what options do I have?
what options do I have?
(OP)
I m dealing with an existing RC slab.
I have a data about existing reinforcement.
After reconstruction (different purpose of structure - larger load on existing slab)I figured that existing reinforcement is not gonna be sufficient - in both zones (on both sides of a slab).
So I was thinking about adding another layer of concrete - let say 50 - 100 mm on an existing slab and reinforce it so I have sufficient reinforcement there and since slab is now thicker the existing reinforcement (tension reinforcement in bottom zone of a slab) is now gonna be sufficient. I have to properly connect new layer of concrete to existing (with dowels that can transfer horizontal shear flow) so slab will act as a composite - one element.
What do you guys think? Any other options?
If existing reinforcement in top zone of a slab is sufficient, then i would normally use/add FRP - fiber reinforced polymer at the bottom of a slab, but since reinforcement is not sufficient in both zones of a slab i think thats not the best idea. BTW can you glue FRP materials on both sides of a slab? I have seen only on the bottom side...
I have a data about existing reinforcement.
After reconstruction (different purpose of structure - larger load on existing slab)I figured that existing reinforcement is not gonna be sufficient - in both zones (on both sides of a slab).
So I was thinking about adding another layer of concrete - let say 50 - 100 mm on an existing slab and reinforce it so I have sufficient reinforcement there and since slab is now thicker the existing reinforcement (tension reinforcement in bottom zone of a slab) is now gonna be sufficient. I have to properly connect new layer of concrete to existing (with dowels that can transfer horizontal shear flow) so slab will act as a composite - one element.
What do you guys think? Any other options?
If existing reinforcement in top zone of a slab is sufficient, then i would normally use/add FRP - fiber reinforced polymer at the bottom of a slab, but since reinforcement is not sufficient in both zones of a slab i think thats not the best idea. BTW can you glue FRP materials on both sides of a slab? I have seen only on the bottom side...






RE: what options do I have?
BA
RE: what options do I have?
Note: This document covers concrete on-grade, but the principles work exactly the same for elevated slabs. An existing elevated slab may have to be "unloaded" (perhaps by jacking) to allow the overlay to fully take it's share of the load.
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RE: what options do I have?
RE: what options do I have?
This is similar to a structural topping on a precast slab.
RE: what options do I have?
RE: what options do I have?
RE: what options do I have?
What if you want to do that only on a part of existing slab? Is there a problem?
Lets say that load is larger only on half of existing slab. Does that mean you still have to add a new layer of concrete above entire slab or is it ok to do it just where you need it?
red - columns
blue - beams
gray - slab
RE: what options do I have?
1. The topping increases the dead load of it's portion of the (elevated) slab.
2. But at the same time, the topping increases the structural capacity of it's portion of the slab.
3. How much the topping increases the structural capacity depends on the details (reinforcing, edge conditions, etc.) of the existing slab.
4. Nothing was done to a portion of the slab, but the changes where the topping is applied will affect the unchanged part.
5. Revised live load rating, will affect each part (topped and untopped) of the slab differently.
Will have to make assumptions and see what the calculations say.
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