Non-Load Bearing Partition Wall Top Connection
Non-Load Bearing Partition Wall Top Connection
(OP)
We have a project with non load bearing wood partition walls on and under wood trusses. We detailed the Simpson Connection that would support the wall out of plane, but had vertical slots to allow for deflection of the roof and floor trusses, so the non-load bearing walls would not become load bearing. The arch/contractor has come back and said this is not standard framing and want it removed from the drawings set. I know in a house you would just attached the non-load bearing wall. This is a 3 level multi use (retail, office and residential). What is your opinion on needing and/or using the vertically slotted top connectors for non-load bearing walls in what application and in what types of buildings. Thanks in advance.






RE: Non-Load Bearing Partition Wall Top Connection
Unless their trusses can handle the point load from the partition walls, and you have a load path below the partition walls that can handle it.
RE: Non-Load Bearing Partition Wall Top Connection
RE: Non-Load Bearing Partition Wall Top Connection
DaveAtkins
RE: Non-Load Bearing Partition Wall Top Connection
I would recommend you get the truss manufacturer involved. Between the two of you, the argument is MUCH better.
RE: Non-Load Bearing Partition Wall Top Connection
RE: Non-Load Bearing Partition Wall Top Connection
Trusses won't really pick up the extra support since they don't have a node there. If a non bearing wall hits between 2 nodes in a bottom chord, the chord will flex and not transfer as much load.
You can CYA by saying, "okay you don't have to do it, but don't come back to me with any drywall cracks in walls or ceilings".
When I am working on a problem, I never think about beauty but when I have finished, if the solution is not beautiful, I know it is wrong.
-R. Buckminster Fuller
RE: Non-Load Bearing Partition Wall Top Connection
RE: Non-Load Bearing Partition Wall Top Connection
-In the past, I worked in a market in the US where the slip connections where unheard of. No problems.
-I now work in a market where the slip connections are common place. So I take advantage of that.
-I worked for the wood truss council of america for a while and the only reported problem that would crop up was roof trusses actually lifting connected walls up into the air. Nifty.
-I'm skeptical of the argument that says that bearing walls won't end up at points of truss stiffness. Walk through a building in progress and you'll see all kinds of situations where non-bearing walls fall within a foot or so of truss bottom chord panel points. With floor trusses, your panel points may only be 14" apart so it becomes quite impractical to try to dodge them.
-As structural engineers, we love do drone on about how wood structures are redundant in all kinds of miraculous ways that, thus far, remain unaccounted for. Gap your non-bearing walls and a lot of that redundancy goes away in my opinion. Just sayin'...
@Manstrom/njlutzwe: with these written disclaimer emails, are these situations where the contractor is also your client? I would hate to find myself having to explain to an owner/architect client why I gave the contractor the liberty of choosing a construction method that led to shabby building performance.
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: Non-Load Bearing Partition Wall Top Connection
Most of the time it's been in design build, where I work for the contractor. If I was working for the owner, I would inform the owner and let the owner make an educated decision. I would tell the owner that they paid for it and I recommend it, but if you want to ease up on the contractor and aren't worried about it, that's fine.
With that said, I only do this with what I deem to be serviceability issues. In those events, when I am working for the contractor it's his or her call. For example, I could argue it's best practice to design a floor for L/480 live load deflection to keep them from being bouncy, but the contractor may not care. It's not a code requirement, it's not a life safety requirement. The contractor can tell me he wants the code minimum and it's totally ok. It may not perform as well as the L/480 floor, but that's their call to make. Same with slab-on-grade control joints. I show a location that works. If they want to change it up, by all means, go for it. Ultimately, the contractor can decide on some of those things if I'm working for them. And, in reality, the owner is part of that decision, albeit passively. If you hire a contractor for design build, you do it assuming you want the bare minimum, except where you specify elsewhere. Contractors aren't in the business of giving things away, and owners know that. So if they want it designed based on best practices, they probably aren't going the design build route.
Just my two cents. I'd love to hear your response and how you deal with these issues.
RE: Non-Load Bearing Partition Wall Top Connection
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: Non-Load Bearing Partition Wall Top Connection
RE: Non-Load Bearing Partition Wall Top Connection
RE: Non-Load Bearing Partition Wall Top Connection
RE: Non-Load Bearing Partition Wall Top Connection
RE: Non-Load Bearing Partition Wall Top Connection
Greatone76;
I will look. The best/spectacular failure was in 1977, I may still have photos.
Most cases I have seen do not photograph well & many other excuses are produced, clouding the issue. Too many times our expansive & collapsible soils are blamed for any cracking or structure movement.
In my experience, most cases are related to heavy (tile) roofs & heavy (tile or concrete surfaces) floors. Complicated trussed roofs seem to factor in. The problem has decreased some since the mid 90's, when the trusses were 'better' designed (better programs), constructed better (better equipment) and the snow loads in Colorado were better appreciated in some of the low load areas.
RE: Non-Load Bearing Partition Wall Top Connection
Dave
Thaidavid
RE: Non-Load Bearing Partition Wall Top Connection
Logically it would seem to me that the slotted connectors would allow for relative movement, would that not increase the likelihood of the GWP cracking?
A confused student is a good student.
Nathaniel P. Wilkerson, PE
www.medeek.com
RE: Non-Load Bearing Partition Wall Top Connection
RE: Non-Load Bearing Partition Wall Top Connection
RE: Non-Load Bearing Partition Wall Top Connection
Just my luck, the file contains 2 copies of every report, inspection report and even the report of the floor truss engineer, who handled everything well, except the plumber with a Sawzall. But the photos are gone.
