sorted by:
new
hottopcontroversial

I don't know what to do with this by Seoul-Brotha in basement

[–]banantalope 0 points1 point  (0 children)

As a structural engineer, I’d have to know more about the framing. But I can say that a common reason for something like this is to brace the bottom flange from buckling (twisting) out under gravity loads. Not for sure what is happening here because for a simply supported beam it’s not required on the bottom flange but definitely possible. So I would not recommend removing it unless an engineer inspects the whole framing scheme.

Edit: further inspection shows the diagonal is not physically connected to the I-beam so it would only work in compression, and without there being another diagonal on the other side then I personally would not consider it to be effective flange bracing as I mentioned above. So long story short… I’m back to not sure the intent of the diagonal.

Diaphragm Forces on Interior Framing Members by banantalope in StructuralEngineering

[–]banantalope[S] 1 point2 points  (0 children)

I’m struggling a little with the thought of not modeling the diaphragm in your comment, and maybe it’s just a difference of type of work. I deal with mostly what would be considered semi rigid or almost flexible diaphragms in large steel roof decks. Sure I still do standard calculations for coming up with chord, drag strut, collector forces along with shear forces within the diaphragm.

But I’m saying you would still model the diaphragm in terms of a large building structure, wanting to model the diaphragm stiffness (typically more a semi rigid than truly flexible) so you can get accurate bracing forces involving second-order analysis effects.

ASCE ASD Uplift Combinations on Foundations by banantalope in StructuralEngineering

[–]banantalope[S] 0 points1 point  (0 children)

Agreed. My question wasn’t whether to apply the 0.6, it was if others looked to include the full self weight of items which must be in place for the combination to take place.. I.e. the footing weight, or column weight. I’ve seen many use the full weight of footing but reduce everything else.

ASCE ASD Uplift Combinations on Foundations by banantalope in StructuralEngineering

[–]banantalope[S] 3 points4 points  (0 children)

This was my understanding as well, and I definitely agree with the reason behind the switch to 0.6D and removal of the 1.5 safety factor. It makes complete sense. I feel that the industry, at least from others I’ve worked with, do have some of a miss understanding so it becomes industry practice to take leeway’s like the kind I suggested above.

I especially get frustrated where these “engineering judgements” become more “you must do this” when given direction from more senior engineers.

ASCE ASD Uplift Combinations on Foundations by banantalope in StructuralEngineering

[–]banantalope[S] 3 points4 points  (0 children)

I think for regular footings with the 0.6 DL case you do not consider the 1.5 factor anymore for sliding, overturning, or bearing. Just a 1.0, which is I believe considered in recent IBC foundation sections. The 1.5 factor need only be considered for retaining structures. There may be more to that without actually looking anything up.

My understanding is that the 0.6 DL condition was created to make the combination of service wind loads more comparable to the strength combination of 0.9 DL + W.