Applies To
Product(s):	AutoPIPE
Version(s):	ALL;
Area:	Loads
Date Logged & Current Version	Aug 2022 12.08.01.010

Problem:

"Once a RS is assigned to the program, can different support groups access a scaled version of the RS without counting toward the limit of 50 RS per model?

As an example:

This would mean that support group 1 could be assigned to some RS1 (leaving 49 more RS definitions open) and support group 2 could be assigned to 0.9 x RS1 using the Response Spectra input box in the program. In this way, two support groups access one response spectra definition."

Solution:

The answer to this is yes. As an example:

Input data for a response spectrum. The response spectrum defines the ground motion response of the earthquake and will be assigned globally to all points in the model in a specific direction, by the user. BUT it can also be scaled (see below).
Insert support groups.
1. Select point(s) to be included in a support group. The support(s) in this group will have the same response spectrum and scaling applied. There is a limit of 20 support groups per SAM case. There is a limit of 10 SAM cases.
2. Click Insert > SAM/MSRS Support Group.
3. Repeat for other support group assignments.
Create Response Spectrum case.
1. Click Analysis > Dynamic Analysis.
2. Click New.
3. Check on MSRS and SAM case. Here you are limited to a single SAM case for each response spectrum case. So you can only include the 20 support groups of a single SAM case in a single Response Spectrum case. Then click Define.
4. Define the response spectrum to be applied to each support group in each direction. Keep in mind that you can scale these here. As an example, below NRCH2 has a factor of 1 applied for Support Group 1 but a factor of 1.5 for Support Group 4.

This is the process but as you can see, you are still limited to 20 support groups being considered in a single response spectrum load case. Generally, each individual support is not considered as a single support group. Rather, we commonly see supports attached to the same floor or having some commonality grouped. So that is an option. Another option to expand this number is to create additional SAM cases (each with up to 20 support groups). And you can set up additional Response Spectrum Load Cases with all settings the same but including SAM Case S2 with R2, S3 with R3, etc. Then the results of these could be combined to get to a total system response. Example below:

My R1 case is including all Support Groups of S1. I have broken this out into R2 through R5, each considering a single support group. I will combined the results once it is analyzed.

After analysis, in the Load Combination dialog on the Code Combination tab, I see my Sus. R1{1} combination which will give me my total response. I want to match that by combining my R2 through R5 cases. So first I create a Total R case using SRSS because that is how the groups are being combined in the single R1 load case (can be seen in the Dynamic Analysis dialog above).

Then I combine this with Sustained.

When I review the code stress results in the Result Grid, we see these are matching.

So in theory, I could have 10 SAM Cases X 20 Support Groups X 50 Response Spectrum Load Cases = 10,000 response spectrum loads applied.

06. Can different support groups access a scaled version of the RS without counting toward the limit

Problem:

Solution:

See Also