Recent content by lordvon

Agreed. This was a few years ago. I could easily replicate it... And of course there is always the possibility i did it wrong and/or interpreted the results incorrectly.

yes i am familiar with buckling, and i mentioned it here in earlier posts. the failure i observed was not due to buckling.

well, agree to disagree then. thanks for the input.

I actually agreed with you at one point. But I did the experiment I described to you in the previous post and got the result that leads to my belief now. Also I believe that the longitudinal shear has to be transmitted throughout the cross-section somehow. But I am happy to be proven wrong.

hmm? joints can definitely be discussed in isolation. how can the weakest link be "not important"?

i think you do not understand that longitudinal shear (by which the moments manifest in a cross section) cannot be transmitted between 2 separate plates.

haha, i was going to cite this example to convince you of the opposite, but somehow you are further convinced of what i believe is the incorrect view. why dont you try this out in an experiment? Get a tube, then get 2 plates and set them apart a distance such that the formula you are using gives...

oh, my mistake, I meant thickness of one plate. but, my point still stands. e.g. (H^3-h^3) is much greater than 2 * thickness^3.

When you say "do not require a web" are you saying the gussets arent the weak point? If not, wouldn't the web (if it could somehow be applied) make the strength of the joint more similar to the beam?

No, that is still incorrect. That formula implies longitudinal shear going through a cross section that is H in height. But, for disparate plate cross sections of height h, the longitudinal shear is only going through a cross section of height h, in 2 plates. Do you understand what I am saying?

well, the question really is how do you calculate the stress in these plates (or geometric instability / buckling limit). so that one can determine the right size/thickness of plate. we can be certain though that the gusset plates cannot be treated as an i-beam.

Unfortunately, that is incorrect. There must be a transfer of longitudinal shear through the section, and in the case of separated plates, that cannot happen. In the I-beam it does happen. If the two thin plates are indeed to be treated separately (this is part of my question), you must use the...

yes, this is what i am trying to get at. the gusset plates could be acting as mere thin plates (that might buckle) in bending, which would be by far the greatest weak point @Baluncore

Isnt the weakest point in between the beams, where there is only gusset plate in the cross-section?

Thanks @jack action, this is what I hoped it would be, but it seems too good to be true. The reason I say that is that the gap between the beams containing only gusset cross section differs from the I-beam in that it is missing the vertical center flange / web. So is it really as strong as an...