2015 Volume 71 Issue 1 Pages 1-11
To estimate the fragility of wooden buildings (houses) in relation to the tsunami water depth and hydrodynamic force during the 2011 Great East Japan tsunami, a numerical simulation was conducted in three different regions using a nonlinear long wave equation model that includes the breaking or washout condition of trees and houses. Fragility curves as a function of water depth, fluid force (FF) and moment by fluid force (MF) were analyzed for different level of house damages. Some differences exist especially for the fragility curve of washing out houses, but the curve where coastal forest was thin and breaching of embankment was not occurred can be utilized because of the high accuracy of the washout situation of houses in numerical simulation. The differences in place were small in case of a collapsed or major/moderate damage level for FF and MF. Although the simulation includes the washout condition defined by the critical moment index, the applicability of FF was better than MF for high Froude numbers near the coast. The efficacy of selecting the smaller curve was proposed within two water depth curves for 50% collapsed or major/moderate damage level based on Froude numbers.