Publication Date:
2020-11-18
Description:
Fragility curves (FCs) constitute an emerging tool for the seismic risk assessment
of all elements at risk. They express the probability of a structure being damaged beyond a
specific damage state for a given seismic input motion parameter, incorporating the most
important sources of uncertainties, that is, seismic demand, capacity and definition of damage
states. Nevertheless, the implementation of FCs in loss/risk assessments introduces other
important sources of uncertainty, related to the usually limited knowledge about the elements
at risk (e.g., inventory, typology). In this paper, within a Bayesian framework, it is developed
a general methodology to combine into a single model (Bayesian combined model, BCM) the
information provided by multiple FC models, weighting them according to their credibility/
applicability, and independent past data. This combination enables to efficiently capture
inter-model variability (IMV) and to propagate it into risk/loss assessments, allowing the
treatment of a large spectrum of vulnerability-related uncertainties, usually neglected. As
case study, FCs for shallow tunnels in alluvial deposits, when subjected to transversal seismic
loading, are developed with two conventional procedures, based on a quasi-static numerical
approach. Noteworthy, loss/risk assessments resulting from such conventional methods show
significant unexpected differences. Conventional fragilities are then combined in a Bayesian
framework, in which also probability values are treated as random variables, characterized by
their probability density functions. The results show that BCM efficiently projects the whole
variability of input models into risk/loss estimations. This demonstrates that BCM is a
suitable framework to treat IMV in vulnerability assessments, in a straightforward and
explicit manner.
Description:
Published
Description:
723-746
Description:
4.1. Metodologie sismologiche per l'ingegneria sismica
Description:
JCR Journal
Description:
open
Keywords:
Fragility curves
;
Bayesian approach
;
Epistemic uncertainty
;
Inter-model variability
;
Seismic risk
;
04. Solid Earth::04.06. Seismology::04.06.11. Seismic risk
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
Permalink
