Durability Analysis of Bridge Foundations over Service Time under Sand-Laden Flow Abrasion Using an SPH Model

Abstract Concrete has been widely adopted as the primary material for bridge foundations. Although it has good performance against corrosion, abrasion damage has become a common threat to bridges exposed to sediment-laden flow. The smoothed particle hydrodynamics (SPH) approach can explicitly account for collisions among sediment particles and provides a useful tool for predicting abrasion damage. To support practical bridge design, it is essential to investigate how abrasion damage evolves under varying hydraulic and structural conditions. This paper presents a durability analysis of bridge foundations subjected to sediment-induced abrasion. First, an SPH-based abrasion solver was developed by embedding a composite abrasion model that accounts for momentum transfer during particle rebound. The accuracy of the solver in predicting abrasion damage was validated. Then, the relationship between hydraulic and structural parameters and the resulting abrasion rate was established through a series of parametric studies. A prediction formula for abrasion rate was derived using the response surface method. The time-varying abrasion depth of a bridge pier was predicted using a series of stochastic flow discharge data. Finally, the long-term durability of the bridge was assessed by comparing percentile distributions of abrasion depth over different service periods with the design thickness of the protective concrete layer. The estimated service life ranges from 8.95 years at the 5th percentile to 9.37 years at the 95th percentile when the design concrete cover thickness is set to 60 mm. The findings provide a practical approach for predicting the service durability of bridges subjected to abrasion.