Damage Detection of Reinforced Concrete Columns Based on Vibration Tests

Many civil structures are subjected to damage caused by either natural disasters or man-made hazards. A large proportion of them are still in service despite the associated potential for damage accumulation. Therefore, the ability to monitor the state of current structures is of increasing importance. In this paper, vibration based damage detection techniques were employed to detect damage in reinforced concrete column after different levels of quasi-static cyclic loadings. Four main stages were carefully examined, including healthy state, concrete cracking, partial yielding and yielding at last. Modal test and analysis was carried out for the RC column in original condition at first. In order to introduce damage to this column, quasi-static cyclic test was carried out. Finally, dynamic test on the damaged RC columns was performed and changes in the dynamic characteristics of the column at different damage levels were examined. Eigen-System Realization Algorithm (ERA) was applied to identify the modal parameters of the RC column based on its impulse responses recorded in its undamaged and various damaged states using accelerometers. These identified modal parameters are then used to identify the damage in the column through a finite element model updating procedure. Results show that the identified damage is consistent with the observed damage in the composite beam.