Technical Booklet D Structure·Page 36·4B.13
Rafter and purlin sizing for unequal spans
When dimensions A and B are not equal, the rafter should be sized for the greater dimension; for continuous purlins with unequal spans, size for the longest span.
When the dimensions A and B in Diagram 4B.5 are not equal the rafter should be sized for the greater dimension. Where the purlin is continuous over an intermediate support and the spans are not equal the purlin should be sized for the longest span.
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