Seismic fragility curves of multi-span masonry arch bridges in Portugal

Many masonry arch bridges (MABs) operate in several railway networks in several European countries, where MABs are the most common bridge typology. In Portugal, MABs represent around 30% of the total stock in the railway network. Their performance assessment is of utmost relevance to the management authorities. However, there is limited research regarding their seismic performance. Moreover, research has shown that the elevated computational cost associated with stochastic analyses is one of the main challenges for implementing stochastic-based assessments to larger sets of bridges. In the present research, fragility curves are derived for a subtype of MABs with similar geometrical parameters. Surrogate models were included to reduce the computational cost associated with the probabilistic analysis, including an adaptive sequential sampling for defining the training experimental design from parameter uncertainties of selected mechanical properties.