Allowable friction coefficient of a ground floor slab on a vapor barrier?
Allowable friction coefficient of a ground floor slab on a vapor barrier?
(OP)
I am trying to figure out how I want to prove how the base shear in my building structure gets resolved. I am looking at the option of the distributing the load from each wind brace into the ground floor slab.
Does anyone know what the allowable friction coefficient would be for a ground floor slab cast over a vapor barrier on a 4" layer of stone over compacted fill? I would like to see how lateral resistance the slab will offer. I may have to distribute the load from the slab into other elements.
Does anyone know what the allowable friction coefficient would be for a ground floor slab cast over a vapor barrier on a 4" layer of stone over compacted fill? I would like to see how lateral resistance the slab will offer. I may have to distribute the load from the slab into other elements.






RE: Allowable friction coefficient of a ground floor slab on a vapor barrier?
RE: Allowable friction coefficient of a ground floor slab on a vapor barrier?
Also important to remember that if you're trying to use the slab as a lateral element, you'll need to make sure it's reinforced enough to actually distribute all those forces. Have to treat it as a diaphragm just like an elevated slab.
RE: Allowable friction coefficient of a ground floor slab on a vapor barrier?
With the addition of the vapour barrier which acts as some form of bond breaker between the crushed stone and the slab I would feel comfortable with using 0.1.
RE: Allowable friction coefficient of a ground floor slab on a vapor barrier?
Mike McCann
MMC Engineering
http://mmcengineering.tripod.com
RE: Allowable friction coefficient of a ground floor slab on a vapor barrier?
RE: Allowable friction coefficient of a ground floor slab on a vapor barrier?
BA
RE: Allowable friction coefficient of a ground floor slab on a vapor barrier?
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RE: Allowable friction coefficient of a ground floor slab on a vapor barrier?
RE: Allowable friction coefficient of a ground floor slab on a vapor barrier?
Interesting. Would you put a factor of safety on that?
RE: Allowable friction coefficient of a ground floor slab on a vapor barrier?
I was actually trying to prove that the piles in the pile caps under my wind braces columns could directly resolve all the lateral loading in each brace. However, with consideration of the shadowing effect in pile groups and assuming the free head condition, the geotechnical engineer was reporting deflections of a little over an inch.
The truth is that there are many different mechanisms that will be engaged other than the piles to resolve the base shear in the structure: passive pressure on the pile caps and grade beams, side friction on the grade beams, slab friction, etc. It is just hard to numbers to the combined mechanisms.
I know the building isn't failing in base shear, especially if I provide a mechanism to develop the load into the ground floor slab. It is just the burden of the proof.
RE: Allowable friction coefficient of a ground floor slab on a vapor barrier?
I thought it was more to provide moisture control.
RE: Allowable friction coefficient of a ground floor slab on a vapor barrier?
BA