The Effect Of Aerodynamic Interference Of Twin Separate Bluff Box Girders On Vortex-induced Vibration

With the continuous increase of traffic flow in recent years,twin separate bluff body box girders are increasingly used in large span continuous beam bridges and continuous rigid frame bridges.Because of aerodynamic interference effect between twin box girders,vortex-induced vibration characteristic of twin separate bluff body box girders is different from that of single bluff body box girder.In order to ensure the wind resistance of the bridges,it is very necessary to study the aerodynamic interference effect on vortex-induced vibration of twin separate bluff body box girders in detail.The research work of this paper mainly includes the following two parts:(1)Basing on sectional model wind tunnel test,the vortex-induced vibration characteristic of twin separate bluff body box girders in horizontal flow condition and thirteen different distances(The variation range of D/B is from 0.05 to 4.0,D is the net distance of twin box girders and B is the width of single box girder.)was tested,and compared with that of single bluff body box girder.Effect of aerodynamic interference of twin separate bluff body box girders on vortex-induced vibration in horizontal flow condition and different distances was studied.By comparing the mean wind pressure coefficient and the root of variance of single bluff body box girder with those of the twin separate bluff body box girders,the aerodynamic interference effect of vortex-induced vibration in different distances was preliminary explained.(2)Under three representative distances(small distance D/B=0.1,middle distance D/B=0.8 and large distance D/B=3),vortex-induced vibration characteristic of twin separate bluff body box girders was tested and compared with that of single bluff body box girder in different wind attacking angles by using sectional model wind tunnel test.Effect of aerodynamic interference of twin separate bluff body box girders on vortex-induced vibration in different wind attacking angles was studied.By comparing the mean wind pressure coefficient and the root of variance of single bluff body box girder with those of the twin separate bluff body box girders,theaerodynamic interference effect of vortex-induced vibration in different wind attacking angles was explained.