Identification of Modal Parameters in a Scale Model for a Railway Bridge

Obtaining the dynamic parameters of a bridge is essential to validation of the model used in the dynamic analysis of the bridge. In order to implement methodologies for damage detection, many experimental modal identification tests are performed for estimating the modal parameters of structures, including the natural frequencies and mode shapes. This paper presents an experimental and numerical study for finding the modal parameters of an aluminum model built to scale of a real railway bridge. Although, so far no test has been performed on the real railway bridge for comparison with the scale model, this paper seeks to apply the scale model experimental and numerical techniques for obtaining the dynamic parameters of the bridge. The software SAP2000 was used for the numerical analyses and for the experimental aspect, the circle fit and the stochastic subspace identification methods are used. Numerical and experimental results showed good correlation.