Relationship between flood damage and repair methods for detached houses: Based on restoration works of flooded houses in Mihara City, Hiroshima prefecture, affected by heavy rains in July 2018

Abstract

This paper aims to clarify the relationship between flood damage and methods of repairing detached houses. The authors examined what repair works for each building part and element were performed in 11 surveyed houses flooded above the floor level, based on the field survey in Hiroshima Pref., an area heavily affected by a flood event in 2018 which included technical interviews with a regional building contractor. The findings indicate the repair methods for flood-damaged houses were similar for those with similar inundation depths, and characterized by the depth of flooding rather than structural types. They analyzed the quantitative relationship between repair cost and flooding magnitude to develop a regression model using “flood water volume,” which is the product of the repaired floor area and the flooding depth above the floor, as the explanatory variable. The analysis shows the regression model was intuitively easy to understand and highly compatible. After confirming the qualitative and quantitative relationship between repair work and flooding magnitude, they considered simulated repair methods for a model house and analyzed cost fluctuations at four flood levels to present the two types of standard repair work: normal plan and minimum plan, that could be assumed for each flooding level.