Verification of the dynamic properties of the Svinesund Bridge by wind-induced acceleration measurements

Abstract

The New Svinesund Bridge had its grand opening in June 2005. Due to the prerequisite that the new bridge should interplay with the old one, the final design ended up in a slender and aesthetic bridge. Because of the slender construction, responses due to traffic and wind loading were of interests. Hence there was installed several measuring instrument to control predictions and behavior of the bridge. As the title says, this thesis reviews verification of the dynamic properties of the New Svinesund Bridge. Verification was to be done by wind-induced acceleration measurements. Basis for the verification was measurements recorded during a winter storm in 2007. The recorded measurements were divided into time series of ten minutes, with a total of 90 time series. Verification was carried out by using system identification when interpreting the full scale measurements. The identification was done in a calculation program in addition to a supporting FE-model. This was done to be more confident in the results. Both model and analyses were calibrated for the first four modes only. Dynamic properties of interest were eigenfrequencies, mode shapes and damping. Results from the analyses showed that dynamic properties can fully be determined using full scale analysis aided by an FE-model. The only uncertainty was the damping estimates, but damping is known to be difficult to estimate precisely.