Do you consider lateral loads in your definition of Load Bearing Walls?

[Ron247]

I was curious about everyone’s perception of what constitutes a “Load Bearing Wall” and a “Non-Load Bearing Wall”. I know the more common perception is whether it supports Vertical loads or not. I call that the Architectural definition. My main question is “Do you consider lateral loads in your definition of “Load Bearing Wall”?

Attached is a history of why I am seeking answers to this question.[URL unfurl="true"]https://res.cloudinary.com/engineering-com/image/upload/v1558106292/tips/Engtips_load_bearing_wall_gmd8fa.pdf[/url]

 

[FoxSE14]

Absolutely. Accompanied by a 'structural behavior crash course' to the questioning party.

 

[TLHS]

Just refer to them as shear walls when talking to people and explain what they do, rather than trying to expand a definition that could lead to confusion because people have pre-existing understandings of terms.

I would say the general understanding of the term 'load bearing wall' is in relation to vertical load. If I were talking to a structural engineer, I would assume that they would distinguish a bearing wall from a shear wall. If I were talking to anyone else, I would assume that they only have a very broad understanding of what they're talking about and I would be taking what they say with a grain of salt anyway.

I've met engineers with questionable understandings of lateral systems, I don't particularly expect a layman to have any real instincts about them.

 

[dauwerda]

I Agree with TLHS. To me, "load bearing" implies vertical load only. A "structural wall" could be a load bearing wall and/or a shear wall. Just because a wall isn't "load bearing" that does not mean that it isn't a structural wall (and that is where people might get themselves into trouble).

 

[cal91]

To the Layperson, DIYer, a non-load bearing wall is one they can take out without any uh-ohs.

 

[msquared48]

Well, yes and no...

Typically, most exterior walls that would see transverse wind forces are vertically load bearing, even in some small way, from vertical loads.

Alternatively, for wind loads parallel to the wall, the wall still sees vertical loads in the form of uplift or download at the ends of the wall at the holddowns, if they are required.

Similarly for earthquake loads.

Mike McCann, PE, SE (WA)

 

[CANPRO]

A lawyer friend of mine once called me to ask what the definition of a load-bearing wall was. My response was "well, technically anything that bears load", to which he responded "thats all I need to know". Vertical or lateral, if its supporting load, I believe it is a load-bearing wall. I agree with others about common terms used among structural engineers - shearwall vs bearing wall, but by strict definition I believe a wall with only lateral loads is still a load-bearing wall.

 

[Ron247]

The "pre-existing understanding" that TLHS is referring to is what I am used to and have seen for years. The problem is less the terminology and more what people then think they can do. At least 90% think if it is Non-Load Bearing then they can remove it. Period. I think the reason I see more of this in recent years is the house fixer upper shows. They say it is not load bearing and take the wall out. They never state that the wall may be "doing other work" or that there may be some additional minor movement elsewhere.

When they ask a professional if it is load bearing and then find out it is not, sometimes the professional should educate them some before leaving.

 

[msquared48]

In thinking further, a wood shear wall resisting in plane forces resists the loads thru lateral bearing on the nails and anchor bolts.

Transverse forces are resisted the same way, but also utilizing bending.

The common use of the term “bearing wall” though is just for vertical loads.

One could think of a “load bearing wall” as one that resists loads through bearing. So, then, I would argue that all walls are load bearing walls, both shear and bearing.

Mike McCann, PE, SE (WA)

 

[jittles]

I see the logic of a lateral element "bearing load" but I think the common and code definition is purely vertical load.

WALL, LOAD BEARING
Metal or wood stud wall that supports more than 100 lb/ft of vertical load in addition to its own weight.
...masonry or concrete... 200 lb/ft...

*edit: This is the IBC definition, for what it's worth.

 

[FoxSE14]

I agree with CANPRO. I think the appropriate response to a layperson would be "Yes, it is load-bearing, but not in the 'traditional sense.'" ...Begin brief education of lateral force behavior catered to the lateral force which dominates the building or local region (wind/EQ).

I would end there, however:
Jittles, I've never had to look up the definition of a load bearing wall, but if the excerpt you share is indeed the code definition...in my opinion it is quite wrong (i.e. incomplete) and should be improved to include 'structural function' or some other nod to lateral forces. With that definition, evidenced by our above discussion, then mix vigorously with lawyers, contractors, DIYers, and SE expert witnesses, I could foresee clunky, fumbling, unnecessary court arguments/rulings being founded on the incomplete definition and the neglect of lateral forces.

Getting myself on a tangent here but....2016 California Residential Code, Ch. 2 Definitions:

"SHEAR WALL. A general term for walls that are designed and constructed to resist racking from seismic and wind by use of masonry, concrete, cold-formed steel or wood framing in accordance with Chapter 6 of this code and the associated limitations in Section R301.2 of this code.
.
.
...later....
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WALLS. Walls shall be defined as follows:

Load-bearing wall. A wall supporting any vertical load in addition to its own weight.
Nonbearing wall. A wall which does not support vertical loads other than its own weight."​

I contend that the load-bearing wall definition be expanded and that a 'shear wall' should be more clearly defined in the code as a type of load-bearing wall.

 

[Ron247]

I had forgotten about the code defining these terms but now that jittles has jogged my memory, I recall the reason I ignored it was there. The fact a LBW had to have 100 lb/ft before it was called LBW but one with 94 plf could be non-load bearing. So I can remove the wall supporting the 94 plf and the load path will shift to my skull.

Since that is in the IBC, it would be considered "correct" in most circles, so now the burden to me is to always make sure I point out the LBW vs NLBW but make sure I also address other structural aspects of the wall.

 

[bob33]

I agree with Ron247 that the fixer-upper shows seem to encourage the removal of interior walls for the "open concept" look that is popular today. If a wall is deemed non-load bearing, it is removed without any thought. If it is found to be load bearing, it is replaced with beams and posts. Some of these walls may be necessary as shear walls, but that is never mentioned.