## 5 Conclusions  
This article covers the maximum wind speed at which a gantry crane remains stable. According to the standard [14], the maximum design wind speed \(V\) is 20 m/s for all cranes installed in the open. Experimental testing and numerical analysis showed compliance with the standard regarding the stability behavior of this type of structure in open space at an average wind speed of 20 m/s. This study assumed that the gantry crane is stopped but not anchored to the rails on which it moves. For cranes installed in coastal areas, the wind situation is different. The standard states that overhead cranes that must continue to operate in high winds have a maximum design wind speed of 28.5 m/s (102.6 km/h), such as container cranes. In this case, the wind speed for such a facility can range from 20 m/s to 40 m/s (wind speed with gusts of 3 s). As is reported from the data presented in this paper, the gantry crane with the truss horizontal girder can be overturned at 32.2 m/s (115.92 km/h) of wind speed. On the other hand, the gantry crane with the box girder can be overturned even at 37.45 m/s (134.75) of wind speed. The critical wind speed values obtained from CFD simulations for three different wind profiles and a box girder crane are almost identical and do not depend much \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Wind Profile (Terrain)** & \(F_{x}\) **(N)** & \(F_{y}\) **(N)** & \(M_{z}\) **(Nm)** & \(C_{M}\) \\ \hline Urban & 11,097.461 & 4192.185 & \(-\)121,687.84 & 1.670 \\ Village & 11,353.304 & 4139.967 & \(-\)122,673.19 & 1.683 \\ Open & 11,721.647 & 4080.948 & \(-\)124,223.43 & 1.705 \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Aerodynamic forces and moments for real-scale structure. on the type of terrain, and the obtained values are \(V_{1}\) = 41.445 m/s (149.202 km/h) for urban terrain, \(V_{2}\) = 41.278 m/s (148.602 km/h) for village terrain, and \(V_{3}\) = 41.020 m/s (147.672 km/h) for the open terrain, which are slightly higher than those determined according to the standards. In other words, estimations based on the standards provide underestimated critical wind speed values; thus, they are safe. Although the standards provide the magnitudes of the moments regardless of wind direction, the results reported in the current work show significant differences due to the variation in the angle theta. The change in angle theta means that the wind direction is not parallel to the horizontal plane. Wind strength depends mainly on the geographical location and the degree of wind exposure of the crane, as evidenced by the gantry crane accidents given in the Introduction, among others, including a box crane at the LNG terminal in Swinoujscie [37] (coastal area) and the truss girder crane example described by [PERSON] [13], where the gantry crane derailed and collapsed after traveling about 60 m in very strong winds of about 30.56 m/s (110 km/h). The given gantry crane disaster examples caused by high winds occurred when the wind speed was comparable to the values reported in this paper. In this study, the authors wanted to draw attention to the importance of changing wind direction in the vertical plane. Usually, the change in wind direction is considered in the horizontal plane. However, as shown in the results, even a small change in the vertical angle, e.g., only up to 6\({}^{\circ}\), causes significant changes in the value of the overturning moment (for selected angles). Thus, we wanted to show that adopting standard calculations for overhead cranes, which are usually located in urban or non-urban areas but not far from the city, can often lead to accidents, especially when the crane is operated in a coastal (seaside) area. Conceptualization, M.A. ; methodology, M.A. and M.B. ; software, M.B. ; validation, M.A. and M.B. ; numerical analysis, M.B. ; experimental investigation, M.A. ; data curation, M.A. and M.B. ; writing--original draft preparation, M.A. and M.B; writing--review and editing, M.A. and M.B. ; visualization, M.A. and M.B.