Snow load modelling for structural load combination methods

New methods of load combination analysis have been developed that describe more accurately the combined loads acting on structures. Present design codes using probability- based load factors have not evolved to the use of these new methods due to a lack of statistical data needed to describe the various load types.

Statistics of water equivalent ground snow load data were obtained for seventeen sites across the United States. These snow loads were modeled as a Poisson square wave pulse process. Daily water equivalent snow load intensity was fitted with a Weibull distribution. Verification of this distribution function was provided by comparison of predicted 50-year snow loads to well established 50-year snow loads.

Occurrence dependence, intensity and duration dependence, and intensity dependence were considered with respect to their effect on load combination analyses. The correlation of snow loads with other loads was also considered.