Damage Identification of Structural Members: Numerical and Experimental Studies

The main objective of the study is to formulate a numerical strategy suitable for structure member assessment in a quantifiable and objective way. Involving both numerical and experimental studies, the emphasis is on nondestructive damage detection of structural members with predominantly flexural deformations such as beams and columns. A time-domain system identification method, namely the extended Kalman Filter method, is adopted with some modifications. To reduce the identification system nonlinearity and hence improve the convergence performance, the method of stiffness-damping uncoupling is introduced. Flexural members with semirigid connections are modeled by the finite element method. Local damage is assumed to manifest itself as reduction in flexural rigidity. Numerical simulation study is carried out to illustrate the performance of the damage identification strategy, accounting for the effects of measurement noise. Dimensionless indicators are used to reveal the damage location and severity effectively. The problem of numerical leakage is reduced, by comparing average identification results before and after damage. Lastly, an experimental study for a reinforced concrete beam with controlled change in local stiffness further substantiates the feasibility of the proposed strategy.