Allowable Axial Load in Purlins

[Chris Achilles]

I recently had to prove a roof with bracing missing at one end was acceptable to BS5950. The loads were small so it only required the purlins to take a nominal amount of wind load down the roof to the braced bay at the other end. I remember using a clause about 20 years back which stated that you could carry 5n/mm² of axial in the cold rolled purlins without any other detailed checks. When I tried to find this it appears to have gone from the later versions of the code. Does anyone remember this clause or is old age getting the better of me, was it just a dream, or is it still knocking around somewhere?