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Stud wall bracing
2

Stud wall bracing

Stud wall bracing

(OP)
I have a question regarding stud wall bracing.

I have 12’ high metal stud walls for a building renovation for an indoor Volleyball court. There is no ceiling, the stud walls are partitions and open above to the 24’ plus roof height. Stud walls usually have diagonal bracing at the top to keep them supported laterally and this is usually concealed by a drop ceiling.

The client doesn’t want to see diagonal bracing all over the place going up to 24’ or 30’ high in some places. This would not look good.

Would anyone happen to have any suggestions on how I can specify the walls to have internal x’bracing or something to make them structurally sound from falling over without using diagonal braced studs from the top track of the partitions all the way up to the roof deck?

Any comments/suggestion are appreciated.

RE: Stud wall bracing

Simpson Strong-tie came up with some moment brackets for the base of CFS studs, however I doubt they'd be capable of 12' tall cantilever studs.

RE: Stud wall bracing

can you put a girt at the top of the wall?

RE: Stud wall bracing

Cantilever tube columns with infilled studs.

RE: Stud wall bracing

Here's what mike20793 is talking about:

RE: Stud wall bracing

(OP)
@mike20793 - Would it be possible to do this 12' up all the way to the roof deck?
@DETstru - Thanks for the picture

RE: Stud wall bracing

Here's another option:

RE: Stud wall bracing

(OP)
@DETstru - So the track or box header acts like a girt? Would it be possible to have 2 rows of this system stacked on top of each other? Would it help add more strength to the bracing system?

RE: Stud wall bracing

Yes the track (or box header) is like a girt. The infill studs' out-of-plane loads react into the track and the track then sends that load into the tall studs. The tall studs send the load into the roof and the slab.

A second track/box header/girt doesn't really help the issue unless you need it based on the distance your infill studs can span. If you're only making them span 12' then you shouldn't need a second row.

RE: Stud wall bracing

(OP)
@DETstru - Thank you for the suggestion. I misspoke about the roof height. There is no ceiling, the stud walls are partitions and open above to the 24’ plus roof height. It goes 24' to 30' high in some places. If it is 24' or 30', then would a second track/box header/girt be required/helpful?

RE: Stud wall bracing

(OP)
Does anyone know of any design guides or reference book that also provide information regarding this type of situation?

RE: Stud wall bracing

Quote (oengineer)

Does anyone know of any design guides or reference book that also provide information regarding this type of situation?

There ain't likely any as it is comes down to a fairly simple analysis. You have plenty of good suggestions here.

RE: Stud wall bracing

I'm still unclear on the construction intent. In your first post you indicate a 12 ft tall wall, in your last post you make it seem like the studs are going full height.

Which is it?

RE: Stud wall bracing

(OP)
@jayrod12 - Regarding whether using the 12' height or 24' height, I just spoke to my colleague who is requesting the answer and this is what I was told:

This is for interior stud walls only. They want the sheetrock on the interior stud walls to go up 12’ high. So, these are essentially 12’ high walls/partitions. Even though these studs may be 16” on center, I’m thinking maybe every 3rd stud goes up all the way to the deck (deck is at 24’ plus) to brace the interior wall from lateral moving, because we always specify a certain amount of bracing above the ceiling. In this case though, there is no ceiling.
Alternatively, I was wondering if there is a solution where every 3rd stud doesn’t have to go all the way up to the deck. Is there a method of bracing within the stud wall itself?

RE: Stud wall bracing

24 ft tall is a big go to only extend every third stud, but that is an option that you could investigate. As someone has already mentioned, you could use hot rolled steel members at a reasonable spacing that went all the way to the roof, then infill between them with standard studs.

RE: Stud wall bracing

(OP)
@jayrod12 - Thank you for your response.

@Everyone - Thank you all for your suggestions.I will suggest the Cantilever tube columns with infilled studs and the second option from DETstru. I will let them know if they seek to go 24 ft tall then they should use hot rolled tube steel members.

RE: Stud wall bracing

(OP)
I have a question regarding the stud wall bracing.

Would it be possible to have the 10 ft to 12 ft high stud wall just brace to the existing metal building and it self? Please see attached drawing:
http://files.engineering.com/getfile.aspx?folder=9...

The yellow highlighted portions are the wall and the pink highlighted portions are horizontal braces to be used. The building is an existing pre-engineered metal building.

How would this work as a solution/ What are the potential benefits? What are the potential issues?

Also, here is more information from the Architect:

This is for interior stud walls only. They want the sheetrock on the interior stud walls to go up 12’ high. So, these are essentially 12’ high walls/partitions. Even though these studs may be 16” on center, I’m thinking maybe every 3rd stud goes up all the way to the deck (deck is at 24’ plus) to brace the interior wall from lateral moving, because we always specify a certain amount of bracing above the ceiling. In this case though, there is no ceiling.
Alternatively, I was wondering if there is a solution where every 3rd stud doesn’t have to go all the way up to the deck. Is there a method of bracing within the stud wall itself?


