A Seismic Performance Classification Framework to Provide Increased Seismic Resilience

Abstract

Several performance measures are being used in modern seismic engineering applications, suggesting that seismic performance could be classified a number of ways. This paper reviews a range of performance measures currently being adopted and then proposes a new seismic performance classification framework based on expected annual losses (EAL). The motivation for an EAL-based performance framework stems from the observation that, in addition to limiting lives lost during earthquakes, changes are needed to improve the resilience of our societies, and it is proposed that increased resilience in developed countries could be achieved by limiting monetary losses. In order to set suitable preliminary values of EAL for performance classification, values of EAL reported in the literature are reviewed. Uncertainties in current EAL estimates are discussed and then an EAL-based seismic performance classification framework is proposed. The proposal is made that the EAL should be computed on a storey-by-storey basis in recognition that EAL for different storeys of a building could vary significantly and also recognizing that a single building may have multiple owners. A number of tools for the estimation of EAL are reviewed in this paper and the argument is made that simplified methods for the prediction of EAL are required as engineers transition to this new performance parameter. In order to illustrate the potential value of an EAL-based classification scheme, a three storey RC frame building is examined using a simplified displacement-based loss assessment procedure and performance classifications are made for three different retrofit options. The results show that even if only limited non-structural interventions are made to the case study, the EAL could be significantly reduced. It is also argued that overall, such a performance classification, coupled with some form of government or insurance-driven incentive scheme, may provide an effective means of reducing the risk, and increasing the resilience, of our societies.