engleski

Influence of Stationary Vehicles on Bridge Aerodynamic and Aeroelastic Coefficients

This study focuses on modifications in bridge aerodynamic and aeroelastic behaviors due to stationary (nonmoving) vehicles for various arrangements of vehicles on a bridge deck. Dimensionless aerodynamic force and moment coefficients, as well as flutter derivatives, are analyzed experimentally in a wind tunnel in the model of a bridge with a semibluff cross section. A comparison is provided for stationary vehicles placed in leeward, windward, and all traffic lanes, as well as for an empty bridge-deck section. Drag, lift static forces, and moment coefficients are determined for various wind incidence angles. Flutter derivatives are obtained using the free-vibration technique for both one and two-degrees-of-freedom systems. Stationary vehicles on the bridge deck are generally observed to change aerodynamic coefficients of the bridge. This is particularly exhibited for the pitch moment. Galloping sensitivity of the bridge does not change considerably in the presence of vehicles, as all studied configurations remain stable. When considering one-degree-of-freedom motion of the bridge-deck section, an empty bridge without the vehicles proved to be more prone to torsional flutter than the bridge with various arrangements of the vehicles. For the twodegrees-of-freedom system, nonmoving vehicles have a rather beneficial effect on the bridge stability. This is particularly exhibited in the experiment with the vehicles placed in the windward traffic lanes, as well as in all traffic lanes. Although these findings cannot be completely generalized because every bridge has its unique geometry, some indications are provided with respect to important design aspects.

Wind-vehicle-bridge system ; Cable-supported bridge ; Bridge aerodynamics and aeroelasticity ; Stationary vehicles ; Wind tunnel tests

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