Steel Beam with Opening Failing but Report & Interaction is OK

Question

Hello, 
 Someone in our office has a building model and has been checking beams with web openings. On one beam in particular, the report does not indicate the beam is failing, but the view update and heat map both show D/C ratio is exceeded. I deleted the opening and the beam is adequate without the opening, so something about the opening is causing the beam to fail but the report does not indicate what is causing this failure. I also changed the opening to be 6" in diameter and then the beam passed. 
 
 I have attached screenshots of the beam in question. 
 
 PDF

Seth Guthrie · Answer

For the case I saw recently the details are below. If the same situation does not fit your case let me know. 
 Version: 17.01.01.05 
 Strength ratio indicates something greater than 1 (e.g. 1.20), but there are no warnings and nothing in the design report looks like a problem (that I see). 
 
 The failing interaction should not have been included in the list of interaction checks. There is an exemption for checking tees for buckling capacity strength when the tees have an aspect ratio less than 4. Tees in the beam met this exemption, however the they were still checked for strength and one tee did fail the strength check&hellip; So we have a situation where an exemption masked a real strength check. 
 Since the tee was not to be considered for a buckling strength check, there was no need to include its ratio in the list of interaction ratios considered in determining the worst interaction. 
 The messaging did not flag the warning because it wasn&rsquo;t required but the method for looking up the worst interaction considered it when it should not have. Alternative, wherever the check was made, there should have been a recognition that the interaction was not needed and set appropriately so that the interaction did not matter at the end of the design process. 
 Will be corrected in the next update.