Monitoring-based performance parameters for assessment of bridges under scour and seismic hazards

In infrastructural networks, bridges can be considered key elements and their functionality must be preserved. Floods (leading to scour erosion) and earthquakes could be considered among the most critical natural events that may become more frequent with climate change, causing significant damage to bridges. Several regions in Europe have both seismic and scour hazards. The two types of hazards are actually independent as to the generation process but the loss of surrounding soil due to scour may significantly reduce the lateral strength of pile foundations thus increasing the earthquake damage potential. Bridge assessment has thus to take into account the possible increased risk induced by the joint action of the two phenomena. Monitoring systems can be an effective support in bridge assessment procedures providing updated information about the structural state and performance thus allowing both the prompt detection of a possible damage state after an event and also support for long term assessment of the structural conditions. Several performance parameters can be used to perform bridge assessment with respect to several hazards at different levels: element, structure, and network. The aim of this paper is to give an overview of monitoring-based performance parameters that can be used for separate seismic and flood related hazard in order to identify possible selection of parameters effective in describing the joint hazard due to both phenomena.