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This paper summarizes the findings from extensive wind tunnel tests carried out by the authors' group for the evaluation of wind load combination effects for various types of building models. Characteristics of correlations of wind force components are examined using the absolute ratio of wind forces, phase–plane trajectories and (absolute) cross-correlation, and then wind load combinations are examined. The necessity to consider wind load combinations is inferred from the instantaneous pressure distributions, and the cross-correlation coefficients of the absolute values of wind force components are found to be more important when examining wind force combinations. Wind load combination effects are directly examined using frame models. Based on the peak normal stresses in columns under various loading conditions, combination factors for low-, middle- and high-rise buildings are proposed. Lastly, effects of wind direction on wind load combinations are discussed.

Pressure tests and Particle Image Velocimetry (PIV) tests were conducted to investigate interference effects between two high-rise buildings. Buildings with the same height but different shapes, rectangular and square in plan, were adopted. Pressure test results show that the largest minimum peak pressure on a building under interference effects can be 50% larger than those on an isolated building. PIV tests were used to describe and explain the interference effects from the flow field point of view. The results show that the specific flow pattern with an interfering building may lead to enlargement of the negative peak pressure on the principal building. The interfering building can also reduce the negative peak pressure on the principal building by affecting the formation of a separated shear layer at its leading edge.

In order to examine wind load combinations, fluctuating surface pressure measurements are made for flat roof building models with square or rectangular plans. The fluctuating pressures are integrated over all their surfaces and results are obtained of along-wind force, across-wind force, vertical force, along-wind overturning moment, across-wind over-turning moment and torsional moment on their frames. The maximum wind force component and other simultaneously observed wind force components are examined, and some interesting facts regarding the effects of wind direction are discussed. In order to directly check the wind load combination effects, the maximum normal stresses in column members of simple frame models are examined, and a wind load combination factor is proposed.

Fluctuating surface pressure measurements are made for four flat roofed building models with square or rectangular plans in order to examine wind load combinations. The fluctuating pressures are integrated over all their surfaces and results are obtained of along-wind force, across-wind force, vertical force, along-wind overturning moment, across-wind overturning moment and torsional moment on their frames. The maximum wind force component and other simultaneously observed wind force components are examined, and some interesting facts regarding the wind force combinations are discussed on the basis of absolute value correlations, phase-plane expressions and so on. The maximum normal stresses in the column members of simple frame models are then examined in order to directly check the wind load combination effects.

This paper discusses the conditionally sampled actual wind pressure distributions causing peak quasi-static internal forces in the structural frames of a low-rise building model with a square plan. The actual extreme pressure distributions are compared with Kasperski's load–response-correlation (LRC) formula and the quasi-steady pressure distributions. The validity of Kasperski's LRC formula is proved to estimate the actual extreme wind load for the general location of the frame including the separation bubble region. The only exception was where the frame was immersed in the vicinity of the leading edge, where the non-Gaussian characteristics are predominant. The reason for the discrepancy in the LRC pressure distribution and the actual extreme pressure distribution is attributed to the intermittent characteristics of the fluctuating pressure field in the vicinity of the leading edge, which cannot be represented by the temporal average characteristics.

This paper first discusses the conditionally sampled actual wind pressure distributions causing maximum quasi-static wind load effects at the base of low-rise building models with square and rectangular plans. The maximum normal stresses in column members were also examined to discuss the wind load combination of the along-wind, across-wind, uplift, and three moments. Then, it examines the actual wind pressure distributions causing the maximum quasi-static stresses in structural frames. These are compared with Kasperski’s load-response-correlation formula and the quasi-steady pressure distributions.

The wind-induced pressure acting on buildings and structures is greatly influenced by the approaching wind. A detailed analysis of correlation between wind and building pressure is difficult using classical statistical methods. Proper orthogonal decomposition (POD) overcomes this difficulty by allowing us to consider separately the principal coordinates and the associated eigenvectors, characterizing the dominant spatio-temporal structures of the analyzed field. In this paper, the fluctuating wind pressure acting on the building models is analyzed using POD and the correlations between the decomposed pressures and the approaching wind are examined.

Dynamic wind pressures acting on buildings are complicated functions of both time and space. Earlier studies have applied the proper orthogonal decomposition (POD) technique to such random wind pressure fields to identify hidden deterministic structures. In this study, the POD technique is applied to fluctuating wind pressures acting on a tall building model, and the following facts are found: the along-wind and across-wind forces can be approximated by only a few dominant modes, while the torsional moment requires approximately 10 modes; and the wind-induced response of a tall building has a maximum evaluation error of less than 6% with the reconstruction of the dominant modes.