EXPERIMENTAL INVESTIGATION OF STRUCTURAL DAMAGE IDENTIFICATION BY COMBINATION INDEX METHOD UNDER AMBIENT EXCITATION

Structural damage identification is one of the major prerequisites of structural health monitoring and structural status assessment. Early detection of the damage and its location can help improving the reliability and safety of the structure, thus reducing the maintenance cost. The paper focuses on how to identify the structural damage under ambient excitation. Since the curvature mode is more sensitive to structural local damage, while the frequency is easy to test with high precision, the paper presents an improved structural damage identification method based on structural curvature mode and the frequency change. In order to identify the structural damage under ambient excitation without interrupting its structural operation, stochastic subspace identification is introduced in the method. Finally, a simple support concrete beam is then tested in the laboratory to verify the effectiveness of the structural damage identification method presented herein. The test results show that the improved method with stochastic subspace identification can effectively identify the structural damage under ambient excitation without interrupting the operation of structure.