Cyclic loading tests were conducted using damaged R/C soft-first story columns retrofitted by sandwiching and bonding UFC panels. The specimen which was loaded to 0.5% in the first stage of loading, the maximum strength in the second stage was greater than that in the first stage by 14%. However, the retrofit method was not effective for the specimen which was loaded to 3% in the first stage in terms of strength and deformation capacities. The ultimate strength calculated by the proposed method with consideration of the damage in the first stage of loading shows good agreement with the experimental one.
