Wood Utility Pole Installation

[Engineerrrd]

I am designing a wood utility pole and the jurisdiction came back and wanted me to specify the required hole width and depth as well as the tampering lift size.

I found out that the excavated hole need to be at least 8" larger than the diameter at the butt of the pole and it needs to be backfilled and tamped in 6" lifts.

The problem is that my pole embedment is 13' deep. If the hole is only 8" larger (4" on either side of the pole) is it possible to tamp in 6" lifts since the space is so small? I could not find a pneumatic tamping device that long.

How are utility poles installed if most tamping devices are not long enough to reach the full embedment? Would I have to make the hole even bigger?

Any advice would help.

Thanks,

 

[Ryanemma]

I use 50ft poles (class 2 or 3) for litter fence at a landfill. We have dug holes and poured concrete around them. Other times we drill out slightly larger holes and backfill with clean dry sand. Once the sand is in the poles don't move, provided the ground is solid and has a good bearing capacity. If you specify backfilling clean sand you might be fine with hand tamping.

 

[oldestguy]

Why not call the local power company construction section for their procedures? If you find significant difference between those methods and the spec., it may be possible to ask for a change in procedure to match local practice. If your job is such that the poles used for the grid between locations of generation and consumption are similar to your job, that such agency may have a standard to use for discussion with owners.

When it comes right down to it, it is likely no one is going to closely inspect that layer thickness at deeper depth. At shallower depth it would be easier and then more important to do the job per specs.

 

[Kuhuh]

As a contractor, I would just pour some 3000 psi mix and call it good. This takes care of any questions of tipping over and soil failure as it increase the effective contact area and weights the bottom down for tipping. Cheaper to pour concrete in this case then to spend the man hours trying to compact that little space.