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Unbalanced snow loads on roofs have been a turbulent and significant problem for the building industry. Gables are one of the most common roof shapes, which are widely adopted as the roof shape for family residences, factories, ware houses, and garages. Series of experiments on an isolated gable-roof with or without scuttles and different roof pitches were done for the purpose of exploring the unbalanced patterns of snow loads. The model buildings made of wood have the same floor space, 2000 × 2000 mm but different roof pitches. A new open air snow–wind combined experimental facility was adopted in the experiments. The facility, which is like an open air wind tunnel with a snowfall simulator, can produce a stable wind field and snowfall environment for a specific duration. Artificial snow was used in the experiments, and particles properties were compared with natural snow previously proposed by the other authors. The experiment results indicated that the unbalanced snow loads were strongly connected with various wind velocities and roof pitches and a scuttle or other salient on the roof would bring an evident influence of patterns of snow distribution on the roofs. [ABSTRACT FROM AUTHOR]

In previous studies, snowdrifts around different buildings have been investigated in wind or water tunnels, or in the outdoor environment, to ensure proper accessibility and the safety of structures. The pattern of snowdrifts is strongly connected to the speed and incidence angle of the wind. Two sets of experiments have been undertaken to investigate the influence of wind on snowdrift accumulation around a model and another set of experiments have been undertaken to explore the influence on two separated models. The building model is a wooden cube with dimensions of 0.5 × 0.5 × 0.5 m. The experiments are carried out in an open air snow-wind combined experimental facility, which is situated outdoors, like an open air wind tunnel with a snowfall simulator. The facility can produce a stable wind field and snowfall environment for a specific duration. During the experiments, environmental conditions, like temperature and humidity were measured on a PC-4 automatic weather station. The snow used in the experiments came from the natural snowfall on 01/19/2016-01/22/2016. After each experiment, the snowdrift geometry was measured by surveying approximately 300 points around the model. The results reveal that the patterns of snow distribution show a close relationship with the surrounding wind field of buildings. [ABSTRACT FROM AUTHOR]

The unified wind pressure spectra model with certain precision can simplify the wind-induced response analysis and standardize the design process of the wind resistance. An auto-spectral model of wind pressure was proposed with three parameters which denote the descending slope, the dominant frequency and the peak value of the reduced auto-spectral curve respectively. The values of the model parameters were identified and studied statistically based on 4 types of rigid large-span roof models in which 115 typical wind tunnel pressures were measured. The results show that the distribution patterns of the parameters is in accord with the flow characteristics and can be expressed in the form of zone area, which may indicate the physical meaning of the parameters. The zone values of the parameters were summarized statistically, and the wind pressure spectral model was validated by 1) comparing the spectral curves with relevant studies and 2) comparing the wind-induced responses calculated through the proposed model with the wind tunnel data on 642 cases of large-span grid structures. It concludes that the spectral model can be applied in further exploring the wind load characteristics as well as calculating wind-induced responses in engineering practices. [ABSTRACT FROM AUTHOR]

Unbalanced snow distribution is one of the main reasons for the collapse of multi-span arch roofs due to excessive snow loads in the valley and leeward areas. The formation of uneven snowdrifts is closely related to the shape of the building as it seriously affects the turbulent structure and snow drifting process. This study aims to investigate the snowdrift characteristics of multi-span arch roofs based on a multiphase snowdrift approach. Firstly, the prediction accuracy of the flow field is tested to select a reasonable turbulence model. Then, the reliability of this multiphase approach is validated by comparing the results with a wind tunnel experiment of snowdrifts on a multi-span arch roof. The result preliminarily proves that this approach could well reproduce the unbalanced snowdrift on each span roof and at the trough. The snowdrift characteristics of multi-span arch roofs are investigated under different rise/span ratio and span number conditions based on the validated approach. The formation mechanism and characteristics of snowdrifts on different roofs are clarified by analysis. Finally, several typical distribution patterns are derived based on the statistical analysis of results. It is found that the middle-span roof bears a larger snow load than the roofs at both ends. • The paper proposes a multiphase approach that could accurately predict the snowdrifts on arch roofs. • The multiphase approach could well reproduce the snow drifting process and the sliding effect at roof edge. • Two kinds of unbalanced triangular snow loads are formed on the single-span arch roof according to the rise/span ratio. • The stacking snow load at the trough of the multi-span roof is about twice the peak snow load of the single-span roof. • The middle-span arch roof bears a larger snow load than the roofs at both ends of the multi-span building. [ABSTRACT FROM AUTHOR]