Research On The Aerodynamic Interference Effects Of Twin Deck Continuous Rigid Frame Bridges With High-pier And Long-span

In recent years, highway network in the western region is extended to loess gully region on a large-scale. When the highway routes pass through the mountains and highland region, the high-pier span continuous rigid frame bridge is often the preferred bridge type. And as traffic increases, the long-span continuous rigid-frame bridge pier besides the characteristics of high pier and large span, it also arranged has up and down separation arrangement, that is, parallel bridge. For the twin deck continuous rigid frame bridge with high-pier and long-span, the greater wake vibration will happens under the action of the strong wind, so it is obviously significant to study comprehensively the aerodynamic interference effect between pairs of bridge considering the airflow obstruction and interference.The factors of various interference effect such as position between parallel bridge, wind direction, attack angle are selected based on the characteristics of reaction to wind for single continuous rigid frame bridge. Test program is designed. The wind tunnel tests are conducted for the first time to study the static and dynamic interference effects of twin-deck continuous rigid frame bridge in Systematic and comprehensive manner. The test method and conclusion can help to study the interference effects of similar structure.Aerodynamic interference effect on aerostatic coefficient of the parallel continuous rigid frame bridge is studied by sectional model wind tunnel tests of double thin-walled hollow piers and different segments of the main beam, and by the introduction of factor. Analysis shows that:Aerodynamic interference of upper and lower has changed compared to the one of single bridge, and the lower aerodynamic interference changed significantly, showing a shielding effect and the wake interference effects; Different forms of the main beam section, the net distance and side-by-side interval between the two bridges, wind attack and direction angles all influent the aerodynamic interferences of aerostatic coefficients. The series aerostatic coefficients test data of the piers and the main beam when the parameters change will provide a theoretical reference for correct estimation the impact between parallel bridge by the designers in the calculation of the static wind loads.The interference effect of static wind response analysis is performed based on sectional model test, aerostatic response is analyzed respectively for the construction and bridge completion phase, and compared with single bridge. The specific impact of the interference effect on the displacement and internal forces response is analyzed quantitatively.Aerodynamic interference effects are studied by aeroelastic model test on construction of the largest double-cantilever state. The wind-induced vibration displacement response has been gotten under a variety of operating conditions such as different net distance between double bridge, cis-bridge dislocation, elevation difference, wind direction and attack angle. The above-mentioned factors of the dynamic interference effects are analyzed. Results showed that the horizontal vibration response of the double bridge, compared with the single bridge, the upstream response changes little and the downstream response reduces to varying degrees.