Snow Load Bug in V17

RE: Snow Load Bug in V17

Eric Feuge-Miller — Wed, 08 Sep 2021 16:27:23 GMT

The best workarounds for this would be to change the snow loads into Roof Live Loads where they exceed the standard design Roof Live Load requirements or to create a simple excel an apply a series of averaged flat-load values for the snow. Be sure if you run the Snow Load method that you include the flat roof snow load, as the loads are not additive in RAM.

Overall, best would be to alter the drift loading to flat loading values, this will allow you to keep all members as gravity since the flat snow load is not impacted by the Concrete module.

RE: Snow Load Bug in V17

Eric Feuge-Miller — Tue, 07 Sep 2021 19:53:00 GMT

Good to know.

RE: Snow Load Bug in V17

Seth Guthrie — Tue, 07 Sep 2021 18:45:22 GMT

The analysis in Ram Frame when the diaphragm is meshed (2-way or semi-rigid) and the snow is drifted also has a problem (average loads seem to be get applied). Internally this is our issue number for that, Defect 961931:Snow Drift on 1Way and 2Way Decks in RAM Frame)

RE: Snow Load Bug in V17

Seth Guthrie — Tue, 07 Sep 2021 18:35:01 GMT

I'll run a test to be sure. I see a second defect logged that makes me think it's also broken in Ram Frame if the diaphragm is meshed.

RE: Snow Load Bug in V17

Eric Feuge-Miller — Tue, 07 Sep 2021 18:31:39 GMT

Perfect! I figured that was the case, just wanted to make sure everything was chronicled on here for others. Thanks a lot for the help Seth!

RE: Snow Load Bug in V17

Seth Guthrie — Tue, 07 Sep 2021 18:22:38 GMT

Yes, you can either simplify the snow loads as flat, or use forces from Ram Frame for Concrete Column design as reasonable work-arounds.

RE: Snow Load Bug in V17

Eric Feuge-Miller — Tue, 07 Sep 2021 18:20:45 GMT

Given this, would it be suggested to convert the gravity columns into lateral, releasing their end constraints to mimic gravity members, and using the member loadings in an external column design software to verify column designs?

RE: Snow Load Bug in V17

Seth Guthrie — Tue, 07 Sep 2021 18:16:30 GMT

The wiki confirms that the design modules would also be affected: https://communities.bentley.com/products/ram-staad/w/structural_analysis_and_design__wiki/33000/incorrect-snow-drift-loads-on-two-way-decks-in-ram-concrete