Properties of vertical and torsional vortex-induced oscillations for a box-girder deck section

From our experimental studies for the effects of handrails, which were simplified as a horizontal bar, vertical posts and curbstone, on vertical and torsional vortex-induced oscillations of a box girder bridge, the following results were obtained. The torsional responses were remarkably influenced by the change of size and position of the horizontal bar. On the other hand, almost all vertical responses were increased by the installation of handrail in comparison with that of basic section. To clarify the mechanism of the effects of the horizontal bar on the vortex-induced oscillations, flow patterns and unsteady pressures around the deck were examined. The relative angle of attack has a great effect on the fluctuation of separated shear flows and the responses of vortex-induced oscillations.