Slab-on-grade w/ embedded rails
Slab-on-grade w/ embedded rails
(OP)
I am a relatively new mechanical engineer doing mostly plant maintenance work. However I have been assigned the task of designing a slab-on-grade for a pushing a loader along a rock pile.
The slab should be 12'x12' with 2 rails embedded @ 4' feet and centered along the slab.
The loader with max capacity filled bucket weight ~100k
My current design based off of the building the loaders are serviced in includes a 12 inch slab with top and bottom #4 bar spaced at 12". Does this seem reasonable?
My other question is how to deal with the embedded rails. Originally they were only going to be 2 inches deep which I figured would be ok. Almost considered a sawcut.
But now they want to use 6" deep 90# rails mainly because we have them on site. A 6 inch rail embedded in a 12 inch slab seems like a big problem to me.
I haven't dealt with concrete before and don't know too much about design. However I feel fairly confident in the slab holding up to the load, not including the rails.
I appreciate any help. Thank you.
The slab should be 12'x12' with 2 rails embedded @ 4' feet and centered along the slab.
The loader with max capacity filled bucket weight ~100k
My current design based off of the building the loaders are serviced in includes a 12 inch slab with top and bottom #4 bar spaced at 12". Does this seem reasonable?
My other question is how to deal with the embedded rails. Originally they were only going to be 2 inches deep which I figured would be ok. Almost considered a sawcut.
But now they want to use 6" deep 90# rails mainly because we have them on site. A 6 inch rail embedded in a 12 inch slab seems like a big problem to me.
I haven't dealt with concrete before and don't know too much about design. However I feel fairly confident in the slab holding up to the load, not including the rails.
I appreciate any help. Thank you.






RE: Slab-on-grade w/ embedded rails
Depending on your loads, 12 inches thick sounds reasonable for the base slab. Put plenty of reinforcing steel in the concrete, maybe #5 or #6 bars instead of #4.
Best to be conservative when designing for industrial applications - things like this have a hard life.
www.SlideRuleEra.net
RE: Slab-on-grade w/ embedded rails
RE: Slab-on-grade w/ embedded rails
I would like to say again however,your bottom slab needs to be 12 inches.than cover with 6 more inches.
If you use an over all slab of 12 inches once you put your rail in you will only have 6 inches under the rail.Not enough to last very long.
Good luck Ed
RE: Slab-on-grade w/ embedded rails
One more quick question though.
What if i used a 2 inch rail instead of the 6.
Could I embed the rails in the top layer and bend the rebar around and under them?
Or should I just pour an extra 2 inch layer. The 2 inch layer couldn't really be reinforced.
My guess, is the 6 inch rail would be the way to go so I could still reinforce the top slab.
RE: Slab-on-grade w/ embedded rails
RE: Slab-on-grade w/ embedded rails
The second method I've used is to cast this as one slab. The rails were welded to steel beams set level on grade. Holes were cut in the web of the beams to allow rebar to pass through. The beam size was adjusted so that the depth of the beam and the depth of the rail were approximately equal to the thickness of the slab.
As for reinforcing, the least I've used is #5 @ 12" EW and the most I've used is #7 @ 10" EW. It just depends on the loads, the situation, and engineering judgement. I've yet to use top and bottom mats.
RE: Slab-on-grade w/ embedded rails
RE: Slab-on-grade w/ embedded rails
Lastly, depending on your soil conditions, you could consider two strip footings under the rails, then a slab between them.