고유직교분해법(POD)를 이용한 가설 중 사장교의 버페팅응답 해석

The results of buffeting analysis applied to the erected cable-stayed bridge using proper orthogonal decomposition (POD) based on spectral proper transformation (SPT) are presented in this paper. In this approach, aerodynamic admittance function for the consideration of unsteadiness and spatial variation in flow field around a deck is included in the procedure of mathematical formulation. The interference between structural modes of bridge and turbulence modes is investigated with a physically meaningful decomposition by POD. This paper shows that the characteristics of buffeting response are influenced considerably by the similarity of lower structural modes and lower turbulence modes shaped like symmetrically/asymmetrically simple sinusoidal waves. Since the higher turbulence modes are almost orthogonal to the structural modes, the structure is stimulated by only the lower turbulence modes. Therefore, it is possible to accurately predict buffeting responses of the erected bridge with only a few lower turbulence modes because the mode shapes of erected bridge are more simple compared with those of completed bridge.