Hi @Anonymous,
Slabs its self could be the steps/ stair like structures, To achieve the result you should model the slab in bits and pieces.
For circular ramp import your cad file and use pick line tool on Modify|Create Ramp sketch context menu to pick the boundaries if ramp in cad file, so thus you can easily create circular ramp. Please do let me know if its not that much clear.
Thanks for reply
I have created the slab as a model in place
the result as in pic
I don't know how to make the stairs the same material as the slab
and Is there any other better way to model a slab like this !!
There are two ways to do this:
1. Manually assign a material to each solid in the model in place family
2. Assign a material parameter to one or more solids in the family. Like for loadable families, this parameter can be instance or type. After assigning that parameter to the solid, finish editing the model in place. When you assign a material to that parameter, all solids that have it assigned will have that material.

Thanks you for your time, I got it.
Could you help me in modeling the ramp.
I want to divide it to parts. each part has four points with different level ans slope.
like the cad pic, because it has built like that.
Check out this simplified example:
I'm using a floor with modified sub elements and i'm specifying the level at lines that cross the ramp.
You can also modify individual points on the edges, but it's easier to specify the level at each line.
I've attached a video and a sample project:Splitting into parts is also straight forward.

Happy to hear that!
The embedded video was recorded using screencast (https://knowledge.autodesk.com/community/screencast)
Originally i just recorded my screen using Camtasia (attached mp4 video), then i re-recorded that using screencast so that i could post it.
