Hurricane Surge-Wave Building Fragility Methodology for Use in Damage, Loss, and Resilience Analysis

Abstract

Physics-based fragilities for damage, loss, and resilience analysis are needed to model a community to earthquakes, hurricane winds, tornados, or floods. Currently, most building flood fragilities such as those available in assessment tools such as HAZUS-MH do not account for the hydrodynamic forces caused by surge and waves, only the depth of a flood. In this paper, a methodology to evaluate forces on all building components including windows, doors, walls, and floor systems for elevated coastal buildings under a combination of hurricane surge and waves is proposed. The model was validated by comparing vertical and horizontal forces from existing laboratory test results of a one-tenth-scale elevated structure under wave loading. A full-scale wood-frame residential building was then modeled as an example to illustrate the method and is intended to be representative of an elevated coastal structure in a typical coastal region of the United States. The hurricane was modeled as a combination of two intensity parameters, namely significant wave height and surge level at the building location and is better able to represent the loading condition and thus damage to the structure than static flood alone. Fragility surfaces for four damage states for the building as a whole were generated as a damage combination of all damageable building components. Finally, a comparison of the loss estimated using the fragility surfaces versus the current loss model in HAZUS-MH is provided to illustrate the effect on loss estimates when including wave height in predicting damage for near-coast buildings under hurricane wave and surge. By calibrating the physics-based fragilities with empirical data, the surface fragilities developed in this paper are ready to use in HAZUS-MH or other loss and resilience-focused analysis at the community level for coastal communities subjected to both waves and storm surge during hurricanes.