Splicing Channel Beam

[BrentStru]

I have an RFI from a contractor saying he can't get a 16' C10x30 beam into place without cutting it in half and splicing it together. For various reasons, I don't believe welding is an option where this beam is, and the contractor wants to splice the beams with bolts and a single plate. A good bit of Googling found pretty much nothing. Am I correct in believing this is not an option, because there is no way to transfer the moment across the splice without including the top and bottom flanges in the splice? There is only 3" of flange, so I don't see any way to avoid having to weld if splicing is the only way to install the beam.

What does everyone else think?

Thanks.

 

[KootK]

I've been able to get bolted web plate splices to work well in the range of about 15 kN*m. If you do that though, it's important for the splice to also be a point of LTB restraint. I prefer to do this with a channel chunk as the splicing member rather than a plate. A bit more weak axis capacity that way.

Any chance there's enough extra length on the channel to arrange the two segments back to back with a 3 x d ish lap?

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[jayrod12]

I'd be inclined to say it's not reasonably possible. I won't speak in definitives because I don't know if it is or not. I've never seen it however.

 

[SlideRuleEra]

Whether a bolted plate splice will work or not depends on how the beam is loaded - you have not mentioned that. Go back to basics, draw the shear and moment diagram for loading on the 16' channel. If there is a point where moment is essentially zero and the cut (splice) can be made at that spot the bolted plate probably can carry the shear. I agree with KootK that there should be lateral support at the splice.

If the channel has simple supports and there is, say a uniform distributed load or a point load on the channel... forget it. A few minutes drawing the diagrams will allow you to make an informed decision. A properly supported plate on edge (bolted to a channel, for example) can resist moment, otherwise a "flitch beam" would not work, However, you are correct that compared to a C10x30 a reasonable size plate won't be of much value for moment.

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[SAIL3]

instead of splicing the channel @ mid-point try splicing it @ 1/3rd pts where the moment could be much less....