橋梁上部工に作用する津波力に与える橋脚の影響  [in Japanese] INFLUENCE OF BRIDGE PIERS ON TSUNAMI FORCE ACTING ON BRIDGE UPPER STRUCTURES  [in Japanese]

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Abstract

橋脚の存在が橋梁上部工に作用する津波力に与える影響を明らかにすることを目的として,水理模型実験および数値解析を実施した.水理模型実験では,ゲート急開法により発生させた段波を模擬津波として用いた.浸水深および橋脚による阻害率をパラメータとして変化させ,橋脚周辺の津波変形および上部工に作用する津波力を計測した.数値解析では,橋脚をポーラスメディアとしてモデル化して,VOF法により津波変形実験を再現した.検討の結果,阻害率が大きくなるにつれて,最大浸水深が増大すること,橋梁上部工に作用する鉛直力も増大することが明らかになった.特に,浸水深が大きい場合は,橋脚から発生する反射波の影響等で,上部工に作用する鉛直力が浮力よりも大きくなることがわかった.

 Hydraulic model experiments and numerical analysis were carried out with the purpose of clarifying the influence of the existence of the piers on the tsunami force acting on the superstructures. In the hydraulic model experiment, the inundation depth and the impediment rate by bridge piers were varied as parameters, and the tsunami deformation around the pier and the tsunami force acting on the superstructure were measured. In the numerical analysis, we modeled the bridge piers as porous media and reproduced the tsunami deformation experiment by the VOF method. As a result, it became clear that as the impediment rate increases, the maximum flooding depth increases, and the vertical force acting on the superstructure also increases. In particular, when the inundation depth is large, it was found that the vertical force acting on the superstructure becomes larger than the buoyancy due to the reflected wave generated from the piers.

Journal

  • Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering)

    Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering) 74(2), I_277-I_282, 2018

    Japan Society of Civil Engineers

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