The corrosion of reinforcing steel bars in concrete threatens the performance of reinforced concrete structures. This study investigates the structural performance of severely corroded RC beams, focusing on rebar section loss, bond loss, and concrete spalling. Seven beam specimens were constructed with varying corrosion levels using the impressed current method, and different cover levels using paper clay. Loading tests provided the mid-span deflection curves, while digital image correlation showed the crack patterns. Flexural capacity decreased with greater corrosion and cover loss, though a residual bond mechanism was observed at 50% cover loss due to partial steel- concrete contact. This mechanism diminished with higher mass losses as rebar lugs deteriorated. Beams with complete cover loss showed lower strength. Finite element analysis using COM3 was conducted on the experimental beams, and beams extracted from an actual wharf structure.