Any comments/suggestion are appreciated.

RE: Stud wall bracing

I doubt it. On some of the short running walls sure. But you've got some walls there that are over 15 feet long. The girt required at the top of those walls to keep them from being flimsy would be ridiculous.

RE: Stud wall bracing

Quote (OP)

How would this work as a solution/ What are the potential benefits? What are the potential issues?

For better or worse, I've seen a lot of that strategy in interior fit out work. Without a ceiling, the potential issue would be that it's ugly as viewed from below.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

RE: Stud wall bracing

(OP)
@Jayrod - Thank you for your response.

Another design option that I have is this:
1.) Use cantilever double angle back to back columns @ 8’-6” o.c. with infilled studs @ 16”o.c. (See Sketch 1). This would be just for the 12’ height. The track (or box header) is like a girt and is composed of double angles front to front. The columns would have 12x12x3/4 base plates with (4) - ¾” dia. HIT-HY 200 + HAS-E ½ Hilti Bolts. The effective embedment of the Hilti Bolts into the slab would need to be a minimum of 3.5 inches. (see attachment) This partition is designed for a 5 psf horizontal load based on IBC 2006 Sec 1607.13.

http://files.engineering.com/getfile.aspx?folder=6...

2.) Extend some of the studs all the way up to the bottom of the deck and provide girts ( as previously mentioned in this post).

@KootK - The client doesn't seem to be concerned with the aesthetics regarding the use of a ceiling for these walls. At this point my main concern is that it will structurally function.

RE: Stud wall bracing

If you're confident in your solution number 1 calculations, that would probably please the architect the most. I do however have my own reservations that double angles at that height and spacing will provide a comfortable wall. Will it be strong enough to not fall over? Likely. Will the wall have some significant give when someone leans against it? also likely. I think the double angles may be better off being channel sections, or light W sections to stiffen them up considerably.

RE: Stud wall bracing

(OP)
@Jayrod - I'm sorry I wrote the wrong thing. I designed it with double channels, double c6×10.5 back to back.The box header is also composed of double channels.Im only using channels.

RE: Stud wall bracing

Without running a number, that's more in line with what I would expect. I'd still keep a close eye on deflection of the box header at mid-span between the posts, taking into account the deflection of the posts as well.

RE: Stud wall bracing

(OP)
@jayrod12 - Thank you for your input.

@Everyone - Thank you all for your help.

RE: Stud wall bracing

In my market, I would get serious push back on anything that involved anything more serious than cold formed framing in something like this. Hot rolled steel would raise eyebrows and, certainly, the base plate projecting beyond the wall plenum would be a problem. For these reasons, I'd be inclined to save myself some effort and skip right to an all cold form solution if at all possible. Cold formed horizontal bracing at the ceiling as required.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

RE: Stud wall bracing

(OP)
@KootK - There is no ceiling for the 12 stud wall. The bottom of deck is 12 ft taller than the stud wall.

RE: Stud wall bracing

I understand oengineer. I thought that you had the option of placing bracing members in the plane of what would be the ceiling if you had one. That's how I interpreted these comments:

Quote (OP)

The yellow highlighted portions are the wall and the pink highlighted portions are horizontal braces to be used.

Quote (OP)

@KootK - The client doesn't seem to be concerned with the aesthetics regarding the use of a ceiling for these walls.

This is, in fact, the approach that I typically see. I do some glass work and much of it is interior office partitions in situations just like this.

Quote (OP)

Would it be possible to have the 10 ft to 12 ft high stud wall just brace to the existing metal building and it self?

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

RE: Stud wall bracing

(OP)
@KootK - The use of this building is for an indoor volleyball arena.

RE: Stud wall bracing

I'm afraid that you've lost me. The plan that you posted showed offices. Are you expecting fast moving sporting equipment to be flying around this space? If so, you probably want block walls or a veneer/cfm alternate.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

RE: Stud wall bracing

And I suppose that my question for you is simply this: can you or can you not have horizontal framing members at the would-be ceiling level? If you can, then I stand by my previous comment. If you can't, then I retract my recommendation.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

RE: Stud wall bracing

(OP)
@KootK - Well my concern, based on other responses in this form, is the overturning of the the wall due to a lack of a top lateral support with adequate load transfer to the main structure. This is why I designed the moment connection base plate, based on previous recommendations in this post.

Are you saying you would not be concerned about the possible overturning of the wall?

RE: Stud wall bracing

Quote (oengineer)

Are you saying you would not be concerned about the possible overturning of the wall?

