Computational and rapid expected annual loss estimation methodologies for structures

Abstract

SUMMARYExpected annual loss (EAL), which can be expressed in dollars, is an effective way of communicating the seismic vulnerability of constructed facilities to owners and insurers. A simplified method for estimating EAL without conducting time consuming non-linear dynamic analyses is presented. Relationships between intensity measures and engineering demand parameters resulting from a pushover analysis and a modified capacity-spectrum method are combined with epistemic and aleatory uncertainties to arrive at a probabilistic demand model.Damage measures are established to determine thresholds for damage states from which loss ratios can be defined. Financial implications due to damage can then be quantified in the form of EAL by integrating total losses for all likely earthquake scenarios. This rapid loss estimation method is verified through the computationally intensive Incremental Dynamic Analysis, with results processed using a distribution-free methodology. To illustrate the application of the proposed method, the seismic vulnerability of two highway bridge piers is compared; one bridge is traditionally designed for ductility while the other is based on an emerging damage avoidance design (DAD) philosophy. The DAD pier is found to have a clear advantage over the conventional pier; the EAL of the DAD pier is less than 20 percent of its ductile counterpart. This is shown to be primarily due to its inherent damage-free behaviour for small to medium earthquake intensities, whose contribution to EAL is significantly more than that of very rare events.2

Seismic loss estimation of non‐ductile reinforced concrete buildings

“…Based on the PEER framework (Figure ), the approach is comprised of four analysis steps: quantification of the seismic hazard, response analysis, definition of the performance groups and damage states, and finally loss analysis. Each of the four steps is described briefly below; further details can be found elsewhere . In subsequent sections, this seismic loss assessment procedure will be used to specifically investigate seismic losses for non‐ductile concrete buildings.…”

Incremental dynamic analysis with consideration of modeling uncertainties

“…It can be used to take into account the effect of the aleatory uncertainty (record-to-record variability) on the engineering 806 M. DOLSEK demand parameter (EDP) through the set of ground motion records (GMR), and is used for multiple purposes. For example, many researchers have used IDA for evaluation of the seismic performance of different types of structures [3][4][5] for studies related to advanced intensities measures [6,7] or damage measure [8], and for the validation of simplified procedures for the prediction of approximate IDA curves [9][10][11][12] or loss estimation methodologies [13].…”

Pricing catastrophe equity put options: Financial implications of engineering decisions

“…The dispersion of all combined uncertainty and randomness (β RS ) is given by root-sumsquares method (Kennedy et al 1980;Solberg et al 2008):…”

“…where β RC = randomness in capacity of the structure = 0.2 (Solberg et al 2008); β U = uncertainty in modeling = 0.25 (Kennedy and Ravindra 1984); and β RD = randomness in demand. The dispersion in estimation of the annual frequency of event; β f |L for a given loss ratio is given by (Damnjanovic et al 2008)…”