Microsoft Word - tv_20_2013_1_155_160

Preliminary notes This paper outlines the research aimed at developing an effective and reliable monitoring method for structural damage identification. A computational procedure for a direct iteration technique based on the non-linear perturbation theory is proposed to identify structural damage, when information about only natural frequencies for the damaged structure is required. The presented damage identification technique is applied to six concrete girder bridges of different ages in Croatia. It is found that the proposed approach is quite sensitive to the quality of measured natural frequencies for structural damage identification due to the ill-conditioned system of governing equations.