pipe and base for slew drives

Hello,

   I've been studying the technology associated with solar power and the hardware on which to mount them.
I ran across the idea of using a slew drive on YouTube and have since found many sources for the drives, both local, and abroad.
Unfortunately, I have been unable to locate a source of the special bases on which the drives are mounted or the pipe on which both are mounted and which is attached to a concrete base.
   Currently, I'm including a linear actuator (10,000N, push/pull) as my primary drive for azimuth tracking. For me, this seems the only alternative.
   Any ideas?

Thank you,