Probabilistic seismic vulnerability assessment of buildings in terms of economic losses

The probabilistic seismic risk assessment in terms of economic losses for building portfolios aims to the estimation of the probability distribution functions (PDF) of economic losses for a set of stochastic events representing the seismic hazard at a particular geographic zone. This paper proposes a methodological approach to evaluate and integrate, in a consistent and rigorous way, the economic losses as a function of the seismic hazard intensity for prototype building constructions. Prototype building models are designed and characterized with a set of reference parameters. By means of 3D structural models, detailed nonlinear response history analyses are performed for a set of seismic records at several increasing intensities. Seismic records are selected to represent particular seismological and geotechnical conditions at the site of analysis. Then, a component-based model is conformed considering structural, non-structural, and content components potentially susceptible to damage. Each component type is assigned a fragility specification for various damage states in terms of costs and times of repair. Using Monte Carlo simulations, the different sources of uncertainty are included in the assessment of the costs and times of repair at different seismic intensities. Uncertainties in the hazard, model response, damage states, and costs and times of repair are considered. Aspects such as geographical variations in the hazard, scale economy, special commercial conditions, minimum or total intervention costs, and business interruption costs are included in the assessment. Finally, the results are represented by means of vulnerability functions for specific building typologies. To illustrate the methodology, a case study is presented in detail for a typical 5-story reinforced concrete moment resisting frame building designed for special seismic code level and located in a typical soft soil deposit of Bogotá, Colombia. Additional results are presented for six (6) different building typologies illustrating variations in results due to different story heights and seismic code levels. The resulting vulnerability functions are compared with equivalent results from other similar methodologies. Conclusions and possible potential applications related to probabilistic risk assessment are summarized.