ASCE 7-22 updated the ground snow load map to reflect ultimate design loads, which increased the values. At the same time, the service-level load combinations now apply a 0.7 multiplier to snow loads.
My concern is with how snow drifts are calculated. Drift loads are based on the drift height and the snow density. However, the equation for snow density wasn’t updated to reflect the switch to ultimate loads.
As a result, while the ground snow load increased, that increase doesn’t really affect drift loads. But in design, we still apply the 0.7 multiplier to those drift loads. This means that when we start using ASCE 7-22, the drift loads we design for will end up being significantly lower than what previous codes required. Am I missing something?
My concern is with how snow drifts are calculated. Drift loads are based on the drift height and the snow density. However, the equation for snow density wasn’t updated to reflect the switch to ultimate loads.
As a result, while the ground snow load increased, that increase doesn’t really affect drift loads. But in design, we still apply the 0.7 multiplier to those drift loads. This means that when we start using ASCE 7-22, the drift loads we design for will end up being significantly lower than what previous codes required. Am I missing something?
