On the dynamic response of bridge piers subjected to foundation scour

Caisson foundations play a pivotal role in supporting long-span bridges. However, their performance is susceptible to the effects of scouring, which is exacerbated by the increasing frequency and intensity of flood events associated with climate change. Therefore, to ensure the structural integrity of caisson-supported bridge piers during seismic events, it is critical to investigate the complex interactions between scour, the soil-caisson-pier system, and seismic forces. This paper presents a series of dynamic analyses carried out on a specific case study including three scouring scenarios: nscoured, general scour, and local scour. The simulations are analyzed in terms of spectral accelerations, cumulative displacements and permanent shear strains to shed light on the different effects of local and general scour. The results show larger cumulative displacements in scoured cases, compromising the serviceability of the structure, but lower accelerations at the deck, reducing the structural seismic demand.