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Roof Live Loads vs. Snow Loads RAM SS

sbouvia
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Has this been done yet?

6) Snow Loads versus Roof Live Loads

Within the Criteria -> Member Loads menu in RAM Manager there is an option to consider either roof live loads or snow loads during the gravity analysis of the structure. Currently it is not possible to consider both types of loading simultaneously. Later this year (2010) this limitation will be removed.

I read this on Josh Taylor's blog and I was wondering if this had been added to RAM SS yet?

http://communities.bentley.com/other/old_site_member_blogs/bentley_employees/b/josh_taylors_blog/archive/2010/01/20/ten-inputs-worth-a-second-look-in-ram-structural-system.aspx

  • in reply to Seth Guthrie
    Ah, yes, I can see that being an issue. At that previous company, we set up the program from the beginning with a very open structure for load factor variables and combinations, so that we could easily add new load combinations with different factors for revised building codes, and save custom combinations for oddball cases or testing. I've done some peer review since then for colleagues at another company that had load factors hard-coded, and the switch from ASCE7-05 wind to ASCE 7-10 was particularly frustrating as they had to scale their input loads to get IBC 2012 results with IBC 2006 factors until they got their software updated. Good luck.
  • A related comment: RAM SS Beam module does not handle Canadian (NBCC) load combinations properly where live loading and snow loading are combined. The NBCC combination would be 1.25D+1.5L+0.5S or 1.25D+1.5S+0.5L, whichever governs. RAM SS incorrectly calculates the combination as 1.25D+1.5L+1.5S.
  • in reply to Andrew Seeton
    Indeed, in all the LRFD based codes we include all the live loads including roof and snow at the higher factor. Most beams only support one type or the other, but for those that support both it can be conservative. This is an existing enhancement request in our system: Enhancement 120493: Load Combinations and Enhancement 178253: Allow Snow and Roof Live loads (and combinations)



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    Any more updates on timeline for this? We also run into cases where we have live loads and snow loads applied to a balcony. This isn't a big deal in low snow areas, but leads to some headaches when you're consistently seeing high snow loads.

    Is there even actually a plan to fix this? OP posted stating the original timeline was 2010 and now 7 years later we haven't seen the fix...

  • Offline in reply to Nulukkizdin

    Unfortunately this annoying limitation is still in the same situation as it was 7 years ago. With limits on resources we have had to focus on more critical items such as Code updates and more advanced analysis, design, and reporting capabilities such as Diaphragm cross section forces and Construction sequence analysis, to name just two. We recognize that we need to modify the program to provide for both Roof and Snow loads, as well as Wind uplift. A surprising amount of work due to the complexity of the surface load distribution and load tracking algorithms. We actually started work on them, but had to divert the resources to something more critical. So while we recognize the need, I can't even guess when we will be able to implement those changes.

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