PERFORMANCE EVALUATION OF A MASONRY ARCH BRIDGE UNDER COMBINED SCOUR AND TRAFFIC LOADING

Masonry arch bridges are highly vulnerable to floods - particularly to scour - due to their stiff and relatively fragile behavior, combined with the fact that they are often built on shallow foundations. In multi-span masonry arch bridges interaction of structural members give rise to a complex response when subjected to scour action combined with traffic loading. The present work evaluates the behavior of a case study scoured masonry bridge under traffic loading with a three-dimensional finite element model developed in Abaqus using a macro-modelling approach. Traffic load model is selected in accordance with a recent guideline for safety assessment of existing bridges in Italy. The scouring process is then imposed through the progressive removal of elements from the model at the foundation. Displacement and internal stress distribution is analyzed under combined action due to increasing traffic load and scour depth. The outcomes of the research lay the basis for an accurate risk assessment and management of masonry arch bridges subjected to multiple hazards. The proposed study can also provide useful information in terms of thresholds levels for bridge monitoring and maintenance.