Beam Splice?
Beam Splice?
(OP)
How would you design a splice for cold formed/light guage steel c-studs? The studs do not overlap. They want to use stud material on the backside for the splice plate.
Moment=12k-in
Rafter is 8" CSJ.
How many screws? Screw pattern?
Moment=12k-in
Rafter is 8" CSJ.
How many screws? Screw pattern?






RE: Beam Splice?
RE: Beam Splice?
RE: Beam Splice?
RE: Beam Splice?
I understand that, but what I am suggesting is to lap the rafters from each side over the support, similar to PEMB construction.
There are some other considerations here that you might want to think about:
Are the splices to be done "up in the air" or "on the ground"? I suspect "on the ground" and lifted into place since a worker would need to be on a scaffold if he will make the connection "in the air".
If done "on the ground", then you need to consider stresses in the connection from lifting it into place.
RE: Beam Splice?
RE: Beam Splice?
RE: Beam Splice?
RE: Beam Splice?
BA
RE: Beam Splice?
RE: Beam Splice?
One suggestion was to treat it like an eccentric load on a bolt group. (instantaneous center concept). Do you think that is an acceptable theory?
That method would require 10 screws on each side:
2 horizontal rows of 5 screws. Row spaced 6" apart. Screw spacing = 2" Any thoughts?
RE: Beam Splice?
you also need to check the joint plate itself, between the two fastener groups ... it'll be smaller than the stud section, no?
RE: Beam Splice?
RE: Beam Splice?
You can add a heavier piece of track over the stud. The flanges are screwed for the tension/compression and the shear is transferred by moment on screw groups. The trick is getting the contractor to place the screws where you designed for the moment resistance.
RE: Beam Splice?
RE: Beam Splice?
I like the track idea. You could attache the web for the shear, but how would you figure the # of screws in the flanges?
RE: Beam Splice?
While the scab piece on the back could work (have to make sure the screws are properly installed) the cap track method is a little more simple to use and has more redundancy in my opinion.
RE: Beam Splice?
Using track attached to the web and flanges to transfer the forces is a superior design. I just need to make sure the track can transfer all of the applied forces.
Thanks CFSEng!
RE: Beam Splice?
BA
RE: Beam Splice?
RE: Beam Splice?
Is it correct that you are splicing members with a 2" flange, remember channel track only has a 1-1/4" flange, not much meat for fasteners.
You might want to also specify PL400 adhesive for extra measure.
I think most are in agreement that from an analysis standpoint it is feasible, but, you need to make it idiot proof and constructable, after all you don't what to be thinking about this job every time it snows or heavy winds are predicted.
You might want to think about specifying sandwiching the web between (2) 6" Scabs (7-1/4" might also work must check lip clearances) or using a 7" web plate with utility angles fastened to the flanges and web.
When you do come up with a solution it would be pretty easy to load test the assembly (this is also recognized by the AISI Specification). Have the contractor set up two members with the plywood deck installed and load it with bricks to at least 2x your calculated moment. If it holds up then you can sleep easy at night.
RE: Beam Splice?
Mike McCann
MMC Engineering