## 4 Analysis of the Measured Fluctuating Wind Speed Data
### Gust Factor  
Figures 9 and 10 present the relationship between gust factors and mean wind speed and between gust factors and mean wind direction, respectively. The left side of the figure shows the synchronously recorded data of buildings A, B, and C. The right side of the figure exhibits the synchronously recorded data of buildings A and C when building B experiences power outage. The line with an ordinate of 1 is used to distinguish the longitudinal and transverse gust factors (\(G_{u}\) and \(G_{v}\)). In the selected samples, the gust duration is 3 s, and Table 2 shows the mean of the gust factors of the three buildings in two phases.  
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Periods** & **Building** & **Samples** & \begin{tabular}{c} **Mean Longitudinal** \\ **Turbulence Intensity** \\ \end{tabular} & \begin{tabular}{c} **Class D** \\ **Terrain** \\ \end{tabular} & \begin{tabular}{c} **Class C** \\ **Terrain** \\ \end{tabular} & \
\begin{tabular}{c} **Class B** \\ **Terrain** \\ \end{tabular} &
\begin{tabular}{c} **Class A** \\ **Terrain** \\ \end{tabular} \\ \hline \multirow{3}{*}{Three sites} & Building A & 109 & 30.4\% & & & & \\  & Building B & 109 & 30.8\% & & & \\  & Building C & 109 & 19.4\% & 17.3\% & 12.6\% & 9.3\% & 8.6\% \\ \cline{1-1}  & Building A & 37 & 20.3\% & & & & \\ \cline{1-1}  & Building C & 37 & 17.7\% & & & & \\ \hline \hline \end{tabular}
\end{table}
Table 1: Comparison of longitudinal turbulence intensity between Chinese load code for the design of building and field measurements.  
Figure 8: Variation in turbulence intensities with 10 min mean wind direction. (**a**) Longitudinal turbulence intensities; (**b**) Lateral turbulence intensities.  
The left side of Figure 9 illustrates that the change law of gust factor with the mean wind speed \(U\) is nearly identical with that of turbulence. When \(U<10\) m/s, the gust factors of buildings A and B decrease with the increase in mean wind speed, whereas the gust factor of building C does not change with the increase in mean wind speed. When \(U\geq 10\) m/s, the change law of gust factor in the three buildings is consistent and decreases with increasing mean wind speed, but the change speed is slow. The right side of Figure 9 shows that the along-wind gust factor of building A increases first and then decreases, and the maximum value is 1.73 when \(U=19\) m/s. The cross-wind gust factor of building A, the along-wind gust factor of building C and the cross-wind gust factor do not change with the increase in mean wind speed. Figure 10 indicates that the change law of gust factor with the mean wind speed is nearly identical with the change law of turbulence.  
The analysis of Figures 7-10 presents that the turbulence and gust factors obtained by investigating the samples at \(U\geq 10\) m/s are reasonable. The gust factors that meet the requirements are  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Periods**} & \multirow{2}{*}{**Building**} & \multirow{2}{*}{**Samples**} & \multicolumn{2}{c}{**Mean Longitudinal**} & \multicolumn{1}{c}{**Mean Lateral**} \\  & & & **Gust Factor** & **Gust Factor** \\ \hline \multirow{3}{*}{Three sites} & Building A & 65 & 1.64 & 0.44 \\  & Building B & 63 & 1.59 & 0.40 \\  & Building C & 59 & 1.35 & 0.24 \\ \hline \multirow{3}{*}{Two sites} & Building A & 37 & 1.42 & 0.35 \\  & Building C & 37 & 1.28 & 0.20 \\ \hline \hline \end{tabular}
\end{table}
Table 2: Mean gust factor of two periods.  
Figure 10: Variation in gust factor with 10 min mean wind direction.  
Figure 9: Variation in gust factor with 10 min mean wind direction.  
evaluated statistically. The mean longitudinal and transverse gust coefficients at the top of building A (102 samples) are 1.428 and 0.356, those at the top of building B (63 samples) are 1.485 and 0.351 and those at the top of building C (96 samples) are 1.319 and 0.225, respectively.