Storeb ae lt suspension bridge - vortex shedding excitation and mitigationby guide vanes

During the final phases of deck erection and surfacing of the suspended spa ns of the Storebaelt bridge, vertical deck oscillations of low frequency we re observed by workers and supervision staff. The results of on-site monito ring of the oscillations and wind speed measurements at the nearby island o f Sprog phi correlated well with wind-tunnel test results obtained during d esign, indicating that the observed oscillations were due to periodic von K arman, type vortex shedding in the wake of the girder. The present paper di scusses the results of the on-site structural and wind monitoring programme , correlation to wind-tunnel tests and the design and erection of guide van es to the main span girder for mitigation of the oscillations. The vortex-i nduced oscillations were found to be harmless from a structural point of vi ew but unacceptable considering possible physiological impact on users of t he bridge. (C) 2000 Elsevier Science Ltd. All rights reserved.