Reinforced Concrete (RC) bridges are a key elements for any transportation network, so that their safety and serviceability is of crucial importance especially after the occurrence of a seismic event. Frequently, RC bridges are exposed to the action of aggressive chemicals, such as in marine or in cold climate environments, for the presence of chloride ions, either due to the salty water or the use of deicing salt. Generally those aggressive environmental actions affect the steel rebars inducing corrosion phenomena with a degradation the mechanical properties of reinforcement. In this paper some modeling issues related to corroded RC piers are presented and discussed, with particular emphasis to their seismic assessment