## 3 Results and Discussion
### Coefficient of Basement Overturning Force  
In wind tunnel experiments, the determination of the base overturning force coefficient is also crucial in structural design, especially for buildings with complex geometries. Underestimating the base overturning force can lead to design issues. Therefore, the base shear and moment are calculated based on the pressure measurement experiments conducted in the two wind tunnels, and the base overturning force coefficient is subsequently determined. Figures 16 and 17 show the average overall force coefficient and RMS overall  
Figure 14: Extreme wind load coefficients: (**a**) in the 0\({}^{\circ}\) direction; and (**b**) in the 90\({}^{\circ}\) direction. Figure 15: Error range of extreme wind load at different wind direction angles. force coefficient at different wind directions, respectively. The calculation formulas for the overall force coefficient are given by Equations (11)-(14). \[C_{\text{Fi}}=\frac{\overline{F}_{\text{i}}}{1/2\rho U_{\text{H}}{}^{2}HD_{ \text{y}}} \tag{11}\]  
\[C_{\text{Mi}}=\frac{\overline{M}_{\text{i}}}{1/2\rho U_{\text{H}}{}^{2}H^{2}D_{ \text{y}}} \tag{12}\]  
\[C_{\sigma\text{Fi}}=\frac{\widetilde{F}_{\text{i}}}{1/2\rho U_{\text{H}}{}^{2} HD_{\text{y}}} \tag{13}\]  
\[C_{\sigma\text{Mi}}=\frac{\widetilde{M}_{\text{i}}}{1/2\rho U_{\text{H}}{}^{2} H^{2}D_{\text{y}}} \tag{14}\]  
where \(C_{\text{Fi}}\) represent the mean value of the base overturning force coefficient in the x and y directions, respectively. \(C_{\sigma\text{Ti}}\) represent the mean value of the moment coefficient of base overturning in the x and y directions, respectively. \(C_{\sigma\text{Ti}}\) represent the RMS value of the moment coefficient of base overturning in the x and y directions, respectively. \(\overline{F}_{\text{i}}\) represent the base mean forces in the x and y directions, respectively. \(\widetilde{M}_{\text{i}}\) represent the base mean moments in the x and y directions, respectively. \(\widetilde{F}_{\text{i}}\) represent the base RMS forces in the x and y directions, respectively. \(\widetilde{M}_{\text{i}}\) represent the base RMS moments in the x and y directions, respectively. \(\widetilde{M}_{\text{i}}\) represent the base RMS moments in the x and y directions, respectively. These results are calculated based on the wind pressure coefficient results obtained from the pressure measurement tests. \(D_{\text{y}}\) represents the length of the longer side of the model's cross-section. From Figure 16, it can be observed that the experimental results from the two wind tunnel facilities are relatively consistent. It is important to note that these data results are obtained without reference to static pressure correction. In practice, the base overturning force is generally calculated by subtracting the negative pressure on the leeward face from the positive pressure on the windward face. Therefore, the error in the reference static pressure will not affect the overall results of the building. Additionally, it can be assumed that the error in the average wind pressure coefficient mentioned earlier is solely caused by the error in the reference static pressure. Figure 17 shows that the RMS values of the base overturning force coefficients for CQU are slightly smaller than those for HIT, which correspond to the results of the RMS wind pressure coefficients. This difference is due to the varying turbulent integral scales, which affect the RMS wind pressure coefficients and subsequently impact the RMS values of the base overturning force. Figure 16: The mean value of the base overturning force and the base overturning moment of the CAARC building model: (**a**) base overturning force; (**b**) base overturning moment. The above study indicates that in open-circuit wind tunnels, attention should be paid to the impact of static pressure errors on the mean wind pressure coefficient, and corrections for static pressure should be implemented when necessary.