/ sinking a pole

This topic has been archived, and won't accept reply postings.
goosebump - on 10 Oct 2013
Hello,
Im installing a wooden pole, which will stick up 5m above the ground (its going to have a 10kg bat box on the top). How much needs to be buried? Or am I better bolting it to a slab? Anyone got any ideas?
KTC - on 10 Oct 2013
In reply to goosebump:
I'd guess it depends entirely on what the ground is like. Into granite, a well drilled 50cm hole might be fine. Into a peat bog, considerably deeper would seem to be wise.
goosebump - on 10 Oct 2013
In reply to KTC:
Itll be earth I reckon. We'll not be drilling into granite thats nuts. Youd just bolt straight to it ;-)
I have it in mind there is a rule, quarter bured 3/4 not? Or a third, two thirds?
wilkie14c - on 10 Oct 2013
In reply to goosebump: Quarter of the pole in the ground. I recently put in a new concrete fence pole, its for 6 foot slide in panels. It was 8 foot long so 2 foot in the ground.
David Barratt - on 10 Oct 2013
In reply to goosebump: I work in an office surrounded by structural engineers... and now you've got a debate started! The answer depends on the soil, but the most senior/experienced engineer went for 1.8m deep. If you can tell me about the soil I'll get you a better number.
Timmd on 10 Oct 2013
In reply to goosebump: As is typical on UKC I'm going to say something different, and say a third into the ground for a single wooded pole in earth with a bat box on top. A quarter might be fine, but I think we've generally done a third when I've been volunteering doing post and wire fencing and things.

arch - on 10 Oct 2013
In reply to goosebump: The standard planting depth of our Electricity poles is 2.4 metres. Poles range from 9mts up to 14mts. Poles taller than that are planted 3 metres deep.

Dig as small a diameter hole as you can. Getting the loose soil consolidated after is difficult and if not done properly could make the pole move slightly in the hole you've dug.
Timmd on 10 Oct 2013
In reply to goosebump: A tamper can help in consolidating the soil around the pole, or as second best jumping up and down a lot on the ground right next to the pole all around it, if you don't have a tamper.
Steve Clark - on 10 Oct 2013
In reply to goosebump:

You will find that most lamp posts are less than 1m deep, but often set in a tube in concrete so the bearing area is larger at shallow depths. The wind load on a single pole Is much less than say a fence post which has a huge area to catch the wind and a relatively small area of soil to resist over-turning.

A quick google suggests the yanks use 10% total pole length plus 2 feet for power distribution poles. These carry line tension too do that should be conservative.

Steve
Dave Perry - on 10 Oct 2013
In reply to goosebump:

Does it have to be on a pole?

Why not fix it to a wall?

As a general rule, bat roosts need stable temperatures for both roosts and hibernation. So out of the sun fixed to an external wall is normally best - Unless, yours is very well insulated..?
Toerag - on 10 Oct 2013
In reply to goosebump: 8m long telephone poles need a hole nearly waist deep. you dig it vertically on one side and like a short stepped trench on the other so you can slide it in and hoist it up between two or three blokes. When you temp down the earth do it every time the hole has been filled in 6inches, you need to tamp as you go. Telephone poles are slightly wider at the base though.
woolsack - on 10 Oct 2013
In reply to goosebump: What is the average weight of your bats? Are they fully laden African or European?
goosebump - on 11 Oct 2013
In reply to David Barratt:

Hahaha I can imagine it! Thank all for the input its really appreciated. Oh, and the reason for poles is cos there are no walls or trees, the bats will be fully laden (hopefully pregnant females), the bat box design is specced accordingly.
Thanks again!
ads.ukclimbing.com
Timmd on 11 Oct 2013
In reply to Toerag:
> (In reply to goosebump) When you temp down the earth do it every time the hole has been filled in 6inches, you need to tamp as you go.

You're right, ideally you do need to tamp as you go...

This topic has been archived, and won't accept reply postings.