vehicle concrete ramp detail

[delagina]

I have a vehicle concrete ramp for a the metal building warehouse.
Vehicle is just a pickup truck or small forklift.

I have 2 go-by drawings and not sure which one is the proper detail to use.
Or maybe combination of these two.

Detail 1 is a 1' ramp and not connected by rebar to the building grade beam.
Detail 2 is a thickened slab with rebar connecting to building grade beam. It also uses sand which I don't know why.

I'm leaning towards detail 1, which looks at lot simpler. My only concern is differential settlement.
Shouldn't this ramp be connected to grade beam but I'm not sure what is the proper detail (smooth rebar?, etc..)

 

[delagina]

i googled and this is similar to driveway connected to house foundation.
i will use Detail 1 and also not connect using rebar.
a properly compacted base on both shouldn't have issue with differential settlement.

curious though if there is a rebar detail (smooth, greased or whatever) connecting the 2 concrete that will not have issues with frost heave. this project is located (south texas) where that should not be an issue though.

 

[KootK]

Texas has some expansive clays does it not?

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[delagina]

@kootk, yes

 

[Compositepro]

Delagina, this is a forum for professional engineers. Please use proper spelling and punctuation, and refrain from text speak.

 

[jayrod12]

On expansive soils around here we tend to dowel and key at the structure, provide voidform for the first 18" or so and then change to slab on grade. This allows the ramp to hinge if the ground heaves or settles.

Kootk, do you like you mail hot .ca, or .com

 

[delagina]

@compositepro, English is not my first language.

 

[delagina]

@jayrod12, Are you saying detail 1 is not proper for expansive soil? Can you provide a detail. thanks

 

[jayrod12]

Detail 1 could be acceptable, but in expansive soils there's the chance of putting a lot of stress at the dowels if the subgrade tries to heave. I'm away from a scanner at the moment. I'll provide something later if someone doesn't beat me to the punch.

 

[delagina]

Detail 1 doesn't have dowel.

 

[jayrod12]

You're correct. Can you live with the top side of the ramp free to move up and down seasonally?

 

[KootK]

On expansive soils around here we tend to dowel and key at the structure, provide voidform for the first 18" or so and then change to slab on grade.

This is exactly what I had typed up before a call came in.

Kootk, do you like you mail hot .ca, or .com

I like my mail warmer than tepid, colder than scalding, and non-country specific.


I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[MotorCity]

We tie any exterior pad to the building when there is a possibility of frost heave. It basically creates a hinge between the pad and the building. Owners tend to get cranky when they can't open their door because a heaved slab is in the way.

 

[jayrod12]

My idea looks something like this crude sketch.

I like my mail warmer than tepid, colder than scalding, and non-country specific.

Tried sending you a test again. If I got it wrong again, then I'm apparently worse at puzzles than previously thought.

 

[WARose]

I agree with not connecting them. Differential settlement would be on my mind as well.

 

[TenPenny]

Also note that while this is designed for a pickup/forklift, at some time, someone will use it for the largest vehicle that will fit through the opening, so the loads may be higher.

 

[delagina]

is that dowel just a regular deformed bar? i'm currently looking at this different joints where some detail use smooth bars

 

[jayrod12]

Yes in my post it is just a standard bar.

 

[dik]

KootK:

I've used that often but usually use about 4' of voidform and provide +ve reinforcing in the slab...

Seems to have worked... and usually use dowels, but straight and generally larger diameter unless a real slope to the driveway (then use cranked) and put formed 'chevron' drainage channels in the concrete shedding water.

Dik