Static and Aero-dynamic Studies on Cable-Stayed Bridges using Steel Pipe-Girders

Two types of new cable-supported bridges using steel pipe-girders and steel orthotropic decks have been proposed in this paper: the two-pipe-girder bridge with two cable planes and the three-pipe-girder bridge with one cable plane. The cable-stayed bridges with a main span of 500 m were designed for these new bridge systems and validated to be feasible by static analyses. Wind tunnel tests were conducted in order to investigate the aerodynamic behaviour of these bridges. For the two-pipe-girder bridge models torsional flutter occurred at a wind speed – over 75,0 m/s for the attack angle of 0° and +3°. In the three-pipe-girder bridge models torsional flutter occurred at a wind speed of over 115 m/s and the three-pipe-girder bridges showed superb aero-dynamic stability. Aesthetics of these new bridges were also studied by computer graphics and wood models, which showed that the new bridges are not only structurally rational but also – attractive, impressive and in harmony with the surrounding environments.