Fig 1.
Workflow of the research framework.
Fig 2.
Efficiency drop due to bridge removal.
Box plots show the distribution of relative efficiency drop in sub-networks within a radius R around the removed bridge, categorized by road type.
Fig 3.
Absolute values of the median relative efficiency drops for specific road types, expressed as a function of the radius around a removed bridge.
Only the road types that feature more than 20 bridges are reported.
Fig 4.
Seismic hazard of the bridges.
The figure was created using the open source tool QGIS with OpenStreetMap as the basemap [42]. The seismic hazard values refer to a return period of 475 years, per the Italian Building Code [43].
Fig 5.
Functionality of the considered bridges.
Fig 6.
Functionality of the considered bridges as a function of the spectral amplitude, for different construction materials, structures, and seismic design prescriptions.
Fig 7.
Criticality score of bridges, with the systemic impact on the road network evaluated at different distances from the disruption.
Each graph includes a scatterplot where the horizontal axis represents the bridge’s functionality, and the vertical axis represents the absolute value of the efficiency loss % after its disruption, evaluated at the considered distance. Points correspond to individual bridges and are colored according to the criticality score. The color coding highlights the distribution of the criticality values across the plot, providing an immediate visual cue for bridges with higher (top left region in the plot) or lower (bottom right) criticality scores.
Fig 8.
Population distribution of inner municipalities at risk of isolation.
Fig 9.
Inner municipalities within bridge buffer zones.
Green circles represent inner municipalities, while blue circles indicate bridges. This map is generated using the Folium open-source library, which uses OpenStreetMap as a map source [50].
Table 1.
Top bridges ranked by their aggregated-level impact on the connectivity of inner area municipalities.
For each bridge, the table also lists the most affected municipalities, alongside their average closeness centrality drop, quantified as the average drop of peripheral nodes.
Table 2.
Description of the road type labels used by OSM, ordered from most important (motorway) to least important (track).
Fig 10.
Graph representation of the Apulian road network illustrating nodes as road LineString endpoints and links as roads.
The map is generated using the Folium open source library, which uses OpenStreetMap as a map source [50].
Fig 11.
Fragility curves of a bridge for different damage states.
The horizontal and vertical axes represent, respectively, the amplitude Sa(1s) of the spectral acceleration at 1.0 seconds, and the conditional probability of reaching and/or exceeding a specific damage state (minor, moderate, extensive, complete).