topic Re: Soil Reactions are 50% of applied load in Robot Structural Analysis Forum

Soil Reactions are 50% of applied load

keith483GL — Wed, 19 May 2021 10:05:35 GMT

I am attempting to model an uncommon situation with a ground bearing slab. To get to grips with how ROBOT models soil support I have a set up a simple model to test it is working as I wish.

I have encountered a problem in that my applied UDL panel load of 30kN/m^2 is resulting in a soil reaction of 15kN/m^2.

I have checked the reactions table. It is telling me that the values add up to 180kN, whereas they should add up to 360kN. The slab area is 2m x 6m, so (2 * 6 * 30) = 360kN.

Does anyone know why this is and how to resolve it?

Thanks,

Keith

Re: Soil Reactions are 50% of applied load

Krzysztof_Wasik — Wed, 19 May 2021 11:06:56 GMT

Hi @keith483GL

Could you share your model for verification?

Re: Soil Reactions are 50% of applied load

keith483GL — Wed, 19 May 2021 11:29:34 GMT

Hi Krzysztof,

I have tried to drag and drop the model file, but it is coming up with an error.

Am I doing something wrong?

Thanks,

Keith

Re: Soil Reactions are 50% of applied load

Krzysztof_Wasik — Wed, 19 May 2021 11:35:03 GMT

Hi @keith483GL

Save model as RTD without results and zip before sharing.

Re: Soil Reactions are 50% of applied load

keith483GL — Wed, 19 May 2021 11:49:49 GMT

Hi @Krzysztof_Wasik

I hope this works.

Re: Soil Reactions are 50% of applied load

HoshangMustafa — Wed, 19 May 2021 13:13:35 GMT

Hi @keith483GL

Please find this fthread:

https://forums.autodesk.com/t5/robot-structural-analysis-forum/tables-sum-of-values/m-p/3347985

Re: Soil Reactions are 50% of applied load

Krzysztof_Wasik — Wed, 19 May 2021 13:41:45 GMT

Hi @keith483GL

You have duplicated supports

1- support is defined in thicknes definition (elastic soil parameters)

2.- support is defined as planar support

They should not be used together. Remove planar supports . Then slab will be supported by elastic soil defined with slab thickness and results will be as expected.

Re: Soil Reactions are 50% of applied load

keith483GL — Wed, 19 May 2021 15:30:36 GMT

That's sorted it @Krzysztof_Wasik

Thanks for your help and assistance.