Analysis of snow loads due to drifting on multilevel roofs

Abstract

Drifted snow loads on multilevel flat roofed structures account for a large percentage of the building roof losses in the United States, yet little information is presently available which quantitatively describes the factors which influence drift formation. As part of continuing research activities at Rensselaer Polytechnic Institute, a database of snowdrift case histories has been established and is statistically analyzed herein. The process of drift formation is discussed and a relationship between drift height and ground snow load, roof lengths, and roof elevation difference obtained using multiple linear regression is presented. Drift slope and snow density characteristics are studied. Finally, comparisons with drift load provisions in building codes and standards are described and recommendations for future research are made.