Slab Strengthening

[duafar]

I have a slab that is deflecting too much, and i would like to know what kind of action regarding it's repair should i should take.

Thank You

 

[JAE]

This is quite a vague, general question. Can you be more specific?

 

[duafar]

The slab is deflecting too much. It's a slab with a 8 m span, and 12 cm thick. Do you think i may lift the slab some way, and maybe glue some steel plates, so that the inertia increases and it doesn't deflect any more??

Thank You

 

[Taro]

That is an extremely thin slab, even if it were prestressed. Based on typical span-to-depth ratios, I would expect the slab to be about twice as thick. I don't think it will be feasible to stiffen the slab by bonding steel plate to the surface. You would need to increase the moment of inertia by a factor of about 8. I would suggest adding intermediate beams to reduce the span. But consider that the layout of the slab reinforcing must be compatible with the positioning of the beams.

 

[duafar]

Taro, how would you undeflect the slab, before adding intermediate beams?

 

[dawn836]

what is around this slab?
Does the floor consist of only this slab and 4 beams surronding it?

What is the function of this slab in the building?

 

[duafar]

dawn836. Yes, the slab is surrounded by 4 beams, and the slab if for a school.

 

[dawn836]

well is it last slab for this building(roof slab)?

what kind of loads is expected on it?!

if any of the beams are not edge beam you may add negative top reinforcemnt over the beam to connect the slab you have probelm with to anoter slab this will reduce positive moment which cause cracks
you may add steel beams also under this slab and undeflect it using Jacks or something like this till instalion of the beams is done