Study On Galloping And Vortex-Induced Vibration Of H Section Hanger Of A Long-Span Arch Bridge

The hangers with H-shape of Long span arch bridges have several characters as follows:high slenderness ratio, low nature frequency, small structure damping, and weak aerodynamic shape. The vortex-induced vibration and galloping are easy to occur at low wind speed, which would bring some failures and damages, shorten service life and endanger bridge security. The wind-resistant performance of H-shaped hanger has been the important control factor in the design of the Long span arch bridges.At first, the static and dynamic effects of wind, and the characters of wind-induced vibration of bridges were introduced, and the research progress of vortex-induced vibration and galloping were reviewed. Taking the Wanzhou Yangze Bridge as the engineering background, the performances of vortex-induced vibration and galloping of H-shaped hangers were researched in details. The influence of cutouts at web and flange were researched by segment models in wind tunnel, and aerostatic coefficients were also obtained by the tests. The aerostatic coefficients of H section hangers were also calculated by CFD method, and the distribution flow field of hangers in smooth flow were obtained in the calculations. The influence of the Reynolds number upon the aerostatic coefficients were also studed by CFD method.The rusults of researches indicate that the cutouts drilling at web and flange can reduce the amplitude of votex-induced vibration efficiently and improve the galloping critical wind speed remarkablely; the results calculated by CFD method are more anatomists with test ones, and aerostatic coefficients are hardly influenced by the Reynolds number.