Scour under bridges: an invisible danger engineering approaches to predict and prevent failure

Abstract

Bridge scour – the erosion of riverbed sediment around bridge supports – is a hidden but serious threat to bridge safety. Scouring alters flow patterns around piers and abutments, increasing shear stress (Dey & Raikar, 2007). Damage from scour can lead to bridge failure, and worldwide it is one of the leading causes. In Sri Lanka, failures have occurred before; the Magalle Bridge, for example, collapsed in 2006 after its foundations were undermined by flood-driven erosion. Several others – Manampitiya, Kotugoda, and Ruwanwella – have also experienced serious scour. These incidents underscore why engineers consider scour one of the most critical threats to bridge safety.