fiberglass rebar in slab-on-grade 3

[MarcusJ]

I have a new job, with a client doing some interesting high-voltage work. They need a fairly elaborate electrical grounding system in their slab-on-grade, and are very concerned about any steel in the slab. They are inquiring about fiber additives in lieu of rebar, but I'm not liking that idea. They'll have a large forklift lifting heavy items and I've only considered fibers for shrinkage cracking. I'd like to suggest fiberglass rebar (or possibly carbon fiber rebar) but I am not familiar with either. Any thoughts, suggestions, lessons learned? Thank you. (Max Loads: 36,000 lb forklift + 28,000 lift capacity = 64 kips.)

MarcusJ

 

[Euler07]

Thanks y'all. I'm reading on unreinforced slab design now.
I might just come around to the idea of using fibers in the mix, just for shrinkage cracking.
Any further comments appreciated, but I think I'm set.

I would recommend looking into Barchip fibre without any reinforcement bars. There are huge projects that use it as a complete replacement. For example this one:

https://barchip.com/takamine-barchip-reinforced-pavement/

There are a lot of other examples on their website including test data etc.

In terms of fibreglass rebar, I have seen this used for road pavements in coastal areas without issue. It is also best to mix in Barchip since the two work in tandem.

 

[dik]

I've designed them for accommodating Boeing 747 weights, and a lot of other heavy stuff... properly done, they can easily support heavy loads... including large transformers of the 200K weight... I've used helical piles for supporting six 400K transformers (on a structured slab)... the size of a house...

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[phamENG]

dik - please read the rest of the post and the posts that follow. Obviously you can put weight on a slab. The point is that for a floating slab on grade, the slab shouldn't be doing the work - it should be the soil below. If the soil is weak enough that the slab flexes more than plain concrete allowable stresses to prevent cracking/rupture, the subgrade has not been properly designed and/or prepared.

When the slab is not floating - like a pile supported slab - then it gets designed as a structural slab.

 

[dik]

It's a soil-slab system... both have an impact on the load capacity.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[Smoulder]

The Uk concrete Association manual is for reinforced slabs on grade. Used to be unreinforced but they changed it because fibres a popular there. Can be used for bars too. Agree that PhamEng was too extreme with the never. Just an optimisation problem like regular RC design except zero steel is the minimum. Ive seen contam sites where concrete was way cheaper than ground prep. Also seen it done where going to have the steel anyway so might as well design for it.