Evaluation of scour effects on structural integrity of highway bridges

Abstract

Scour, defined as water-induced erosion of soil around bridge piers, poses a significant threat to the stability and safety of bridges. Investigation of scour effects around the bridge piers is essential to ensure the long-term performance of bridges. This study examines the effects of local scour on the structural integrity of highway bridges by integrating on-site measurements, 3D computational fluid dynamics (CFD) simulations, and nonlinear finite element (FE) analysis. A highway bridge located over the Senoz Stream in & Ccedil;ayeli, Rize (T & uuml;rkiye), which suffered significant pier damage due to time-induced local scour, is considered. Since site investigation on the damaged bridge was not feasible, a nearby structurally identical bridge was selected for ambient vibration testing and numerical simulations. The local scour depth around bridge piers was estimated for different scenarios using validated 3D CFD simulations based on a synthetic flow input derived from different return periods calculated using the Gumbel distribution. The scour depth was then incorporated into a nonlinear FE model using a Concrete Damage Plasticity (CDP) approach to simulate failure mechanisms. The numerically obtained damage patterns were found to closely match the actual collapse observed in the damaged bridge. The novelty of this study lies in the integrated use of field-based modal testing, advanced CFD scour modelling, and nonlinear damage assessment to realistically simulate scour-induced bridge failure. The results emphasise the importance of coupling hydraulic and structural analyses to improve bridge safety assessments under complex environmental hazards.