Exclude some load cases in envelope?

[larcix]

Simple question, I know I can disable some load cases for design operations, this is good, but I also don't want to see those same load cases in my envelope results. Unfortunately, I have found no way to do this.

There is an option when running the analysis to "Envelope (only) of Marked Combinations" but this actually just solves all the LC's and throws away the individual LC data, giving you only the envelope.

I can either turn off those load cases entirely, make a new model without them, or dig into the individual LC results to find the real numbers I need. I wish there was a better solution.

Thoughts? Thanks!

 

[Maslov]

It sounds like you want to use "Batch Solution of Marked Combinations". This will solve all marked LCs, and it allows you to toggle between the filtered envelope and the entire LC batch:

 

[jayrod12]

Agreed with the above poster. Have the solve box checked for the LCs you want to run, and not checked for the remainder, choose batch solution and ensure include envelope is checked. That will give you all the LC results for the chosen cases, and also an envelope.

 

[larcix]

I meant to state in my OP that I always use the Batch Solution, which is explicitly not a solution to my request.

Batch includes all calc'd LC's as well as an enveloped solution. So if I want to run all of my 1.0D, 1.0L, 1.0S, 1.0W, 1.0E, 1.0Ice, etc load cases, those are always included as part of the envelope, even tho I can turn them off while designing, it always includes them in the envelope. This is not an issue when designing with LRFD as 1.0 loads will never control and never be the max for the envelope, but for an ASD analysis, 1.0W and 1.0E will ALWAYS control over [1.0 or 0.6]D ± 0.6W.

The next most common suggestion may be to review the BLC outputs if that's all I really wanted, but A) I don't think you can do that, it has to be a load combo, and B) I only have Wx and Wz in BLC's (Standard modeling), not the other 10 directions, so I need the LC's setup to run all the analyses ([1.0,0], [0.877,0.5], [0.707,0.707], etc.).

So, back to the last paragraph of my OP, the only ways I can see to do this is that I have to turn off those 1.0LC's whenever I want to see real envelope results.

EDIT: Apparently I cannot edit the OP anymore, weird forum policy.... So I can't reference the OP back down to this post. Anyways, I'm pretty sure there is no way to be able to run a single analysis to show all the info I want, even tho we are SOOOO close, it's just not something the programs allows. Wish it just had envelope follow the Use For Design checkbox, that's all I would need to happen.

 

[jayrod12]

Maybe I'm mis-understanding, but you don't have the option to turn solve off for the load combos you don't want included? Or does the program include those cases even if the solve box is unchecked?

 

[Maslov]

It sounds like you may want to transfer your data over to a spreadsheet. That way you can add the data for every LC and filter them as you see fit.

I don't know why exactly you want to exclude certain cases from the envelope. Non "control" cases like 0.6D±0.6W are for checking sliding and overturning, so I like to check them individually.

 

[larcix]

Maybe I'm mis-understanding, but you don't have the option to turn solve off for the load combos you don't want included? Or does the program include those cases even if the solve box is unchecked?

Oh yes, you can turn off any load combo you don't want run, but I do want all load cases run, otherwise I wouldn't have included then, what I don't want is to see all of the results from all load cases included in the envelope results.

Thanks everyone for the suggestions, but I've come to the conclusion there is no easy/automatic way of doing this, but maybe with a more thorough explanation someone might have some clever idea:

The reason for this is that while RISA can complete many designs pretty well, it can't do everything, and depending on what program or spreadsheet you need to use the results from RISA in, that software may either want 1.0 loads from each of the dead/live/snow/wind/EQ/etc loads, or it may want the max design load combo reactions. I haven't found a way to easily and consistently setup a model that allows you to get max load combos if I want AND 1.0 load combos if I want -- I either need to edit which combos run, make an alternate model, or do all the combo work in a spreadsheet. What bugs me about this, and why I made this post to begin with, is that the software is SO CLOSE to doing this for me, all that needs to happen is for envelope to also ignore the LC's stated as not to be used in design. It already knows which LC's should be ignored for design, but envelope isn't design, it's envelope, so I totally understand why it includes all LC's in the envelope, I just wish there was a checkbox in the options or in the analysis run somewhere that asks if I want to include or exclude bypassed LC's in envelope as well.

Again, thanks for taking the time to try and understand my question/request, as I clearly haven't fully explained myself very well.

PS: The extra annoying part is this isn't even a problem in LRFD, as the max envelope reaction will always be greater than 1.0 loads, but in ASD, W and E have reduced load combo factors, so when 1.0 wind or earthquake run, they always control uplift and will even control compression if the dead load isn't as large as the reduction in wind or seismic forces.

 

[larcix]

It sounds like you may want to transfer your data over to a spreadsheet. That way you can add the data for every LC and filter them as you see fit.

I don't know why exactly you want to exclude certain cases from the envelope. Non "control" cases like 0.6D±0.6W are for checking sliding and overturning, so I like to check them individually.

I have a gnarly spreadsheet that does dig into RISA and pulls out the specific loads and load combos I want, but if I want to quickly grab the maximum reactions out of that same model, I need to disable 1.0W and 1.0E so they don't accidentally control, as they are not "real" load cases in ASD. It would be nice if I could just take my LC's 116 to 157 for all of my 1.0 loads, one load combo per load type, and then envelope all the other LC's from 1 to 115, which are all my actual ASCE combos.