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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. [ABSTRACT FROM AUTHOR]

The strength reduction method (SRM) is one of the main methods for evaluating slope stability and its key step is to select failure criteria reasonably and correctly. At present, non-convergence of numerical iteration, penetration of plastic zone, and the catastrophe of characteristic points displacement are usually used as slope failure criteria. To avoid the randomness of selecting characteristic points and the subjective error, this paper presents a new criterion: residual displacement increment criterion based on the displacement catastrophe criterion of characteristic points. In this criterion, the average residual displacement increment is calculated after each reduction, and the strength reduction factor corresponding to the maximum average residual displacement increment is regarded as the safety factor of the slope. This new criterion avoids the randomness of selecting characteristic points and the subjective error of judging the displacement mutation point artificially. The two-dimensional slope stability calculated by this criterion is compared with the other three criteria and Spencer method, which verifies the applicability and accuracy of this criterion. [ABSTRACT FROM AUTHOR]