A mechanism-based assessment framework for masonry arch bridges under scour-induced support rotation

Increase in the frequency of flash floods owed to climate change, excessive sand mining, and urbanisation of watersheds has accelerated the need to quantify the structural effect of scour-induced structural damages in masonry arch bridges. The structural effects of scour-induced rotation are unaddressed in literature. In this context, a mechanism-based framework based on limit state principles is developed for masonry arch bridges subjected to scour-induced rotation. Critical collapse mechanisms caused by scour-induced rotation are identified, and analysis framework is developed using rigid-body kinematics. The spectrum of bridges under consideration is classified into subsets, and an assessment scheme is developed using fragility curves as a function of scouring location as well as bridge typology.