warping constant, h for lipped sections
 

warping constant, h for lipped sections
i am trying to do a spreadsheet to design a purlin section made of a back to back cold formed lipped channel and cold formed lipped angle. i need an expression for the warping constant (h in mm6) to do the calc. i have a reference which gives an expression for this for built up i sections but not for my particular case. can anyone help?
carl bauer
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thanks 0404,
that's a great little program and it answered my question but i am still concerned that i don't know the theory behind it. can anyone point me to a reference?
carl bauer
carl,
the reference "design of cold-formed steel structures" by prof greg hancock is a good one, with a balance between theory and design.
it used to be available from the australian institute of steel construction, but my copy is dated 1988.
i am not sure exactly what you want in terms of "reference" but a book that describes the two components of torsion - uniform and non-uniform torsion - of steel structures should describe warping torsion and the derivation of the warping section constant. one good reference is "bahaviour and design of steel structures" by trahair and bradford - thinned walled sections are detailed in a chapter without too mnay differential equations.
hth
formulas for stress and strain by roark & young, 5th edition has the formulas for warping coefficients of many types of sections in table 21 of chapter 9.