engleski

Effects of violent vibrations of cables on dynamic behaviour of cable-stayed bridges

Shortly after the opening of Dubrovnik (Croatia) cable-stayed bridge in 2002 the violent vibrations of the bridge deck, pylon and cables in a strong wind "Bora" combined with light rain were observed about twelve times a year. This paper analyses effect of violent vibrations of cables and their influence on the overall dynamic behaviour of cable-stayed bridge. Firstly, the vibration of a massive cable which is connected to a vibrating cable-stayed bridge deck and pylon is presented analytically. Equations describing a change of the cable's force and its eigenvalues due to the cable’s undamped and damped vibrations are also derived. Mathematical lamped models substituting the behaviour of a massive bridge cable and its effect on the dynamic properties of the overall cable-stayed bridge is presented. Finally, the measures for Dubrovnik bridge rehabilitation are presented in a way of suppressing cables vibrations by devices. After installing the Maurer Adaptive Cable Dampers (ACD) in cables, regular long distance monitoring of the Dubrovnik cable- stayed bridge behaviour was established.

dynamic analysis; long span bridges/structures; retrofit/rehabilitation; vibration/vibration control; wind loads

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