Axial load capacity of C-purlins
Axial load capacity of C-purlins
(OP)
I know C-purlins can buckle and so can't officially take vertical loads.. but I'm wondering how to compute for it's buckling and the axial load the top of it (2 meters vertical height) can theoretically take.. assume the purlin is 2 inches by 4 inches in size and 0.07" thick (1.8mm).. would it be able to take say 40 lbs of weight or 20 lbs for its 2 meters vertical length? How to compute?






RE: Axial load capacity of C-purlins
RE: Axial load capacity of C-purlins
C-purlins are not wide flange or tube, they are not strictly HSS (Hollow Structural Sections).. how do you compute for the buckling of C-purlins.. what is the common formulas used?
RE: Axial load capacity of C-purlins
For example:
RE: Axial load capacity of C-purlins
RE: Axial load capacity of C-purlins
Computations of capacity of light cold formed sections is very complex, and won't be explained easily here. In addition to computation, these systems are usually load rated by full scale testing by manufacturers like Stramit.
RE: Axial load capacity of C-purlins
Link
How many designers out there take advantage of this? What are your analysis and design methods? Interested to hear the responses.
RE: Axial load capacity of C-purlins
RE: Axial load capacity of C-purlins
I understand Kliplok would be rubbish for in plane stiffness.
EDIT: Seems as though Lysaght calls up use of sealing washers, this should do the trick - right?
RE: Axial load capacity of C-purlins
Valley fixings are sometimes used on wall sheeting.
If using roofing for diaphragm action were acceptable practice, I think the US preengineered metal building companies would do it, but they don't.
RE: Axial load capacity of C-purlins
@Hokie, I have a seen a couple PEMB's in the past that used diaphragms instead of rod bracing.
RE: Axial load capacity of C-purlins
RE: Axial load capacity of C-purlins
RE: Axial load capacity of C-purlins
Don't recall, but it was probably 50x100. I have a sheet from Butler (a major PEMB manufacturer) somewhere that shows the diaphragm capacities of their roof. If I find it, I will scan it.
RE: Axial load capacity of C-purlins
Without discrete bracing, there are a lot of practical (and safety) issues to consider during erection. Spare a thought for the installers.
RE: Axial load capacity of C-purlins
RE: Axial load capacity of C-purlins
What would happen if a beam is supported by many vertical supports below it.
RE: Axial load capacity of C-purlins
Standing seam panels, which may or may not have much in the way of diaphragm strength, can be tested through the same AISI protocols, however there is no calculation based method for those panels. The strength of the standing seam panel is in direct relationship to the tightness of the mechanically formed seam. Snap together or hand-seamed panels are not logical for diaphragm strength.