ANALYTICAL PROBABILISTIC RESILIENCE ESTIMATION FOR BRIDGES UNDER NEAR-FAULT EARTHQUAKES

Abstract

The seismic resilience is becoming an important indicator for the performance assessment of structures and infrastructure systems. This paper proposes a probabilistic approach based on seismic fragility analysis to assess the seismic resilience of steel-concrete composite bridges. By considering the structural and seismic uncertainties in different analysis steps of this approach, the sample generation process for probabilistic demand models is simplified, which largely reduced the computational burden. To deeper understand the seismic resilience and better describe the uncertainties, the estimation interval of the expected resilience is given, while the uncertainties are considered in fragility and propagated to the resilience. This approach is applied to a new typology of steel-concrete composite bridge endowed with concrete cross beams, which has been analyzed within the European Research Project SEQBRI. The results show that this probabilistic approach can largely speed up the process of seismic resilience assessment, while both the aleatory and epistemic uncertainties are considered. Mean-while, the resilience of the bridge is assessed under both the near-fault and the far-field ground motions which aim to study the influence of near-fault earthquakes on the seismic resilience.