Study On Reynolds Number Effects On Vortex-induced Vibration Of Twin-box Bridge Sections By Wind Tunnel Test

As a new bridge section, twin-box bridge sections with the advantage to preventflutter because of the existence of gap in the center, has been adopted in manysuper-span bridges. However, the improvement of flutter resistance is on the conditionthat vortex-induced vibration of girder would become much more common than normalbridge sections. In order to precisely predict and prevent vortex-induced vibration, aswell as to satisfy the requirements of refinement of bridge wind resistance, the ReynoldsNumber effects on vortex-induced vibration of twin-box bridge sections is significant.This paper analysed the Reynolds Number effects on vortex-induced vibration oftwin-box bridge sections by wind tunnel test (static test and dynamic test) with threedifferent scale ratio model (1:80,1:40,1:25). The change of the Reynolds number canbe achieved by changing the model scale. For the static test the Reynolds Number isfrom7×10~4to1.2×10~6. For the dynamic test the Reynolds Number is from7×10~4to2.2×10~5.The main contents of this paper is as follows: by static test we analysed Reynoldsnumber effects on drag coefficient, lift coefficient, Strouhal number and surfacepressure distribution; by dynamic test we analysed Reynolds number effects on theinitial reduced velocity, the width of synchronization regime, VIV amplitude. It isproved that Reynolds number effects exist apparently. However, due to the limit of testcondition, it only draw qualitative conclusions and can’t draw accurate and compellingvariation. There should be more systematic dynamic test on vortex-induced vibration oftwin-box bridge sections.