Wall - hollow core slab connection

[mammut]

I have to calculate reinforced concrete wall which are supporting hollow core slabs.
I wonder - will that be enough if i consider only vertical force from upper wall and vertical force from hollow core + moment caused by eccentricity? Or will there be some "clamping" moment from the hollow core?

 

[KootK]

There absolutely will be some clamping moment. In practice, I've never known a designer to account for it in the wall design however. I have the same issue with cip slabs. Designers will assume that, if the slab can simple span to the centre of the walls, the the walls don't need to take moment. That's only the case in some select instances IMO.

Somewhere, I've seen recommendations for providing negative moment capacity in the precast in such situations for similar reason. The primary concern is preserving shear capacity in the plank at the support. If someone could help track that recommendation down for us, that might be a suitable moment to design the walls for.

The greatest trick that bond stress ever pulled was convincing the world it didn't exist.

 

[mammut]

Thanks KootK..

 

[Ron]

If hollow core slabs were only stacked on the wall with no attachment, you could neglect; however, the hollow core slabs are "locked" at the wall by a topping slab and grout pocket. Any unbalanced load on the topping slab will then induce rotation over the wall.