Background component of buffeting response of cable-stayed bridges

For practical purpose, buffeting response of cable-stayed bridges to wind excitation is usually analytically determined by single-mode-based method, and the resultant response is written as the composition of the resonant component and the background component by the square root of sum squares (SRSS) method. The background component is sometimes neglected for simplifying computations. In the present paper, numerical computations on four representative cable-stayed bridges in China indicate that the background component usually has a significant contribution to the buffeting response of long-span cable-stayed bridges. Parametric studies on the effects of structural parameters on the buffeting background components for these four bridges are also performed. A simplified method introduced in literatures for estimation of the background component of buffeting response is then briefly discussed. Finally an approximate method for estimating the first vertical bending mode-buffeting response of cable-stayed bridges is proposed.