Newel post

[DoubleStud]

I do not have much experience with light gauge framing. I usually work with timber. I have a mezzanine in a prefab steel building that will be supplied/fabricated by the steel manufacturer. The joists will be 10C12 joists and at the end it cantilever about 5 ft. At the end of the cantilever they put a rim channel? They label it CH-200. It didn't yield any result when I googled it. I just assume it is a C channel. I need to add HSS newels at the end of this cantilever. How would you detail it? I am thinking about side mounting it on the rim but I am not sure how to go about it. The architect wants to use wood blocking between joists, but mixing these 2 different material confuses me. If the joists were wood, I know what to do. Not sure what to do here. Help?

 

[KootK]

I'm sure that is some kind of cee shaped track piece at the end of the cantilevers. That's what I would expect for several reasons, chief among them to rotationally brace the cantilever tips.

Fastening the railing posts to the face of the track piece sounds like a great idea to me.

Using CFM blocking / bridging would be my preference as well just because it strikes me as the simplest path forward with the lowest chance of squeaks etc. That said, if I had a client that had their mind set on wood blocking for some reason, I'd be willing to go along with it.

 

[RPGs]

It probably wouldn't hurt to ask for some clarity from the manufacturer on what those designations mean and the connection detail at the cantilevered ends. Those callouts aren't familiar to me personally, but it's not crazy for me to imagine that the manufacturer's shop drawings call components out in a way that doesn't mean much to an outside observer. I would normally expect some typical details included in the shop drawings though, so that's a bit weird.

I haven't gone through this particular exercise for this situation with the cantilever, but my personal favorite cold-formed steel manufacturer, Clark Dietrich, and Simpson have extensive catalogs for cold formed steel connectors for potentially detailing your HSS guard post to resolve the load back into the joists in a similar fashion to the classic AWC DCA6 wood guard posts for wood deck details. That said (and as KootK mentioned), directly attaching the HSS post to the rim track (via connector or weld) may be acceptable, if you can convince yourself the load on the guard post can be resolved via the connection between rim track and cantilevered joist ends--whatever that looks like.

 

[DoubleStud]

The newel will be spaced 8 ft O.C. Max. So if I do the 50PLF linear load at 3.5 ft above the floor, that is 1400 lb ft. That is quite a bit of load to transfer to the bolts from prying action?

 

[KootK]

That does sound a fair bit of load for that setup. Let the numbers be your guide.

 

[XR250]

Gonna need a pretty heavy gage track for that unless you can get the load directly into a joist as other have mentioned. Hard to coordinate that though as they won't likely align unless you have some field freedom for the placement of the posts. The light gage guy is gonna be long gone by the time the newel post guy gets there.

 

[DoubleStud]

I am thinking of using a flat long 2x wood blocking to the plywood maybe and simpson hold down? That will take care of the 50 plf pushing on top. Not sure about 200 lb on any direction part of the code.

 

[Eng16080]

It's been years since I've done anything substantial with light gauge, but I think the overall approach would be similar to wood. Connecting to the rim board/track channel (whatever it's called) is only the first step. From there (as already mentioned) you need to be sure that the load can get into the floor diaphragm (joists and sheathing). For loads pushing outward, I would probably use a hold-down (as you mention) located near the top of the joist. For an inward load, another hold-down can be used closer to the bottom of the joist.

I recently revised my guardrail/railing post detail for wood framing to have 2 hold-downs, given the requirement for the load applied in any direction. Also, it's not just the 200 lb load that can be applied in any direction but also the 50 plf load.

Depending on how this is detailed, you need to be a little careful of the case where the post is located halfway between joists on the track or where joists are running parallel to the track (if that's a concern). In those cases, additional blocking might be needed. Otherwise, the railing force might cause the rim board/track channel to deflect excessively (like it does with wood).

 

[DaveAtkins]

I have done a lot of cold formed steel framing design, and I don't like the concepts above.

Is this a solid knee wall? If so, I would fasten a vertical stud to each joist (16" on center). It will probably take 8 screws in a square pattern to connect the stud to the joist. I don't think the rim track is a good way to transfer load from knee wall to floor framing.

Or is this truly an open railing with newel posts at wide spacing? If so, weld each newel post to a floor joist. Screws will not be able to handle that much moment. Fortunately, your floor joists are 14 GA and 12 GA, so they can be welded to with ease.

DaveAtkins