Flange-to-flange beam splice

[bugbus]

I have a situation where there will be two steel beams bolted flange-to-flange and subject mainly to in-plane bending, the intention is to create a full moment splice.

Does this kind of steel connection have a name? And are there any design guides or papers that discuss it?


Are there any peculiarities for this kind of connection I would need to consider?

Designing the connection to achieve section capacity is straightforward enough. But what about LTB considerations? Would this need web stiffeners to maintain torsional stiffness through the connection similar to below? I appreciate this probably heavily depends on the loading and support arrangement, but general advice would be great.



Appreciate any insights, thanks all

 

[CJLCivilStruct]

Interesting. I suppose there's an argument to be made that there's a composite section mid span which would actually increase the LTB capacity. However, it's making sure the connection is sufficient to be confident in this behaviour. I would include stiffeners as shown in the second image to limit flange bending and maintain as much stiffness as possible. Would also potentially also include bolts across the entire splice at increased centres. Although, I'm not quite sure what numbers I'd run to prove all this so this response is probably no help at all!

 

[KootK]

1) I've no idea of the name.

2) One complexity that might be worth be considering is prying action amplifying the bolt group tension. Unless there moments on either end of the joint are identical, it may be the case that the tendency for the beams to push together between bold groups outweighs their tendency to pull apart.

3) I definitely like the stiffeners. Single pairs might do if their only purpose is to keep the cross section from distorting in torsion.

4) If at all possible, I would seek to add rotational restraint bracing at the start and end of that confection.

5) For the sake of predictability, I would much rather go with conventional flange plate splicing. What makes this arrangement desirable?

6) Accurate LTB determination could be difficult. Were I to do this I might consider an FEM buckling model to investigate it. As you've suggested, this may be highly dependent on the load and support arrangement. I feel as though there are a lot of scenarios where this would be worse for LTB than a conventional, same elevation splice.