Cross-winds of relatively low
velocities have often set into vortex-induced oscillations the lightly damped
and remarkably long three continuous spans of the steel twin-box-girders
Rio-Niterói bridge. Whenever this happens the bridge is closed to
traffic of
any vehicle, for the sake of user’s comfort and overall safety. However,
because of inherent operational difficulties, in many of these events the
traffic barrier is lay too late and users are left frightened when crossing the
oscillating bridge. This deterrent aspect of the world largest steel box-girder
bridge is explored herein to briefly present the conceptual design of
passive control devices to attenuate the observed oscillation amplitudes. For that an
appraisal of the actual bridge
dynamic behaviour is made first by using an
experimentally calibrated mathematical-numerical model, including correlated
aeroelastic forces along the spans. The derived dynamic modal equations, are
further combined with optimisation techniques to assist in designing feasible
mechanical and robust dynamic absorbers, or tuned-massdampers, to upgrade this
bridge serviceability and user’s comfort. The performance of these absorbers is
demonstrated through comparison of numerical results obtained for time
responses of the original and controlled
structure.