Not that I could cite. When I was working on the MM99 toll booth on I-75 I did spend some time with the engineers and they say the spec's the duct banks should be 5-6 feet below the sub bed of the road. Florida DOT says there is quite a pounding going on under a road when you have big trucks and lots of traffic.
Most of the actual protection is the concrete itself and the pipe is just a place holder until the concrete cures.
Hi, Thanks Greg and Hotline...our specs call for "schedule 40 HEAVY WALL" there is a diff between reg sch 40 and sch 40 heavy wall am I correct? I contacted cantex and they said they would send me the specs and that the wall thickness is different.
AT a large senior citizens complex around here, the EE stated that all underground MV wiring had to be in sch 20. Then it had red concrete poured all around it. I can't remember the thickness, I think it was 1' of concrete. I had a second EE sign off on the MV wiring.
Yeah, it was real thin stuff, but it was encased a lot of concrete so the EE didn't care. I questioned the EE but it was his design. This goes back almost 15 years ago, but I am pretty sure it was sch 20.