| As one of the live loads,the snow load on the roof of the long-span spatial structure can have a negative impact on the structure when it is too large,leading to the destruction of the envelope structure and even the main structure,resulting in huge property losses and casualties.For the snow distribution coefficient on the surface of large-span planar roof structure,the current load code only provides a general regulation without considering the influence of plane shape of planar roof on snow distribution and uneven distribution of local snow caused by the interference effect of shielding buildings.Therefore,in order to accurately predict the snow distribution on the surface of large-span planar roof and avoid economic losses and casualties caused by local damage and collapse of the roof,it is necessary to study the snow distribution coefficient on the surface of large-span planar roof considering the interference effect and the influence of plane shape.In order to more accurately predict the snow distribution of large-span plane roof and improve the safety of structural design,this paper,based on the modified Euler-Euler method,uses Fluent fluid computing software and combines with user-defined compiled UDF interface.The Computational Fluid Dynamics(CFD)method for numerical simulation of wind-induced snow drift is used to study two kinds of large-span planar roof structures: The Wuxi Ecological Park and the Shenyang Henglong Municipal Government Square.The snow distribution coefficient of large-span planar roof structure with interference effect is studied.The main research contents and conclusions are as follows:(1)The Euler-Euler method and the Mixture model are used to generate boundary conditions based on the jump and overhang motion modes in wind-induced snow drift,and consider the underdeveloped wind and snow flow,which is applied to the numerical simulation of the cube model.Compard with the field measured results,the simulated results based on the Mixture model are in good agre.(2)Taking Wuxi Ecological Park as an example to investigate the snow distribution coefficient of the superimposed large-span flat roof.Firstly,the distribution law of snow under three wind speeds of 5m/s,7.5m/s and 10m/s is studied to analyze the influence of wind speed on snow distribution.Secondly,a typical roof is selected to study the influence of different wind direction angles on snow distribution.It is found that roof snow erodes and accumulates in different positions with the change of wind direction angle.Finally,the roof is divided according to the building form,the uneven distribution of snow on the roof is quantitatively analyzed,and the local snow distribution coefficient is emphatically studied as well.The results indicate that the local snow distribution coefficient of the superimposed roof is larger at the superimposed position,and the snow deposition place is less affected by the wind speed.The value is appropriately enlarged.(3)Shenyang Henglong Municipal Plaza is taken as an example to study the distribution coefficient of snow cover on large-span flat roofs with complex shapes.Firstly,the influence of the incoming wind from different directions on the distribution of snow on the roof before and after the disturbance of the surrounding buildings is considered.By comparison,it is found that the interference effect is more obvious,and the snow distribution law will change greatly.Finally,the roof is partitioned according to the building form.The typical partition covering the entire roof is selected to study the local snow distribution coefficient before and after different wind direction angles.Considering the interference effect,the value of the local snow distribution coefficient is given for reference in the actual engineering design. |
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