Damage index based on statistical properties of structural dynamic responses

For improving the reliability and efficiency of damage identification for civil engineering structures, a novel damage index based on statistical properties of structural dynamic responses is proposed in this paper. Based on the theory of structural random vibration, the relationship between statistical properties, including the mean and variance of the structural dynamic responses, including displacement, velocity and acceleration, and structural damage location and level is obtained. Through sensitivity analysis, the variance of structural dynamic displacement is selected as a damage index for structural damage identification. The dynamic response of a six-floor RC frame is numerically simulated under the excitation of white noise. The feasibility of the proposed damage index is evaluated by investigating the change of the variance of structural dynamic displacement in the case of different damage locations and levels. A conclusion is drawn that it is feasible to use the statistical properties of the structural dynamic responses as the damage index in the damage identification for the civil engineering structures