Numerical prediction of the eigenfrequencies of an idealized bridge pier under local scour

Foundation scour is a major cause of bridge collapse worldwide (e.g., [1]). Indeed, several studies have demonstrated its detrimental effects on the soil-structure system, both in terms of the foundation capacity and stiffness (e.g., [2]). Furthermore, the difficulty in detection of foundation scour and the budgetary delays in retrofitting increase the likelihood that scour-prone piers will be exposed to events as earthquakes. For this reason, it is essential to investigate the dynamic response of bridge piers before and after foundation scour. This study addresses the dynamic behavior of an idealized reinforced concrete bridge pier supported on a cylindrical caisson foundation embedded in sand, and it estimates the system eigenfrequencies under various scour scenarios.