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Do Openings always span vertically? When do they span horizontally? 2

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Revv

Structural
Aug 23, 2021
87
Hey guys,

So I have a situation where I have long horizontal windows and have HS posts offset several inches or more away from the edge of opening. I need to infill the gap with studs but assuming my sill and header both extend to the HSS posts, my jamb studs shouldn't be seeing really any load right? How do I know if the opening is spanning vertically or into my jamb studs?
 
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Two major variables: the framing within the opening (i.e., window mullions) and the stiffness of your framing.

But my rule of thumb is aspect ratio. Assuming Height:Length, anything between 2:1 and 1:2 is either going to be a 2-way distribution (large, plate glass windows, for example) or will be highly dependent on the window/door frame (double hung windows transfer their load to the jambs). Anything wider than 1:2 will be dumping its wind load into the header and sill, anything taller than 2:1 puts its load into the jambs.
 
It depends on the kind of window we're talking about but, at the least, I would assume that your jamb studs would see at least the amount of tributary shown below.

C01_n05bee.png
 
I mean if the load goes up and down to the sill and header then where does it go? The King studs. The load ends up in the same place with perhaps a different distribution of loads. One being a uniform load over the height of the windows and one being two point loads at the sill and header of the window.

Similar to series of point loads vs uniform distributed load I would expect the magnitude of moment in the jamb studs to be close to the same using either approach.

 
I read OP's situation as this. In this scenario, pretty much all windows would deliver some load to the jamb studs when closed.

C01_tk62qx.png
 
Unless the aspect ratios are ridiculous, I typically do not sharpen my pencil on these. I do worst case for the headers and sills and then check the jambs with the gross horizontal trib.
If the members are getting out of hand, I will check them more throughly.
 
@kootK exactly thank you for drawing it. Seems like the jamb studs wouldn't really be receiving much in that scenario but it depends on when way it is spanning.
 
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