what's this HSS upstand for? 2

[palk7 EIT]

Hi,

Attached a pic. which is beneath the window sill, there are 4x4 HSS posts installed inside the CFS stud wall framing @ 3'-6" O.C. and drilled epoxied into foundation wall, what's the exact purpose of these upstands, is it acting like a wind girt to prevent that wall from lateral displacement. If so then I dont see a positive connection between the track and HSS or is it for some other reason. is it not common to provide a HSS girt for that purpose?

Really appreciate it, thank you

 

[Boiler106]

A girt can be provided if it has a jamb to frame in to, however, sometimes there is a door at the end of the opening with a thin mullion that prevents having one. Also, this could be a ribbon window where the span of the girt between jambs would be impractical.

I would say this is a relatively typical detail for these conditions

 

[palk7 EIT]

Boiler106, Thank you so much, I am understanding that you are referring these upstands are for lateral loads? In that case how is the connection formed to this HSS upstands from the window, is it like cap plate welded to top of HSS and lateral connection provided by window supplier?

 

[XR250]

Pretty stout post for the situation considering the paltry edge distance on the "fully grouted" epoxy anchors. There are many ways to skin this cat. I would normally attach one of the studs to the side of the tube steel and just use the light gage track spanning tube to tube as the girt.

 

[palk7 EIT]

XR250, the span in between is 25 feet bw. the openings. Thanks for the Idea I guess its the convenient way to do it.

 

[XR250]

XR250, the span in between is 25 feet bw. the openings. Thanks for the Idea I guess its the convenient way to do it.

The drawing says the posts are 3'-6" O.C.

 

[palk7 EIT]

yeah, I meant the window openings, HSS are at 3'-6" O.C

 

[jayrod12]

Where I am, we do this but usually just with angles as the cantilevering member. Then a continuous CFS track is mounted to the top of the posts flanges down. Then they infill with steel studs.

 

[Boiler106]

in our region of the US, the storefront is connected to the cold formed sill track. The sill track is then screwed or PAF'd into the cantilevered member. We usually use channels that are attached to the track with a cold formed clip.

 

[271828]

I've seen this done a little differently. Use the smallest 4 in. hot-rolled channel instead of the HSS. Screw one CFS stud do the backside of each channel.

As someone typed above, HSS4x4x3/8 with 1/2 in. plate seems a bit out of proportion.

 

[palk7 EIT]

271828, Thank you. But the base plate and anchor rods into FDNT. wall has to be installed right whether its an HSS or a channel section, is that correct?

 

[jayrod12]

That's correct, regardless of section, the anchors and baseplate need to provide moment fixity.

 

[phamENG]

Another alternative is to use some of the proprietary fixed connections for light gauge. It meas a bit more drilling since you usually need one at every stud, but they can be nice when edge distance is a problem for the other options since the anchor is relatively shallow and centered in the wall.

 

[bones206]

I think you would actually be slightly ahead with only one anchor per 16" (0.75 anchor/ft) versus 4 anchors per 42" (1.14 anchor/ft).

 

[phamENG]

hmmm...can't argue with that math. Forgot they put it at 3'6" o/c. When I use tubes like that they're MUCH further apart. And often have a rectangular tube LSH sitting on top as a girt.

 

[Aesur]

@phamENG & bones206 - I have tried to use kneewall connectors (Simpson RCKW) before and typically am unable to get them to calculate out without very tight spacing (Vult in my area is low at only 105 mph). Even their highest capacity connector isn't that great when you are dealing with wind from the window applied to the top of kneewall. We typically end up useing an HSS with a baseplate for ribbon windows, but try to do with only 2 anchors instead of 4. Using an HSS we can typically space out further apart which is either a wash or cheaper from what I'm told by contractors. Those moment clips are 5 to 10 dollars each not including the anchors. I know it seems silly, but around here it seems like contractors are fighting to shave pennies off a project.