NUMERICAL MODEL FOR THE RESIDUAL SEISMIC CAPACITY OF SEISMICALLY DAMAGED REINFORCED CONCRETE COLUMNS

Based on the reinforced concrete (RC) column test data in the Pacific Earthquake Engineering Research Center (PEER) database and the existing seismic damage index models, the damage characteristics of the RC columns at different damage levels were summarized. Damage evaluation criteria for damaged columns were proposed. The evolutionary damage to the sectional materials, including the cover concrete, confined concrete and longitudinal reinforcement, during the earthquake damage process was investigated. Evolutionary damage models for the sectional materials were proposed, where the uneven damage to the materials at different positions of the plastic hinge zone of the RC column was considered. Based on the OpenSees platform and the fiber model, a numerical model of the seismic damaged RC frame columns was established, which was directly based on the constitutive relationship of materials. The model considered the damage difference of materials in different positions of the damage area and the damage difference of materials in different positions of the same section. The test data of 13 existing RC frame columns were randomly selected to verify the numerical model calculation results of seismic damaged RC frame columns. The results show that the model accurately predicted the post-earthquake behavior of the RC columns. These results provide an analytical model for the performance evaluation of and retrofitting decisions for RC structures after an earthquake.