past 3 times in order to grasp a degradation tendency, and the result is also reported.

【海外報告】Overseas report

  • カザフスタン(イルティシュ川橋梁維持管理支援)

    Overseas Report (Republic of Kazakhstan: Technical Advice Services for Maintenance of Irtysh River Bridge)


    Kazuo Endo

【技術ニュース】Technical news