Effects of geometrical shape on vortex-induced oscillations of bridge tower

Abstract

Focused on the vortex-induced oscillations which often appear in bridge towers during erection and in free standing state, experimental considerations were given to the aerodynamic properties and the mechanisms of the generation of such vortex-induced oscillations. Two tandem rectangular cylinders, which are used as main towers of bridge frequently show rather strong aerodynamic instability such as vortex-induced oscillations when two cylinders are placed in series in flow. Thus, it is presumable that in case another body exists in the wake of the rectangular section cylinder, by far a larger number of factors are contributing than the factors contributing in case a single body is involved. Through the present research it was clarified that the geometrical shape of the tower column sections play an important role for the aerodynamic stability of the bridge tower. The results obtained from experimental studies suggest that the projecting objects attached to the rectangular cylinder, the corner cut amount of the cruciform section column and other parameters such as the angle of incidence, the spacing ratio of rectangular cylinders and B ∗/D , etc. are specially important and that it may be possible to improve the aerodynamic stability of the bridge tower by properly controlling such parameters.