Damage identification procedure for seismically isolated bridges

Abstract

SUMMARY This paper deals with a procedure for the identification of the damage in bridge structures equipped with isolators and/or energy dissipating devices. The procedure is based on the availability of accelerometric records from any simple sensor network installed on existing bridges. The proposed algorithm provides an assessment of the performance degradation of conventional structural components as well as installed isolators and energy dissipators, obtained from changes in modal characteristic of the structural response. A new index localization and severity index is introduced to be used for ordinary structural elements and anti-seismic devices. For the validation of the procedure, the algorithm has been applied to a continuous beam as well as to a bridge structure equipped with Friction Pendulum devices. The proposed procedure shows a high level of accuracy in the damage localization and severity assessment also in a complex scenario of damage. The severity index is also interpreted in terms of physical quantities (e.g. friction coefficient) representative of the specific device performance. For this reason the procedure appears feasible for implementation on real structures with the advantage of providing direct indicators of the early stages of degradation of performance parameters. This information can be used to design inspection and maintenance plans. Copyright © 2011 John Wiley & Sons, Ltd.