Attributed to the developments of bridge engineering, modern cable-supported bridge
design requires not only the needs of transportation but also the aesthetical appearance. As
the curved bridge is subjected to wind excitation, the yaw angles along the bridge axis are
continuously varied because of the curved appearance. In other words, the yaw angle of each
deck element is different in the finite element analysis. Therefore, the wind effects on the
curved bridges can be regarded as the further applications of straight bridges under various
yaw winds. In conventional analysis, the “Cosine Rule” and the “Skew Wind Theory” were
often used for dealing with these effects. However, these approximate theories were
demonstrated valid only for small yaw angles or low wind speeds.
This study aims at developing a reasonable theory for flutter and buffeting analysis of
the curved bridge. The proposed method is based on the aerodynamic coefficients and the
flutter derivatives obtained from section model tests for different yaw angles. In order to
demonstrate the validity and applicability of the theory, a curved cable-stayed bridge was
designed and the full aeroelastic model test was conducted. A rectangular cross section with
the width-to-depth ratio of 5 was adopted for the bridge. The curvature and the included angle
of the target are 250 m and 60°, respectively.
The experimental results show that the critical flutter wind speed is about 85.38 m/s. The
numerical predictions obtained from both the proposed theory and the Cosine Rule are less
than 1%. For the buffeting responses, the Cosine Rule overestimates the vertical responses
especially at high wind velocities. The results obtained from both the proposed theory and the
Cosine Rule agree well with the experimental results in the drag direction. However, both the
proposed method and the Cosine Rule overestimate the torsional responses. The phenomenon
is more obvious for the results predicted from the approximate method. The possible reason
for the discrepancies in the torsional responses is that the negative aerodynamic damping is
overestimated in the section model test under smooth flow.
