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[Ganeshds]

Dear All,

We would like to have suggestion on subgrade modulus applying for design of foundations. In general the spring value mentioned in STAAD model is linear to the reaction on foundation model. But in general this is not, because the SBC of soil specified should have linear to the calculated settlement, there after it should be straight line.

Should any one has inputs on this point.

Thanks & Regards,

Ganesh

[AmitD]

You may use Multi-linear Spring option. Enter displacement and spring stiffness data pairs for a multi-linear spring definition, which can be used for a Fixed But support type.

[Ganeshds]

Thank you Mr. Amit for the input. We have already tried this. But this has some issues in analysis reported to STAAD with abnormal bearing pressures and moment values. They given reply as below for your information. We need to work as the SBC value calculated to the settlement will be constant after the displacement reached to the settlement value.

"
Multilinear springs for plate mat were not correctly used in your model"Model 2 - muiti linear.std". Please find the attached modified modelwhere this command is used correctly in the input file. Please ignore the errorwhich you will get while opening the model. Also, do not save the model fromthe GUI as this removes the spring data from the input file for some reasons.We will report these issues for the development team in order to fix it in theupcoming releases of STAAD.Pro.
"

[AmitD]

Thanks Mr. Ganesh. This type of structural modeling is really very interesting !!
May I request you to upload that input file here so that I can have a look into the matter.