Cable vibrations at Dubrovnik bridge

Abstract

The only cable-stayed bridge in Croatia, the Dubrovnik bridge, was opened for traffic in 2002. The main cable-stayed bridge with composite superstructure is jointed in span to the prestressed concrete approach bridge by a hinge-type connection. The bridge has experienced vibrations of cable stays under certain wind conditions, as with many other cable-stayed bridges around the world. After a short review of results of wind tunnel tests and various numerical analyses, field observations of cable-stay vibrations are highlighted. Only after extremely violent movements of cable stays and the superstructure under a heavy, damp snowstorm occurred, resulting in substantial damage, was it decided to apply vibration mitigation measures. Adjustable cable dampers, based on the latest MagnetoRheological (MR) technology, were installed on the bridge to raise low structural damping of the most affected cable stays.

Investigation of Strouhal number of ice-accreted bridge cables at moderate flow turbulence

“…The St results obtained at the mean turbulence intensity about 12% matched well with those reported in the literature within the Re range that was studied in this paper, i.e. from Re = 2.1·10 4 to 10.2·10 4 . Therefore, the adopted methodology of the St investigations was confirmed as suitable.…”

“…7b). For Re < 6.6·10 4 the St values obtained for configuration No. 1 are greater than for the smooth cylinder.…”

“…In this case, the full-scale monitoring of slender bridge elements proved that ice accretion on the bridge cables has a significant influence on the flow field around the cables and their aerodynamics and can leads to a much larger amplitude of cable vibrations under wind action than without the ice [4]. It should be noticed that the literature concerning the icing influence on aerodynamics of cables of cable supported bridges is still limited, e.g.…”

“…For the investigations of St, a new iced cable model was made at a scale of 1:1.6 using a 3D printing procedure. The St values were determined at the flow turbulence intensity of the order of 12%, within the range of the Reynolds number from 2.4·10 4 to 12.9·10 4 , based on the dominant vortex-shedding frequencies measured in the wake of the model. The correctness of the St investigations was proved based on the St test of a circular smooth cylinder with the same experimental arrangement.…”

Semi-Active Control Systems in Bridge Engineering: A Review of the Current State of Practice

“…The CEC approach was implemented in Sutong Yangtze River Bridge ( Figure 5), a cable-stayed bridge with a free span of 1080 m (12 MR dampers on the six longest cables and passive oil dampers on 19 additional cables). The same approach was adopted on the Franjo Tudjman Bridge in Croatia 58 , and the Alamillo Bridge in Spain 59 , where the CEC approach was used as a retrofit measure to counteract observed wind-and rain-induced vibrations. As far as the application of the second approach is concerned, 10 CVD controlled MR dampers were installed in the 5 longest cables of the Russky cablestayed bridge in Russia (world record free span of 1104 m and stay cables of up to 580 m), along with passive oil dampers in 16 additional cables.…”