Simulation of roof snow loads based on a multi-layer snowmelt model: Impact of building heat transfer

Abstract

To investigate the impact of building heat transfer on roof snow loads, roof snow loads and snow load thermal coefficients from 61 Chinese sites over a period of 50 years are simulated based on basic meteorological data such as temperature, humidity, wind speed, and precipitation, and a multi-layer snowmelt model considering the building heat transfer. Firstly, the accuracy of the multi-layer snowmelt model is validated using the data of observed ground snow load and roof snow melting tests. The relationship between meteorological conditions, snow cover characteristics, and thermal coefficients of snow loads in three representative sites is then studied. Furthermore, the characteristics of thermal coefficients in each zone are analyzed by combining them with the statistical results of meteorological data from 1960 to 2010, and the equations of thermal coefficients in different zones on indoor temperatures and roof heat transfer coefficients are fitted separately. Finally, the equations in this paper are compared with the thermal coefficients in the main snow load codes. The results indicate that the snowmelt model using basic meteorological data can effectively provide samples of roof snow loads. In the cold zone where the snow cover lasts for a long time and does not melt easily, the thermal coefficients of the snow loads on the heating buildings are lower than those in the warm zone due to the long-term influence of the heat from inside the buildings. Thermal coefficients are negatively correlated with indoor temperatures and roof heat transfer coefficients. When the indoor temperature is too low or the roof insulation is good, the roof snow load may exceed the ground snow load. The thermal coefficients for heated buildings in the main snow load codes are more conservative than those calculated in this paper, and the thermal coefficients for buildings with lower indoor temperatures tend to be smaller.