non-bearing poured concrete wall thickness

[planc]

If it is a non-bearing 3 meter high concrete wall with 0.47" (20mm) rebar spaced horizontally and vertically every 8 inches (200mm) apart connected to the beam and column. Is there any guidelines about minimum thickness of the concrete wall?

Remember you can put wood or cardboard in the gap and it has no load bearing since there is beam above and below it. So what controls the thickness of the 3 meter high concrete wall? Can you just use 4 inches thick? Some precast wall are also 4" so it is the rebar reinforcement that controls the design?

 

[rowingengineer]

EQ or wind load in the walls out of plane direction would provide some loads to design towards.

 

[planc]

I read this

https://www.govinfo.gov/content/pkg...VPUB-C13-7892fae6f60fdf7fd84ad08549fc7018.pdf

"The minimum thickness of plain concrete exterior nonbearing walls
shall be 10 inches for the uppermost 70 feet of their height, and
shall be increased 4 inches for each successive 35 feet or fraction
thereof, measured downward from the top of the wall; except that
the top story wall of a building not exceeding three stories or 40
feet in height, or the wall of a one-story commercial or industrial
building may be 8 inches thick, provided that such 8-inch wall does
not exceed 12 feet unsupported height, and that the roof beams are horizontal ;
and except that exterior nonbearing walls of one and two family dwellings may be 6 inches
thick when not more than 30 feet in height.".

What is the reason for 6 inches for exterior concrete wall of 2 storey building and 8 inches for 4 storey building top floor? Is it due to weathering? If there are sufficient reinforcement vertical and horizontal with wall 9.8 feet (3 meters) high. Can 4 inches be sufficient for nonbearing concrete wall?

 

[hokie66]

As you described it, the thickness would be controlled by the ability to cast the concrete, assuming you are casting it vertically. Maybe 6", in order to get a pencil vibrator between the formwork and reinforcement.

 

[planc]

We have done formworks on a 6" thick concrete wall (see attached photo) poured every 4.9 feet (1.5 meters). The rebar is 0.47" (12mm) spaced every 8 inches both vertical and horizontal. The gravel was 3/4". We used a a long rebar to move the fresh pour at bottom to avoid honeycombs (we don't have pencil vibrator).

Do you think it will work on a a 4" concrete? Same 0.47" (12mm) rebar at 8 inches vertical and horizontal? Using rebar to move the bottom pour to avoid honeycombs?

The 3/4" gravel may be too big. How about 1/2" gravel? Have you or anyone tried it on a 4" concrete wall before 9.8 feet (3 meters) high poured every 59 inches (1.5 meters)?

We want to avoid 6" wall because per meter beam weight is a ton! (10 Kilonewton) and we want ot avoid unnecessary dead weight.

 

[jayrod12]

Where I practice, the nominal aggregate diameter must be less than total thickness divided by 3. So 20mm stone still works for a 4" thick piece. However if you're to do that, buy/rent a proper vibrator.

There are miles of non-loadbearing interior partion single wythe brick walls in the world and they seem to work just fine, I don't see why a 4" concrete wall wouldn't.

 

[dik]

It seems like an awful pile of reinforcing in a 4" wall; are you sure you can place concrete, given the height? You might want to look at how the load is transferred to the beam, as a UDL or as two point loads at each end... might help. I've done that ofter for steel and for concrete design... also including arching action, or treating the wall as a deep beam... I've used that approach for supporting 20 storey tall shear walls.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[dik]

Just because it says you can... doesn't mean you should... rebar at 8" o/c BW in a 10' wall, may be problematic, even if using a teaspoon to place the concrete.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[planc]

You can pour half height first like in the attached photo. Why do you have to pour it with full formworks??

The reasons the rebar is 8" apart vertical and horizontal is because the beam top and bottom is just drilled 4" deep and the rebar inserted with low viscosity epoxy. Can this work? Is 4 inches drilled epoxy inserts enough for lateral resistance? Or is your wall always have existing dowels in the original beam inserted 16" deep? And you never accept any usage of drill and epoxy? How do you then put a wall? demolish the existing beams and rebuild everything?