ETABS release slab (pin) at core walls for a tower
ETABS release slab (pin) at core walls for a tower
(OP)
Hello all,
I am new to ETABS and I am trying to setup a lateral stability model for a tower. I have modelled the building, with the slabs as shell elements. I would like to release the slabs, eg pin them, to the core walls as the slabs will be connected via a corbel. There will be no moment transfer and I want to model it as such. Is this possible in ETABS and if so how do I do it? I see you can assign frame releases but I am not sure how this works. Essentially I need to release the slab for rotation at the core wall.
Any advice would be greatly appreciated!
thank you
Phil
I am new to ETABS and I am trying to setup a lateral stability model for a tower. I have modelled the building, with the slabs as shell elements. I would like to release the slabs, eg pin them, to the core walls as the slabs will be connected via a corbel. There will be no moment transfer and I want to model it as such. Is this possible in ETABS and if so how do I do it? I see you can assign frame releases but I am not sure how this works. Essentially I need to release the slab for rotation at the core wall.
Any advice would be greatly appreciated!
thank you
Phil





RE: ETABS release slab (pin) at core walls for a tower
http://www.eng-tips.com/viewthread.cfm?qid=374257
RE: ETABS release slab (pin) at core walls for a tower
RE: ETABS release slab (pin) at core walls for a tower
RE: ETABS release slab (pin) at core walls for a tower
If anyone does know of a 'release' type joint for shell plates let me know.
cheers
RE: ETABS release slab (pin) at core walls for a tower
One thing to keep in mind is that while it's okay to check as pinned to be conservative and make sure you're not getting helped by the slab in seismic events, are you really pinned for non-ultimate events? If the connection really is going to attract moment and you don't want it to fail under service conditions, you would need to account for that in your modeling.
Especially at top of wall conditions where you have uneven spans (or slab on one side), you're going to attract moment at the joint that would then transmit into your walls unless you do some special detailing to specifically release it. Whether you like it or not. The built structure doesn't really care how it was modeled. For thicker walls with two layers of reinforcing it likely wouldn't make a difference. But for thin walls that are lightly loaded and one layer of reinforcement, it absolutely could.
RE: ETABS release slab (pin) at core walls for a tower
We are going through the same problem on a model that we are doing. We don't want the slab to take unrealistic moments during lateral movement but it is also not realistic to assume that the slab is fully pinned. We have used modification factors on the moment capacity of the walls and we set them to 0.1. However the slab still take moment because it is fixed in two directions and especially in the corners you can stop it to be stiff and attract moment. It is good to put some top and bottom steel on the corners to avoid crackings during lateral movement.
You should also apply modification factors to the slab stiffness in order to account that the slab is cracked or partially cracked.
RE: ETABS release slab (pin) at core walls for a tower
i have attached, may it help.