Sure I'd be concerned about it. I'd evaluate it and deal with it by supplying some form of bracing to the wall tops with cold formed members. That is, of course, if such cold formed bracing members could be installed at the tops of the walls. You still haven't let me know if that's the case.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

RE: Stud wall bracing

(OP)
@KootK - you can have horizontal framing members at the would-be ceiling level. Based on several of the comments in this post, the question is what should be done to resist the overturning since the wall are no longer have lateral support a the top with adequate load transfer to the main structure. How would keep the wall from twisting?

RE: Stud wall bracing

(OP)
@KootK- What type of form of bracing to the wall tops with cold formed members would supply for the situation?

RE: Stud wall bracing

- split diamond
- add bays as needed to make the top track spanning member work.
- hang the bracing from the structure above as needed.
- drag lateral load back back to parallel shear walls or base building.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

RE: Stud wall bracing

(OP)
@KootK - I see what you are doing. Interesting. But to some degree you are making a type of ceiling over the rooms. Interesting concept though.

RE: Stud wall bracing

(OP)
@Kootk - And by doing this, you are allowing the studs in the walls to act as supply supported instead of cantilever.

RE: Stud wall bracing

Quote (OP)

But to some degree you are making a type of ceiling over the rooms.

Well, yeah, that’s why I keep asking if it was acceptable to put bracing in the would be ceiling plane.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

RE: Stud wall bracing

(OP)
@KootK - Thank you for the suggestion!

I thought you were going to brace it like I show in that sketch.

I will investigate your idea.

RE: Stud wall bracing

(OP)
What are your thoughts on allowing the other walls to act as a brace to the proposed wall? This proposed solution would not have the moment connection base plate nor the diamond ceiling plane bracing. It would just be the corner bracing. Any comments /suggestions are appreciated.

RE: Stud wall bracing

Quote (oengineer)

What are your thoughts on allowing the other walls to act as a brace to the proposed wall? This proposed solution would not have the moment connection base plate nor the diamond ceiling plane bracing. It would just be the corner bracing. Any comments /suggestions are appreciated.

You could probably do that but would need a girt on top of the wall capable of spanning from corner to corner. Maybe a 10" stud capped with a track would do the trick.

RE: Stud wall bracing

(OP)
@XR250 - Would this situation resolve possible overturning of the wall?

RE: Stud wall bracing

What if you used cables for bracing? less visible.

RE: Stud wall bracing

Quote (OP)

What are your thoughts on allowing the other walls to act as a brace to the proposed wall?

That's what my proposed solution does. The only difference between my proposal and your corner bracing proposal is that I've made the corner bracing so large that it fully trusses the roof. I've seen solutions where bracing is provided at 4' off the corners, kind of between your idea and mine. It can work but leaves some gaps in the load path in that the ceiling becomes a horizontal moment frame of sorts and it can be tough to detail the top tracks to follow that logic through.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

RE: Stud wall bracing

(OP)
@KootK - You included the diamond bracing in the top of the ceiling plane of the stud wall. This new proposed solution wouldn't have that. It would pretty much be the picture I sent you with a diagonal brace inside the stud wall.

RE: Stud wall bracing

I know. Your system is a much weaker cousin to mine. Same basic concept though.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

RE: Stud wall bracing

Quote (oengineer)

@XR250 - Would this situation resolve possible overturning of the wall?

It would if..
a) The girt was capable of resisting the wall stud out-of-plane loads.
b) The perpendicular walls were capable of acting as shearwalls to brace the girt - including out-of-plane stability themselves..


You just need to run the numbers and see.

RE: Stud wall bracing

(OP)
@XR250 - These walls are going inside a pre-engineered metal building. Would I need to find out the properties of the girts (i.e. cross-sectional area, section modulus, moment of inertia, yield strength, etc.) before I attach anything on to them to use as supports?

RE: Stud wall bracing

(OP)
@KootK - In your diamond sketch, how do you plan to construct the red top tracks on top of the wall? Would it be composed of one long member (say 18'-0" long) or of several short spanning members (say 8'-6" long)?

The reason I bring this up is I wanted to make my top track composed of several 8'-6" long members and have it connected together by field bolting. I figured this would be more economical then field welding and the member would be too long to shop weld.

One of the issues I am having in my analysis is instability. This is due to having the top track (or box header)pinned @ every 8'-6" and having pinned supports as well. If I treat it as a continuous member it will allow for moment to be carried throughout the top of the wall, but I am not sure how this could be economically built.

RE: Stud wall bracing

Why couldn't they just have an 18ft long member? that's nothing out of the ordinary.

RE: Stud wall bracing

Can you not use bolted splice plates designed to carry the moment between each of the 8'-6" beams?

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