建築物に作用する津波力の低減対策に関する研究  [in Japanese] STUDY ON COUNTERMEASURES FOR REDUCING TSUNAMI FORCE ACTING ON BUILDINGS  [in Japanese]

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Abstract

津波避難ビル等の耐津波性能を向上させるため,建築物の管理者が設置可能な規模の津波対策工に着目し,対策工が建築物に及ぼす影響について数値計算により検討した.その結果,対策工によって建築物への津波の到達および最大津波力の発生を遅らせられることを示した.また,建築物前面での最大打上高と最大津波力は同時に発生するとは限らず,鉛直壁前面で局所的に発生する流速により非線形な波圧分布になる場合があることを明らかにした.さらに,建築物近傍に対策工を設置する際は高さを低くすることで,津波力の低減効果が期待できることを示した.ただし,対策工を建築物のごく近傍に設置した場合は衝撃波圧が作用することに留意する必要があることに言及した.以上から,建築物近傍に設置した対策工が津波力の減衰に有効であることを明らかにした.

 To enhance the tenacity of buildings located along coasts such as tsunami evacuation buildings, the effectiveness of small-scale countermeasures that can be constructed by their administrators is investigated using a coupled fluid-structure-sediment interaction numerical model that can compute air-water two-phase flow. The investigation focuses on an impermeable tsunami-resistant wall at the seaward side of a building as the countermeasures, and generates a single leading long-period wave against the building with the wall. Numerical results show that the maximum tsunami force acting on the building can be overestimated by the resultant force of hydrostatic pressure calculated from the maximum inundation depth in front of it, suggesting that the numerical model is a useful tool to evaluate the maximum tsunami force using the vertical distribution of the wave pressure. Furthermore, when the wall is placed in the vicinity of the quay wall, a higher wall can effectively reduce the tsunami force acting on the building. In contrast, when the wall is placed in the vicinity of the building, it can be effective to shorten the wall in terms of the reduction in the tsunami force. In addition, the wall can delay the impingement of the tsunami and the onset of the maximum tsunami force for large tsunami height. From these results, it is demonstrated that the construction of the short wall near the building would be an effective countermeasure.

Journal

  • Journal of Japan Society of Civil Engineers, Ser. B3 (Ocean Engineering)

    Journal of Japan Society of Civil Engineers, Ser. B3 (Ocean Engineering) 69(2), I_413-I_418, 2013

    Japan Society of Civil Engineers

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