Abstract
Based on the proposed emergency bridge scheme, the flutter performance of the emergency bridge with the new-type cable-girder has been investigated through wind tunnel tests and numerical simulation analyses. Four aerodynamic optimization schemes have been developed in consideration of structure characteristics of the emergency bridge. The flutter performances of the aerodynamic optimization schemes have been investigated. The flutter derivatives of four aerodynamic optimization schemes have been analyzed. According to the results, the optimal scheme has been determined. Based on flutter theory of bridge, the differential equations of flutter of the emergency bridge with new-type cable-girder have been established. Iterative method has been used for solving the differential equations. The flutter analysis program has been compiled using the APDL language in ANSYS, and the bridge flutter critical wind speed of the optimal scheme has been determined by the program. The flutter analysis program has also been used to determine the bridge flutter critical wind speed of different wind-resistance cable schemes. The results indicate that the bridge flutter critical wind speed of the original emergency bridge scheme is lower than the flutter checking wind speed. The aerodynamic combined measurements of central-slotted and wind fairing are the optimal scheme, with the safety coefficients larger than 1.2 at the wind attack angles of −3°, 0°, and +3°. The bridge flutter critical wind speed of the optimal scheme has been determined using the flutter analysis program, and the numerical results agree well with the wind tunnel test results. The wind-resistance cable scheme of 90° is the optimal wind cable scheme, and the bridge flutter critical wind speed increased 31.4%. However, in consideration of the convenience in construction and the effectiveness in erection, the scheme of wind-resistance cable in the horizontal direction has been selected to be used in the emergency bridge with new-type cable-girder.
Highlights
As compared to normal bridges, the emergency bridge has the characteristics of small stiffness and damping
A 2D unsteady Reynolds-averaged Navier-Stokes (URANS) approach adopting Menter’s SST k-ε turbulence model was employed for computing the flutter and the static aerodynamic characteristics, and the conclusions indicated that the results provided by the proposed methodology agree well with the experimental data [10]
Assuming that the emergency bridge structure damping ratio is 0.5%, the flutter derivative is obtained from the wind tunnel test, and the flutter program was compiled based on the APDL language in ANSYS
Summary
As compared to normal bridges, the emergency bridge has the characteristics of small stiffness and damping. As the wind resistibility of the combined plate beam is not strong, the flutter of the emergency bridge is worth studying. Dung [2] and Ge [3] developed the mode superposition method for flutter analysis of a suspension bridge. Wind tunnel tests were performed to investigate the effects of different aerodynamic measures on the flutter stability of a steel truss girder suspension bridge. Based on wind tunnel tests and computational fluid dynamics (CFD) simulations, a study on the flutter performance of twin-box bridge girders at large angles of attack was presented [20]. In this study, using wind tunnel tests and numerical simulation analyses, the wind-resistance performance of the emergency bridge has been investigated. The results can be used as a reference for other similar studies
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