Non load bearing concrete panel to RC slab?

[Ey_2]

Hi fellows,
I am looking for some advices on the connection between RC slab and non-load bearing precast concrete panel that 'hangs' on the facade. I think of the using the rebars or the like as below but I believe that the panel become load bearing with connection like this. i.e. panel will brings the loads from slab L2 to slab L1, which is not my intention. Any thoughts or advice?

 

[hokie66]

The usual course if to put a haunch on the bottom of the panel, and bear that on the slab. All the precast facade companies have details for that.

 

[r13]

Suggest to get a copy of PCI design manual, and familiar with connection methods/details for precast panel.

 

[Ey_2]

Thank you. I cannot picture what you are saying to be honest. Is it similar to the one I found online as below. Mind if you send any links?

 

[Ey_2]

I also have this 'weird' scenario that the lowest panels will become load bearing as shown below. Any comments?

 

[Ey_2]

Thank you. I will try to find one.

 

[r13]

It used to be free, now could cost a bundle, but truly worth to own it.

 

[Ey_2]

Is it called PCI design handbook? (Below is what pops up when I search 'PCI design manual'...)

https://www.academia.edu/43064369/P...PRECAST_AND_PRESTRESSED_CONCRETE_7_TH_EDITION

If so, it looks like the only section that covers the non-loadbearing panel is section 7 as shown below?
Didn't really find specific connection detail.
And I don't quite understand how detail like this can stop panel carrying vertical loads from slabs above?

 

[jayrod12]

What is the intent of the connection from your eyes? Are you trying to only provide a lateral connection to each slab, or are you trying to support a potion of the panel weight on each slab?

If the former, just lateral, then I would do something similar to the angle connection detail you posted, but that angle with slot would be a vertical slot so you'd likely need a larger angle leg than they are showing there.

If you need the weight of the panel to be shared between slabs, then I think you may have a hard time ensuring that the panel weight is shared, but any other floor loads are not. However in my mind, that shouldn't matter significantly. The panel will just enforce deflection compatibility between the two slabs which actually may improve things more than harm one slab or the other.

I am not a fan of dowels being used for pre-cast connections like you indicated in your first post. In that type of scenario you must temporary support the panel until the epoxy has cured, whereas when you use weld plate connections, once the welder has made the connection, the panel is structurally stable and no temporary supports are required.

 

[KootK]

This is a pretty good source for precast wall panel connection detials: Link

I sometimes work for precasters designing these things. In the real world, there's pretty much only one practical problem that anybody has with their wall panels: they crack and upset the folks who want them to stay pretty. As such, as a precast engineer, I try hard to get things detailed in such a way that the wall panes are not restrained from moving as they wish under conditions of changing temperature and humidity. This is the primary reason that I would steer clear of your doweled connections. The doweled connections will set up a stiff and unforgiving shear transfer mechanism for:

1) Restraining the lateral dilation and contraction of the wall panels.

2) Telegraphing any dilation and contraction of the building slab to the wall panels.

 

[r13]

The precast panel needs to past its load to the structural slabs, either to the slab L1, or L2, or both. Design a bearing seat at the lowest level, then use a clip that is capable of restraining the precast panel in lateral direction only - an angle with vertical slotted hole on top of slab L2 will do. Most of the manuals/handbooks are focusing on the bearing type connection/support, you have to think and come up a flexible connection/support.

 

[jayrod12]

Based on his section, it appears he may be able to bear the gravity loads from the panel at the bottom on the foundation wall. That's preferable by everyone's standards if it is in fact true.

 

[r13]

Based on his section, it appears he may be able to bear the gravity loads from the panel at the bottom on the foundation wall.

That's normally the case, isn't it!

 

[Ey_2]

Thank you everyone and sorry for the wording. The intent of the connection is the pass the panel weights & lateral loads to the slab instead of carry the loads from slab. So as you have pointed out, the bottom fixing is going to be a bearing seat while the top one provides lateral restraint only.
So my questions are,
1. I might be overthinking but for the top connection, if I use EA with bolts to panels and slab, how is this connection going to prevent slab from passing its loads to the connection and cause failure in the connection? (Say you have cantilevered slab and the slab deflects more due to long term effect) Do you leave gap between the angle and the top slab?
2. Is the gap between panel & slab necessary? Instead of having gap, will grouted recess in panel at where the connections are do the same job?

 

[r13]

Horizontally, the panel will move with the slab, if the slab ever moves, so there is negligible force transfer, if any. Vertically, the slab can deflect, the slot on the angle needs to be sized to accommodate the movement.

 

[Ey_2]

Thank you for your explanation. Appreciate that.

 

[r13]

You are welcome.