Formulae for peak background and resonant moments using Aerodynamic Loads Database information

In this discussion and the accompanying online database, the measured aerodynamic loads are defined in terms of the RMS base moment coefficient and the non-dimensional Power Spectral Density (PSD) as follows:



where = non-dimensional moment coefficient and = reference moment or torque, which is defined by , and for the alongwind, acrosswind and torsional directions, respectively. Here r = air density, B = building width normal to the oncoming wind, D = building depth, = mean wind velocity evaluated at the building height, H, and subscripts D, L and T = alongwind, acrosswind and torsional directions, respectively. It is noteworthy that, except for the alongwind load, different definitions have been used in the literature, e.g., the D is replaced with a B for the acrosswind load, and BD is expressed in terms of B2 for the torque (Marukawa et al. 1992; Choi and Kanda 1993; Kijewski and Kareem 1998). These definitions will lead to significant differences in the RMS coefficients in (9), while having no impact on the normalized spectrum in (10).

The non-dimensional aerodynamic loads can be directly used in the above analysis procedure, e.g., the background and the resonant components of the base bending moment or base torque can be computed, respectively, by



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Notes :

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