Damage diagnosis of a two-storey spatial steel braced-frame model

Abstract

To verify the effectiveness of the damage diagnosis methods, an experimental study of a two-storey spatial steel braced-frame structure model was carried out. The test model had plan dimensions of 1.50 m × 1.50 m and a height of 2.82 m. Four known damage patterns, including single damage, symmetric damage, asymmetric damage and multi-storey damage, were simulated by removing different braces. Modal parameters of undamaged and damaged structures were obtained by employing the natural excitation technique (NExT) in conjunction with the eigensystem realization algorithm (ERA) from acceleration responses induced by hammer impacts and simulated ambient excitation. Finite element analysis using SAP2000 was performed to validate the identified modal parameters of the test model. The damage index method and the damage locating vectors (DLVs) method were utilized to locate damaged elements, respectively. Based on the identified modal information the damage extent (the stiffness loss) was estimated by using the second-order eigensensitivity approximation method. It is demonstrated that the above vibration-based methods are effective for damage diagnosis. Copyright © 2006 John Wiley & Sons, Ltd.