Core wall to take the whole lateral loads?

[StruTie]

Hi Guys, I have a 7-storey building of which the plan layout looks like below. Slabs and walls are all concrete.

My questions are:

1. Can I use the core wall only to resist the lateral loads including wind and earthquake in Y direction? The core is slightly eccentrically located in the centre. I have built a model for this and everything seems fine: deflection is less than limit; first mode is in translation in Y direction. But I am still concerned that whether it is reliable to treat the slab as a long cantilever beam (diaphragm) to transfer the shear in Y direction to the core wall? I know the slab have strong out-of-plane stiffness but what about the connection of slab to core wall? What other analysis results should I check in my model (I am using Etabs)?

2. The first floor will be a transfer slab (or transfer beams), if I add some walls in Y direction on both sides of core walls on level 2 - level 7, which will be transferred on first floor. Can these walls be considered shear walls for level 2 - level 7 even if they don't go to the ground? (I don't think they will be significant as the stiffness of these walls will be very small if they don't continue to the ground).

3. How do you guys design a structure like this if it is not possible to have walls going to footing in Y direction on both sides of core walls?

4. Are there any good books in lateral analysis for structures like this that you guys would recommend?

Thank you.

 

[MIStructE_IRE]

I don’t like it. I’ve often found my gut to be far more reliable than any FEA, I think many of us do.

Clear load paths are desirable. In this case, I would also question the fire escape strategy. If the single core is out of use or blocked due to fire, everyone dies?

Similarly, in terms of robustness (and the collapse not being disproportionate to the cause) it would appear that a single wall blowout at any level results in a loss of lateral stability for the entire structure.

Do you not require a movement joint in a 100m long RC Frame? If so then this entire stability theory goes out the window anyway.

The diaphragm flexibility will wildly affect your answers I think. The software I use assumes ‘rigid’ diaphragms, so YMMV.

Some architects just need a slap!

 

[Tomfh]

Good point about there only being one way out via the middle of the building. Surely that violates egress rules?