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  4. Vol.16 No.62 1992.4


Vol.16 No.62 1992.4


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

【巻頭言】Prefatory note

  • 明石海峡大橋の主塔基礎の完成

    Completion of Tower Foundations for the Akashi Kaikyo Bridge


    Shoichi Saeki

【技術論文】Technical report

  • 鋼橋等塗装基準の改訂

    Revision of Steel Bridges Coating Standards of HSBA


    Toshimitsu Itohiya


    The Honshu-Shikoku Bridges, being characterized by a number of its long spans across the straits, located in a severe atmospheric environment where it may easily cause corrosion. Corrosion control is based on the Steel Bridge Coating Standards of HSBA set up in March, 1980. The system of coating steel bridges had been tested from the viewpoint of maintenance until a full revision of the standards was made in April, 1990.

    The revised standards are intended to lower the frequency of repainting so as to reduce their maintenance costs. The fluororesin paint, more resistant to the action of the weather, has newly been adopted instead of the polyurethane paint for finish coating of them across the straits. Various other improvements comprise the specifications concerning the cables and the bridge steel galvanizing specifications. The specifications for repainting them have been also supplemented besides the newly-established standards. This paper aims to show this revision in brief outlines.

  • 明石海峡大橋4Aアンカレイジ土留工の設計と施工

    Design and Work of Earth-Retaining Structure for Akashi Kaikyo Bridge 4A Anchorage


    Isamu Arima, Kiyofuyu Suenaga, Tomoji Murata


    Anchorage foundation of 4A for Akashi Kaikyo Bridge is located at the northernmost of Awaji Island, which is one of the most picturesque places. This report describes the design and construction of the earth-retaining wall for anchorage foundations considering social and geological conditions. The nation's biggest deep earth-retaining wall was planned to be built by the lined-steel pipe piles method, facilitating inner excavation using earth anchors. The steel pipe piles were drived by all moving casing cutters and air hummers. The design of the deep earth retaining wall has been performed by the elasto-plastic method. The details of earth-anchoring, chemical grouting, instrumentation plan of the entire earth-retaining wall for accident prevention are introduced.

  • 橋梁用マスコンクリートにおけるニ成分系低発熱型高流動コンクリートの開発(その1)

    Development of Highly-Plasticized concrete Composed of Binary-Blended Low Heat Cement for Massive Bridge Structures


    Katsuyoshi Kanazawa, Isamu Arima,
    Kiyofuyu Suenaga, Tomoji Murata


    The legal and social conditions impose many restrictions on the placement of mass concrete; a large amount of cast-in-place concrete for large bridge foundations has to be placed rapidly, and it is very important to maintain its quality during placement. The authors have developed unprecedented highly-workable-concrete which is mixed with binary low-heat cement and coarse aggregate with a grain size of max. 40mm designed for bridge foundations.

    Such concrete can prevent the quality deterioration which is often caused of recent lack of skillful workers, and also can raise efficiency of the work, because the concrete flows to wide area or to concentrated steel portion without segregation and fills even narrow space with it own. The authors have been conducting laboratory and field tests to examine the problems of material selection, the basic physical properties, the design and construction methods, and so on in order to apply the concrete to the anchorage foundation of 4A for Akashi Kaikyo Bridge, and in this report result of the laboratory test for basic physical property will be mentioned.

  • 生口橋塔独立時の同調液体型制振装置

    Tuned Liquid Damper used for Freestanding State of the Tower of Ikuchi Bridge


    Tohru Fujiwara


    A wind tunnel test to verify the wind resistant design of the freestanding tower of lkuchi Bridge has revealed that vibrations due to eddy excitations often occur at comparatively low levels of wind velocity. These vibrations rarely cause serious damage to the structural strength of the tower, but their occurrence right near the joint, structurally peculiar to this bridge, where a steel girder and a PC girder meet in the body of the tower, poses a serious problem for gaining the required strength of the concrete placed : therefore vibration control measure have been applied to solve concrete quality problems during placement or after hardening. The Tuned Liquid Damper TLD has been adopted as a vibration control device to withstand the dynamic movement of the liquid within a water tank. A free damped vibration test is conducted at the site to confirm its vibration control performance, and to adjust the frequency and damping factor. These results show that the installation of TLD allows the apparent damping factor of the tower to remarkably increase, and the required effect of vibration control can be achieved.

  • 来島大橋上部工の耐震性

    A Seismic Study on superstructure of Kurushima Bridge


    Harukazu Ohashi, Tetsuya Nakamura

    三連吊橋である来島大橋の上部工について、来島大橋の下部工に関する耐震設計法が定められたことを受け、その耐震性に関しての検討を行った。検討項目は、①タワー・ピア系モデルを用いた地盤と構造物応答特性の感度分析 ②吊橋全体系を用いた応答特性 ③三連吊橋の応答特性 ④長周期地震動の影響 ⑤位相差地震の影響である。①、②、③は応答スペクトル解析、④、⑤は時刻歴応答解析によった。また、この結果と従来の耐震設計法による結果との比較を行った。


    An earthquake resistance design of the superstructure of Kurushima Bridges, three continuous suspension bridges, is examined in connection with the fact that a code for the aseismic design of its substructure was set. The following items are considered; ①A sensibility analysis of the ground and the structural response using a tower-pier model; ②Response characteristics of an entire system of one suspension bridge; ③Response characteristics of three continuous suspension bridges; ④An influence of long period earthquake motion; ⑤ Effects of phase difference inputs of earthquake motion. ① ,②and ③ are based on a response spectrum analysis, while ④ and ⑤ on a time history response analysis. These results are compared with those obtained by the conventional aseismic design. It becomes clear that it is sufficient to analyse the entire model of one suspension bridge and it is not necessary to analyse three continuous suspension bridges as a whole, and that earthquake force does not predominate in the design of main towers.

【海外報告】Overseas report

  • IABSE出張報告

    Report of a IABSE Symposium in Leningrad


    Hiroki Matsumoto

【技術ニュース】Technical news