Research On Simulation Of Snowdrift On Long Span Structures

The construction of long span structures was booming with the development of the society. But collapses of long span structures were occured due to the large snow load or the decline of carrying capacity. The snowstorms were frequently happened in recent years so that people's lives were severely threated by the collapse of structures owing to snowstorms. The nonuniform snow load caused by snowdrift was harmful to structures especially. So it was necessary to research on snowdrift on long span structures.The rationale of snowdrift was summed up about the cause of snowdrift, the motion of snowdrift, the mathematical model and how to determine several key parameters in numerical simulation of snowdrift. Two different methods of numerical simulation were summarized—the governing equation of snow method and the MIXTURE multiphase flow model method.The structure behavior of a long span space truss string structure in Guangrao International Expo Center's exhibition halls was researched, by comparing with other roof schemes, this system could cross long span at lower height of roof structure and was performed better in the steel consumption and structural stiffness which dynamic performance was significantly better than flat-panel grid structure. The force on the structure was influenced by the snow loads in different distributions especially in unbalanced snow loads, so it was very important to considering unbalanced snow loads which was formed by snowdrift when we designed buildings. Based on the meteorological data, the actual ground snow loads for 2013-2014 winter were simulated near Guangrao International Expo Center and based on the assumption of snow drift for gable roof were distributed as triangle on leeward,the actual drift loads for 2013-2014 winter were simulated on the gable roof in Expo Center' exhibition halls. The actual drift loads on the gable roof were not significant due to the local less snow and the less sufficient wind speed in 2013-2014 winter.The computational domain was meshed respectively by structured mesh, unstructured mesh and hybrid mesh. Based on the FLUENT software, the snowdrifting of a spherical shell roof and a seashell-shaped shell in Yujiapu was simulated by using the governing equation of snow method and the MIXTURE multiphase flow model method. Using FLUENT software with re-development method by C Programming Language, the nonuniform snow load was simulated after the snow deposition and erosion happened on the roofs.Compared with the results of different mesh generate methods and numerical simulation methods in this paper, structured mesh performed better than hybrid mesh, hybrid mesh performed better than unstructured mesh; governing equation of snow method performed better than the MIXTURE multiphase flow model method. Reasonable suggestions were given to the selection of mesh generate method and numerical simulation method about snowdrifting on long span structures.