Multilinear springs - how to define them properly

Hi,

I'm working in STAAD.Pro V8i

I need to define a support with the following:

FX  - multilinear spring

FY - fixed

FZ - multilinear spring

MX - fixed

MY - fixed

MZ - releazed

So far I successfuly used "FIXED BUT" with Linear springs for FX and FY where I defigned KFX and KFZ as 16666kN/m but when I tried to define a multi-linear spring I could not assign it and it was not recorded in the file.

'Help' topic on this subject is not very clear. Could I assign Multilinear Springs in such way that they will substitute previously defined KFX and KFZ or 'FIXED BUT" and "Multilinear Spring' do not work in conjuction at all? Than, what degrees of freedom actually got assigned when I use 'Multilinear' ?

Could you, please, help me with this problem?

Thank  you,

Len Bogdanov

 

Parents
  • Dear Team,

    Apparently, this topic does not initiate a lot of interest but I'll try again; let me tell you about my 'achievements' sofar...

    I assigned MultiLinear Spring(s) "on top" of "Fixed but" supports (FX and FZ) and they do work (thou the pictograms at supports changed to old-style rectangles).

    To run analyses I had to erase "P-DELTA 33 ANALYSIS" and put "PERFORM ANALYSIS" instead.

    Statements in the 'run' sequence:

    "++Re-analyzing for bi/multi-linear spring support"

    and

    "++bi/multi-linear spring converged. Iters = (number of iteration)"

    convinced me that mulilinear spring are legitimate and considered in the analyses.

    My next question is: Can I put for each lateral spring both positive and negative deflections?

    I need it because the Pile head can deflect both +FX and -FX as well as +FZ and -FZ

    Than, 'k' values would decline symmetrically at both positive and negative side of the curve and the spring would fully and more realistically represent pile behavior.

    Thank you in advance

    Best Regards,

    Len

Reply
  • Dear Team,

    Apparently, this topic does not initiate a lot of interest but I'll try again; let me tell you about my 'achievements' sofar...

    I assigned MultiLinear Spring(s) "on top" of "Fixed but" supports (FX and FZ) and they do work (thou the pictograms at supports changed to old-style rectangles).

    To run analyses I had to erase "P-DELTA 33 ANALYSIS" and put "PERFORM ANALYSIS" instead.

    Statements in the 'run' sequence:

    "++Re-analyzing for bi/multi-linear spring support"

    and

    "++bi/multi-linear spring converged. Iters = (number of iteration)"

    convinced me that mulilinear spring are legitimate and considered in the analyses.

    My next question is: Can I put for each lateral spring both positive and negative deflections?

    I need it because the Pile head can deflect both +FX and -FX as well as +FZ and -FZ

    Than, 'k' values would decline symmetrically at both positive and negative side of the curve and the spring would fully and more realistically represent pile behavior.

    Thank you in advance

    Best Regards,

    Len

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