From EN 1994-1-1
220.127.116.11(4) If the plastic resistance moment exceeds 2,5 times the plastic resistance moment of the steel member alone, additional checks on the adequacy of the shear connection should be made at intermediate points approximately mid-way between adjacent critical cross-sections.
What additional checks mentioned in this article?
First of all those kinds of connections are considered to be shear only connections (if their bolts are not preloaded), thus once should not use these for cantilever applications, by which I mean not cantilevering the long beam in the direction perpendicular to the fin plates which make up the connection but rather parallel to them (in the direction of uniformly distributed loads). Besides of that the two plates should not exhibit a lot of torsion from the long beam cantilevering out perpendicular to the plates, because of their low stiffness in torsion - they will make up a moment by two opposite reactions to fix the long cantilever beam. To get the exact value of torsional moment in every plate you should do FEA.
I have a bit of an unusual situation. So, in reality I'm designing some stairs in which the flights/landings cantilever off of columns in the central well of the structure.
All sections of the structural members will be hollow section (beams and columns) and the senior engineer doesn't want to use hollo-bolts or anything similar.
His suggestion for the connection is illustrated in the picture attached.
My concern is, this thin plate connection would need to resist bending plus torsion, would it be any effective in doing so? Or am I overthinking it?
If you have any suggestions on how to design the connection and make sure it works as intended that would also be great!
Hello once again.
I am designing a crane bridge girder with capacity 10T, span 12m and running on bottom flange (1st time) according to CMAA74.
It will be box section made from joining plates.
I have made the calculations for the global and local stresses, as well as checked the combinations.
But I have doubt, when shall we use the intermediate stiffeners (diaphragms).
Section 18.104.22.168 tells the requirements when
h/t>240/(tau)^0.5 and buckling stability requirements as per section 3.4.8 are not satisfied.
I am not able to interpret the section 3.4.8; My interpretation for section 3.4.8 is as follows (please correct me)
"If ϑB>DFB, then no stiffeners (diaphragm) are required."
I have tried many combinations with many load cases(with comp and shear stress close to their allowable limits), but never found the requirement for stiffeners according to section 3.4.8.
Please do reply.