Predicting Roof Snow Loads on Gabled Structures

Abstract

Probabilistic models are developed from laboratory and field data to predict roof snow loads for cold slippery gabled roofs. The models account for the frequency and amount of snow sliding during an event by using actual measured probabilities. One model is based on temperature and precipitation and the other on degree‐hours and precipitation. Field data are obtained from three gabled roof structures with slopes of 10°, 30°, and 45° during the winter of 1986–1987. Additionally, artificial snow is deposited on small, gabled model roofs in the laboratory. Measured laboratory roof loads are related to prototype snow loads through similitude. Using simulation techniques, with the probabilistic models and 35 yr of meteorological data from the field site, 50‐yr mean recurrence‐interval roof snow loads are calculated and compared to published design standards. The simulated design roof snow loads for gabled structures are larger than those for comparable shed roofs. The standard‐specified design roof snow loads are conservative for the 30° and 45° roofs, and reasonable for 10° roofs.