Fatality risk and its application to the seismic performance assessment of a building

Abstract

A fatality risk-based decision model for the performance assessment of buildings is proposed as an alternative to the frequently used collapse risk-based verification format. Earthquake fatalities as a measure of the consequences of collapse are studied in order to introduce a model for the tolerated annual fatality risk. It is assumed that the tolerated annual fatality risk depends on the tolerated individual annual fatality risk and the expected number of fatalities given collapse of a building. The latter parameter accounts for the consequences of the collapse of a building via the number of people exposed in the building and the performance of the structural system of a building in relation to the risk of death in the case of collapse. The use of the proposed decision model is demonstrated on an example of three reinforced concrete frames. It is shown that it is challenging to achieve an earthquake fatality risk that could be considered negligible if the structure is designed according to standards for earthquake-resistant design. Therefore further studies are needed to develop a firm scientific basis for the decision model which will address safety as well as costs of construction and expected losses. The proposed fatality risk-based decision model can be the first step towards such improvements, and thus it can be used for the performance assessment of a building. This opens up new possibilities for research in earthquake engineering since it is necessary to understand better the collapse modes of different types of buildings and the risk of death given a building’s collapse.