[en] The present report discusses the change of load capacity and deformation performance of reinforced concrete members arising from various kinds of defects. It is a part of research to establish the structural performance evaluation system for ageing underground structures. The following results were identified from the dynamic loading tests of members with cracks or corroded rebars. First, cracks along the core and cover concrete boundary plane had either role on increases or decrease to ultimate deformation. This difference was attributed to the relative position of initially introduced crack with concrete compressive strut. Second, the energy absorption performance was improved in the existence of corroded rebars. Dispersion of bond stress prevented the member ends from cracking. On the other hand, in one of two specimens with corroded rebars, brittle failure with an inclined crack was observed in the middle part. The progress of split between concrete and rebars caused this mode which was unlikely to appear in the sound state. The core concrete over enough length was led to the state without reinforcement. (author)