Study on the Evaluation of Temporal Change in Horizontal and Vertical Tsunami Forces Acting on a Bridge Superstructure
Study on the Evaluation of Temporal Change in Horizontal and Vertical Tsunami Forces Acting on a Bridge Superstructure
复制标题
桥梁上部结构水平和垂直海啸力随时间变化的评估研究
DOI：
10.1142/s0578563416400209
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发表时间：
2016
影响因子：
2.4
通讯作者：
N. Mizutani
中科院分区：
文献类型：
--
作者：
Tomoaki Nakamura;Yutaro Sawa;N. Mizutani
桥梁上部结构在2011年东北地震海啸中被冲走。为了确定桥梁上部结构是否以及何时被冲走，必须评估水平和垂直tsuneimi力的时间变化。本文从水工模型试验和数值模拟两方面研究了海啸对桥梁上部结构的作用力及其估算公式。根据试验结果，可以通过比较考虑竖向海啸力的水平海啸力与静摩擦力随时间的变化来判断桥梁上部结构是否发生移动以及何时发生移动。此外，对于水平方向的海啸力，提出了考虑水面高程的投影面积拖曳力方程和在拖曳力方程中加入惯性力的Morison方程，对于垂直方向的海啸力，提出了由浮力和向下升力组成的估算公式。通过与数值计算结果的比较，发现该估算公式可以预测水平和垂直方向海啸力的时间变化，但不包括短波周期，这表明该估算公式可以用来评估桥梁上部结构是否发生移动以及何时发生移动。
Bridge superstructures were washed away in the 2011 Tohoku earthquake tsunami. To determine whether and when bridge superstructures are washed away, it is essential to evaluate the temporal change in horizontal and vertical tsuneimi forces. In this study, tsunami force acting on bridge superstructures and its estimation formulae are investigated from hydraulic model experiments and numerical simulations. Prom experimented results, it is found that it can be determined from a comparison between the temporal change in horizontal tsuneimi force and that in static friction force taking into account vertical tsunami force whether and when a bridge superstructure move. Furthermore, a drag force equation with the projection area taking into account water surface elevation and a Morison equation in which inertia force is added to the drag force equation are proposed for horizontal tsunami force, and an estimation formula composed of buoyancy force and downward lift force is proposed for vertical tsunami force. From a comparison with numerical results, it was revealed that the estimation formulae can predict the temporal change in the horizontal and vertical tsunami forces except for short wave period, suggesting that it can be evaluated using the estimation formulae whether and when a bridge superstructures moves.