The issue was 3 floors, constructed with 2' high floor trusses, each capped with 3" of concrete and a trussed roof. The interior walls were framed tight and the issue in 1 structure was apparently excessive deflection of the roof hip masters, with the problem telegraphing to the lowest floor.
The other 3 structures had much the same problems, but 'minor' installation issues, minor manufacturing deficiencies and the occ. plumber with a Sawzall resulted in a BIG repair.
RE: Non-Load Bearing Partition Wall Top Connection
I want to address njlutzwe's summary to KootK's comments, without regard to the merits of a slip connection or not......
For us design professionals, if we put a requirement in the plans or specifications, and subsequently a building permit is obtained based on that information, it becomes a building code violation to deviate from the plans and specs (administrative section of the International Building Code and its state variants.....yes, I know it's routinely violated!!). There is a procedure, rarely followed, for resubmittal of changes by the design professional. These are usually just done on the fly.
Fast forward a few years when construction defects become evident (also more likely to manifest in wood framed structures early on).....lawyers get involved and an investigation of the design and construction ensues. Chances are that there is no paper trail available to the investigation team at the time because of legal discovery rules and legal civil procedure. Each party hunkers down and rallies its cause, without respect to any of the other parties.
The investigation gets done as reasonably as practicable with given information and field investigation. Sometimes analysis is done, sometimes not depending on the legal process. The investigation team reaches a conclusion that the in-place construction is different than shown on the plans and specs. Then the assessment has to be taken to a different level of cause and effect. As you can see it spirals downward with higher investigative costs and legal costs until the real answer (hopefully) is found.
So fundamentally, if you put a requirement on your plans or in your spec, enforce it. If you are waffling on putting it in, follow the standard of care of your area for design professionals.
RE: Non-Load Bearing Partition Wall Top Connection
Thanks for your comments. Please provide the admin code reference location in IBC. I am not familiar with it. As for my area, and I would guess most areas, things during construction change all the time. By your analysis, it seems to me as though you would have to resubmit to the permitting office every time there was an RFI or a small field tweak. In all seriousness, where would it end?
RE: Non-Load Bearing Partition Wall Top Connection
Require a best practice detail like this and avoid potential serviceability problems down the road. Cost of construction goes up. Get branded as the engineer who requires expensive details. Lose clients.
Don't require the detail and let them build it using conventional typical construction practices. Possibility of serviceability problems down the road. If problems occur and fingers point back at the engineer, then we should have known that this was a bad detail. Lose clients.
It's lose-lose
Option 3 - "recommend" the detail as best practice. Let the owner / builder make an educated decision and put the ball in their court.
When I am working on a problem, I never think about beauty but when I have finished, if the solution is not beautiful, I know it is wrong.
-R. Buckminster Fuller
RE: Non-Load Bearing Partition Wall Top Connection
Technically yes. But like Ron said, nobody ever does it, and most jurisdictions don't care. It is more or less left up to the design professionals to decide when a change is big enough to let the Building Dept know about it.
Manstrom,
I like your option 3, but I suspect a moderately competent lawyer will argue that you should have known better and not left it up to the owner who is a poor uneducated fool in these matters.
RE: Non-Load Bearing Partition Wall Top Connection
dcarr. Good points, but ultimately you can get sued for anything. I say you do the best you can and don't stress about it. Every litigation case I recall hearing about was some ridiculous there is no way it could have been prevented.
I'm not going to live my life worrying about getting sued. I'll do what I can to prevent it, but ultimately all lawyers can dream something up that I didn't think of. That's outside of my control.
And no matter what option you pick, a lawyer could pick you apart. Let's say that you choose to require they install the clips. Then, the contractor does it reluctantly, does a poor job and there are still issues. You get dragged into a lawsuit because they didn't install them correctly. You say, you showed a detail that was correct but they didn't do it that way. Then, the lawyer says, "well, yes that's true, but you knew it wasn't standard practice for them, you should have made sure they did it right". You say, that wasn't in my scope. The lawyer says, "yes, but given the circumstances." You argue the letter of the law, your insurance provider is still scared, they settle, you pay the deductible.
Point is, do the best you can. You dream of a way to not get sued and a lawyer will come at you another way...
RE: Non-Load Bearing Partition Wall Top Connection
During the crash, I did a fair number of home investigations for owner's that were trying to dump their properties. Home inspectors locked onto excessive floor deflections and drywall cracking and typically came to us with concerns about the foundations. Most problems I encountered were on stick built multistory wood, and the vast majority of them were from a floor loading a demising wall loading and then the demising wall loading a floor (or floors) below. You would get drywall cracking as drywall panels experienced shearing/racking. You would get pronounced humping of the floor below sometimes with degradation of the floor finishes. I have never experienced any issues with trusses and demising walls.
If contractors push back on my detail as "non-standard" construction, I will write an email to the Architect (to be forwarded to the owner) that explains the potential consequences of providing a hard connection. I then let the owner and contractor hash out what they want to do. So long at the expected consequences are related only to serviceability, I look at it as a question of funding and tolerance to defects on the part of the owner. I also think that if I ever expect this to become "standard" construction practice in my area, then I have to be a catalyst of change.
RE: Non-Load Bearing Partition Wall Top Connection
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: Non-Load Bearing Partition Wall Top Connection
RE: Non-Load Bearing Partition Wall Top Connection
RE: Non-Load Bearing Partition Wall Top Connection
RE: Non-Load Bearing Partition Wall Top Connection
It sounds more complicated then it is. The only cost difference between the non-load bearing and load bearing walls is then the labour for this connection, and the longer fasteners. No galvanized connectors are needed. That's what bothers carpenters the most, additional hangers that cost money.
RE: Non-Load Bearing Partition Wall Top Connection
Most issues I see with multi-story wood structures is excessive floor deflection.
RE: Non-Load Bearing Partition Wall Top Connection