Need advice on garage floor slab on grade

[Cap07]

Hi -

I've been asked for advice on the "reinforcing" required for a residential garage. The largest loading it will see is a Chevy truck.

The garage floor will be a 4" slab on grade on top of a 4" crushed rock base. The garage will be heated - so between the slab and base will be a 2" R-10 rigid insulation board.

The owner would like to cut down on costs and wants to eliminate the rebar that was initially specified. He would like to use WWF or steel fiber reinforced concrete, or if possible use unreinforced concrete.

If he goes with the unreinforced option, according to ACI 360 a control joint spacing of 8' to 12' apart should be used for a 4" slab.

If the owner doesn't want a lot of joints in the floor, then my recommendation would be the WWF in the middle to upper third of the slab.

I haven't been able to find a lot of information on steel fiber reinforced concrete... would using the steel fiber be comparable to WWF as far the joint spacing is concerned?

Also, does anyone have information on the relative cost of steel fiber reinforced concrete compared to WWF?

 

[msquared48]

That was Lexas...

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[hokie66]

I'm not insulted or anything, was just trying to figure out your comment, as I seemed to be the only one to have mentioned curing. Am originally from Virginia, but now live in Australia.

 

[a2mfk]

You can take a Hokie out of Virgina and move him to Oz, but you can't take the ? out of the Hokie... (Go Noles! I know you got us this year..)

FWIW I think miecz's garage slab sounds like a good idea if you can find a concrete sub to do that correctly and not step all over the WWF and push it down into the soil. That's why I think when I do my dream house garage I may try no joints and #4 @ 18" o.c., maybe 5" thick, so the guys can step on or around the bars...

But if you want to use fibers only for micro crack control, the only thing I have seen work in the field is lots of CJs...