Signature Turbulence Effect on Buffeting Responses of a Long-span Bridge with a Centrally-Slotted Box Deck

摘要

Shanghai Bridge over Yangtze River is a steel cablestayed bridge with a main span of 730m and a centrally-slotted twin-box deck. The equivalent aerodynamic admittances with and without signature turbulence effect were identified at first for the windward and leeward deck boxes, respectively, via sectional model wind tunnel tests of force measurement, and fitted using proposed model functions of fraction (series). The buffeting responses of the bridge with and without signature turbulence effect were then analyzed using a CQc method in frequency domain, where, the buffeting forces on the windward and leeward deck boxes were separately modeled. The analyzed responses were then compared with those obtained via full bridge aeroelastic model test. The results show that the calculated buffeting responses using measured aerodynamic admittances approach well to the tested results, and the signature turbulence exerts almost no effect on the buffeting responses at the wind speeds higher than 10m/s, but fairly significant influence that at lower wind speeds about 7m/s. This means that the signature turbulence will not prick up the strength issue of bridge structure, but may significantly aggravate the fatigue issue of bridge structure due to buffeting and vortex-excited resonance at lower wind speeds.