Post-earthquake structural damage assessment and damage state evaluation for RC structures with experimental validation

Accurate post-earthquake damage evaluation of real-world structures is essential to ensure the safe operation of buildings. To this end, we propose a damage evaluation method for earthquake-excited structures relying on the hysteresis curve reconstruction approach. Central to this method is the use of an equivalent single-degree of freedom (ESDOF) system, designed to model structural overall hysteresis and to facilitate an acceleration-based Damage Indicator (DI). Differently from the previously investigated hybrid damage index, a data-driven variant of this DI, configured for reduced reliance on model information and enhanced computational efficiency, is here introduced. This DI is integrated into a framework for assessing structural damage and seismic performance levels, leveraging Seismic Structural Health Monitoring data. The reliability and robustness of the DI with respect to earthquake excitation of different characteristics and for a varying number of floors is assessed by adopting a simulated five-degree-of-freedom degradation model. A large-scale RC frame shaking table test is employed for a comprehensive evaluation of the proposed scheme, allowing to illustration of the damage assessment and the damage state evaluation performance of the proposed data-driven DI. Though the utilization of the ESDOF concept precludes the evaluation of the intensity and location of structural damage, the damage state evaluation results may still provide effective physical information besides the DI values. The relatively low requirements for prior model information and nonlinear behavior render the proposed DI applicable to real-world implementation. This promising characteristic may consequently facilitate the rapid post-earthquake decision-making process.