Structural damage localisation in slab-on-girder bridges using vibration characteristics

This paper uses dynamic computer simulation techniques to develop and apply a procedure using non-destructive methods for damage assessment in slab-on-girder bridges. In addition to changes in natural frequencies, this multi-criteria procedure incorporates two methods, namely the modal flexibility and the modal strain energy method. Using the numerically simulated modal data obtained through finite element analysis software, algorithms based on flexibility and strain energy changes before and after damage are obtained and used as the indices for the assessment of structural health state. The application of the two proposed methods in literature is limited to beam-type and plate-type elements separately. The multi-criteria based damage identification procedure is therefore developed for slab-on-girder bridges. The application of the approach is demonstrated through numerical simulation studies of a single-span simply supported slab-on-girder bridge with seven damage scenarios corresponding to type of deck damage and girder damage individually. Results show that the proposed multi-criteria method incorporating modal flexibility and modal strain energy method is effective in damage assessment in this type of bridge superstructure.