Relative Tsunami Vulnerability of Structural Materials Across Tsunami Events

Abstract

The influence of structural material on tsunami vulnerability is well established. However, there are shortcomings in incorporating this effect into vulnerability models. This study was conducted to compute the overall building damage due to a tsunami from fragility curves and replacement cost coefficients, and to identify the influence of different structural materials on structural vulnerability. The damage curves were of negative exponential form, with the influence of differing structural materials characterized by the single parameter defining those curves, i.e. the 'n' value. The results confirmed the established knowledge that vulnerability increased from RC through steel and masonry to timber structures. More importantly, they highlighted the fact that relative vulnerability is coupled with inundation depth, since, at depths approaching around 6 m, all materials will incur similar heavy damage. The most important finding of this work is that there is less modelling variance across tsunami events if a relative vulnerability approach is used (with each material compared to reinforced concrete), rather than using a mean 'n' value for each material across all tsunami events.