Experimental study on wind-rain-induced and vortex-induced vibration in bridge deck sections of long-span bridges

The vortex-induced vibration test in bridge deck sections of long-span bridges was carried out by considering vortex-induced vibration characteristics under the simultaneous actions of wind and rain, taking a separated twin-box girder bridge and its closed form as research objects. A system of simultaneous actions of wind and rain built in an atmospheric boundary layer wind tunnel was also utilized. Experimental results display that the wind speed at the start of oscillation and the wind speed of the lock-in region for the slotted section model show no difference in various rainfall intensities, but the maximal amplitudes of vortex-excited resonance display some differences. The time histories of stochastic vibration for the closed section model have some differences in various rainfall intensities, and the amplitude of vibration increases with rising wind speed. The displacement amplitude under the simultaneous actions of wind and rain is larger than the displacement amplitude under a single wind load; the highest increment reaches one quarter. Experimental results also show that the amplitude of vortex-induced vibration in bridge deck sections is increased by rainfall. The closed model has better performance in resisting vortex-induced vibration than the slotted model.