海氷群を伴った遡上津波のピロティ形式の建築物への作用に関する研究  [in Japanese] INTERACTION BETWEEN SEA ICE FLOES DRIVEN BY RUN-UP TSUNAMI AND A STRUCTURE WITH PILOTI COLUMN CONSTRUCTION  [in Japanese]

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Abstract

本研究では,海氷群を伴った遡上津波による,津波避難施設等にも採用されているピロティ構造への作用形態やリスク等を明らかにするため水理模型実験を実施した.氷群や多量の漂流物がない場合には,ピロティ構造が有効であることを確認したが,氷群存在時には,氷群が柱間で閉塞(ジャム形成)して,流れをせき止め,水位が大きく上昇する事,氷群による衝突力に続き,氷群なしに比べ1オーダー大きい主流方向の静的な荷重が持続する事,同時にその荷重と同程度の鉛直上向の荷重も作用する事,等が分かった.大量の漂流物が存在する場所でのピロティ構造や窓等の開口を有する施設の設計には,その部分の津波力低減を考慮しない方が安全側である事,避難に際しては,水位上昇や氷塊のパイルアップにより,通常の津波時より高所へ避難する必要がある事が提言できた.

 We performed model experiments to clarify the increased risks caused by sea ice floes driven by runup tsunami against a structure with piloti column construction, which has been applied to a tsunami evacuation facility. After the collision force imparted by the ice floes acts on the columns, the run-up flow is dammed by the formation of ice jams and ice pile-ups between the columns, and a large static force in the main flow direction. The force is one order of magnitude greater than that in case without ice floes, also acts on the structure because of the water level rise and the ice pile-ups in front of the structure and because of hydrostatic pressure between the columns due to the ice-jam, and this steady state remains for some time. A large force in the vertical direction also acts on the structure, which is the same level as that in the main flow direction. We suggested that, in designing of structures with openings, such as windows and space between columns, the design force for tsunami flow acting on such parts should not be reduced because of the formation of the ice jams and pile-ups. We also suggested that we should evacuate to higher places than usual, because of the water level rise and the ice pile-ups.

Journal

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

    Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering) 71(2), I_919-I_924, 2015

    Japan Society of Civil Engineers

Codes

  • NII Article ID (NAID)
    130005109434
  • Text Lang
    JPN
  • ISSN
    1884-2399
  • NDL Article ID
    027085432
  • NDL Call No.
    YH267-236
  • Data Source
    NDL  J-STAGE 
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