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  4. Vol.17 No.65 1993.1


Vol.17 No.65 1993.1


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

【巻頭言】Prefatory note

  • ネクストウェイ



    Hirosuke Tamada

【技術論文】Technical report

  • 中間橋脚を有する斜張橋の構造特性

    Structural Characteristics of Cable Stayed Bridge with Intermediate Piers


    Atushi Okukawa, Nobuhiko Takagi, Kazunori Yamaguchi


    The Tatara Bridge will have a center span of 890m, which almost doubles the record of center span length of conventional cable-stayed bridges. This required a precise study on structural characteristics associated with elongation of the center span .To seek a viewpoint from which the center span of 890m of Tatara Bridge should be examined, the study included a series of comparative designs that clarified differences in structural characteristics (induced stresses, buckling properties, vibration characteristics, etc.) inhered to respective center span of 500m, 890m, 1400m, and 2000m. This paper introduces results and findings of this analytical study.

  • TBMによる掘削工事報告

    A Report on Excavation Work by TBM for The Maiko Tunnel


    Yoshihiro Mishima



    掘削には、従来の発破工法による施工が困難なため、TBM(Tunnel Boring Machineを採用している。


    Work execution of the Maiko Tunnel should be done with the least influence on the surrounding environment of highly - populated area.

    To avoid trespassing of work vehicles into this residential area, a pilot tunnel was first bored to convey excavated rocks and soils over the section composed of hard granite.

    Excavation was carried out by the tunnel Boring Machine (TBM) instead of the blasting method that might cause adverse effects on social environment.

    This report outlines the work procedure of excavation by TBM for the Maiko Tunnel, which was finished in time, without any trouble.

  • 吊橋ケーブルバンドボルトの軸力管理

    In-situ Tension Control for Cable Clamp Bolts of Suspension Bridges


    Yoshinobu Hayashi, Shinichi Hirano



    The cable clamp (band) plays an important role in carrying the load from the suspender rope to the main cable of suspension bridge; the bolt tension to fasten the cable clamps should be induced under control so that required friction force could be obtained between both surfaces of clamp and cable. Re-tightening of the cable clamp bolts for the suspension bridges in the Seto Ohashi (Shimotsui-seto, Minami and Kita Bisan-seto bridges) were carried out during 1989 - 1991 for the first time since its opening to the traffic.

    This paper proposes a statistical estimation procedure for both to process selectively measured data on the cable clamp bolt tensions and to estimate, from such selected data, tensions of the rest bolts and safety factors for the friction force in the entire bolts. The paper also examines the ultrasonic measurement system for the bolt tension, and shows the system can effectively be applied to the quality control in construction for newly-erected bridges, such as the Kurushima Bridge.

  • 多々羅大橋全体耐荷力試験

    Full-model Loading Test on the Tatara Bridge


    Yuji Fujii, Ryuichi Toriumi


    Results from a elasto-plastic deformation analysis on the Tatara Bridge, the unprecedented long-span cable-stayed bridge, predicted the bridge would terminate itself with the buckling of the girder at a section near the tower. This forecast differed from the conventional understanding that the cable-stayed bridge would normally have its limit state with the buckling of the tower shaft; this difference seemed to be caused by the elongation of the center span.

    Probability of this prediction depended on how accurate the numerical analysis could estimate a limit state of the girder of cable-stayed bridge that had numerous elastic supports by the cables and the Towers. Suitability of the numerical analysis for loading capacity had been confirmed only for simple structures. A full model loading test was thus carried out for the Tatara Bridge.

    Results of this model test well agreed with the numerical solution for both the loading capacity and the limit state, and thereby clarified fitness of the numerical analysis to evaluation of the loading capacity on the structure of Tatara Bridge.

  • 生口橋実橋振動実験

    A Field Vibration Test on The Real Ikuchi Bridge


    Tohuru Fujiwara, Takashi Tamakoshi


    The Ikuchi Bridge, which is a cable-stayed bridge having a center span of 490m, adopted a composite girder system, composed of steel for the center span and prestressed concrete for both side spans, for the first time in Japan. This paper outlines the vibration test carried out on the real Ikuchi Bridge, using a large oscillatory machine.

    The test was conducted to obtain knowledge on a resonance effect expected to be observed in the dynamic response of the cables in cable-stayed system, as well as to grasp vibration characteristics of the structure such as natural frequency and structural decrement, etc.

    As a result, natural frequencies and modes of vibration of the structure measured were well agreed with those calculated by numerical analysis. Obtained values of logarithmic decrement were as equal as or greater than the values specified in the Wind-Proof Design Standard of HSBA (0.02 for box girder).

  • 来島大橋補剛桁の耐風性

    Aerodynamic Study of Stiffening Girder for the Kurushima Bridge


    Harukazu Ohashi


    Aerodynamic performance for the Kurusima Bridge, three suspension bridges in alignment, was studied through wind tunnel tests and analyses. The center span lengths of three bridges are 600m, 1,020m, and 1,030m respectively. Wind characteristics at the bridge site were investigated by wind tunnel test using a terrain model, and the result was compared with field observation data. Major results obtained through this study are:

    ① Wind tunnel test using a terrain model proved to be useful for estimating wind characteristics. Wind properties such as wind profile, distribution of mean wind velocity, inclination angle, and turbulence intensity were obtained at tower height and spanwise.

    ②Wind stability at completion stage was studied by section models. Flat-hexagonal sections of the girder which satisfy required wind stability were obtained. In the wind tunnel tests, girder depth.shape of fairing, rail for inspection vehicle, and net fence for pedestrian-bike ways also were, studied.

    ③Wind stability for a 2-box section with center air-gap was also investigated.

    ④Gust response due to three components of aerostatic forces was analyzed for the flat-hexagonal section and the 2-box section with center air-gap. Obtained gust factor was for the former section approximately 2.0.

    ⑤Wind stability during erection stage was studied by a three-dimensional elastic model.

【海外報告】Overseas report

  • トルコでの有料道路セミナー報告

    Report of Seminar on motorway in Turkey


    Shozo Yoshikawa

【技術ニュース】Technical news