Ram Elements Wood Design Repetitive Member Factor Cr

I am using spaced wood sections defined by your Leo SPCa.leo.  There is one section in the standard United States group and we added several sections to a custom group for our office.

Our sections typically use 4 combined members.  The members are typically 2x12's.  So, we would have (2)2x12's nailed together with a space of 5.5" and another set of (2)2x12's on the other side.  The total width of the beam-column is 11.5".  These sections have bending in the major axis and axial stress.  I have attached an Output Report for a beam-column  that has a total of (2)4x12's and (2)2/12's as one example.

The program has a check box to apply the Repetitive Member Factor Cr in the Wood Design Parameters.  The output shows that the member is a repetitive member under the heading "DESIGN CRITERIA", but the section "DESIGN FOR FLEXURE" for M33 shows Cr = 1.00 instead of 1.15.  I checked the box to use 1.15.  Why is Ram Elements ignoring this factor?

On another note for the same type spaced sections using SPCa.leo, the program will let me set Lu, but the spreadsheet tools will not assign Le.  The error message says it only works for rectangular or circular sections.  Why?

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  • The help topic for Cr indicates it only applies to dimension lumber (e.g. S4S) which is probably why it's not being considered here. 

    Repetitive Member

    This flag can be applied to joists, truss chords, etc. which are in contact or spaced not more than 24" on centers and fulfill the conditions specified in Section 4.3.9. of the Specifications.

    This parameter defines the value to be used for the repetitive member factor (Cr) for dimension lumber.

    You could possibly modify the .leo to force the program to consider your section as dimension lumber. I think it's the line that says FORMULATION='LUMBER' that matters here (vs. 'GLULAM')



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  • The help topic for Cr indicates it only applies to dimension lumber (e.g. S4S) which is probably why it's not being considered here. 

    Repetitive Member

    This flag can be applied to joists, truss chords, etc. which are in contact or spaced not more than 24" on centers and fulfill the conditions specified in Section 4.3.9. of the Specifications.

    This parameter defines the value to be used for the repetitive member factor (Cr) for dimension lumber.

    You could possibly modify the .leo to force the program to consider your section as dimension lumber. I think it's the line that says FORMULATION='LUMBER' that matters here (vs. 'GLULAM')



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