Aerodynamic admittance and the 'strip theory' for horizontal buffeting forces on a bridge deck

In wind tunnel tests of bridges for buffeting arising from fluctuating wind velocity, one of the items requiring attention is how to simulate the natu ral wind characteristics of the construction region. In wind tunnel tests o f long-span cable-stayed bridges under construction, when two types of turb ulent boundary layer with different wind characteristics were used, there w as a tendency for the match between the wind tunnel test values and buffeti ng analysis values to vary with the type of turbulent boundary layer. Horiz ontal buffeting was considered for which there are fewer previous examples than for Vertical buffeting. As a result of pursuing the cause of the lack of matching, it was found that the aerodynamic admittance used in the analy sis and the measured aerodynamic admittance were quite different. This diff erence arose from the fact that the correlation of the fluctuating velocity spanwise was smaller than the value assumed in the analysis, Also, accordi ng to past research, there are many examples in which strip theory accordin g to which the fluctuating wind velocity correlation and the fluctuating ae rodynamic correlation are equivalent is not valid. Here, it is also conside red whether or not the strip theory is valid for horizontal buffeting. (C) 1999 Elsevier Science Ltd. All rights reserved.