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  4. Vol.21 No.82 1997.4


Vol.21 No.82 1997.4


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

【巻頭言】Prefatory note

  • 125年前

    125 years ago


    Tokuya Kikuchi

【技術論文】Technical report

  • 舞子トンネル明かり巻部におけるプレキャスト化工法の設計・施工

    Design and Construction by Precast Work Method Over Open-Cut Section of Maiko Tunnel


    Tomiharu Iwagaki, Yoshiaki Hamamura


    この区間の施工にあたり、トンネルのアーチ部にプレキャスト部材を活用したPre-Cast Arch Tunnel(PAT)工法を開発し、施工の省力化、工期短縮、工事に伴う騒音・振動の低減、施工の安全性の向上を図った。


    The Maiko Tunnel with a length of 3.3 kilometers is located on the on-land portion of Kobe-Naruto Route at the Kobe side, consisting of parallel tunnels with a width to 3-lane highway each. The portion over a length of 232 meters from the south portal of the tunnels was constructed by the open-cut method whose top was resurfaced by the earthwork to prepare a site for a park by the Kobe City to preserve a good environment for residential area. For the construction of this portion, the precast arch tunneling (PAT) method was developed that would be expected to cut down man-power, construction period, and construction noise and vibration, but raise the safety. Although the use of precast segment was rare in such a tunnel with a wide cross section, enough performance was achieved as it was expected. This paper reports the outline of design and construction work of the tunnel.

  • 撫養橋(上下線並列橋)の耐風応答特性

    Aerodynamic Responses of Muya Bridge in Parallel Arrangement


    Hiroaki Hoashi, Takashige Taniguch, Yuuki Kishi


    The Muya Bridge has two separate decks: one for the north- and the other for the south-bound lanes, and the decks are arranged alongside each other. In the aerodynamic study on the bridge, wind tunnel tests were carried out using two dimensional and three-dimensional elastic models.

    As a result, it was required that a side maintenance deck, which would play a role as a damping plate, installed alongside of the decks to suppress galloping with the deck in both cases of single and parallel arrangement, and the deck for the north-bound lanes has been already completed and opened to public.

    This paper introduces the further study on the aerodynamic stability of the bridge by elastic model wind tunnel test, which was carried out to investigate feasibility of stabilization without the side maintenance deck.

    As a result, it was found that the aerodynamic responses would be greatly affected by the difference between natural frequencies of both decks, and the galloping would be reduced in a turbulent flow and transformed into the buffeting with increment of turbulent intensity.

  • 北備讃瀬戸大橋ケーブル送気試験

    Cable inside dry up test on Kitabisanseto Bridge


    Motoi Okuda, Satsuki Yamashita, Nobufumi Ikoga


    For the purpose of anti-corrosion of the cable for the suspension bridge, the Cable wrapping systems have ordinarily been employed to cover the peripheral of the cable for waterproofing. However, this system was found to be insufficient to prevent corrosion of the cable in a corrosive environment such as one around the Honshu-shikoku Bridges, which is oceanic and with quite a few rainfalls throughout the year. A new system was worked out to dry up the moisture inside the cable that was produced by the residual water inside the cable. The system consists of air dryer, blower, desalinate filter, and air injection piping, as well as a watertight cable seethe. The measurements were made on the following items:

    1. Air humidity inside the Cable

    2. Air pressure inside the Cable

    As a result, it was found that the dehumidified area in the cable corresponded to the lapse of time for air injection and the quality of air-tightness of the cable cover. Also found was that the pressure change was observed over a length of 100 meters from the point of air injection, although the length of dehumidfied area along the cable far exceeded that. The system has still been under experiments, and this paper reports the outline of the system as an interim one.

  • 吊橋主塔の引張接合継手の製作架設

    Fabrication and Erection of Towers with Bolted-Flange joints on a Suspension Bridge


    Masatoshi Sasaki, Norihiro Miyaguchi, Kazunori Yamaguchi



    A bolted-flange joint system was designed for a part of towers, from a horizontal member at the roadway-height to the topmost part, of 2P and 3P of Kurushima Bridge, in order to reduce man power and construction period and raise safety with the site work, as well as to achieve easy maintenance and good aesthetics on the bridge. This paper introduces a course of design, fabrication, and erection on the joint system, which had been unprecedented in Japan.

  • 長大トラス吊橋のハンガーピン定着部補強構造の力の伝達機構と疲労挙動

    Force Transfer Mechanism and Fatigue Behavior of a Pin-Connection Anchor of Hanger for a Long-Span Suspension Bridge


    Harukazu Ohashi, Muneo Okawa


    Through pin-connection parts of suspender ropes attached to chord members of stiffening truss on a suspension bridge, all loads are transmitted by bearing of the pin and the pin plate. With a strong wind condition, the out-of-plane force acts repeatedly on the connection, which would be produced by the horizontal component of a tension in the suspender rope that would occur from a relative movement between the stiffening truss and the cable. This recurrent action creates a non-uniform condition of the bearing stress in the pin connection. This report presents results of static loading test and fatigue test that were carried out to verify weak points and the fatigue strength, using full-scale specimens representing two types of pin-connection structure for a long-span, truss-stiffened suspension bridge.

【海外報告】Overseas report

  • 鋼橋の耐震設計、評価、補修に関する米国の最近の情報(セミナー報告)

    Seismic Design,Evaluation and Retrofit of Steel Bridges,(2nd US seminar,San Francisco)


    Haruki Akiyama

  • タンザニア動物保護区における道路及び橋梁の建設・補修工事の現状報告

    Report on Construction and Repair Works of Roads in Tanzania


    Futoshi Fujita

【技術ニュース】Technical news