In buffeting analysis of low-frequency structures such as long-span bridges, Davenport's simple formula for the coherence of turbulence is known to lead to overestimation of responses. This paper presents extended Roberts-Surry and Thompson formulas for application to such situation. The effect of modal response correlation is also discussed by Complete Quadratic Combination (CQC) method. Responses by analysis of 890m-long cable-stayed bridge showed good agreement with the measured responses of a model in wind tunnel test.
