Patterning (skip loading) of Live Loads in RAM

Question

I have been doing some extensive reading on these forums and in the help but still don't have clarity, so please help me with a few questions: 
 I am modeling a 4 story reinforced concrete moment frame in RAM and then will export the model to RCDC (Advanced Concrete) after running RAM Frame and RAM Concrete. I am using Indian Standards. 
 
 It appears load patterning (skip loading) is not done for roof live loading (nor in RAM Frame). I would like load patterning to still be implemented at the roof level. Is there any downside to using Live Load - Reducible instead of Live Load - Roof at the roof level? I will be using Indian Standards and LLR includes the roof as one of the floors that is counted. 
 RAM Concrete has an Analysis option that reads "Consider Load Polygons as Load Cases on Two-way deck (for pattern loading). However, the documentation also says that "Currently, the surface loading applied to two way decks does not generate any skip loading cases on beam lines". What does this Load Polygons option do? Ideally load patterning would have been done from the Surface LL (yes I know this is complicated), but since I read the second note about it not applying to two-way decks, I have resolved my surface LL to line loads. Is there a way to get patterned live load from a surface load using this load polygons option? 
 RAM Frame apparently does not use skip loading. What are the gravity loads in RAM Frame used for? 
 
 Thank you for your time. 
 Regards, 
 Dan

Seth Guthrie · Accepted Answer

It is a fairly complex topic, and we do different things in each module as required for the properly design of the parts. 
 Ram Steel beam - in this module, we are evaluating individual beams. For beams with cantilevers, the live loads (acting downward) in the cantilever are part of the Negative LL case, those on the back span are part of the Positive LL case and we consider the patterns. This wiki will help: https://communities.bentley.com/products/ram-staad/w/structural_analysis_and_design__wiki/16742/ram-steel-beam-pattern-loading 
 Note, this is true for all kinds of live loads, including Roof ro Snow. An enhancement to to 50% patterns for Snow is on the backlog. 
 In Ram Steel Column we do another kind of patterning of live loads. We look at the beam reactions on each side of the column (top and bottom) and adjust the axial loads and unbalanced moments for these patterns. Then determine which condition leads to the most conservative design. See also: https://communities.bentley.com/products/ram-staad/w/structural_analysis_and_design__wiki/2055/ram-steel-columns-faq 
 In Ram Frame our model is of the lateral skeleton only. The gravity beams provide point load reactions and brace points but are not in the finite element model. So it is the point load reactions that we consider as Positive Live loads (acting downward on the frames) or Negative Live Loads (acting upward). The back-span reaction of a beam with a long cantilever is the common example of a Negative LL in Ram Frame. 
 In Ram Concrete analysis our model is of each floor including every beam and if skip-loading is turned on then the live load of each beam is a separate load case. We then calculate the envelope the results of all these loads to determine the greatest positive or negative bending effect on each concrete beam we design. 
 I would never recommend to use the polygon pattern option in Ram Concrete analysis. It's contrary to what we do elsewhere in the program where the rule is "only the top load polygon counts".

Patterning (skip loading) of Live Loads in RAM

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