Sectional model experiments at high Reynolds number for the deck of a 1018 m span cable-stayed bridge

摘要

Experiments on a 1:20 scale sectional model of the twin-box deck of a 1018 m span cable-stayed bridge are presented in this paper. The purpose of the experiments was to study the vortex-shedding induced vibration phenomenon at a Reynolds number at least one order of magnitude larger than conventional sectional model tests. A 4.87 m long model was suspended in a custom-built frame by an array of eight extension springs. Vortex-shedding induced vibrations were observed for the sectional model in its nominal configuration. The vibrations were recorded for Reynolds numbers ranging from 0.48 to 1.0 x 10~6 based on the width of one box. Two sets of aerodynamic appendages composed of longitudinal guide vanes and maintenance gantry rails completely eliminated the vortex-shedding excitation for the range of Reynolds numbers investigated in this study. The same appendages proved to be less efficient at lower Reynolds numbers. Static aerodynamic force coefficients were also measured for Reynolds numbers ranging from 0.5 x 10~6 to 2.5 x 10~6. The drag coefficient appeared to be sensitive to Reynolds number increasing until a Reynolds number of 1.5 x 10~6 was reached.