# Snow Load Shape Coefficients and Snow Prevention Method for Stepped Flat Roofs
## 5 Conclusions  
This study combines field measurements and numerical simulations to study the snow accumulation processes and final patterns of snow distribution on a stepped flat roof. By integrating the measured results with different codes, a formula for the snow load shape coefficient is presented. Moreover, a viable design option to minimize the potential for  
Figure 16: Snow accumulation on the lower roof at different angles.  
Figure 17: Snow removal rate and maximum snow depth on the lower roof at different angles.  
Figure 18: Snow load shape coefficient on the lower roof at different angles.  
any drift is proposed for snow prevention on stepped flat roofs. Through these efforts, the following conclusions are obtained:  
1. During the snow accumulation processes on stepped flat roofs, an erosion region whose length varies linearly with time is formed on the lower roof due to reverse flow. The erosion disappears when the snow accumulation process is almost half-finished. As the snow develops to its final pattern, no measurable snow is observed on the upper roof, while the snow shapes on the lower roof vary with different wind directions. The final windward snow on the lower roof is distributed in a triangle. When the upper roof is on the windward side, the final snow distribution is close to uniform.
2. The codes of different countries have various snow load shape coefficients on stepped flat roofs, but it is generally accepted that the nonuniform snow distribution on stepped flat roofs is close to linear. The measured snow load shape coefficients are more in line with a quadratic function. Through the combination of measured results and different codes, it is recommended that the value of the snow load shape coefficient conform to a linear regularity: \(\mu=\left\{\begin{matrix}-1.22(x/\mathrm{H})+3.44&0\leq x/\mathrm{H}\leq 2\\ 1&x/\mathrm{H}>2\end{matrix}\right.\), where \(x/\mathrm{H}\) is the distance normalized by the level difference \(\mathrm{H}\).
3. An increase in the slope can effectively reduce the snow accumulation on stepped flat roofs. As the slope increases, the snow removal rate of the roof gradually increases, while the maximum snow depth and snow load shape coefficients subsequently decrease. When the snow load on the roof is less than the ground snow load, there is an optimal slope of the lower roof, making the snow removal rate the maximum and the area of the lower roof the minimum. Finally, considering snow removal efficiency and economic factors, the slope of the lower roof is recommended to be \(11^{\circ}\).  
Conceptualization, Z.Z. and W.M.; methodology, Z.Z. and S.L.; software, Z.Z., W.M. and Q.L.; validation, Z.Z., W.M. and Q.L.; formal analysis, Z.Z.; investigation, W.M.; resources, S.L.; data curation, Z.Z.; writing--original draft preparation, Z.Z.; writing--review and editing, Z.Z.; visualization, W.M.; supervision, S.L.; project administration, Q.L.; funding acquisition, W.M. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the National Natural Science Foundation of China, grant number 52278511.  
Not applicable.  
The data presented in this study are available on request from the corresponding author. The data are not publicly available due to privacy.  
The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results.