Mechanism of aerodynamic stabilization for long-span suspension bridge with stiffening truss-girder

The development of a countermeasure known as a “vertical stabilizer”, for the suppression of the aerodynamic instability of long-span suspension bridges with stiffening truss-girders is presented. At first, the suppression effect is demonstrated by wind tunnel dynamic response tests. Subsequently, the mechanism of aerodynamic stabilization is investigated using flow visualization and pressure measurements. From these test results, it is concluded that the wind induced oscillation of stiffening truss-girders is due to the reattachment of the separated flow from the leading edge. When the vertical stabilizer is installed, however, the resulting reseparation from the bottom edge of vertical stabilizer and the air stream blowing through the center grating of the deck, lead to the suppression of wind induced oscillation. Evidence is presented that these effects are maintained in a turbulent flow.