The assessment of performance of damaged RC components based on material damage distribution model by fiber-based damage index

To evaluate quantitatively the performance of earthquake-damaged structures, the damage distribution model (DDM) for damaged RC components based on fiber-based damage index (FDI) is developed. Firstly, 25 RC columns under cyclic loadings from the Pacific Earthquake Engineering Research Center Structural Performance Database (PEERSPD) are selected as the database to develop DDM. The material damage, including concrete material damage and steel bars material damage, is represented by FDI computed based on the stress-strain history of the material. The threshold of concrete regarding tensile failure and compressive failure are determined. Compared with the Park-Ang damage index, FDI is associated with the observed damage and can more accurately determine the damage displacement corresponding to four damage states. Furthermore, the damaged section is divided into five regions and five DDMs regarding four damage states corresponding to various quantiles are determined. The proposed DDM-50th is realized on six column specimens and is verified by the comparison of the responses between the damaged column model established based on DDM-50th with the experimental results. Furthermore, the properties of the skeleton curve of the damaged column established based on five DDMs are compared with experiment results. The DDM-84th is recommended to evaluate the post-earthquake performance of the RC structure. Moreover, the DDM-50th and DDM-90th are proposed to respectively evaluate the upper limit and lower limit post-earthquake performance of RC structure to obtain comprehensive results. In contrast, DDM-10th and DDM-16th, which are prone to dangerous results, are not recommended to evaluate the performance of RC structures.