How does Prokon calculate imperfection moments in slender columns?

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Discussion Overview

The discussion revolves around the calculation of imperfection moments in slender columns using Prokon design software. Participants explore the differences in imperfection moments about different axes for both braced and unbraced columns, questioning the underlying principles and calculations involved.

Discussion Character

  • Homework-related
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant expresses confusion regarding the calculation of imperfection moments in Prokon, noting a discrepancy between the moments about the x-axis and y-axis.
  • Another participant asserts that the imperfection moments should be the same for both axes at various heights of the column, suggesting a potential error in the software's output.
  • A later reply indicates that the asymmetry in the column's slenderness may explain the differing imperfection moments, as the column is rectangular.
  • Participants inquire about how to obtain the exact values for the imperfection moments and suggest that Prokon must adhere to specific standards and design rules.

Areas of Agreement / Disagreement

There is no consensus on whether the imperfection moments should be equal or why they differ. Multiple competing views exist regarding the calculations and the nature of the column's geometry.

Contextual Notes

Participants reference the need for design standards that Prokon may be based on, but there is no resolution on the specific calculations or assumptions made by the software.

dccd
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Homework Statement:: Anyone familiar with prokon column design ? I have no idea how the program caluculate the imperfection moment in the slender column (braced/unbraced...
Relevant Equations:: I have attached an example here , it's an unbraced slender column here. Why the imperfection moment about y-axis and y-axis arent the same ? X axis imperfection moment = 0.85kNm, while the y-axis imperfection moment is 4.41kNm,

[Mentor Note -- thread moved from the schoolwork forums to ME since it is a general question]

I think it's wrong, imperfection moment should be the same for both axis , at intermediate height, top , bottom of column, correct me if I am wrong. ...

https://we.tl/t-Fw9Tvf8fhL
 
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dccd said:
Homework Statement:: Anyone familiar with prokon column design ? I have no idea how the program caluculate the imperfection moment in the slender column (braced/unbraced...
Relevant Equations:: I have attached an example here , it's an unbraced slender column here. Why the imperfection moment about y-axis and y-axis arent the same ? X axis imperfection moment = 0.85kNm, while the y-axis imperfection moment is 4.41kNm,

I think it's wrong, imperfection moment should be the same for both axis , at intermediate height, top , bottom of column, correct me if I am wrong. ...

https://we.tl/t-Fw9Tvf8fhL
Can you just attach a PDF of that file? (Click "Attach files" below the Edit window) I'm getting strange notifications when I try to click on that link. Thanks.
 
berkeman said:
Can you just attach a PDF of that file? (Click "Attach files" below the Edit window) I'm getting strange notifications when I try to click on that link. Thanks.

Here you go ..The uploading speed was extremely slow when I was trying to upload the file.
 

Attachments

dccd said:
X axis imperfection moment = 0.85kNm, while the y-axis imperfection moment is 4.41kNm,
Because the column is rectangular, the slenderness is asymmetric, and so the imperfection moment is asymmetric.
 
Baluncore said:
Because the column is rectangular, the slenderness is asymmetric, and so the imperfection moment is asymmetric.
Do you know how to get the exact value
?
 
dccd said:
Do you know how to get the exact value ?
The Prokon design software must reference the standards and design rules it follows.
You should look for the design references on which the Prokon software is based.
 

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