Hot Rolled Steel Sections for Framing Double Doors

[interstructeng]

I do a lot of work in steel frame industrial buildings that have heavy duty steel double doors. We have been framing these doors out with proper hot rolled steel box sections (100mm x 100mm x 10mm box section for example - I think these are equivalent to 4 x 4 x 3/8 US size). The framing includes a post either side of the door, and a header beam above the door.

We then have to pick these up at roof level which could be a single story or double story height.

The partitions either side of the door are stud and plasterboard. We don't use timber generally.

I always have a sneaking suspicion that what we do is overkill, but the external Architects are always pushing for them - so am reluctant to push back.

Does anyone have any experience with this or do this also? Or even better an example where it wasn't done and caused an issue? (Cracked finishes, problems fitting the door etc.).

 

[driftLimiter]

Which part do you think is overkill? The posts on both sides of the door (jamb studs) need to either go up to a roof or another framing element that has a connection to the main frames. This is order to maintain the walls out of plane strength.

If you have a schematic drawing of what your talking about that would help get better responses.

 

[interstructeng]

I've sketched it out below (excuse the quality - I am using trackpad on laptop with some free software).

It's the use of hot rolled steel I am querying as maybe being overkill. In my mind I would have thought the contractor framing the partitions can come up with a stiff detail (double stud/stiff cold form section) to restrain the door adequately against the ceiling, or up to the roof. I've shown the stud wall ending just above the door in the sketch, but it actually continues up to floor level.

It introduces an interface between sub contractors (steelwork install contractor, studwork contractor, door contractor) etc. that I would like to remove if possible and keep everything with the same design/install package

 

[driftLimiter]

Yes I see jamb studs for this type of building made of cold-rolled light gauge sections quite frequently. About restraining the door to the ceiling I think thats a no-go. The jambs could go up to another framing element that spans over to the columns for an exterior wall at least.

In order to get the stiffness you need the element needs to frame into a system that eventually makes its way to some stiff lateral element. In the US typically that means the main PEMB portal frames.

 

[interstructeng]

Great, yes that's what I thought was possible - jamb studs made to be stiff enough from light gauge sections. I don't do much (if any) light gauge design so don't have a feel for it. The fact they are heavy doors might be the only kicker - I think they have proper thick fixings so may not be suitable for very thin sections.

As regards restraining the top of the partitions/door jamb, it would be a stiff ceiling grid (example

https://www.british-gypsum.com/documents/white-book/british-gypsum-wb-gypceiling-mf.pdf

Quote "Allows you to reduce partition heights as the partition channel can be supported by the ceiling framework rather than the soffit"). Or else braced back to the main framing as you have mentioned.

 

[driftLimiter]

Perhaps for interior walls that could work. We don't do that in the US though because ceilings are built in wildly different fashion than structure. Also ceilings are often removed through the life of a structure.

But for a light infill interior partition I think people may opt use that load path (not me lol).

 

[interstructeng]

Sorry yes these are interior doors - non load bearing partitions etc. Just room dividers really.
In this project the stud walls are full height so no issue tying into proper structure.
I have seen it done with a ceiling grid detail - especially in cleanrooms etc. where the partitions are a designed system with ceilings integrated. Effectively a self supporting box that braces itself..