Settlement Analysis in Midas Gen

Question:

Dear Midas Customer Online Support Team,

I have a few questions regarding settlement analysis in Midas Gen.
I sent 3 models with this message. The structural model is a raft foundation with point spring piles. 

The differenceS between them is the Group Settlement and Load Case Settlement.
First, the name is CASE 1 is with 1 Group settlement with 1 Settlement Load Case
Second, the name is CASE 2 is with 2 Groups settlement with 1 Settlement Load Case.
The last one, the name is CASE 3 is with 2 Group Settlement with 2 Settlement Load Cases.

The result of CASE 1 looks right. DZ value is the same as the settlement value on the nodes that I inputted before.
In CASE 2, I added another one Group Settlement (but still in the same load cases) then the result is DZ settlement value on nodes that I inputted become almost 0 (zero).
I try CASE 3. Still, consist of 2 Group Settlement like CASE 2, but each of Group Settlement has its Load Case. When I see the result of Settlement Load Case 1, DZ value on Group 1 is the same as I inputted before, DZ value on Group 2 became almost 0 (zero) and it is vice-versa when I see the result of Settlement Load Case 2.

What I want to ask are :
1. From certain things that I try, may I assume that it is best to do: 1 Group Settlement has its own Settlement Load Case? (e.g: 10 Groups Settlement with a different settlement value have 10 Settlement Load Cases)
2. If I have more than 1 Settlement Load Cases, how to combine the result from all the Settlement Load Cases? And combine it with other Load Case such Dead Load, Live Load etc.?

Thank you very much for your help.
Please let me know if you need information about my questions.

Best Regards,





Answer:

Hi,

Regarding your query, 
Case 2. You said, " the result is DZ settlement value on nodes that I inputted become almost 0 (zero)."
According to the image CASE2.png, the wrong load case was selected. SMmin should be selected instead of SMmax.

Case 3. You said, "When I see the result of Settlement Load Case 1, DZ value on Group 1 is the same as I inputted before, DZ value on Group 2 became almost 0 (zero) and it is vice-versa when I see the result of Settlement Load Case 2." 
Settlement load case 1 (S1) should show the displacements of the structure when settlement group 1 (S1=760) is settled down by 76 cm. So, the displacement of group 1 is -76 cm, but the displacement of group 2 is zero because it is far enough from the group 1 nodes.
Likewise, Settlement load case 2 (S14) should show the displacements of the structure when settlement group 2 (S14=500) is settled down by 50 cm. So, the displacement of group 2 is -50 cm, but the displacement of group 1 is zero because it is far enough from the group 2 nodes.

Your queries:
1. From certain things that I try, may I assume that it is best to do: 1 Group Settlement has its own Settlement Load Case? (e.g: 10 Groups Settlement with a different settlement value have 10 Settlement Load Cases)
It is not necessary. If you assign 10 groups to one settlement load case, just like case 2 in your test, the settlement analysis will find the envelope of 10 settlement groups.
2. If I have more than 1 Settlement Load Cases, how to combine the result from all the Settlement Load Cases? And combine it with other Load Case such Dead Load, Live Load etc.?
I don't understand what you mean by "combining the results from all the settlement load cases", but I think you need the envelope of all different settlement groups. If so, the way of case 2 (different settlement groups with one settlement load case) of your test will provide the envelope.  In this way, you can also combine the envelope with other type of load cases such as dead, live loads.

Regards,
DK Lee



Creation date: 6/21/2019 2:21 AM (dklee@midasit.com)      Updated: 6/21/2019 11:52 AM (dklee@midasit.com)
Files   
CASE 1.png
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CASE 2.png
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Env. Service.png
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Settlement Analysis.zip
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