Masonry (or concrete) core walls and LFRS members - torsion for C Shape

[RFreund]

When using masonry walls as shear walls (say elevator or stair walls). Typically you have some sort of C-shape. Do you account for some sort of shear stress due to torsion for the non-symmetrical shape?

Does anyone analyse these walls as Tubes with holes? Any references to do this? Pointers?

(I thought we discussed this somewhere before...)

Thanks!!

EIT

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[DaveAtkins]

The lateral force is resisted by the "web" of the elevator shaft, and the moment due to the lateral force is resisted by the "flanges" of the elevator shaft.

DaveAtkins

 

[PicoStruc]

I would All that for a C-Shaped wall, the flange of the C will resist torsion induced shear too !!

So, you need to check bending with overall sectional analtysis and check the shear for all wall segment locally (Global shear + Torsional effect)

 

[KootK]

I do account for torsion induced shear stress. If it's a taller shaft, I think that it's appropriate to consider warping torsion as well.

Generally, for an elevator shaft, I treat it as a true channel shape and take no account of the headers. This is because there usually isn't enough meat on either side of the elevator shaft opening to obtain any meaningful coupling. Additionally, whatever meat you might have is subject to being replaced with masonry infill. You can make an argument for coupling if the header beam spans multiple floors uninterrupted but that's getting fancy.

For a typical stair shaft, I typically do treat it as a perforated tube. This is because the door is usually placed to one side of the shaft and I'm able to get meaningful, one sided coupling on the other. This works better when the door is on the long side of the shaft as opposed to the short side.

Any reference for concrete shafts would suffice. Taranath; Coull & Smith; Zalka.

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