Bending capacities for Single Angles designed as per CSA S16-09 or CSA S16-14 are being calculated incorrectly by STAAD.Pro. This error affects flexural capacity calculation for both equal and unequal angles.The CSA S16-09 and S16-14 specifications, does not provide specific guidelines on the determination of the bending capacity of single-angle sections. In absence of such guidelines, STAAD.Pro uses corresponding expressions from Clause No. F10.2 of the AISC 360-05 (for CSA S16-09) and AISC 360-10 (for CSA S16-14) codes, for the evaluation of the bending capacity of single angle sections. However due to a coding error, the expression was improperly implemented in the program, due to which the bending capacity was being over-estimated leading to an unconservative design of single angle sections.
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Workaround
No workaround is available as of now for this defect.
Solution
The defect is being addressed and a fix will be available in the upcoming STAAD.Pro CONNECT Edition V22 Update 5, scheduled to be released during the fall of 2020.