Design Ground Snow Loads: Historical Perspective and State of the Art | Journal of Structural Engineering | Vol 148, No 6

AbstractThis paper reviews the development of snow load research since the contemporary introduction and calibration of the ANSI A58-1982 provisions (and subsequent ASCE 7-88). The ASCE 77-88 ground snow loads were based on the data and methods available at the time and subsequently updated in 1995. The provided loads are based on 50-year mean recurrence intervals, with design loads for each category being obtained through a combination of partial safety and importance factors. Changes and improvements in snow load design over the last 40 year necessitate a reconsideration of the original calibration of these safety and importance factors. This paper discusses the need for a movement away from a uniform-hazard snow load design approach in combination with uniform load and importance factors, in favor of reliability-targeted design snow loads. This paper reviews the concept of reliability targeted loads as a means of meeting the ASCE 7 goal of uniform risk/reliability in the US. This paper further describes the incremental changes in both reliability and snow load research that will culminate in a change from uniform hazard (i.e. 50-year) loads to uniform-reliability loads. The purpose of this paper is to describe the motivation for, and historical context of E 7, the forthcoming changes to design ground snow loads in ASCE 7-22. Furthermore, the paper discusses the future of snow load prediction and its impact on the engineer and the code, particularly in regards to the implications of climate change for future snow load design.



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