Nonsynoptic Wind-Induced Transient Effects on Linear Bridge Aerodynamics

This contribution focuses on the nonsynoptic wind-induced effects on linear bridge aerodynamics. More specifically, the transient nature of the downburst events and its effects on the aerodynamic parameters are investigated. Because an additional timescale is introduced in the wind-structure interaction system attributable to the time-varying transient nonstationarity of the nonsynoptic winds, the conventional one-dimensional (1D) indicial response function needs to be extended to a two-dimensional (2D) case. Buffeting response of a bridge deck based on the time-domain linear analysis framework associated with 2D and 1D indicial response functions, representing aerodynamics under nonsynoptic winds and corresponding synoptic equivalents, was calculated. The results highlighted the important effects of the transient nature on the nonsynoptic wind-induced structural response. The presented approach could provide a straightforward physical explanation on the underlying mechanism of the changing aerodynamics attributable to time-varying transient effects. The study may facilitate a more appropriate design of the flexible horizontal structures considering nonsynoptic wind loads. (C) 2017 American Society of Civil Engineers.