Development of wind load evaluation methods considering possible extreme wind pressure distributions applicable to performance based design

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Fluctuating wind pressures acting on the surfaces of low-rise and high-rise building models with various aspect ratios and side ratios were measured. Maximum quasi-static wind load effects were calculated, such as shear forces, bending moments and frame stresses. The instantaneous pressure distributions causing the maximum load effects were examined in detail based on a sufficient number of samples. The obtained possible wind pressure distributions for various wind load effects were quite different from the quasi-steady wind load distributions based on mean pressure distributions. The load-response correlation (LRC) formula by Kasperski was applied to the internal forces of the frames, and the results were compared with possible wind pressure distributions. Then, the scope of LRC formula was examined.The correlations and phase plane trajectories of wind force components were also investigated. The results suggest that the cross-correlation of the absolute values of wind force components was more appropriate for examining the wind load combinations than ordinary cross-correlations. Then, the contribution of each wind load component to the maximum normal stresses in column members was examined. It was clearly recognized that the maximum normal stress was significantly underestimated if only the along-wind load component was taken into account for calculation. This strongly suggests the importance of considering the combinations of along-wind, across-wind and torsional wind load components even for low-rise or middle-rise buildings.Additionally, non-elastic responses of frame models of high-rise buildings were analyzed for extremely high wind speeds, and the building behaviors around the ultimate states were clarified.Based on these comprehensive studies of wind loads and building behaviors, wind load evaluation methods wee developed that consider possible extreme wind pressure distributions applicable to performance based design.