Panel support reactions

[M_Nahle_00]

Hello Everyone

I have this model where I applied soil load to the basement walls. I noticed that most of the reactions at panel supports are negative. Is it normal? I had negative reactions at the columns connected to the walls but I applied linear releases which made most of the reactions positive (except one I guess). So my questions are:

1- is the linear releases principle correct here?

2- What about the negative reactions in the panels?

3- When soil load is applied I notice huge displacement in the slabs in horizontal directions. Is this correct? and how to overcome?

Thank You

[Simau]

@M_Nahle_00 

1- is the linear releases principle correct here?

No, in the real world walls and columns are linked. What you can do is to delete columns nested in the walls, you don’t need them in the basement.

2- What about the negative reactions in the panels?

 This is normal, uplift is created by global bending moment due to the soil horizontal load

3- When soil load is applied I notice huge displacement in the slabs in horizontal directions. Is this correct? and how to overcome?

In the attached model (whithout releases) horizontal displacements are not so big. What range do you expect?

If however you want to decrease them, add 2 shear walls in Y direction at the left and right side

[M_Nahle_00]

Thank you simau

1- if i delete the columns in the basement how am i supposed to get the reaction for this particular column? (What steps to follow in robot)?

2- I know it won't make a huge difference in this model but for higher buildings the column should be the element carrying the axial load  not the wall. I won't be designing the wall for axial load.

3- In a previous model I had 3cm Ux displacement for the slab when applying soil loads. Adding shear walls makes sense but isn't 3cm huge for horizontal displacement (generally speaking)?

Regards

[Simau]

I was referring to your model where axial force in the column is not huge. In this case the effort will diffuse in the wall and you'll only have to design a strip footing. Obviously in case of high rise building, the columns must be kept

Isn't 3cm huge for horizontal displacement (generally speaking)?

Difficult to say without the concerned structure