Aalborg Universitet Ambient Response Analysis of the Great Belt

In this paper an ambient response analysis of the Great Belt Bridge is presented. The Great Belt Bridge is one of the largest suspension bridges in the world, and the analysis was carried out in order to investigate the possibilities of estimating reliable damping values from the ambient response due to traffic and wind. The response data were analysed using tbree different techniques: a non-parametric technique based on Frequency Domain Decomposition (FDD), a parametric technique working on the raw data in time domain, a data driven Stochastic Subspace Identification (SSI) algorithm and finally a covariance driven SSI technique. In a small frequency band from 0.17-0.30 Hz 5 modes were identified, and the quality of the modal estimates were evaluated based on MAC values on the mode shapes estimates and standard deviations on damping estimates.